Search
Submit Manuscript
1.9CiteScore
Advanced Search
MAP  >  Fruit Research
2023 Volume 3
Article Contents
Abstract
Introduction
Materials and methods
Plant material and growth conditions
Measurements of growth and physiological traits
Rna extraction and sequencing
Statistical analysis
Results
Effects of supplemental red/blue light on growth and photosynthetic indexes
Effects of supplemental r/b light on strawberry yield and fruit quality
Transcriptome sequencing
Go and kegg pathway enrichment
Transcriptomic analysis of some degs in response to red/blue light supplementation
Discussion
Acknowledgments
Conflict of interest
Supplementary information
Rights and permissions
References
About this article
Next Previous
ARTICLE   Open Access    

Positive effect of red/blue light supplementation on the photosynthetic capacity and fruit quality of 'Yanli' strawberry

  • Liaoning Key Laboratory of Strawberry Breeding and Cultivation, College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China

More Information
  • In order to meet people’s demand for strawberry during winter and early spring, strawberry is usually cultivated in solar greenhouses with forcing cultivation in northern China. However, low light intensities and short-days are the major obstacles that restrict strawberry growth. Therefore, it is crucial to solve the problem of insufficient light in strawberry production. In this study, we established LED facilities to supplement the red/blue light (R/B = 4:1) before sunrise and after sunset in the solar greenhouse. We found that the plant height of the strawberry under supplemental R/B light was 13%−17% higher than that of the control, and the crown diameter of the plants was increased by 1.07−1.38 fold compared with the control for two consecutive years. The net photosynthetic rate of strawberry plants was 19% higher than that of the control. In addition, the strawberry primary fruits’ fresh weight during the stage of full ripeness and the total fruit weight/plant was 18%−24% and 27%−33% higher than that of control for two years, respectively. Fruit soluble solid content and firmness were increased by 1.05−1.21 fold and 1.06−1.18 fold compared with those of control during the two years, respectively. Moreover, we found some differentially expressed genes between red/blue light supplementation and control by RNA-seq, including light-responsive genes (PRR95/LHY/CDF3/CO16/bHLH63/BBX21/PAR1/SIGE) and sucrose metabolism-related genes (SWEET9/BAM1). This study provided a foundation for revealing the mechanism of red/blue light supplementation on photosynthesis and fruit quality of strawberries and could help to improve the cultivation techniques for 'Yanli' strawberry.

  • INTRODUCTION

    Strawberry is an important economic crop with delicious and nutritious fruit[1,2]. In north China, strawberry is usually cultivated in solar greenhouses with forcing cultivation during the winter and early spring season. Forcing cultivation has the advantages of breaking dormancy and prolonging the harvest time in strawberry. However, under this condition, low light intensities and short-days are the major obstacles that restrict strawberry growth and development. There are many reasons for this problem, including short sunshine time and frequent hazy weather in winter, covering for heat preservation, and reducing light transmittance after the surface of the shed film absorbs dust, etc. These conditions may lead to reduced photosynthesis and thus affect plant growth and development of strawberry. Therefore, it is crucial to solve the problem of insufficient light in strawberry production.

    The artificial supplemental light source is an important cultivation technology for strawberry plants grown in greenhouses[3,4]. LED (Light Emitting Diode) was widely used in horticultural production in controlled environments due to the advantages of small size, relatively low heat release, great wavelength controllability, long lifetime, and low power consumption[5,6]. Different light wavelengths have different effects on strawberry plants' development and fruit quality[7,8]. To improve light-use efficiency in a greenhouse, more and more researchers pay attention to which corresponding light wavelengths are required for different growth and development processes of plants[9].

    Red light is one of the most efficient light qualities for powering plants' photosynthesis[10,11], but monochromatic red light may cause abnormal phenotypes because of a lower photosynthetic rate in several crop plants, such as leaf curling and leaf thickness, etc[12,13]. Adding blue light can suppress these symptoms[12−14]. Other studies showed that red and blue light mixed wavelength is beneficial to enhance strawberry production and fruit quality[15,16]. However, the effective model of R/B light supplementation in strawberry cultivar 'Yanli' is poorly understood.

    Strawberry cultivar 'Yanli' was released from Shenyang Agricultural University, China. The fruit has excellent flavor and aroma and the exterior is a regular conic shape and bright red. It is grown in different provinces of China, especially cultivated by forcing cultivation in solar greenhouses in northern China[17]. Therefore, it is necessary to study its effective cultivation practices. We established LED facilities to supplement the red/blue light (R/B = 4:1) for 'Yanli' before sunrise and after sunset in the solar greenhouse. The results showed that the photosynthetic efficiency, soluble solid content and yield were increased. In addition, we initially screened the candidate genes for improving photosynthesis and fruit quality in 'Yanli' strawberry under the condition of red/blue light supplementation by RNA-seq. These results will help to perfect the cultivation techniques for strawberry cultivar 'Yanli'.

    MATERIALS AND METHODS

    Plant material and growth conditions

    'Yanli' (Fragaria × ananassa Duch.) plants were grown in the greenhouse at Shenyang Agricultural University (Liaoning province, China). Runner plants of 'Yanli' were planted in the greenhouse in early September every year. After 30 d, 20 of them were subjected to the condition of a mixture of red (R) and blue (B) light at 06:30−08:00 AM (before sunrise) and 15:50−19:00 PM (after sunset) daily. Supplemental light treatments were provided using LED lamps (North Brilliancy Technology Co., LTD, Shenzhen, China). These LED lamps were installed at 1.5 m above the strawberry plants. The photosynthetic photon flux density (PPFD) was measured by a quantum sensor (LI-250A, LI-COR, USA), and the PPFD ratio of red (3.9261 μmol·m–2·s–1) to blue (0.9716 μmol·m–2·s–1) to supplemental light (R/B) was 4:1. Plants without any supplemental light were used as control.

    Measurements of growth and physiological traits

    The height and crown diameter of strawberry plants were measured before reproductive growth. Plant height was measured from the ground to the highest blade. The crown diameter was the diameter of the leaf clusters. Primary fresh fruits were weighed. During the ripening stages of strawberry, the soluble solid content (SSC) of the strawberry juice was measured by a digital pocket refractometer ATAGO PAL-α (Atago Co. Ltd., Tokyo, Japan), and the firmness of fresh fruit was measured using a texture analyzer (GY-4, Handpi). Two opposite sites on the fruit shoulder were measured for each fruit, and the average firmness value of each fruit was recorded. Photosynthetic indexes, including net photosynthetic rate(Pn), stomata conductance (Gs), intercellular CO2 (Ci), and transpiration rate (Tr), were measured with a portable photosynthesis system (CIRAS-2, PP Systems, Massachusetts, USA) within the hours of 8:30−11:30 AM under sunny conditions. Third fully opened and new leaves from each plant were used for the photosynthetic indexes data. Twenty plants were measured for treatment and control, and three fruits were measured per plant.

    RNA extraction and sequencing

    After 50 d of irradiation, the fully opened and new leaves of treated strawberry plants and controls in three biological replicates were selected for sampling and frozen in liquid nitrogen. Total RNA was extracted by a modified CTAB method[18]. RNA concentration was measured using a NanoDrop 2000 (Thermo Fisher Scientific, Wilmington, DE, USA). cDNA library and high-throughput sequencing were conducted by Biomarker Technologies Co, LTD (Beijing, China). The Illumina HiSeq™ platform was performed. Reads from each library were de novo assembled separately. Gene expression levels were measured in the RNA-Seq analysis as fragments per kilobase per million mapped fragments (FPKM).

    Statistical analysis

    The data for the physiological parameters were analyzed using DPS 7.05 software. Significant differences between treatment and control were evaluated with Student's t-test, and the significance level was set at * p < 0.05 and ** p < 0.01, respectively.

    RESULTS

    Effects of supplemental red/blue light on growth and photosynthetic indexes

    Aiming to elucidate whether red/blue (R/B) light supplementation affects the growth and development of 'Yanli' strawberry, we compared the plants growing under R/B light supplementation and control conditions. We found that R/B light supplementation significantly increased the growth of strawberry plants in two years (Supplemental Fig. S1). During 2019−2020 and 2020−2021, the plant height of the strawberry under supplemental R/B lighting was 17% and 13% higher than that of the control, respectively (Table 1). Meanwhile, the crown diameter of the plants under light treatment was increased by 1.38-fold and 1.07-fold compared with that in the control during the two years, respectively (Table 1). To further explore the effect of supplemental R/B light on the photosynthesis of 'Yanli' strawberry, we measured the photosynthetic parameters of 'Yanli' strawberry plants during the flowering and fruit setting stage. The results showed that the Pn, Gs and Tr of strawberry plants under R/B light supplementation were 19%, 55% and 27% higher than those in the control, respectively (Fig. 1).

    Table 1.  Comparison of strawberry plant height and crown diameter between red/blue light supplementation and control.
    YearLight treatmentPlant height (cm)Crown diameter (cm)
    2019−2020Control17.1122.42
    RB19.96**30.86**
    2020−2021Control17.2224.23
    RB19.44*26.04**
     | Show Table
    DownLoad: CSV
    Figure 1.  Effect of R/B light supplementation on photosynthetic parameters of strawberry cultivar 'Yanli' cultured in solar greenhouse. (a)−(d) net photosynthetic rate (Pn), stomata conductance (Gs), intercellular CO2 (Ci), and transpiration rate (Tr). Vertical bars represent the SD. Statistical significance was measured using Student's t-test. (n = 20, * p < 0.05, ** p < 0.01).
    DownLoad: Full-Size Img PowerPoint

    Effects of supplemental R/B light on strawberry yield and fruit quality

    To investigate whether supplemental R/B light affected strawberry yield and fruit quality, we analyzed strawberry primary fruit fresh weight, total fruit weight/plant, SSC, and the fruit firmness under supplemental R/B light and control. As shown in Fig. 2a, the R/B light supplementation led to a remarkable improvement (18% and 24%) in the strawberry primary fruit fresh weight during the stage of full ripeness compared with that in control conditions during the years 2019−2020 and 2020−2021. And total fruit weight/plant under supplemental R/B light was 27% and 33% higher than that of the control during two consecutive years, respectively (Fig. 2b). Under R/B light supplementation, strawberry fruit SSC was increased by 1.21-fold and 1.05-fold compared with that in the control during the two years, respectively (Fig. 2c). Similarly, fruit firmness was also increased by 1.18-fold and 1.06-fold compared with that in the control for two years, respectively (Fig. 2d). These results suggested that supplemental R/B light could improve 'Yanli' strawberry yield and fruit quality.

    Figure 2.  Effect of R/B light supplementation on production and fruit quality of strawberry cultivar 'Yanli' cultured in solar greenhouse. (a) Primary fruit fresh weight, (b) total fruit weight/plant, (c) soluble solid content and (d) firmness of the 'Yanli' fruit under R/B light supplementation and control. Vertical bars represent SD. Statistical significance was measured using Student's t-test. (n = 20, * p < 0.05, ** p < 0.01).
    DownLoad: Full-Size Img PowerPoint

    Transcriptome sequencing

    To study the effect of supplemental R/B light on 'Yanli' strawberry plants, total RNA from six samples (CK-1, CK-2, CK-3 and RB-1, RB-2, RB-3) were used for RNA-seq. The treatment and control group respectively contain three biological repeat samples. After filtering dirty tags from the raw data, a total of 38.36 Gb of clean data were obtained, with an average of 6.21 Gb of clean reads per sample. Of the clean reads, the average GC content is approximately 46.96%, and the Q30 percentage was over 93.05%. The percentage of clean reads mapped to the unigene database ranged from 79.07% to 80.42% (Table 2).

    Table 2.  Summary of transcriptome data.
    SampleClean read numberClean base numberGC contenta% ≥ Q30bMapped readsMapped ratio
    CK-121,222,1926,353,022,70046.98%93.13%16,779,94979.07%
    CK-223,479,2917,032,924,42447.23%93.04%18,653,55179.45%
    CK-320,727,3676,210,109,12647.07%93.09%16,668,43980.42%
    RB-120,756,1396,218,258,99846.63%93.07%16,594,03479.95%
    RB-220,842,5206,243,435,53846.83%92.85%16,552,37779.42%
    RB-321,022,7526,297,302,71246.99%93.09%16,753,65479.69%
    a GC Content: the percentage of G and C bases in the total bases in clean reads.
    b % ≥ Q30: the percentages of clean reads with Phred qualities scores over 30.
     | Show Table
    DownLoad: CSV

    The FPKM values were used to analyze the gene expression levels in the RNA-seq analysis. R (Pearson correlation coefficient) was used as the evaluation index of correlation between each sample, the results of Fig. 3a showed that there was a strong correlation between the three biological replicates from each group. 1.5 fold change and P value less than 0.05 were used to define differentially expressed genes (DEGs). A total of 165 DEGs were identified, among which 76 were up-regulated and 89 were down-regulated by supplementing R/B light, respectively (Supplemental Table S1, Fig. 3b).

    Figure 3.  Overview of the transcriptome sequencing under supplemental R/B lighting in strawberry leaves. (a) Pearson correlation between samples analysis. (b) Number of up- and down-regulated expressed genes. CK-1, CK-2, CK-3 are controls, RB-1, RB-2, and RB-3 are the experimental groups treated with supplemental R/B lighting.
    DownLoad: Full-Size Img PowerPoint

    GO and KEGG pathway enrichment

    GO (Gene ontology) functional classes showed that the putative function of DEGs. The enriched genes were classified into three major categories, including Biological Processes (BP), Cellular Components (CC), and Molecular Functions (MF). Metabolic process, cellular process and single-organism process were enriched mainly in biological processes. Among CC, cell, cell part, membrane, membrane part and organelle were the main terms. Molecular functions such as binding, catalytic activity and transporter activity were mainly enriched (Fig. 4). And TopGO was used to analyze the function enrichment of DEGs, including in the oxidation-reduction process (GO:0055114, KS = 9.5e-10), photosynthesis (GO:0015979, 6.7e-05), chloroplast thylakoid membrane (GO:0009535, 0.00014; Supplemental Table S2). The annotated unigenes were classified into 14 COG (Cluster of Orthologous Groups of proteins) categories (Fig. 5). And the largest group is 'carbohydrate transport and metabolism'.

    Figure 4.  Gene ontology (GO) enrichment analysis of differentially expressed genes in strawberry leaves by supplementing R/B light.
    DownLoad: Full-Size Img PowerPoint
    Figure 5.  Histogram of COG (cluster of orthologous groups) classification.
    DownLoad: Full-Size Img PowerPoint

    In addition, KEGG (Kyoto Encyclopedia of Genes and Genomes) annotation was used to analyze the functional enrichment of DEGs. There were 18 significantly enriched KEGG pathways (Fig. 6). In the comparison of the control and R/B light supplementation groups, the identified DEGs were mainly enriched in plant hormone signaling transduction, base excision repair, circadian rhythm-plant, and alpha-Linolenic acid metabolism.

    Figure 6.  KEGG enrichment analysis of DEGs regulated by supplementing R/B light in strawberry leaves.
    DownLoad: Full-Size Img PowerPoint

    Transcriptomic analysis of some DEGs in response to red/blue light supplementation

    Transcription factors (TFs) play an important role in plant response to changing environments[19]. In 'Yanli' leaves, the expressions of a total of 13 TF genes were significantly affected by supplementing R/B light. These TF genes belong to different families (NAC, PRR, MYB, bZIP, ZAT, CDF, CO, bHLH, BBX and PAR) (Table 3). The gene families including PRR, MYB, CDF and CO play an important role in the regulation of the circadian clock[20−23]. bHLH, BBX and PAR participate in the light signal transduction[24−26]. We found that PRR95 (PRR family), LHY (MYB family) and CDF3 (CDF family) were up-regulated, while CO16 (CO family), bHLH63 (Arabidopsis thaliana CIB1 homologous gene, bHLH family), BBX21 (BBX family) and PAR1 (PAR family) were down-regulated in 'Yanli' leaves during supplementing R/B light. In addition, we found that the SIGE regulating the expression of the chloroplast genes in the light-signaling pathway was upregulated (Supplemental Table S1). The results indicated that these TFs and SIGE maybe participate in the photosynthesis process of 'Yanli' during R/B light supplementation.

    Table 3.  List of differentially expressed TF genes.
    Gene familyTF nameAnnotation functionlogFCRegulation
    NACNAC72NAC domain-containing protein 72-like0.931857Up
    PRRPRR95Two-component response regulator-like PRR950.893515Up
    MYBLHYProtein LHY-like0.657352Up
    bZIPTRAB1bZIP transcription factor TRAB10.651141Up
    ZATZAT8Zinc finger protein ZAT8-like0.628283Up
    CDFCDF3Cyclic dof factor 30.641524Up
    COCO16Zinc finger protein CONSTANS-LIKE 16−0.66291Down
    bZIPbZIP34Basic leucine zipper 34−1.07449Down
    bZIPbZIP61Basic leucine zipper 61-like−0.9109Down
    bHLHbHLH63Transcription factor bHLH63−0.66341Down
    BBXBBX21B-box zinc finger protein 21−0.67538Down
    PARPAR1Transcription factor PAR1−0.61181Down
    MYBRADTranscription factor RADIALIS-like−0.61324Down
     | Show Table
    DownLoad: CSV

    DISCUSSION

    Light is one of the most vital environmental factors for plant growth and development. Too much or too little light can have adverse effects on some horticultural crops[27−29]. In winter, the cultivation of horticultural crops in solar greenhouses is widely used to meet people's nutritional needs, in northern China[30]. In addition to insufficient light time in northern winter, low PPFD under greenhouse conditions is also one of the important factors restricting the yields and quality of horticultural crops[28,31]. More and more studies found that combined red and blue light supplementation have a widely positive effect on the process of growth and development, and fruit quality for horticultural plants[32−34]. There are also individual differences between different red and blue ratios, different horticultural plants and different varieties[15,32,35]. The supplementation of red/blue (4:1) light for 3 h every day improved the growth of pepper seedlings in solar greenhouse[36]. Tomatoes grown under red/blue light (ratio = 3:1) have optimum growth[37]. In order to explore suitable cultivation measures for the 'Yanli' strawberry, and LED red and blue light (ratio = 4:1) was supplemented without changing other conditions in the solar greenhouse. Combined with transcriptome analysis and phenotypic identification, we found that supplementation of red and blue light could improve photosynthesis, yield and soluble solid content in strawberry cultivar 'Yanli'.

    For plant morphology and physiological indicators, we observed that the plant height, crown diameter and photosynthesis were significantly increased in 'Yanli' strawberry under R/B light supplementation before sunrise and after sunset every day. Previous studies have also shown that red and blue light can improve plant growth and photosynthesis. Strawberry quality and production were improved by promoting the stomatal opening and accumulation of the photosynthetic products under the condition of supplementary morning lighting with blue light[5]. In addition, we compared the transcriptomes of the leaves of 'Yanli' strawberry plants under supplemental red and blue light and control.

    Many TFs regulate photosynthesis gene expression and response to changing environmental conditions[30,38]. We found several different expression TF genes in 'Yanli' leaves between supplementing R/B light and control. PRR95, LHY and CDF3 were up-regulated, bHLH63, BBX21 and PAR1 were down-regulated. Among them, PRR and LHY are the downstream photoreceptors and the key component of the circadian clock[39]. Photosynthesis is regulated by the circadian rhythm, and it is very important that the circadian clock coordinates photosynthesis to improve the efficiency of light-energy capture and carbon fixation[20]. In Jatropha curcas, CDFs (cycling dof factors) responded to the photoperiod[23]. CDFs also play an important role in improving photosynthetic efficiency, coordinating carbon/nitrogen balance and promoting plant growth[40]. For CIB1 (CRYPTOCHROME-INTERACTING BHLH 1), FvebHLH63 homologous gene, previous studies show that CIB1 negatively regulates the photosynthetic rate in soybean[41]. BBXs play an important role in photomorphosis. BBXs and HY5 are components that control a variety of light-regulated genes expression[42−44]. PAR regulated hypocotyl length under simulated shade in Arabidopsis[45]. The function of PAR1 in strawberry needs to be further studied. Besides, RNA polymerase sigma factor gene SIGE (a homolog of SIG5 in Arabidopsis) was upregulated by supplementing R/B light. SIG5 is mainly induced by red light and blue light to participate in photosynthesis[46,47]. SIG5 regulates the chloroplast genes psbD and psbA (PSII core proteins) in chloroplasts at the post-transcriptional level[48,49]. In the present study, transcriptome analysis indicated PRR95, LHY, CDF3, CO16, bHLH63, BBX21, PAR1 and SIGE exhibited different expressions between supplemental R/B light and control in 'Yanli'. We speculate that these eight differentially expressed genes maybe participate in the photosynthesis process of 'Yanli' during R/B light supplementation.

    For fruit quality and yield, previous studies have shown that tomato fruit quality was improved by increased photosynthetic efficiency under red and blue LED (red : blue = 8:2) supplementation in the greenhouse[50]. In the condition of an artificial climate chamber, supplementing R/B light in the morning promoted the accumulation of health-promoting substances in the tomato fruits, such as vitamin C, organic acids, carotenoids, etc. While the content of sugars, flavonoids, and aromatic substances in tomato fruits were significantly increased by supplementing R/B light at night[51]. In addition, the photosynthetic activity, and fruit productivity were increased in strawberry plants under different ratios of red and blue LED light[52,53]. In this study, we found that the SSC content, primary fruit weight, and fruit weight per plant were increased by R/B light supplementation in 'Yanli' strawberry. At the same time, transcriptome analysis found that the expression of genes related to sucrose transport (sugar transporter： SWEET9-like, c50514.graph_c0) and amylolysis (beta-amylase: BAM1, c61305.graph_c0) were up-regulated (Supplemental Table S1). This may be related to strawberry fruit quality. Some studies showed that there were no effects on the strawberry fruit firmness after monochromatic red or blue light treatment[54,55]. However, our studies found that the strawberry fruit firmness was increased by supplementing R/B light. This is probably a consequence of different strawberry varieties or different cultivation environments. Next, we will further explore the differentially expressed genes in 'Yanli' between R/B light supplementation and control.

    For the most suitable ratio of supplementary R/B light and the photoperiod for strawberry cultivars 'Yanli', we are investigating the growth and development of 'Yanli' strawberry plants in the artificial climate culture chamber under different R/B light ratio and photoperiod, so as to be applied to 'Yanli' cultivation and production more accurately. Different red and blue ratios have different effects on different species or different traits of the same species[35,37]. In this study, we found that the growth, photosynthesis, yield and fruit quality of 'Yanli' strawberries were improved under R/B light (red : blue = 4:1) supplementary in solar greenhouses of northern China. The cost for LED lights is about $600 per thousand square meters, and the LED lights could be used for 3−5 years. The economic benefits far outweigh the costs of LED lights. Therefore, these studies provide evidence for establishing the effective cultivation measures of 'Yanli' strawberry. The internal molecular mechanism still needs to be further studied.

    ACKNOWLEDGMENTS

    This work was supported by National Natural Science Foundation of China (Grant No. 32130092, 32102350, 31872072) and LiaoNing Revitalization Talents Program (No. XLYC1902069).

  • Zhihong Zhang is the Editorial Board member of the journal Fruit Research. He was blinded from reviewing or making decisions on the manuscript. The article was subject to the journal's standard procedures, with peer-review handled independently of this Editorial Board member and his research group.

  • Supplemental Table S1 All DEGs.
    Supplemental Table S2 Top GO.
    Supplemental Fig. S1 Phenotype of strawberry cultivar ‘Yanli’ under supplemental R/B lighting (B) and control (A).
  • [1]

    Afrin S, Gasparrini M, Forbes-Hernandez TY, Reboredo-Rodriguez P, Mezzetti B, et al. 2016. Promising Health Benefits of the Strawberry: A Focus on Clinical Studies. Journal of Agricultural and Food Chemistry 64:4435−49

    doi: 10.1021/acs.jafc.6b00857

    CrossRef   Google Scholar

    [2]

    Palei S, Das AK, Rout GR. 2015. In vitro studies of strawberry-an important fruit crop: a review. The Journal of Plant Science Research 31:115

    Google Scholar

    [3]

    Hidaka K, Okamoto A, Araki T, Miyoshi Y, Dan K, et al. 2014. Effect of photoperiod of supplemental lighting with light-emitting diodes on growth and yield of strawberry. Environmental Control in Biology 52:63−71

    doi: 10.2525/ecb.52.63

    CrossRef   Google Scholar

    [4]

    López-Aranda JM, Soria C, Santos BM, Miranda L, Domínguez P, et al. 2011. Strawberry production in mild climates of the world: a review of current cultivar use. International Journal of Fruit Science 11:232−44

    doi: 10.1080/15538362.2011.608294

    CrossRef   Google Scholar

    [5]

    Wei H, Liu C, Hu J, Jeong BR. 2020. Quality of Supplementary Morning Lighting (SML) during propagation period affects physiology, stomatal characteristics, and growth of strawberry plants. Plants 9:638

    doi: 10.3390/plants9050638

    CrossRef   Google Scholar

    [6]

    Zheng L, He H, Song W. 2019. Application of light-emitting diodes and the effect of light quality on horticultural crops: A review. Hortscience 54:1656−61

    doi: 10.21273/HORTSCI14109-19

    CrossRef   Google Scholar

    [7]

    Nadalini S, Zucchi P, Andreotti C. 2017. Effects of blue and red LED lights on soilless cultivated strawberry growth performances and fruit quality. European Journal of Horticultural Science 82:12−20

    doi: 10.17660/eJHS.2017/82.1.2

    CrossRef   Google Scholar

    [8]

    Zahedi SM, Sarikhani H. 2017. The effect of end of day far-red light on regulating flowering of short-day strawberry (Fragaria × ananassa Duch. Nv. Paros) in a long-day situation. Russian Journal of Plant Physiology 64:83−90

    doi: 10.1134/S1021443717010198

    CrossRef   Google Scholar

    [9]

    Miao L, Zhang Y, Yang X, Xiao J, Zhang H, et al. 2016. Colored light-quality selective plastic films affect anthocyanin content, enzyme activities, and the expression of flavonoid genes in strawberry (Fragaria × ananassa) fruit. Food Chemistry 207:93−100

    doi: 10.1016/j.foodchem.2016.02.077

    CrossRef   Google Scholar

    [10]

    Hogewoning SW, Wientjes E, Douwstra P, Trouwborst G, van Ieperen W, et al. 2012. Photosynthetic quantum yield dynamics: From photosystems to leaves. The Plant Cell 24:1921−35

    doi: 10.1105/tpc.112.097972

    CrossRef   Google Scholar

    [11]

    Paradiso R, Meinen E, Snel JFH, De Visser P, Van Ieperen W, et al. 2011. Spectral dependence of photosynthesis and light absorptance in single leaves and canopy in rose. Scientia Horticulturae 127:548−54

    doi: 10.1016/j.scienta.2010.11.017

    CrossRef   Google Scholar

    [12]

    Hogewoning SW, Trouwborst G, Maljaars H, Poorter H, van Ieperen W, et al. 2010. Blue light dose - responses of leaf photosynthesis, morphology, and chemical composition of Cucumis sativus grown under different combinations of red and blue light. Journal of Experimental Botany 61:3107−17

    doi: 10.1093/jxb/erq132

    CrossRef   Google Scholar

    [13]

    Trouwborst G, Hogewoning SW, van Kooten O, Harbinson J, van Ieperen W. 2016. Plasticity of photosynthesis after the 'red light syndrome' in cucumber. Environmental and Experimental Botany 121:75−82

    doi: 10.1016/j.envexpbot.2015.05.002

    CrossRef   Google Scholar

    [14]

    Ouzounis T, Heuvelink E, Ji Y, Schouten HJ, Visser RGF, et al. 2016. Blue and red LED lighting effects on plant biomass, stomatal conductance, and metabolite content in nine tomato genotypes. Acta Horticulturae 1134:251−58

    doi: 10.17660/actahortic.2016.1134.34

    CrossRef   Google Scholar

    [15]

    Choi HG, Moon BY, Kang NJ. 2015. Effects of LED light on the production of strawberry during cultivation in a plastic greenhouse and in a growth chamber. Scientia Horticulturae 189:22−31

    doi: 10.1016/j.scienta.2015.03.022

    CrossRef   Google Scholar

    [16]

    Díaz-Galián MV, Torres M, Sanchez-Pagán JD, Navarro PJ, Weiss J, et al. 2021. Enhancement of strawberry production and fruit quality by blue and red LED lights in research and commercial greenhouses. South African Journal of Botany 140:269−75

    doi: 10.1016/j.sajb.2020.05.004

    CrossRef   Google Scholar

    [17]

    Li H, Dai H, Liu Y, Ma Y, Wu D, et al. 2015. A new strawberry cultivar 'Yanli'. Acta Horticulturae Sinica 42:799

    doi: 10.16420/j.issn.0513-353x.2014-0485

    CrossRef   Google Scholar

    [18]

    Chang L, Zhang Z, Yang H, Li H, Dai H. 2007. Detection of strawberry RNA and DNA viruses by RT-PCR using total nucleic acid as a template. Journal of Phytopathology 155:431−36

    doi: 10.1111/j.1439-0434.2007.01254.x

    CrossRef   Google Scholar

    [19]

    Strader L, Weijers D, Wagner D. 2022. Plant transcription factors - being in the right place with the right company. Current Opinion in Plant Biology 65:102136

    doi: 10.1016/j.pbi.2021.102136

    CrossRef   Google Scholar

    [20]

    Chen C, Tian X, Li J, Bai S, Zhang Z, et al. 2022. Two central circadian oscillators OsPRR59 and OsPRR95 modulate magnesium homeostasis and carbon fixation in rice. Molecular Plant 15:1602−14

    doi: 10.1016/j.molp.2022.09.008

    CrossRef   Google Scholar

    [21]

    Liu Y, Ma M, Li G, Yuan L, Xie Y, et al. 2020. Transcription factors FHY3 and FAR1 regulate light-induced CIRCADIAN CLOCK ASSOCIATED1 gene expression in Arabidopsis. The Plant Cell 32:1464−78

    doi: 10.1105/tpc.19.00981

    CrossRef   Google Scholar

    [22]

    Lv X, Zeng X, Hu H, Chen L, Zhang F, et al. 2021. Structural insights into the multivalent binding of the Arabidopsis FLOWERING LOCUS T promoter by the CO-NF-Y master transcription factor complex. The Plant Cell 33:1182−95

    doi: 10.1093/plcell/koab016

    CrossRef   Google Scholar

    [23]

    Yang J, Yang M, Wang D, Chen F, Shen S. 2010. JcDof1, a Dof transcription factor gene, is associated with the light-mediated circadian clock in Jatropha curcas. Physiologia Plantarum 139:324−34

    doi: 10.1111/j.1399-3054.2010.01363.x

    CrossRef   Google Scholar

    [24]

    Hao Y, Zhang X, Liu Y, Ma M, Huang X, et al. 2022. Cryo-EM structure of the CRY2 and CIB1 fragment complex provides insights into CIB1-mediated photosignaling. Plant Communications 11:100475

    doi: 10.1016/j.xplc.2022.100475

    CrossRef   Google Scholar

    [25]

    Bursch K, Toledo-Ortiz G, Pireyre M, Lohr M, Braatz C, et al. 2020. Identification of BBX proteins as rate-limiting cofactors of HY5. Nature Plants 6:921−28

    doi: 10.1038/s41477-020-0725-0

    CrossRef   Google Scholar

    [26]

    Roig-Villanova I, Bou J, Sorin C, Devlin PF, Martínez-García JF. 2006. Identification of primary target genes of phytochrome signaling. Early transcriptional control during shade avoidance responses in Arabidopsis. Plant Physiology 141:85−96

    doi: 10.1104/pp.105.076331

    CrossRef   Google Scholar

    [27]

    Gruda N. 2005. Impact of environmental factors on product quality of greenhouse vegetables for fresh consumption. Critical Reviews in Plant Sciences 24:227−47

    doi: 10.1080/07352680591008628

    CrossRef   Google Scholar

    [28]

    Peet MM. 1997. Greenhouse crop stress management. International symposium on growing media and hydroponics 481:643−54

    Google Scholar

    [29]

    Weston LA, Barth MM. 1997. Preharvest factors affecting postharvest quality of vegetables. HortScience 32:812−16

    doi: 10.21273/HORTSCI.32.5.812

    CrossRef   Google Scholar

    [30]

    Wang T, Wu G, Chen J, Cui P, Chen Z, et al. 2017. Integration of solar technology to modern greenhouse in China: Current status, challenges and prospect. Renewable and Sustainable Energy Reviews 70:1178−88

    doi: 10.1016/j.rser.2016.12.020

    CrossRef   Google Scholar

    [31]

    Ottosen CO, Rosenqvist E, Sorensen L. 2003. Effect of a dynamic climate control on energy saving, yield and shelf life of spring production of bell peppers (Capsicum annuum L.). European Journal of Horticultural Science 68:26−31

    Google Scholar

    [32]

    Hernández R, Kubota C. 2016. Physiological responses of cucumber seedlings under different blue and red photon flux ratios using LEDs. Environmental and Experimental Botany 121:66−74

    doi: 10.1016/j.envexpbot.2015.04.001

    CrossRef   Google Scholar

    [33]

    Li Y, Liu C, Shi Q, Yang F, Wei M. 2021. Mixed red and blue light promotes ripening and improves quality of tomato fruit by influencing melatonin content. Environmental and Experimental Botany 185:104407

    doi: 10.1016/j.envexpbot.2021.104407

    CrossRef   Google Scholar

    [34]

    Wang J, Lu W, Tong Y, Yang Q. 2016. Leaf morphology, photosynthetic performance, chlorophyll fluorescence, stomatal development of lettuce (Lactuca sativa L.) exposed to different ratios of red light to blue light. Frontiers in Plant Science 7:250

    doi: 10.3389/fpls.2016.00250

    CrossRef   Google Scholar

    [35]

    Warner R, Wu B, MacPherson S, Lefsrud M. 2021. A review of strawberry photobiology and fruit flavonoids in controlled environments. Frontiers in Plant Science 12:611893

    doi: 10.3389/fpls.2021.611893

    CrossRef   Google Scholar

    [36]

    Tang Z, Yu J, Xie J, Lyu J, Feng Z, et al. 2019. Physiological and growth response of pepper (Capsicum annum L.) seedlings to supplementary red/blue light revealed through transcriptomic analysis. Agronomy 9:139

    doi: 10.3390/agronomy9030139

    CrossRef   Google Scholar

    [37]

    Liang Y, Kang C, Kaiser E, Kuang Y, Yang Q, et al. 2021. Red/blue light ratios induce morphology and physiology alterations differently in cucumber and tomato. Scientia Horticulturae 281:109995

    doi: 10.1016/j.scienta.2021.109995

    CrossRef   Google Scholar

    [38]

    Chen F, Zheng G, Qu M, Wang Y, Lyu MJA, et al. 2021. Knocking out NEGATIVE REGULATOR OF PHOTOSYNTHESIS 1 increases rice leaf photosynthesis and biomass production in the field. Journal of Experimental Botany 72:1836−49

    doi: 10.1093/jxb/eraa566

    CrossRef   Google Scholar

    [39]

    Dodd AN, Belbin FE, Frank A, Webb AAR. 2015. Interactions between circadian clocks and photosynthesis for the temporal and spatial coordination of metabolism. Frontiers in Plant Science 6:245

    doi: 10.3389/fpls.2015.00245

    CrossRef   Google Scholar

    [40]

    Yanagisawa S. 2004. Dof domain proteins: Plant-specific transcription factors associated with diverse phenomena unique to plants. Plant and Cell Physiology 45:386−91

    doi: 10.1093/pcp/pch055

    CrossRef   Google Scholar

    [41]

    Meng Y, Li H, Wang Q, Liu B, Lin C. 2013. Blue light–dependent interaction between cryptochrome2 and CIB1 regulates transcription and leaf senescence in soybean. The Plant Cell 25:4405−20

    doi: 10.1105/tpc.113.116590

    CrossRef   Google Scholar

    [42]

    Zhao X, Heng Y, Wang X, Deng XW, Xu D. 2020. A positive feedback loop of BBX11-BBX21-HY5 promotes photomorphogenic development in Arabidopsis. Plant Communications 1:100045

    doi: 10.1016/j.xplc.2020.100045

    CrossRef   Google Scholar

    [43]

    Xu D. 2020. COP1 and BBXs-HY5-mediated light signal transduction in plants. New Phytologist 228:1748−53

    doi: 10.1111/nph.16296

    CrossRef   Google Scholar

    [44]

    Song Z, Bian Y, Liu J, Sun Y, Xu D. 2020. B-box proteins: pivotal players in light-mediated development in plants. Journal of Integrative Plant Biology 62:1293−309

    doi: 10.1111/jipb.12935

    CrossRef   Google Scholar

    [45]

    Liu Y, Wei H, Ma M, Li Q, Kong D, et al. 2019. Arabidopsis FHY3 and FAR1 regulate the balance between growth and defense responses under shade conditions. The Plant Cell 31:2089−106

    doi: 10.1105/tpc.18.00991

    CrossRef   Google Scholar

    [46]

    Lysenko EA. 2007. Plant sigma factors and their role in plastid transcription. Plant Cell Reports 26:845−59

    doi: 10.1007/s00299-007-0318-7

    CrossRef   Google Scholar

    [47]

    Mellenthin M, Ellersiek U, Börger A, Baier M. 2014. Expression of the Arabidopsis sigma factor SIG5 is photoreceptor and photosynthesis controlled. Plants 3:359−91

    doi: 10.3390/plants3030359

    CrossRef   Google Scholar

    [48]

    Chi W, He B, Mao J, Jiang J, Zhang L. 2015. Plastid sigma factors: their individual functions and regulation in transcription. Biochimica et Biophysica Acta (BBA)-Bioenergetics 1847:770−78

    doi: 10.1016/j.bbabio.2015.01.001

    CrossRef   Google Scholar

    [49]

    Kanazawa T, Ishizaki K, Kohchi T, Hanaoka M, Tanaka K. 2013. Characterization of four nuclear-encoded plastid RNA polymerase sigma factor genes in the liverwort Marchantia polymorpha: blue-light-and multiple stress-responsive SIG5 was acquired early in the emergence of terrestrial plants. Plant and Cell Physiology 54:1736−48

    doi: 10.1093/pcp/pct119

    CrossRef   Google Scholar

    [50]

    Paponov M, Kechasov D, Lacek J, Verheul MJ, Paponov IA. 2020. Supplemental light-emitting diode inter-lighting increases tomato fruit growth through enhanced photosynthetic light use efficiency and modulated root activity. Frontiers in Plant Science 10:1656

    doi: 10.3389/fpls.2019.01656

    CrossRef   Google Scholar

    [51]

    Wang S, Jin N, Jin L, Xiao X, Hu L, et al. 2022. Response of tomato fruit quality depends on period of LED supplementary light. Frontiers in Nutrition 9:833723

    doi: 10.3389/fnut.2022.833723

    CrossRef   Google Scholar

    [52]

    Naznin MT, Lefsrud M, Gravel V, Hao X. 2016. Using different ratios of red and blue LEDs to improve the growth of strawberry plants. Acta Horticulturae 1134:125−30

    doi: 10.17660/actahortic.2016.1134.17

    CrossRef   Google Scholar

    [53]

    Nhut DT, Takamura T, Watanabe H, Okamoto K, Tanaka M. 2003. Responses of strawberry plantlets cultured in vitro under superbright red and blue light-emitting diodes (LEDs). Plant Cell, Tissue and Organ Culture 73:43−52

    doi: 10.1023/A:1022638508007

    CrossRef   Google Scholar

    [54]

    Campbell SM, Sims CA, Bartoshuk LM, Colquhoun TA, Schwieterman ML, et al. 2020. Manipulation of sensory characteristics and volatile compounds in strawberry fruit through the use of isolated wavelengths of light. Journal of Food Science 85:771−80

    doi: 10.1111/1750-3841.15044

    CrossRef   Google Scholar

    [55]

    Wang L, Luo Z, Yang M, Liang Z, Qi M, et al. 2022. The action of RED light: Specific elevation of pelargonidin-based anthocyanin through ABA-related pathway in strawberry. Postharvest Biology and Technology 186:111835

    doi: 10.1016/j.postharvbio.2022.111835

    CrossRef   Google Scholar

  • Cite this article

    Wang Y, Tang X, Wang B, Dai H, Zhang Z. 2023. Positive effect of red/blue light supplementation on the photosynthetic capacity and fruit quality of 'Yanli' strawberry. Fruit Research 3:4 doi: 10.48130/FruRes-2023-0004
    Wang Y, Tang X, Wang B, Dai H, Zhang Z. 2023. Positive effect of red/blue light supplementation on the photosynthetic capacity and fruit quality of 'Yanli' strawberry. Fruit Research 3:4 doi: 10.48130/FruRes-2023-0004
    shu

Figures(6)  /  Tables(3)

Download PDF

Article Metrics

Article views(5693) PDF downloads(906)

Other Articles By Authors

ARTICLE   Open Access    

Positive effect of red/blue light supplementation on the photosynthetic capacity and fruit quality of 'Yanli' strawberry

  • Liaoning Key Laboratory of Strawberry Breeding and Cultivation, College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China

  • Received: 18 November 2022
  • Accepted: 26 January 2023
  • Published online: 24 February 2023
Fruit Research  3,  Article number: 4  (2023)  |  Cite this article

Abstract: In order to meet people’s demand for strawberry during winter and early spring, strawberry is usually cultivated in solar greenhouses with forcing cultivation in northern China. However, low light intensities and short-days are the major obstacles that restrict strawberry growth. Therefore, it is crucial to solve the problem of insufficient light in strawberry production. In this study, we established LED facilities to supplement the red/blue light (R/B = 4:1) before sunrise and after sunset in the solar greenhouse. We found that the plant height of the strawberry under supplemental R/B light was 13%−17% higher than that of the control, and the crown diameter of the plants was increased by 1.07−1.38 fold compared with the control for two consecutive years. The net photosynthetic rate of strawberry plants was 19% higher than that of the control. In addition, the strawberry primary fruits’ fresh weight during the stage of full ripeness and the total fruit weight/plant was 18%−24% and 27%−33% higher than that of control for two years, respectively. Fruit soluble solid content and firmness were increased by 1.05−1.21 fold and 1.06−1.18 fold compared with those of control during the two years, respectively. Moreover, we found some differentially expressed genes between red/blue light supplementation and control by RNA-seq, including light-responsive genes (PRR95/LHY/CDF3/CO16/bHLH63/BBX21/PAR1/SIGE) and sucrose metabolism-related genes (SWEET9/BAM1). This study provided a foundation for revealing the mechanism of red/blue light supplementation on photosynthesis and fruit quality of strawberries and could help to improve the cultivation techniques for 'Yanli' strawberry.

    HTML

    INTRODUCTION

    • Strawberry is an important economic crop with delicious and nutritious fruit[1,2]. In north China, strawberry is usually cultivated in solar greenhouses with forcing cultivation during the winter and early spring season. Forcing cultivation has the advantages of breaking dormancy and prolonging the harvest time in strawberry. However, under this condition, low light intensities and short-days are the major obstacles that restrict strawberry growth and development. There are many reasons for this problem, including short sunshine time and frequent hazy weather in winter, covering for heat preservation, and reducing light transmittance after the surface of the shed film absorbs dust, etc. These conditions may lead to reduced photosynthesis and thus affect plant growth and development of strawberry. Therefore, it is crucial to solve the problem of insufficient light in strawberry production.

      The artificial supplemental light source is an important cultivation technology for strawberry plants grown in greenhouses[3,4]. LED (Light Emitting Diode) was widely used in horticultural production in controlled environments due to the advantages of small size, relatively low heat release, great wavelength controllability, long lifetime, and low power consumption[5,6]. Different light wavelengths have different effects on strawberry plants' development and fruit quality[7,8]. To improve light-use efficiency in a greenhouse, more and more researchers pay attention to which corresponding light wavelengths are required for different growth and development processes of plants[9].

      Red light is one of the most efficient light qualities for powering plants' photosynthesis[10,11], but monochromatic red light may cause abnormal phenotypes because of a lower photosynthetic rate in several crop plants, such as leaf curling and leaf thickness, etc[12,13]. Adding blue light can suppress these symptoms[12−14]. Other studies showed that red and blue light mixed wavelength is beneficial to enhance strawberry production and fruit quality[15,16]. However, the effective model of R/B light supplementation in strawberry cultivar 'Yanli' is poorly understood.

      Strawberry cultivar 'Yanli' was released from Shenyang Agricultural University, China. The fruit has excellent flavor and aroma and the exterior is a regular conic shape and bright red. It is grown in different provinces of China, especially cultivated by forcing cultivation in solar greenhouses in northern China[17]. Therefore, it is necessary to study its effective cultivation practices. We established LED facilities to supplement the red/blue light (R/B = 4:1) for 'Yanli' before sunrise and after sunset in the solar greenhouse. The results showed that the photosynthetic efficiency, soluble solid content and yield were increased. In addition, we initially screened the candidate genes for improving photosynthesis and fruit quality in 'Yanli' strawberry under the condition of red/blue light supplementation by RNA-seq. These results will help to perfect the cultivation techniques for strawberry cultivar 'Yanli'.

    MATERIALS AND METHODS

      Plant material and growth conditions

    • 'Yanli' (Fragaria × ananassa Duch.) plants were grown in the greenhouse at Shenyang Agricultural University (Liaoning province, China). Runner plants of 'Yanli' were planted in the greenhouse in early September every year. After 30 d, 20 of them were subjected to the condition of a mixture of red (R) and blue (B) light at 06:30−08:00 AM (before sunrise) and 15:50−19:00 PM (after sunset) daily. Supplemental light treatments were provided using LED lamps (North Brilliancy Technology Co., LTD, Shenzhen, China). These LED lamps were installed at 1.5 m above the strawberry plants. The photosynthetic photon flux density (PPFD) was measured by a quantum sensor (LI-250A, LI-COR, USA), and the PPFD ratio of red (3.9261 μmol·m–2·s–1) to blue (0.9716 μmol·m–2·s–1) to supplemental light (R/B) was 4:1. Plants without any supplemental light were used as control.

      Measurements of growth and physiological traits

    • The height and crown diameter of strawberry plants were measured before reproductive growth. Plant height was measured from the ground to the highest blade. The crown diameter was the diameter of the leaf clusters. Primary fresh fruits were weighed. During the ripening stages of strawberry, the soluble solid content (SSC) of the strawberry juice was measured by a digital pocket refractometer ATAGO PAL-α (Atago Co. Ltd., Tokyo, Japan), and the firmness of fresh fruit was measured using a texture analyzer (GY-4, Handpi). Two opposite sites on the fruit shoulder were measured for each fruit, and the average firmness value of each fruit was recorded. Photosynthetic indexes, including net photosynthetic rate(Pn), stomata conductance (Gs), intercellular CO2 (Ci), and transpiration rate (Tr), were measured with a portable photosynthesis system (CIRAS-2, PP Systems, Massachusetts, USA) within the hours of 8:30−11:30 AM under sunny conditions. Third fully opened and new leaves from each plant were used for the photosynthetic indexes data. Twenty plants were measured for treatment and control, and three fruits were measured per plant.

      RNA extraction and sequencing

    • After 50 d of irradiation, the fully opened and new leaves of treated strawberry plants and controls in three biological replicates were selected for sampling and frozen in liquid nitrogen. Total RNA was extracted by a modified CTAB method[18]. RNA concentration was measured using a NanoDrop 2000 (Thermo Fisher Scientific, Wilmington, DE, USA). cDNA library and high-throughput sequencing were conducted by Biomarker Technologies Co, LTD (Beijing, China). The Illumina HiSeq™ platform was performed. Reads from each library were de novo assembled separately. Gene expression levels were measured in the RNA-Seq analysis as fragments per kilobase per million mapped fragments (FPKM).

      Statistical analysis

    • The data for the physiological parameters were analyzed using DPS 7.05 software. Significant differences between treatment and control were evaluated with Student's t-test, and the significance level was set at * p < 0.05 and ** p < 0.01, respectively.

    RESULTS

      Effects of supplemental red/blue light on growth and photosynthetic indexes

    • Aiming to elucidate whether red/blue (R/B) light supplementation affects the growth and development of 'Yanli' strawberry, we compared the plants growing under R/B light supplementation and control conditions. We found that R/B light supplementation significantly increased the growth of strawberry plants in two years (Supplemental Fig. S1). During 2019−2020 and 2020−2021, the plant height of the strawberry under supplemental R/B lighting was 17% and 13% higher than that of the control, respectively (Table 1). Meanwhile, the crown diameter of the plants under light treatment was increased by 1.38-fold and 1.07-fold compared with that in the control during the two years, respectively (Table 1). To further explore the effect of supplemental R/B light on the photosynthesis of 'Yanli' strawberry, we measured the photosynthetic parameters of 'Yanli' strawberry plants during the flowering and fruit setting stage. The results showed that the Pn, Gs and Tr of strawberry plants under R/B light supplementation were 19%, 55% and 27% higher than those in the control, respectively (Fig. 1).

      Table 1.  Comparison of strawberry plant height and crown diameter between red/blue light supplementation and control.

      YearLight treatmentPlant height (cm)Crown diameter (cm)
      2019−2020Control17.1122.42
      RB19.96**30.86**
      2020−2021Control17.2224.23
      RB19.44*26.04**

      Figure 1. 

      Effect of R/B light supplementation on photosynthetic parameters of strawberry cultivar 'Yanli' cultured in solar greenhouse. (a)−(d) net photosynthetic rate (Pn), stomata conductance (Gs), intercellular CO2 (Ci), and transpiration rate (Tr). Vertical bars represent the SD. Statistical significance was measured using Student's t-test. (n = 20, * p < 0.05, ** p < 0.01).

      Effects of supplemental R/B light on strawberry yield and fruit quality

    • To investigate whether supplemental R/B light affected strawberry yield and fruit quality, we analyzed strawberry primary fruit fresh weight, total fruit weight/plant, SSC, and the fruit firmness under supplemental R/B light and control. As shown in Fig. 2a, the R/B light supplementation led to a remarkable improvement (18% and 24%) in the strawberry primary fruit fresh weight during the stage of full ripeness compared with that in control conditions during the years 2019−2020 and 2020−2021. And total fruit weight/plant under supplemental R/B light was 27% and 33% higher than that of the control during two consecutive years, respectively (Fig. 2b). Under R/B light supplementation, strawberry fruit SSC was increased by 1.21-fold and 1.05-fold compared with that in the control during the two years, respectively (Fig. 2c). Similarly, fruit firmness was also increased by 1.18-fold and 1.06-fold compared with that in the control for two years, respectively (Fig. 2d). These results suggested that supplemental R/B light could improve 'Yanli' strawberry yield and fruit quality.

      Figure 2. 

      Effect of R/B light supplementation on production and fruit quality of strawberry cultivar 'Yanli' cultured in solar greenhouse. (a) Primary fruit fresh weight, (b) total fruit weight/plant, (c) soluble solid content and (d) firmness of the 'Yanli' fruit under R/B light supplementation and control. Vertical bars represent SD. Statistical significance was measured using Student's t-test. (n = 20, * p < 0.05, ** p < 0.01).

      Transcriptome sequencing

    • To study the effect of supplemental R/B light on 'Yanli' strawberry plants, total RNA from six samples (CK-1, CK-2, CK-3 and RB-1, RB-2, RB-3) were used for RNA-seq. The treatment and control group respectively contain three biological repeat samples. After filtering dirty tags from the raw data, a total of 38.36 Gb of clean data were obtained, with an average of 6.21 Gb of clean reads per sample. Of the clean reads, the average GC content is approximately 46.96%, and the Q30 percentage was over 93.05%. The percentage of clean reads mapped to the unigene database ranged from 79.07% to 80.42% (Table 2).

      Table 2.  Summary of transcriptome data.

      SampleClean read numberClean base numberGC contenta% ≥ Q30bMapped readsMapped ratio
      CK-121,222,1926,353,022,70046.98%93.13%16,779,94979.07%
      CK-223,479,2917,032,924,42447.23%93.04%18,653,55179.45%
      CK-320,727,3676,210,109,12647.07%93.09%16,668,43980.42%
      RB-120,756,1396,218,258,99846.63%93.07%16,594,03479.95%
      RB-220,842,5206,243,435,53846.83%92.85%16,552,37779.42%
      RB-321,022,7526,297,302,71246.99%93.09%16,753,65479.69%
      a GC Content: the percentage of G and C bases in the total bases in clean reads.
      b % ≥ Q30: the percentages of clean reads with Phred qualities scores over 30.

      The FPKM values were used to analyze the gene expression levels in the RNA-seq analysis. R (Pearson correlation coefficient) was used as the evaluation index of correlation between each sample, the results of Fig. 3a showed that there was a strong correlation between the three biological replicates from each group. 1.5 fold change and P value less than 0.05 were used to define differentially expressed genes (DEGs). A total of 165 DEGs were identified, among which 76 were up-regulated and 89 were down-regulated by supplementing R/B light, respectively (Supplemental Table S1, Fig. 3b).

      Figure 3. 

      Overview of the transcriptome sequencing under supplemental R/B lighting in strawberry leaves. (a) Pearson correlation between samples analysis. (b) Number of up- and down-regulated expressed genes. CK-1, CK-2, CK-3 are controls, RB-1, RB-2, and RB-3 are the experimental groups treated with supplemental R/B lighting.

      GO and KEGG pathway enrichment

    • GO (Gene ontology) functional classes showed that the putative function of DEGs. The enriched genes were classified into three major categories, including Biological Processes (BP), Cellular Components (CC), and Molecular Functions (MF). Metabolic process, cellular process and single-organism process were enriched mainly in biological processes. Among CC, cell, cell part, membrane, membrane part and organelle were the main terms. Molecular functions such as binding, catalytic activity and transporter activity were mainly enriched (Fig. 4). And TopGO was used to analyze the function enrichment of DEGs, including in the oxidation-reduction process (GO:0055114, KS = 9.5e-10), photosynthesis (GO:0015979, 6.7e-05), chloroplast thylakoid membrane (GO:0009535, 0.00014; Supplemental Table S2). The annotated unigenes were classified into 14 COG (Cluster of Orthologous Groups of proteins) categories (Fig. 5). And the largest group is 'carbohydrate transport and metabolism'.

      Figure 4. 

      Gene ontology (GO) enrichment analysis of differentially expressed genes in strawberry leaves by supplementing R/B light.

      Figure 5. 

      Histogram of COG (cluster of orthologous groups) classification.

      In addition, KEGG (Kyoto Encyclopedia of Genes and Genomes) annotation was used to analyze the functional enrichment of DEGs. There were 18 significantly enriched KEGG pathways (Fig. 6). In the comparison of the control and R/B light supplementation groups, the identified DEGs were mainly enriched in plant hormone signaling transduction, base excision repair, circadian rhythm-plant, and alpha-Linolenic acid metabolism.

      Figure 6. 

      KEGG enrichment analysis of DEGs regulated by supplementing R/B light in strawberry leaves.

      Transcriptomic analysis of some DEGs in response to red/blue light supplementation

    • Transcription factors (TFs) play an important role in plant response to changing environments[19]. In 'Yanli' leaves, the expressions of a total of 13 TF genes were significantly affected by supplementing R/B light. These TF genes belong to different families (NAC, PRR, MYB, bZIP, ZAT, CDF, CO, bHLH, BBX and PAR) (Table 3). The gene families including PRR, MYB, CDF and CO play an important role in the regulation of the circadian clock[20−23]. bHLH, BBX and PAR participate in the light signal transduction[24−26]. We found that PRR95 (PRR family), LHY (MYB family) and CDF3 (CDF family) were up-regulated, while CO16 (CO family), bHLH63 (Arabidopsis thaliana CIB1 homologous gene, bHLH family), BBX21 (BBX family) and PAR1 (PAR family) were down-regulated in 'Yanli' leaves during supplementing R/B light. In addition, we found that the SIGE regulating the expression of the chloroplast genes in the light-signaling pathway was upregulated (Supplemental Table S1). The results indicated that these TFs and SIGE maybe participate in the photosynthesis process of 'Yanli' during R/B light supplementation.

      Table 3.  List of differentially expressed TF genes.

      Gene familyTF nameAnnotation functionlogFCRegulation
      NACNAC72NAC domain-containing protein 72-like0.931857Up
      PRRPRR95Two-component response regulator-like PRR950.893515Up
      MYBLHYProtein LHY-like0.657352Up
      bZIPTRAB1bZIP transcription factor TRAB10.651141Up
      ZATZAT8Zinc finger protein ZAT8-like0.628283Up
      CDFCDF3Cyclic dof factor 30.641524Up
      COCO16Zinc finger protein CONSTANS-LIKE 16−0.66291Down
      bZIPbZIP34Basic leucine zipper 34−1.07449Down
      bZIPbZIP61Basic leucine zipper 61-like−0.9109Down
      bHLHbHLH63Transcription factor bHLH63−0.66341Down
      BBXBBX21B-box zinc finger protein 21−0.67538Down
      PARPAR1Transcription factor PAR1−0.61181Down
      MYBRADTranscription factor RADIALIS-like−0.61324Down
    DISCUSSION

    • Light is one of the most vital environmental factors for plant growth and development. Too much or too little light can have adverse effects on some horticultural crops[27−29]. In winter, the cultivation of horticultural crops in solar greenhouses is widely used to meet people's nutritional needs, in northern China[30]. In addition to insufficient light time in northern winter, low PPFD under greenhouse conditions is also one of the important factors restricting the yields and quality of horticultural crops[28,31]. More and more studies found that combined red and blue light supplementation have a widely positive effect on the process of growth and development, and fruit quality for horticultural plants[32−34]. There are also individual differences between different red and blue ratios, different horticultural plants and different varieties[15,32,35]. The supplementation of red/blue (4:1) light for 3 h every day improved the growth of pepper seedlings in solar greenhouse[36]. Tomatoes grown under red/blue light (ratio = 3:1) have optimum growth[37]. In order to explore suitable cultivation measures for the 'Yanli' strawberry, and LED red and blue light (ratio = 4:1) was supplemented without changing other conditions in the solar greenhouse. Combined with transcriptome analysis and phenotypic identification, we found that supplementation of red and blue light could improve photosynthesis, yield and soluble solid content in strawberry cultivar 'Yanli'.

      For plant morphology and physiological indicators, we observed that the plant height, crown diameter and photosynthesis were significantly increased in 'Yanli' strawberry under R/B light supplementation before sunrise and after sunset every day. Previous studies have also shown that red and blue light can improve plant growth and photosynthesis. Strawberry quality and production were improved by promoting the stomatal opening and accumulation of the photosynthetic products under the condition of supplementary morning lighting with blue light[5]. In addition, we compared the transcriptomes of the leaves of 'Yanli' strawberry plants under supplemental red and blue light and control.

      Many TFs regulate photosynthesis gene expression and response to changing environmental conditions[30,38]. We found several different expression TF genes in 'Yanli' leaves between supplementing R/B light and control. PRR95, LHY and CDF3 were up-regulated, bHLH63, BBX21 and PAR1 were down-regulated. Among them, PRR and LHY are the downstream photoreceptors and the key component of the circadian clock[39]. Photosynthesis is regulated by the circadian rhythm, and it is very important that the circadian clock coordinates photosynthesis to improve the efficiency of light-energy capture and carbon fixation[20]. In Jatropha curcas, CDFs (cycling dof factors) responded to the photoperiod[23]. CDFs also play an important role in improving photosynthetic efficiency, coordinating carbon/nitrogen balance and promoting plant growth[40]. For CIB1 (CRYPTOCHROME-INTERACTING BHLH 1), FvebHLH63 homologous gene, previous studies show that CIB1 negatively regulates the photosynthetic rate in soybean[41]. BBXs play an important role in photomorphosis. BBXs and HY5 are components that control a variety of light-regulated genes expression[42−44]. PAR regulated hypocotyl length under simulated shade in Arabidopsis[45]. The function of PAR1 in strawberry needs to be further studied. Besides, RNA polymerase sigma factor gene SIGE (a homolog of SIG5 in Arabidopsis) was upregulated by supplementing R/B light. SIG5 is mainly induced by red light and blue light to participate in photosynthesis[46,47]. SIG5 regulates the chloroplast genes psbD and psbA (PSII core proteins) in chloroplasts at the post-transcriptional level[48,49]. In the present study, transcriptome analysis indicated PRR95, LHY, CDF3, CO16, bHLH63, BBX21, PAR1 and SIGE exhibited different expressions between supplemental R/B light and control in 'Yanli'. We speculate that these eight differentially expressed genes maybe participate in the photosynthesis process of 'Yanli' during R/B light supplementation.

      For fruit quality and yield, previous studies have shown that tomato fruit quality was improved by increased photosynthetic efficiency under red and blue LED (red : blue = 8:2) supplementation in the greenhouse[50]. In the condition of an artificial climate chamber, supplementing R/B light in the morning promoted the accumulation of health-promoting substances in the tomato fruits, such as vitamin C, organic acids, carotenoids, etc. While the content of sugars, flavonoids, and aromatic substances in tomato fruits were significantly increased by supplementing R/B light at night[51]. In addition, the photosynthetic activity, and fruit productivity were increased in strawberry plants under different ratios of red and blue LED light[52,53]. In this study, we found that the SSC content, primary fruit weight, and fruit weight per plant were increased by R/B light supplementation in 'Yanli' strawberry. At the same time, transcriptome analysis found that the expression of genes related to sucrose transport (sugar transporter： SWEET9-like, c50514.graph_c0) and amylolysis (beta-amylase: BAM1, c61305.graph_c0) were up-regulated (Supplemental Table S1). This may be related to strawberry fruit quality. Some studies showed that there were no effects on the strawberry fruit firmness after monochromatic red or blue light treatment[54,55]. However, our studies found that the strawberry fruit firmness was increased by supplementing R/B light. This is probably a consequence of different strawberry varieties or different cultivation environments. Next, we will further explore the differentially expressed genes in 'Yanli' between R/B light supplementation and control.

      For the most suitable ratio of supplementary R/B light and the photoperiod for strawberry cultivars 'Yanli', we are investigating the growth and development of 'Yanli' strawberry plants in the artificial climate culture chamber under different R/B light ratio and photoperiod, so as to be applied to 'Yanli' cultivation and production more accurately. Different red and blue ratios have different effects on different species or different traits of the same species[35,37]. In this study, we found that the growth, photosynthesis, yield and fruit quality of 'Yanli' strawberries were improved under R/B light (red : blue = 4:1) supplementary in solar greenhouses of northern China. The cost for LED lights is about $600 per thousand square meters, and the LED lights could be used for 3−5 years. The economic benefits far outweigh the costs of LED lights. Therefore, these studies provide evidence for establishing the effective cultivation measures of 'Yanli' strawberry. The internal molecular mechanism still needs to be further studied.

      Acknowledgments

      • This work was supported by National Natural Science Foundation of China (Grant No. 32130092, 32102350, 31872072) and LiaoNing Revitalization Talents Program (No. XLYC1902069).

      Conflict of interest

      • Zhihong Zhang is the Editorial Board member of the journal Fruit Research. He was blinded from reviewing or making decisions on the manuscript. The article was subject to the journal's standard procedures, with peer-review handled independently of this Editorial Board member and his research group.

      Supplementary information
      Rights and permissions
      • Copyright: © 2023 by the author(s). Published by Maximum Academic Press, Fayetteville, GA. This article is an open access article distributed under Creative Commons Attribution License (CC BY 4.0), visit https://creativecommons.org/licenses/by/4.0/.
    Figure (6)  Table (3) References (55)
  • About this article
    Cite this article
    Wang Y, Tang X, Wang B, Dai H, Zhang Z. 2023. Positive effect of red/blue light supplementation on the photosynthetic capacity and fruit quality of 'Yanli' strawberry. Fruit Research 3:4 doi: 10.48130/FruRes-2023-0004
    Wang Y, Tang X, Wang B, Dai H, Zhang Z. 2023. Positive effect of red/blue light supplementation on the photosynthetic capacity and fruit quality of 'Yanli' strawberry. Fruit Research 3:4 doi: 10.48130/FruRes-2023-0004
    shu

Catalog

  • Html

  • Introduction
  • Materials and methods

  • Plant material and growth conditions

  • Measurements of growth and physiological traits

  • Rna extraction and sequencing

  • Statistical analysis

  • Results

  • Effects of supplemental red/blue light on growth and photosynthetic indexes

  • Effects of supplemental r/b light on strawberry yield and fruit quality

  • Transcriptome sequencing

  • Go and kegg pathway enrichment

  • Transcriptomic analysis of some degs in response to red/blue light supplementation

  • Discussion
  • Acknowledgments
  • Conflict of interest
  • Supplementary information
  • Rights and permissions
  • About this article
logo

Contents

Policies

Services

Partnerships

© 2025 Maximum Academic Press, except Open Access articles. MAP is a member of ALPSP, COPE, CrossRef, cOAlition S, OASPA and STM.

Privacy Policy  |  Site Map  |  Terms and Conditions

/

DownLoad:  Full-Size Img  PowerPoint
Return
Return