Figures (6)  Tables (2)
    • Figure 1. 

      Drought treatment and the analysis of gene sequence functional annotation in blueberry. (a) Relative SWC and RWC changes of blueberry, and the determination of three drought stress groups. CK, control group; MD, moderate drought stress group; SD severe drought stress group. (b) Differences of SWC and RWC of the blueberry leaf under drought stress groups. (c) Growth status of blueberry seedlings under three drought stress groups. (d) Expression of VcCBF4 f blueberry under drought stress. (e) Expression of VcRAB18 f blueberry under drought stress. (f) Functional annotation analysis of blueberry gene under drought stress. (g) PCA plots of genes identified by RNA-seq of blueberry leaves and roots under drought stress. Each value was represented as the mean value ± standard error of three independent determinations. Different letters indicate that Duncan's multiple range test is significantly different at P < 0.05.

    • Figure 2. 

      Weighted gene co-expression network analysis and identification of DEGs in response to drought. (a) Heatmap of correlations (P-value in parentheses) of module eigengenes with the drought treatment, soil relative water content, and leaf relative water content. (b) Identification of DEGs in response to drought in leaves (Venn diagram of 'WGCNA_Drought' and 'All_Leaf_5M'). (c) Identification of DEGs in response to drought in roots (Venn diagram of 'WGCNA_Drought' and 'All_Root_5M').

    • Figure 3. 

      Analysis of the key genes of signal transduction pathway in leaves and roots under drought stress. (a) KEGG enrichment analysis of plant signal transduction-related DEGs in leaves. (b) KEGG enrichment analysis of plant signal transduction-related DEGs in roots. (c) PPI analysis of 'All_Leaf_signal'. (d) PPI analysis of 'All_Root_signal'. (e) Venn analysis of 'Leaf_signal_10' and 'Root_signal_10'. (f) Hot map analysis of 'Leaf_signal_10' and 'Root_signal_10'. S indicates the difference between 'Leaf_signal_10' and 'Root_signal_10', different genes between the two groups were represented by red color while those being the same are shown in green; function corresponding to each gene in two groups was shown in the N line, purple is reactive oxygen species metabolic and biosynthetic process-related gene, yellow indicates MAPK signaling pathway-related gene, orange is plant hormone signal transduction-related gene, and blue represents calcium signaling pathway-related gene. (g) Relative gene expression (VcPP2C51, VcXTH3, and VcPNC1) in blueberry leaves and roots exposed to drought stress as determined by qRT-PCR with VcUBC28 as the internal reference gene. (h) POD activities in blueberry leaves and roots under drought stress. (i) ABA content in blueberry leaves and roots under drought stress.

    • Figure 4. 

      Analysis of key TFs in leaves and roots under drought stress. (a) PPI analysis of 'All_Leaf_TFs'. (b) PPI analysis of 'All_Root_TFs'. (c) Venn analysis of 'Leaf_TFs_10' and 'Root_TFs_10'. (d) Hot map analysis of 'Leaf_TFs_10' and 'Root_TFs_10'. S indicates the difference between 'Leaf_TFs_10' and 'Root_TFs_10', different genes between the two groups were represented by red color while those being that same are shown in green; TFs families corresponding to each gene in two groups was shown in N line, yellow, orange, purple, blue, grey and black indicates AP2/ERF family, bHLH family, WRKY family, MYB family, bZIP family and MYB_related family, respectively. (e) Relative gene expression (VcABF2, VcABR1, VcMYB93, and VcMYB108) in blueberry leaves and roots when exposed to drought stress as determined by qRT-PCR with VcUBC28 as the internal reference gene. (f) ZT content in blueberry leaves and roots under drought stress.

    • Figure 5. 

      Analysis of key genes of metabolism and biosynthesis in leaves and roots under drought stress. (a) KEGG enrichment analysis of the metabolism and biosynthesis-related DEGs in leaves. (b) KEGG enrichment analysis of the metabolism and biosynthesis-related DEGs in roots. (c) PPI analysis of 'All_Leaf_MB'. (d) PPI analysis of 'All_Root_MB'. (e) Venn analysis of 'Leaf_MB_10' and 'Root_MB_10'. (f) Hot map analysis of 'Leaf_MB_10' and 'Root_MB_10'. S indicates the difference between 'Leaf_MB_10' and 'Root_MB_10', Different genes between the two groups were represented by red color while those being the same are shown in green; metabolisms corresponding to each gene in two groups was shown in N line, purple, yellow, blue, brown, black, grey and indigo indicates monoterpenoid biosynthesis, starch and sucrose metabolism, cutin, submarine and wax biosynthesis, flavonoid biosynthesis, phenylpropanoid biosynthesis, fatty acid biosynthesis, and tyrosine metabolism, respectively. (g) Relative gene expression (VcCYP75A1) in blueberry leaf and root from plants exposed to drought stress as determined by qRT-PCR with VcUBC28 as the internal reference gene. (h) Anthocyanin concentration in blueberry under drought stress.

    • Figure 6. 

      A model for mechanisms underlying the enhanced drought tolerance shared by blueberry leaves and roots. * Important genes also identified in other categories.

    • Accession numberBiological processNumber of enriched genes
      Leaf_ Drought_5MRoot_ Drought_5M
      GO:0055114Oxidation-reduction
      process
      310227
      GO:0005975Carbohydrate metabolic process194123
      GO:0009056Catabolic process170111
      GO:0050896Response to stimulus170106
      GO:0055085Transmembrane transport162131
      GO:0044248Cellular catabolic process12595
      GO:0006950Response to stress12373
      GO:0006811Ion transport122100
      GO:0071554Cell wall organization or biogenesis biogenesis8628*
      GO:0034220Ion transmembrane transport8467
      GO:0044550Secondary metabolic process73*54
      * Not included in the 10 GOs with the highest enrichment.

      Table 1. 

      GO analysis of blueberry leaf and root DEGs under drought stress.

    • PathwayNameNumber of enriched genes
      Leaf_ Drought_5MRoot_ Drought_5M
      map04010MAPK signaling pathway10369
      map04621NOD-like receptor signaling pathway10265
      map04075Plant hormone signal transduction9261
      map04064NF-kappa B signaling pathway8860
      map04626Plant-pathogen interaction7832
      map00940Phenylpropanoid biosynthesis6863
      map04141Protein processing in endoplasmic reticulum6748
      map00010Glycolysis / Gluconeogenesis20*39
      map00902Monoterpenoid biosynthesis3426
      map00983Drug metabolism - other enzymes3325
      map00480Glutathione metabolism3326
      map00982Drug metabolism - cytochrome P4503230
      map00980Metabolism of xenobiotics by cytochrome P4503230
      map00520Amino sugar and nucleotide sugar metabolism3129
      map00500Starch and sucrose metabolism3127
      map00052Galactose metabolism2926
      map00350Tyrosine metabolism2529
      map00561Glycerolipid metabolism2715
      map00360Phenylalanine metabolism2513*
      map00400Phenylalanine, tyrosine and tryptophan biosynthesis2410*
      map00941Flavonoid biosynthesis2311*
      map00592alpha-Linolenic acid metabolism18*22
      map00071Fatty acid degradation6*18
      * Not included in the 20 pathways with highest enrichment.

      Table 2. 

      KEGG pathway enrichment analysis of blueberry leaf and root DEGs under drought stress.