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

      The main phases and time required for each phase in the somatic embryogenesis of banana and critical questions (Q). (SE) somatic embryo; (IMFs) immature male flowers.

    • Figure 2. 

      Schematic representation of genetic transformation steps of banana using embryogenic cell suspension. Scalps and immature male flowers (IMFs) are the most used explants to establish a renewable ECS for seedless banana cultivars. The photos of scalps and friable embryogenic callus are cited from Tripathi et al.[31].

    • TraitGeneSourcesTransformation methodResultCultivarReference
      Fungal
      Foc Race2 resistanceMSI-99SyntheticAgrobacterium/EHA105/ ECSImproved disease resistance against Foc and black leaf streak diseaseRasthali (AAB)[67]
      Foc Race1 resistanceβ–1,3–endoglucanaseSoybeanAgrobacterium/LBA4404/Single budsIncreased tolerance to Foc Race 1Rasthali (AAB)[68]
      Bcl-xL, Ced-9, Bcl-2 3' UTRAnimalAgrobacterium/LBA4404/ECSApoptosis-inhibition-related genes confer resistance to Foc Race 1Lady Finger (AAB)[69]
      PhDef1 and PhDef2PetuniaAgrobacterium/EHA105/ECSImproved fungal resistance with normal growth and no stunting phenotypeRasthali (AAB)[70]
      ihpRNA-VEL and ihpRNA-FTF1Agrobacterium/EHA105/ECSIncreased resistance to Foc Race 1Rasthali (AAB)[71]
      MusaDAD1, MusaBAG1 and MusaBI1BananaAgrobacterium/EHA105/ECSIncreased resistance to Foc Race 1Rasthali (AAB)[72]
      Sm-AMP-D1Stellaria mediaAgrobacterium/EHA105/ECSImproved resistance against Foc Race 1 and no gross growth abnormalitiesRasthali (AAB)[73]
      Ced9SyntheticIncreased resistance against Fusarium wiltSukali Ndiizi (AAB)[74]
      Ace-AMP1Onion seedsAgrobacterium/LBA4404/ECSEnhanced resistance to Foc race 1Rasthali (AAB)[75]
      Ace-AMP1 + Ca-pflpAllium cepa L; Capsicum annum L.Agrobacterium/AGL1/ ECSStacked Ace-AMP1 and pflp transgenic plants showed resistance to Foc race 1Rasthali (AAB)[76]
      Foc TR4 resistanceHuman lysozyme (HL)Agrobacterium/EHA105/corm slicesImproved resistance to Foc TR4Taijiao (AAA)[77]
      PflpSweet pepperAgrobacterium/EHA105/
      multiple bud clumps
      Enhanced resistance to Foc TR4Pei Chiao (AAA) and Gros Michel (AAA)[78]
      TLP or PR-5RiceBiolistics/Single
      cauliflower-like bodies
      Enhanced resistance to Foc TR4Pisang Nangka (AAB)[79]
      ThChit42Trichoderma harzianumAgrobacterium/EHA105/ECSEnhanced resistance to Foc TR4Furenzhi (AA)[80]
      RGA2 or Ced9BananaAgrobacterium/EHA105/ECSImproved promising resistance against Fusarium wiltGrand Nain (AAA)[81]
      MaPR-10bananaAgrobacterium/−/ECSImproved tolerance against Fusarium infectionBerangan[82]
      MaLYK1BananaAgrobacterium/EHA105/ECSIncreased resistance to Foc TR4Cavendish (AAA)[83]
      Synthesis of ergosterol (ERG6/11)Agrobacterium/EHA105/ECSstrong resistance to Fusarium wiltBrazil (AAA)[84]
      MpbHLHBananaAgrobacterium/EHA105/ECSEnhanced Foc TR4-resistance of Cavendish bananaBrazil (AAA)[85]
      Sigatoka resistanceThEn-42 + StSy + Cu,Zn-SOD co-transformationTrichoderma harzianum
      + grape + tomato
      Biolistics/ECSEnhanced tolerance to SigatokaGrand Nain (AAA)[86]
      rcc2 or rcg3RiceAgrobacterium/EHA105/ ECSEnhanced host plant resistance to black SigatokaGros Michel (AAA)[87]
      Bacterial
      BXW resistanceHrapSweet pepperAgrobacterium/AGL1/ ECSAbout 20% of the Hrap lines showed
      100% resistance for both mother and
      ratoon crops under field conditions
      Sukali Ndiizi (AAB) and Mpologoma (AAA)[88, 89]
      PflpSweet pepperAgrobacterium/EHA105/ ECSAbout 16% of the Pflp lines showed
      100% resistance for both mother and
      ratoon crops under field conditions
      Sukali Ndiizi (AAB) and Nakinyika (AAA)[89, 90]
      Stacked Harp and PflpSweet pepperAgrobacterium/AGL1/ ECSStacked Harp and Pflp transgenic plants
      had higher resistance to X cm
      Gonja manjaya (AAB)[91]
      Xa21RiceAgrobacterium/EHA105/ ECS50% of the transgenic lines showed complete resistance to X cmGonja manjaya (AAB)[92]
      ViralRepBBTVCompletely resistant to BBTV infection was found under glasshouse conditionsBrazilian (AAA)[93]
      BBTV-G- cpBBTVBiolistics/apical meristemWilliams (AAA)[94]
      Rep, ProRepBBTVRasthali (AAB)[95]
      Abiotic stress
      Salt, oxidative stressMusaWRKY71bananaAgrobacterium/EHA105/ ECSEnhanced tolerance towards oxidative and salt stressRasthali (AAB)[96]
      Cold, drought, saltMusabZIP53bananaAgrobacterium/EHA105/ ECSTransgenic plants displayed severe growth retardationRasthali (AAB)[97]
      ColdMpMYBS3bananaAgrobacterium/EHA105/ ECSThe transgenic lines had higher cold toleranceBrazil (AAA)[98]
      Salt, droughtMusaNAC042bananaAgrobacterium/EHA105/ ECSMusaNAC042 is positively associated with drought and salinity toleranceRasthali (AAB)[99]
      Drought, saltMusa-DHN-1bananaAgrobacterium/-/ ECSImproved tolerance to drought and salt-stressRasthali (AAB)[100]
      Salt, droughtAhSIPR10Arachis hypogaeaAgrobacterium/EHA105/
      multiple shoot clump
      Transgenic plants showed better tolerance of salt and drought conditionsMatti (AA)[101]
      Drought, salt, oxidative stressMusaSAP1bananaAgrobacterium/EHA105/ ECSTransgenic plants displayed better stress endurance characteristicsRasthali (AAB)[102]
      Cold, salt, droughtMusaPIP1;2bananaAgrobacterium/EHA105/ ECSTransgenic plants showed better abiotic stress survival characteristicsRasthali (AAB)[103]
      SaltMusaPIP2;6bananaAgrobacterium/EHA105/ ECSTransgenic plants showed better tolerance under salt stressRasthali (AAB)[104]
      Salt, droughtMaPIP1;1bananaAgrobacterium/EHA105/
      thin cell layers from shoot tips
      Improved tolerance to salt and drought stressesBrazilian (AAA)[105, 106]
      Drought, cold ,saltMaPIP2-7bananaAgrobacterium/EHA105/
      thin cell layers from shoot tips
      Improved tolerance to salt, drought, and cold stressesBrazilian (AAA)[107]
      MaSIP2-1bananaAgrobacterium/EHA105/
      thin cell layers from shoot tips
      Transgenic plants had a stronger drought and cold tolerance than the controlBrazilian (AAA)[108]
      Salt, droughtAhcAPXArachis hypogeaAgrobacterium/EHA105/
      multiple shoot clump
      Enhanced the tolerance to drought and salt stressGrand naine (AAA)[109]
      Fruit quality and others
      Biofortified Iron ferritinsoybeanAgrobacterium/EHA105/ ECSA 6.32-fold increase in iron accumulation and a 4.58-fold increase in the zinc levels were noted in the leaves of transgenic plantsRasthali (AAB)[110]
      Biofortified pro-vitamin AMtPsy2abanaanAgrobacterium/AGL1/ ECSA high content of β-CE (75.1 µg/g dw) was found in the fourth generation with no variation in critical agronomical features such as yield and cycle timeDwarf Cavendish (AAA)[111]
      Fruit ripeningMaMADS1 and MaMADS2bananaAgrobacterium/-/ ECSRepression of either MaMADS1 or
      MaMADS2, resulted in delayed ethylene
      synthesis and maturation
      Grand Nain (AAA)[112]
      Sense and anti-sense MaMADS36bananaAgrobacterium/GV3101/
      thin cell layers from shoot tips
      MaMADS36 represents a central molecular switch in regulating banana fruit ripeningRed banana (AAA)[113]
      Foc, Fusarium oxysporum f. sp. cubense; ECS, embryogenic cell suspension; BBTV, Banana bunchy top virus; NM, not mention.

      Table 1. 

      Genetic transformations of banana (Musa spp.).

    • CultivarExplantStrategy of transformationCas9 promotersgRNA promoterTarget geneTarget traitResultEditing efficiencyReference
      Baxi; AAAECSAgrobacterium-mediated transformation
      EHA105
      UbiOsU6aMaPDSAlbino and variegated phenotypeMurtation in target genes; Albino phenotype in transgenic plants55%[118]
      Rasthali; AABECSAgrobacterium-mediated transformation
      Agl1
      2 × CaMV35SOsU3MaPDSAlbino and variegated phenotypeMurtation in target genes; Albino phenotype in transgenic plants59%[119]
      Williams; AAAECSAgrobacterium-mediated transformation
      EHA105
      Ubi;CaMV35sOsU3MaPDSAlbino and dwarf phenotypeMurtation in target genes; Albino and dwarfing phenotype in transgenic plants63%[120]
      Sukali Ndiizi; AAB;Gonja Manjaya; AABECSAgrobacterium-mediated transformation
      EHA105
      2 × CaMV35SOsU6MaPDSalbino and variegated phenotypesGeneration of mutants with albino and variegated phenotypes100%[121]
      Williams; AAAECSAgrobacterium-mediated transformationNMNMMaCHAOSPale-green phenotypesMurtation in target genes; Pale-green phenotypes and normal growthNM[122]
      Baxi; AAAprotoplastPEG-mediated transformationUbiOsU3MaPDS-The efficiency of CRISPR/Cas9-mediated mutagenesis was higher than that of CRISPR/Cas12a, and RNP-CRISPR-Cas91.04% (Cas9), 0.92% (RNP), 0.39% (Cas12a)[61]
      Brazilian; AAAprotoplastPEG-mediated transformationUbiMaU6MaPDS-Increased mutation efficiency of CRISPR/Cas9 genome editing in banana by optimized construct4-fold[123]
      Gonja Manjaya; AABECSAgrobacterium-mediated transformation
      EHA105
      UbiOsU6Viral genesBanana streak virus (BSV)Inactivation of endogenous banana streak virus (eBSV) intergated in host genome and generated resistant banana plants against eBSV95%[124]
      Sukali Ndiizi; AABECSAgrobacterium-mediated transformation
      EHA105
      2 × CaMV35SOsU6MusaDMR6Banana Xanthomonas wilt (BXW)Improved resistance to BXW disease in mutants with normal growth100%[125]
      Grand Naine; AAAECSAgrobacterium-mediated transformation
      Agl1
      CaMV35SOsU3MaLCYεRegulation synthesis of β-caroteneImproved nutritional trait in transgenic plants with normal growthNM[127]
      Rasthali; AABprotoplasts and ECSelectroporation-mediated transformation;
      particle bombardment method
      CaMV35SOsU3MaCCD4Regulatory mechanism of β-carotene homeostasisCCD4 negatively regulates β-carotene biosynthesisNM[128]
      Brazilian; AAAECSAgrobacterium-mediated transformationUbiOsU6aMaACO1Shelf lifeMore vitamin C and improved shelf life in transgenic plants98%[129]
      Gros Michel; AAAECSAgrobacterium-mediated transformationUbiOsU6a/
      OsU3
      MaGA20ox2Semi-dwarf phenotypeA lower active GA content and a semi-dwarf phenotype in transgenic plantsNM[130]
      NM, not mentioned.

      Table 2. 

      Application of CRISPR/Cas9 gene editing technology in Musa.