| Summary: | Fungicides play an immense role in quenching the infection of Panama wilt in banana. However, the use of fungicides and the monoculture of banana cultivars have resulted in the development of new races like race 4 which challenges scientists across the globe to identify new candidates for biological suppression of Fusarium oxysporum f.sp. cubense (Foc). Hence, attempts were made to dissect the endophytes from resistant banana cultivar YKM5 (Yengambi–AAA) to suppress Foc KP (race 4) infecting cv. Karpooravalli (ABB; Pisang Awak). Among the various endophytes, Bacillus velezensis YEBBR6 inhibited the mycelial growth up to 63% over control and hyper-parasitized the mycelium of Foc KP. Scanning electron microscope analysis revealed the ramification by B. velezensis over the hyphae of Foc KP leading to lysis. Analysis of VOCs/NVOCs compounds from the zone of inhibition, confirmed the presence of unique biomolecules including linoelaedic acid, nonanol, acetylvaleryl, 5–hydroxyl methyl furfural, clindamycin, allobarbital, 3-thiazolidine carboxamide, azulene, aminomorpholine, procyclidine, campholic acid, 3 amino-4 hydroxy phenyl sulfone, 3–deoxy mannoic lactone, hexadecanoic acid, oleic acid, and dihydroacridine of an antifungal and antimicrobial nature. Considering the diverse antimicrobial property, biohardening of micropropagated banana cv. Karpooravalli (ABB) with a liquid formulation of B. velezensis YEBBR6 (8 × 108 cfu/ml) and challenge inoculation with Foc KP promoted plant growth compared to uninoculated control. Besides, incidence of Fusarium wilt was reduced by 100% over inoculated control in greenhouse conditions. Furthermore, the expression of transcription factors and defense genes WRKY, MAPK, CERK 1, LOX, and PAL increased by several folds compared to inoculated and healthy control and thus suppressed Fusarium wilt of banana cv. Karpooravalli (ABB). Also, cytoscape analysis of defense genes indicated the coordinated expression of various other genes associated with it. Hence, our study confirmed the scope for exploring B. velezensis on a commercial scale for the management of Fusarium wilt race 4 causing wilt across genomes of banana. Copyright © 2022 Saravanan, Nakkeeran, Saranya, Kavino, Ragapriya, Varanavasiappan, Raveendran, Krishnamoorthy, Malathy and Haripriya.
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