AUTHOR=Saravanan R. , Nakkeeran S. , Saranya N. , Kavino M. , Ragapriya V. , Varanavasiappan S. , Raveendran M. , Krishnamoorthy A. S. , Malathy V. G. , Haripriya S. 

TITLE=Biohardening of Banana cv. Karpooravalli (ABB; Pisang Awak) With Bacillus velezensis YEBBR6 Promotes Plant Growth and Reprograms the Innate Immune Response Against Fusarium oxysporum f.sp. cubense

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=6

YEAR=2022

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2022.845512

DOI=10.3389/fsufs.2022.845512

ISSN=2571-581X

ABSTRACT=<p>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 <italic>Fusarium oxysporum</italic> f.sp. <italic>cubense</italic> (<italic>Foc)</italic>. Hence, attempts were made to dissect the endophytes from resistant banana cultivar YKM5 (Yengambi–AAA) to suppress <italic>Foc</italic> KP (race 4) infecting cv. Karpooravalli (ABB; Pisang Awak). Among the various endophytes, <italic>Bacillus velezensis</italic> YEBBR6 inhibited the mycelial growth up to 63% over control and hyper-parasitized the mycelium of <italic>Foc</italic> KP. Scanning electron microscope analysis revealed the ramification by <italic>B. velezensis</italic> over the hyphae of <italic>Foc</italic> 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 <italic>B. velezensis</italic> YEBBR6 (8 × 10<sup>8</sup> cfu/ml) and challenge inoculation with <italic>Foc</italic> KP promoted plant growth compared to uninoculated control. Besides, incidence of <italic>Fusarium</italic> 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 <italic>Fusarium</italic> 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 <italic>B. velezensis</italic> on a commercial scale for the management of <italic>Fusarium</italic> wilt race 4 causing wilt across genomes of banana.</p>