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Characterization of fungal antagonistic bacilli isolated from aerial roots of banyan ( F icus benghalensis ) using intact‐cell MALDI ‐ TOF mass spectrometry ( ICMS )
Author(s) -
Pathak K.V.,
Keharia H.
Publication year - 2013
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12161
Subject(s) - banyan , surfactin , bacilli , bacillus amyloliquefaciens , biology , aerial root , bacillus subtilis , microbiology and biotechnology , lipopeptide , bacillus (shape) , botany , bacteria , ecology , genetics , mangrove
Abstract Aims To characterize fungal antagonistic bacilli isolated from aerial roots of banyan tree and identify the metabolites responsible for their antifungal activity. Methods and Results Seven gram positive, endospore‐forming, rod‐shaped endophytic bacterial strains exhibiting a broad‐spectrum antifungal activity were isolated from the surface‐sterilized aerial roots of banyan tree. The isolates designated as K 1, A 2, A 4 and A 12 were identified as B acillus subtilis , whereas isolates A11 and A13 were identified as B acillus amyloliquefaciens using Biolog Microbial Identification System. The antifungal lipopeptides, surfactins, iturins and fengycins with masses varying in the range from m/z 900 to m/z 1550 could be detected using intact‐cell MALDI ‐ TOF mass spectrometry ( ICMS ). On the basis of mass spectral and carbon source utilization profile, all seven endophytes could be distinguished from each other. Furthermore, ICMS analysis revealed higher extent of heterogeneity among iturins and fengycins produced by B . subtilis K 1, correlating well with its higher antifungal activity in comparison with other isolates. Conclusion Seven fungal antagonistic bacilli were isolated from aerial roots of banyan tree, exhibiting broad spectrum of antifungal activity, among which B . subtilis K 1 isolate was found to be most potent. The ICMS analysis revealed that all these isolates produced cyclic lipopeptides belonging to surfactin, iturin and fengycin families and exhibited varying degree of heterogeneity. Significance and Impact of the study The endophytes are considered as a potential source of novel bioactive metabolites, and this study describes the potent fungal antagonistic bacilli from aerial roots of banyan tree. The isolates described in this study have a prospective application as biocontrol agents. Also ICMS analysis described in this study for characterization of antifungal metabolites produced by banyan endophytic bacilli may be used as a high throughput tool for screening of microbes producing novel cyclic lipopeptides.