ISHS Acta Horticulturae 1256: VI International Conference Postharvest Unlimited
Role of lipopeptides produced by Bacillus amyloliquefaciens BUZ-14 against Botrytis cinerea and Monilinia species |
| Authors: | I. Mendiara, H. Calvo, D. Blanco, R. Oria, M.E. Venturini |
| Keywords: | postharvest moulds, biological control, stone fruits, seed fruits, iturin A |
| DOI: | 10.17660/ActaHortic.2019.1256.59 |
| Abstract:
Biological control agents (BCAs) have revealed a promising alternative treatment for reducing the use of synthetic fungicides. In recent decades, some antagonistic microorganisms such as Bacillus spp., have been identified as BCAs for postharvest diseases. This work is focused on the characterization of B. amyloliquefaciens BUZ-14 subsp. plantarum as a BCA against Botrytis cinerea, Monilinia fructicola and M. laxa, which are responsible for grey and brown rot, respectively. The antifungal activity of cell-free supernatant (CFS), the non-butanolic fraction (NBF) and the lipopeptide fraction (LPF) was tested in vitro, CFS and LPF being the most active fractions. Their antifungal activity increased along the incubation time reaching a maximum after 96 h of incubation in 863 medium. Thin layer chromatography revealed three lipopeptide families: Fengycins (Rf=0.1-0.2), Iturins (Rf=0.26-0.4) and Surfactins (Rf=0.45-0.60) and combined with bioautography studies showed that Iturins was the most active family. The isolation of the active spot and its analysis by LC-MS-MSE confirmed that Iturin A was the most inhibitory compound presented in the lipopeptide fraction and the HPLC quantification establish a minimum inhibitory amount of 6.6 µg. Although the involvement of another antimicrobial compounds cannot be excluded, this study provides experimental evidence that antibiosis based on Iturin A is the main responsible of the antinfungal activity of BUZ-14 against B. cinerea, M. fructicola and M. laxa. | |
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