Lipopeptides as main ingredients for inhibition of fungal phytopathogens by Bacillus subtilis/amyloliquefaciens

Abstract

Some isolates of the Bacillus subtilis/amyloliquefaciens species are known for their plant protective activity against fungal phytopathogens. It is notably due to their genetic potential to form an impressive array of antibiotics including non-ribosomal lipopeptides (LPs). In the work presented here, we wanted to gain further insights into the relative role of these LPs in the global antifungal activity of B. subtilis/amyloliquefaciens. To that end, a comparative study was conducted involving multiple strains that were tested against four different phytopathogens. We combined various approaches to further exemplify that secretion of those LPs is a crucial trait in direct pathogen ward off and this can actually be generalized to all members of these species. Our data illustrate that for each LP family, the fungitoxic activity varies in function of the target species and that the production of iturins and fengycins is modulated by the presence of pathogens. Our data on the relative involvement of these LPs in the biocontrol activity and modulation of their production are discussed in the context of natural conditions in the rhizosphere.

El género Bacillus como agente de control biológico y sus implicaciones en la bioseguridad agrícola

“…Despite lipopeptides not being the only metabolites of the antibiome of the Bacillus genus involved in the biological control of phytopathogens, they have been proposed as the most efficient metabolites for this biological activity, due to its ecological role and antimicrobial capability, which explains their use in the search and selection of promissory BCA of this genus (Cawoy et al, 2015;Mora et al, 2015).…”

Effect of temperature, pH and substrate composition on production of lipopeptides by Bacillus amyloliquefaciens 629

“…The lipopeptides were detected in electrospray positive ion mode by setting the SQD parameters as follows: source temperature, 130°C; desolvation temperature, 400°C; and nitrogen flow, 1000 L.h -1 . A cone voltage of 120 V was used (Cawoy et al, 2015). After the analyses, the lipopeptides were identified in the chromatogram and spectrogram by mass comparison and retention time.…”

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“…З літератури [7,19,20] відомо, що ліпопептиди є ефективнішими антимікробними агентами, ніж гліко-ліпіди. Це й зрозуміло, оскільки вони по суті є поліпептидними антибіотиками [6,17]. Так, наприклад, МІК ліпопептидів щодо B. subtilis становлять 10-16 мкг/ мл [19,20], у той час як рамноліпідів -до 128 мкг/мл [11].…”