Key Impact of an Uncommon Plasmid on Bacillus amyloliquefaciens subsp. plantarum S499 Developmental Traits and Lipopeptide Production

Abstract

The rhizobacterium Bacillus amyloliquefaciens subsp. plantarum S499 (S499) is particularly efficient in terms of the production of cyclic lipopeptides, which are responsible for the high level of plant disease protection provided by this strain. Sequencing of the S499 genome has highlighted genetic differences and similarities with the closely related rhizobacterium B. amyloliquefaciens subsp. plantarum FZB42 (FZB42). More specifically, a rare 8008 bp plasmid (pS499) harboring a rap-phr cassette constitutes a major distinctive element between S499 and FZB42. By curing this plasmid, we demonstrated that its presence is crucial for preserving the typical physiology of S499 cells. Indeed, the growth rate and extracellular proteolytic activity were significantly affected in the cured strain (S499 P−). Furthermore, pS499 made a significant contribution to the regulation of cyclic lipopeptide production. Surfactins and fengycins were produced in higher quantities by S499 P−, whereas lower amounts of iturins were detected. In line with the increase in surfactin release, bacterial motility improved after curing, whereas the ability to form biofilm was reduced in vitro. The antagonistic effect against phytopathogenic fungi was also limited for S499 P−, most probably due to the reduction of iturin production. With the exception of this last aspect, S499 P− behavior fell between that of S499 and FZB42, suggesting a role for the plasmid in shaping some of the phenotypic differences observed in the two strains.

Biocontrol Potential of a Novel Endophytic Bacterium From Mulberry (Morus) Tree

“…Genome sequencing and analysis of B. amyloliquefaciens ZJU1 revealed that it encodes an impressive arsenal of antimicrobial compounds, among which four products exhibiting highly antifungal activity were detected in situ (Loeffler et al, 1986;Chen et al, 2009;Um et al, 2013;Li et al, 2014;. In particular, non-ribosomally synthesized lipopeptides and polyketides have been demonstrated to make a significant contribution to plant disease protection (Molinatto et al, 2017). In addition, ZJU1 can produce a variety of bioactive VOCs to antagonize phytopathogens.…”

Root‐associated microbes in sustainable agriculture: models, metabolites and mechanisms

“…B. amyloliquefaciens subsp. plantarum S499 harbors an 8‐kb plasmid absent from strain FZB42, as well as genes encoding putative regulatory and transport proteins that may help to explain why the two strains differ in CLP production as well as in how they perceive and respond to environmental cues . The plasmid‐cured derivative of S499 produced increased quantities of surfactins and fengycins, but fewer iturins than did the wild type.…”

“…CLP concentrations in both strains were increased in the presence of the pathogens Cladosporium cucuminerum and Fusarium oxysporum f.sp. radicis‐lycopersici , implicating the activity of regulatory signal molecules produced by the fungi . However, it also has been proposed that concentrations of CLPs produced in situ by strains like FZB42 are insufficient to mediate direct pathogen inhibition and instead, that the main mechanism responsible for biocontrol activity is ISR.…”

“…radicis-lycopersici, implicating the activity of regulatory signal molecules produced by the fungi. 34 However, it also has been proposed 32 that concentrations of CLPs produced in situ by strains like FZB42 are insufficient to mediate direct pathogen inhibition and instead, that the main mechanism responsible for biocontrol activity is ISR. Given surfactin is an excellent elicitor of ISR on plants like bean and tomato, 32 it is likely that both direct pathogen inhibition and resistance induced by CLPs and other metabolites produced by antagonistic strains of Bacillus act to suppress plant pathogens.…”

Strains of soil microorganisms promising for the creation of a complex plant protection product against mycoses and harmful insects

“…Серед антагоністів фітопатогенних мікроорганізмів слід відмітити представників роду Bacillus, які продукують різні антимікробні речовини, такі як циклічні ліпопептиди, а також літичні ферменти та хітинази (Alvarez et. al., 2012;Ji et al, 2013;Meena & Kanwar, 2015;Yamamoto et al, 2015;Bodhankar et al, 2017;Dimkić et al, 2017;Molinatto et al, 2017;Rishad et al, 2017). Ліпопептиди, які продукуються B. subtilis, B. amyloliquefaciens, B. pumilus (мікосубтилін, фенгіцини А і В, ітурин), проявляють антифунгальну дію, тоді як сурфактин має широкий спектр антибактеріальної дії (Ji et al, 2013;Khong et al, 2013;Meena & Kanwar, 2015).…”