Stimulation of Fengycin-Type Antifungal Lipopeptides in Bacillus amyloliquefaciens in the Presence of the Maize Fungal Pathogen Rhizomucor variabilis

Abstract

Most isolates belonging to the Bacillus amyloliquefaciens subsp. plantarum clade retain the potential to produce a vast array of structurally diverse antimicrobial compounds that largely contribute to their efficacy as biocontrol agents against numerous plant fungal pathogens. In that context, the role of cyclic lipopeptides (CLPs) has been well-documented but still little is known about the impact of interactions with other soil-inhabiting microbes on the expression of these molecules. In this work, we wanted to investigate the antagonistic activity developed by this bacterium against Rhizomucor variabilis, a pathogen isolated from diseased maize cobs in Democratic Republic of Congo. Our data show that fengycins are the major compounds involved in the inhibitory activity but also that production of this type of CLP is significantly upregulated when co-cultured with the fungus compared to pure cultures. B. amyloliquefaciens is thus able to perceive fungal molecules that are emitted and, as a response, up-regulates the biosynthesis of some specific components of its antimicrobial arsenal.

Exploring plant‐microbe interactions of the rhizobacteria Bacillus subtilis and Bacillus mycoides by use of the CRISPR‐Cas9 system

“…Production of antimicrobials by rhizobacteria is one of the major mechanisms for its antagonistic activity against phytopathogens, and they have great application potential being used as biocontrol agents. It has been reported that lipopeptides are the main antifungal compounds produced by Bacillus during the interactions with fungi (Zihalirwa Kulimushi et al ., ). Antagonistic experiments showed that B. subtilis HS3 has significant antifungal activity against several phytopathogenic fungi (data not shown).…”

Fungal-bacterial interaction selects for quorum sensing mutants and a metabolic shift towards the production of natural antifungal compounds

“…In this sense, B. subtilis , secretes numerous secondary metabolites including the antibiotic compound subtilin, the bacteriocin subtilosin, lipopeptides as surfactins, plipastatins, and others, and the polyketide/nonribosomal peptide hybrid compound bacillaene (25). Many of these metabolites play dual roles as antimicrobial compounds and signaling molecules during interactions, participating in development modulation, biofilm formation and inhibition of virulence factors of competitor individuals (4, 26, 38). In a previous work, we isolated a strain of B. subtilis subsp.…”

“…One could think that the lack of surfactin is a mere consequence of the metabolic change that arise along with the phenotype variation experienced by BsA01 and that is not directly related to the antagonism per se . However, it has been suggested that surfactins could interfere with the activity of other lipopeptides with proven antifungal activity such as fengycins/plipastatins and iturins (38, 41). In a study, B. amyloliquefaciens FZB42 mutants selectively repressed in the synthesis of one or two types of lipopeptides revealed that the co-production of surfactin and fengycin lowered the global antifungal activity (38).…”

“…However, it has been suggested that surfactins could interfere with the activity of other lipopeptides with proven antifungal activity such as fengycins/plipastatins and iturins (38, 41). In a study, B. amyloliquefaciens FZB42 mutants selectively repressed in the synthesis of one or two types of lipopeptides revealed that the co-production of surfactin and fengycin lowered the global antifungal activity (38). Such an effect of mixed lipopeptides was previously observed against the fungus Verticillium dahliae (42).…”

Bacillus lipopeptides as powerful pest control agents for a more sustainable and healthy agriculture: recent studies and innovations

“…This family is mainly composed of fengycin A and B (Vanittanakom et al 1986) and plipastatin A and B (Umezawa et al 1986). Fengycin mostly displays antimicrobial activity against a range of yeasts and filamentous fungi (Zihalirwa et al 2017).…”