ABSTRACT
The mycotoxigenic pathogen Fusarium verticillioides threatens the quality and utility of maize across industrial and agricultural purposes. Chemical control is complicated by the intimate endophytic lifestyle of the pathogen with its host. Bacillus mojavensis RRC101, a maize-endophytic bacterium, has been observed to reduce F. verticillioides disease severity and fumonisin accumulation when coinoculated to maize. Genome sequencing and annotation identified a number of biocontrol-relevant pathways in RRC101. Biochemical assays confirmed the presence and activity of surfactin- and fengycin-type lipopeptides, with fengycins responsible for antifungal activity against F. verticillioides. This antagonism manifests as inhibition of filamentous growth, with microscopy revealing hyphal distortions, vacuolization, and lysis. F. verticillioides secondary metabolism also responds to antagonism, with lipopeptide challenge inducing greater fumonisin production and, in the case of fengycins, eliciting pigment accumulation at sites of inhibition. Together, these data suggest that antibiotic and toxin production are components of a complex biochemical interaction among maize endophytes, one pathogenic and one beneficial.
Subject(s)
Antifungal Agents/pharmacology , Bacillus/chemistry , Fusarium/drug effects , Lipopeptides/pharmacology , Plant Diseases/microbiology , Zea mays/microbiology , Antifungal Agents/chemistry , Antifungal Agents/metabolism , Bacillus/physiology , Endophytes , Fumonisins/chemistry , Fumonisins/metabolism , Fumonisins/pharmacology , Fusarium/cytology , Fusarium/physiology , Lipopeptides/chemistry , Lipopeptides/metabolism , Peptides, Cyclic , Pest Control, BiologicalABSTRACT
Here, we report the whole-genome shotgun sequence of Bacillus mojavensis strain RRC101, isolated from a maize kernel. This strain is antagonistic to the mycotoxigenic plant pathogen Fusarium verticillioides and grows within maize tissue, suggesting potential as an endophytic biocontrol agent.
