A group from College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China has reported that the biofilm formation enhanced Bacillus root colonization and its biocontrol activity against phytopathogens.
https://www.frontiersin.org/articles/10.3389/fmicb.2022.972393/full
Bacilli are used as biocontrol agents (BCAs) against phytopathogens and most of them can produce poly-γ-glutamic acid (γ-PGA) as one of the major extracellular polymeric substances (EPSs).
In this study, Bacillus atrophaeus NX-12 (γ-PGA yield: 16.8 g/l) was compared with its γ-PGA synthesis gene knocked out strain NX-12Δpgs from a view point of antifungal ability. The antifungal ability of γ-PGA synthetase-deficient strain NX-12Δpgs (γ-PGA yield: 1.65 g/l) was improved in vitro, while the biocontrol ability of NX-12Δpgs was greatly diminished in situ.
It was proved that γ-PGA produced by NX-12 contributes to the biofilm formation and rhizosphere colonization, which effectively improved biocontrol capability suggesting that the effective colonization of Bacilli as biocontrol agents in the rhizosphere is very important for its function.
NX-12Δpgs (pMA5-pgs) means that the mutant NX-12Δpgs was complemented with a primer pMA5-pgsBCA, where pgsBCA is a γ-PGA synthase gene of NX-12.