Inoculation of Bacillus cabrialesii modulates plant growth and wilt disease of chickpea cultivars pre-challenged with Fusarium oxysporum f.sp. ciceris.
Abstract
Background
Bacillus cabrialesii, a plant growth-promoting (PGP) and biocontrol bacterium, was first reported in Mexico in 2018. This study evaluates the PGP and antagonistic potential of two B. cabrialesii strains, IS-10 and BATS-13, isolated from the chickpea rhizospheric soils of Chhattisgarh, India. It also assesses the impact of strain IS-10 on the growth, yield, and disease resistance of chickpea cultivars under Fusarium wilt stress.
Methods
PGP traits and antifungal activity of the isolates were characterized in vitro, including biosurfactant production. The biosurfactant nature was analyzed using thin-layer chromatography (TLC) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Strain IS-10 was used for seed bacterization in sterile soil amended with 0.2% vermicompost and 0.02% gum acacia, in the presence or absence of Fusarium oxysporum f. sp. ciceris (FOC), to evaluate its effects on plant growth and disease suppression in two chickpea cultivars, Vaibhav and JG-62.
Results
Both strains demonstrated multiple PGP attributes and inhibited FOC growth in vitro. TLC revealed the presence of lipids and peptides in the crude biosurfactant, and further UPLC-MS/MS analyses confirmed the presence of surfactin and fengycin. In the pot trials, strain IS-10 treatment significantly improved plant performance. In pathogen-free conditions, strain IS-10 increased straw yield by 39.17% (Vaibhav) and 39.47% (JG-62), and grain yield by 46.8% (Vaibhav) and 50.32% (JG-62), respectively, over untreated controls. Under FOC challenge conditions, strain IS-10 reduced disease incidence by 20.80% (Vaibhav) and 26.85% (JG-62), while enhancing straw yield by 53.92% and 36.6%, and grain yield by 57.14% and 50.81%, respectively, compared to pathogen controls.
Conclusions
B. cabrialesii IS-10 possesses significant PGP and biocontrol traits, including production of antifungal lipopeptides. Its application enhances chickpea growth and yield and mitigates the effects of Fusarium wilt, highlighting its potential as a bioinoculant for sustainable chickpea cultivation under both healthy and pathogen-infested conditions in the state of Chhattisgarh, India.