Native rhizobacteria suppresses spot blotch disease, improves growth and yield of wheat under salt–affected soils

Abstract

The simultaneous occurrence of biotic and abiotic stresses affects the performance of the crops in salt–affected agroecologies. The plant–microbe interaction with effective rhizobacteria can effectively manage these stresses. This study characterized the biocontrol, plant growth promotion, and responsiveness of rhizobacteria in wheat under salt-affected soils. Out of the 184 rhizobacteria isolates, the 20 isolates showed 41–72% growth inhibition of fungal phytopathogens of seedling blight of wheat (Fusarium sp), head blight of wheat (Fusarium oxysporum), onion molds (Penicillium sp and Aspergillus sp), root rot of wheat (Rhizoctonia solani), ear rot of corn (Aspergillus sp.) and spot blotch of wheat (Bipolaris sorokininana). The potent three rhizobacterial isolates identified as close neighbours of Bacillus amyloliquefaciens strain TA124, B. subtilis strain SB67 and B. subtilis strain BJ171 caused 65.5–71.1% growth inhibition of B. sorokiniana. The extracellular organic acid, siderophore, and chitinase enzymes played a significant role in rhizobacterial performance for fungal growth inhibition; and P and Zn solubilization in growth media. The foliar spray of bioformulation aids 15–20% reduction in the B. sorokiniana disease severity. The rhizobacterial responsiveness to the dual inoculation through seed treatment and foliar spray was 12.6–51, 15.8–46.3, and 13.2–148.1% for grain yield, P uptake, and disease suppression, respectively. The changes caused by rhizobacterial bioformulation in soil (Olsen's–P and microbial biomass carbon) and plant (proline, malondialdehyde, peroxidase, and Na+/K+ratio) explained 85% variability in the yield, P nutrition, and disease severity. Therefore, native rhizobacteria with biocontrol and plant growth-promoting capabilities can be an effective option for managing multiple stresses of crops in salt–affected agroecologies.