Plant growth promoting rhizobacterium Bacillus sp. BSE01 alleviates salt toxicity in chickpea (Cicer arietinum L.) by conserving ionic, osmotic, redox and hormonal homeostasis

Abstract

Soil salinity leading to sodium toxicity is developing into a massive challenge for agricultural productivity globally, inducing osmotic, ionic, and redox imbalances in plants. Considering the predicted increase in salinization risk with the ongoing climate change, applying plant growth‐promoting rhizobacteria (PGPR) is an environmentally safe method for augmenting plant salinity tolerance. The present study examined the role of halotolerant Bacillus sp. BSE01 as a promising biostimulant for improving salt stress endurance in chickpea. Application of PGPR significantly increased the plant height, relative water content, and chlorophyll content of chickpea under both non‐stressed and salt stress conditions. The PGPR‐mediated tolerance towards salt stress was accomplished by the modulation of hormonal signaling and conservation of cellular ionic, osmotic, redox homeostasis. With salinity stress, the PGPR‐treated plants significantly increased the indole‐3‐acetic acid and gibberellic acid contents more than the non‐treated plants. Furthermore, the PGPR‐inoculated plants maintained lower 1‐aminocyclopropane‐1‐carboxylic acid and abscisic acid contents under salt treatment. The PGPR‐inoculated chickpea plants also exhibited a decreased NADPH oxidase activity with reduced production of reactive oxygen species compared to the non‐inoculated plants. Additionally, PGPR treatment led to increased antioxidant enzyme activities in chickpea under saline conditions, facilitating the reactive nitrogen and oxygen species detoxification, thereby limiting the nitro‐oxidative damage. Following salinity stress, enhanced K+/Na+ ratio and proline content were noted in the PGPR‐inoculated chickpea plants. Therefore, Bacillus sp. BSE01, being an effective PGPR and salinity stress reducer, can further be considered to develop a bioinoculant for sustainable chickpea production under saline environments.

Exploring Synergistic Effects of Levan and Levan‐MetabolizingBacillaceae in Promoting Growth and Enhancing Immunity of Tomato and Wheat

“…Moreover, several strains not only combine PGPR and disease tolerance (Mehmood et al, 2023), but some strains also show plant protective properties under abiotic stresses (Xia et al, 2020; Sarker et al, 2021; Naing et al, 2021; El‐Saadony et al, 2022). For example, B. amyloliquiefaciens and Bacillus megaterium (renamed Priestia megaterium ) protect several plant species against salt stress (Chen et al, 2016; Hwang et al, 2022; Basu et al, 2023) while Bacillus pumilus alleviates drought stress (Zhang, Xie, et al, 2021) and Bacillus safensis counteracts heat stress (Mukhtar et al, 2023).…”