ACC deaminase producing endophytic bacteria enhances cell viability of rice (Oryza sativa L.) under salt stress by regulating ethylene emission pathway

Salt stress induced ethylene emission from plants regulates diverse arrays of functionalities and ethylene levels can be decreased by the inoculation of 1-aminocyclopropane-1-carboxylic acid ACC deaminase (ACCD) producing methylotrophic bacteria that is important for enhancing plant biomass and stress tolerance. This study was conducted to evaluate the efficacy of ACC deaminase producing methylotrophic bacteria in enhancing cell viability of rice roots by restricting salt-induced apoptosis and delaying of senescence by monitoring plant physiological, biochemical and genetic characteristics. We put forth here, a new dimension in stress amelioration machinery by using an ACCD(+) multifaceted plant growth promoting (PGP) Methylobacterium oryzae strain CBMB20 in enhancing cell viability of rice roots by regulation of ethylene emission pathway under salt stress. The senescence-associated protein (SAP) mRNA expression was upregulated along with the associated enzymes in coordinated harmony with major phytohormones. Our study provides a mechanistic understanding on the plant-microbe interactions important for stress alleviation where regulation of ethylene emission by Methylobacterium spp. plays the central role in enhancing plant biomass through restriction of apoptosis.