High‐temperature resilience in Bacillus safensis primed wheat plants: A study of dynamic response associated with modulation of antioxidant machinery, differential expression of HSPs and osmolyte biosynthesis

Abstract

Changing climate scenario is posing a major threat to agricultural sector worldwide. Wheat, a weather sensitive crop, is envisaged to face significant yield loss in coming decades due to accelerating global average temperature. In recent years Plant Growth Promoting Bacteria (PGPR) have been successfully used in sustainable crop improvement programme and abiotic stress alleviation. However, PGPR mediated thermal adaptation and underlying crosstalk of diverse signalling networks have mostly remained obscure. Hence, this study aims to investigate the adaptive modifications of PGPR primed wheat plants at biochemical and gene expression levels which make them more resilient to high temperature. Our findings suggested that B. safenisis priming mostly dealt with shielding the cellular functions and particularly chloroplast organization from heat induced oxidative injury. B. safensis priming positively modulated expressions of HSPs and small HSPs before and during heat stress. Better performance of various redox enxymes and antioxidants associated with ascorbate - glutathione cycle together with low proline profusion due to high PDH expression provided efficient heat adaptive path without generation of excessive ROS. Bacterial priming elicited expression of ADC1 and ADC2 linked to putrescine synthesis and also significantly enhanced accumulation GB, TSS and phenols in response to heat stress. B. safensis priming induced multilevel systematic modulation minimizes heat injury, chloroplast damage and improved heat endurance.