Bacterial Endophytes as Elicitors of Drought Stress Responsive Genes Expression in Wheat (Triticum aestivum L.)

Bacterial Endophytes and Wheat drought-Responsive genes

Abstract

Drought stress is one of the major abiotic stresses, which adversely affects plant growth and grain yield. This study aims to examine the effect of 11 different drought-tolerant plant growth promoting endophytic bacterial strains in expression of seven drought responsive genes in wheat using quantitative real-time PCR. Genes DREB2A, CAT1 and APX1 showed up-regulation in non-inoculated drought stressed (NC) wheat plants, while majority of the endophytic bacteria primed seedlings, displayed reduced transcript accumulation signifying their role in expression of these genes under drought stress conditions. Expression analysis of HSP 17.8 and SAMS1 genes also showed up-regulation in NC seedlings, while majority of the bacterial endophytes primed seedlings showed down-regulation under drought stress. Transcript accumulation of TaCYP707A1 gene was lower in NC seedlings compared to positive control, PC (non-inoculated with water supply) seedlings but it was still higher than majority of the endophytic bacteria primed seedlings. In case of DHN, expression in NC was higher than PC and majority of the bacteria primed seedlings. Consequently, bacterial strains namely Priestia aryabhattai (KDT-WRB2), Priestia sp. (KDTWRB4), P. megaterium (KDT-WRB5), Bacillus subtilis (KDT-WRB7), B. safensis (KDT-WRB8)and B. zhangzhouensis (KDT-WRB13) were recorded to alleviate the deleterious effects of the drought stress in wheat plants.