Drought stress amelioration in wheat through inoculation with Burkholderia phytofirmans strain PsJN

Plant growth promoting endophytic bacteria Burkholderia phytofirmans PsJN was used to investigate the potential to ameliorate the effects of drought stress on growth, physiology and yield of wheat (Triticum aestivum L.) under natural field conditions. Inoculated and uninoculated (control) seeds of wheat cultivar Sahar 2006 was sown in the field. The plants were exposed to drought stress at different stages of growth (tillering stage and flowering stage) by skipping the respective irrigation. The results showed that drought stress adversely affected the physiological, biochemical and growth parameters of wheat seedlings. It decreased the CO2 assimilation, stomatal conductance, relative water content, transpiration rate and chlorophyll contents in wheat. Inoculation of wheat with PsJN significantly diluted the adverse effects of drought on relative water contents and CO2 assimilation rate thus improving the photosynthetic rate, water use efficiency and chlorophyll content over the uninoculated control. Grain yield was also decreased when plants were exposed to drought stress at the tillering and flowering stage, but inoculation resulted in better grain yield (up to 21 and 18 % higher, respectively) than the respective uninoculated control. Similarly, inoculation improved the ionic balance, antioxidant levels, and also increased the nitrogen, phosphorus, potassium and protein concentration in the grains of wheat. The results suggested that B. phytofirmans strain PsJN could be effectively used to improve the growth, physiology and quality of wheat under drought conditions.