An improvement in water stress tolerance in rice by altering morpho-physiological and biochemical mechanisms using root colonizing endophyte Piriformospora indica

Drought poses a serious threat to the livelihood and food security of millions of people on the planet by causing water shortage in agriculture practices and thereby affecting the growth and development of crops. In this study, the role of Piriformospora indica a root-colonising endophytic fungus reported for its abiotic stress tolerance ability, in water stress management of rice in contrasting rice varieties were elucidated. P. indica-colonized seedlings were able to maintain greenness when treated upto 20% PEG 6000 solution with limited growth. Root length and root volume of colonized plants under water stress was higher in the two varieties of rice investigated. Cell membrane stability index, photosynthetic rate, transpiration rate and stomatal conductance were increased in P. indica colonized plants of Ptb 23 (susceptible variety) and Ptb 29 (tolerant variety) under both water stressed and irrigated conditions and thereby possibly contributing to increased yield. MDA content reduced while SOD and CAT content increased on colonization of rice plants with P. indica. P. indica-colonization improved the number of tillers, productive tillers, panicle length and a reduction in spikelet sterility. P. indica-colonization contributed to a considerable hike in grain weight of Ptb 23 under water stress.