Effect of drought stress on expression oftwo important miRNAs in anther of two different wheat genotypes in term of drought stress

A large amount of the world lands under the cultivation of wheat is under drought stress. In cereals, the reproductive stage is the most sensitive phase to drought stress. Despite the importance of drought stress in reproductive stage and its role in wheat yield reduction, the mechanisms involved in it have been less studied. In the present study, the expression of miR166 and miR167 in mature anthers of two tolerant (Dezfoul or D-10) and susceptible (Shiraz) wheat genotypes under drought conditions in reproductive stage was investigated. Stress tolerance index (STI) for grain number per spike, grain set and pollen viability was higher in tolerant genotype, Dezfoul, compared to susceptible genotype, Shiraz. Drought stress induced expression level of both miRNAs in both genotypes. The amount of miR166 increase in the susceptible genotype, Shiraz (over 14 times compared to the non-stress conditions) was about twice more than the tolerant genotype,Dezfoul (about 8 timesmore than the non-stress conditions). Under drought stress conditions, expression of miR167 in Dezfoulgenotype was more than two fold and in Shiraz genotype more than four timeshigher thanthe non-stress conditions. Both miR166 and miR167 regulate development of floral organs such as microspore development. In conclusion, the effect of drought stress on their expression changes can affect male sterility in wheat, and modifying the expression of these two miRNAscan lead to efficiency of pollen development and successful anther dehiscence which is rooted in signal transduction.