Expression of genes involved in drought stress in two soybean cultivars (Glycine max) treated with methyl jasmonate and salicylic acid

Soybean (Glycine max) is one of the most important oilseed crops in the world. However, its cultivation is limited in many areas with water shortage, and is affected by drought. This study investigated the expression of genes involved in drought stress in two soybean cultivars, i.e. Williams (tolerant) and L17 (sensitive) after drought stress and treatment with methyl jasmonate (MeJA) and salicylic acid (SA). In addition, the impact of drought and hormone treatments were validated with morpho-physiological evaluation of these two cultivars. Experiment was conducted in a factorial basis with completely randomized design. The results showed that the expression of basic-leucine zipper (BZIP19), NAM-ATAF1, 2-CUC2 (NAC), dehydration-responsive element-binding (DREB1), and vascular plant one zinc finger protein (VOZ1G) was higher in the resistant cultivar, i.e. Williams. Gene expression was induced after simultaneous application of SA and MeJA in Williams cultivar. According to the morpho-physiological results, plant height and root length, fresh and dry weight of roots and shoots, nodes and number of lateral roots, number of pods and number of seeds per pod, leaf area, and percentage of relative leaf moisture, number of stem nodes and internode distance, pod weight and harvest index were significantly different between the two cultivars. Increase in the expression of VOZ gene, under treatment with SA was more effective on shoot height and nodule formation of Williams than in L17. Results of this investigation should be useful for developing tools for breeding new soybean genotypes with an improved tolerance to drought.