Exogenously applied methyl jasmonate improves the drought tolerance in wheat imposed at early and late developmental stages

Drought stress is one of the most detrimental abiotic stresses limiting wheat productivity worldwide. Methyl Jasmonate (MeJA), a stress signaling compound, may be effective in alleviating drought-induced adversities in wheat. Current study examined the role of exogenously applied MeJA in improving drought tolerance in five different wheat cultivars (Yu-Mai-1, Lu-Nong-116, Huai-Mai-19, Yan-Nong-19, Bai-Maizi). Drought stress (35 % field capacity) was imposed either at jointing (DS1), heading (DS2) or grain filling (DS3) stage. A control was maintained at field capacity of 90 % for comparison. The MeJA was applied at 0.5 mM after 1 week after imposition of drought. Data regarding different growth and yield attributes was recorded. Results depicted that drought stress at any growth stage substantially reduced the growth and yield of all wheat cultivars. More severe reductions in plant height, peduncle length, dry biomass (leaves, culm, root), and in yield components were observed in DS1 compared with DS2 or DS3. Exogenous application of MeJA effectively assuaged the damaging effects of drought. Beneficial effects of MeJA on dry biomass, number of grains per spike, and grain weight led to higher grain and biological yield in MeJA-treated plants under drought as well as control conditions. Variations were also apparent among cultivars regarding their response to drought stress. The cultivar Yu-Mai-1 remained superior to rest of cultivars in terms of wheat yield. In summary, our results suggested the involvement of MeJA in improving the drought tolerance of wheat by maintaining growth and yield performance of plants.