Physiological and molecular responses of wheat plants to mycorrhizal and epibrassinolide interactions under salinity

Soil salinity is a major constraint on plant growth and metabolism. This work was carried out to study the possible responses of wheat (Triticum aestivum L.) plants to 24-epibrassinolide (EBL) and the arbuscular mycorrhizal (AM) fungus, Glomus mosseae, supplied alone or in combination under salt stress. Plants were leaf sprayed with 5 µM EBL, and then were treated with 0 and 150 mM NaCl for 10 days. Then plants were harvested for biochemical and gene expression (Real-time PCR) analyses involved. All data were analyzed by SPSS v.18 and the treatment means were compared by using Duncan’s test at P < 0.05 level of significance. The findings showed improved protein biosynthesis, K+ accumulation and K+/Na+ ratio in shoots as well as reduced Na+ levels in shoots and roots when EBL and G. mosseae were applied together under saline conditions. In addition, the expression of the NHX1 gene was up-regulated in EBL and AM fungi treatments and their interactions compared to control plants under salinity, however, no differences were found when compared with single applications. These results point to the possibility that BRs and AM fungi may have potential in alleviating salt stress by maintaining ion homeostasis in cells and modulating Na+/H+ antiporters.