Profiling the expression of expansin genes in barley roots under salinity stress at the germination stage

Salinity is a major abiotic stress that inhibits seed germination, plant growth, and consequently the productivity of many important crops such as barley. Expansins are a major group of cell wall-loosening proteins, which play important roles in plant growth and development, and in response to different environmental stresses. In this study, salinity tolerance and changes in the expression of expansin genes in barley were tested. The germination percentage of Yarmouk was 72.3% of the control after 48 hours of salt stress, and that of Rum was 27.4%. Reserve mobilization was 61.6% and 43.6% of the control in Yarmouk and Rum, respectively. The decrease in the total soluble sugars was 0.3, and 0.54 mg. ml-1. g-1 FW in Yarmouk and Rum, respectively. Yarmouk has a higher number of induced expansin genes under salt stress compared to Rum. This indicates a significant role for expansins in the improvement of salinity tolerance of barley.