Study the expression of SOS1, P5CS1 and PMP3-6 genes in maize under salt stress

High concentration of salt in soil and water is one of the major factors limiting crop growth and production worldwide. A factorial experiment based on completely randomized design with two biological and three technical replicates was performed in 2018-2019 to study the ion leakage rate and chanes in relative expression of SOS1, P5CS1 and PMP3-6 genes in the root and leaf of Zea mays L. tolerant and susceptible lines under normal and 8 dS/m salinity conditions using real-time PCR technique after 24-hours and 7-days (as short-time and long-time, respectively) of applying salt stress. The results showed that ion leakage rate at long-time was high in the susceptible line than that of the tolerant line. The highest relative expression of P5CS1 and PMP3-6 genes in 8 dS/m salinity stress was observed in the roots of tolerant line. In contrast, the highest increase in the reltive expression of SOS1 gene was observed in the leaf tissue of susceptible line at short-time. Correlation analysis among the relative expression of studied genes revealed a positive significant correlation (P≤0.05) between P5CS1 and PMP3-6 genes expression. Probabiliy, the high expression of PMP3-6 and P5CS1 genes in the root tissue of the tolerant line in the ealier time post salt stress application is responsible for regulating osmotic pressure and preventing excessive Na+ entry into the plant that results in icreasing the tolerance of plant to salt stress. The results of this study can be useful in Zea mays L. breeding programs for producing salinity tolerant varieties.