SALT STRESS REDUCES THE PEA GROWTH AND INDUCESTHE EXPRESSION OF SELECTED ANTIOXIDANT GENES

Pea (Pisum sativum L.) is an important edible leguminous seed crop. In the current study, salt stress was induced in Pea and the expression pattern of Mn-superoxide dismutase, Peroxiredoxin, Thioredoxin, and Alternative oxidase genes was studied. The research was performed in hydroponic system, with three replicates. Ten days old seedlings of Pea variety "Meteor" were exposed to four different levels of salt stress i.e., 0 mM, 50 mM, 75 mM and 100 mM NaCl. The expression of selected genes was studied by reverse transcriptase polymerase chain reaction (RT-PCR). Results showed that shoot and root length, root and shoot biomass were significantly reduced under salt stress as compared to the control Pea plantlets. Results showed7.77 cm shoot length and 9.89 cm root length under 100 mM NaCl as compared to 22.45 cm shoot length and 24.53 cm root length in control. Fresh shoot biomass of 0.81 g and fresh root biomass of 2.3 g was observed under 100 mM salt stress as compared to 1.5 g fresh shoot biomass and 1.2 g fresh root biomass in control plantlets. Mn-SOD gene showed expression in all treatments but high expression was observed under 75 mM NaCl and 100 mM NaCl treatments. Trxo 1 gene showed expression in all treatments but was more pronounced in 75 mM NaCl. The PrxIIF gene also showed the expression in all salt treatments and the expression increased with increasing salt stress. AOX gene showed high expression in 50 mM and 100 mM NaCl and was less expressed in 75 mM NaCl. As the expression of selected genes was upregulated in Pea leaves under salinity, therefore, the results suggest that these genes are involved in salt stress and these may help to cope salt stress and could be used in developing salt resistant Pea varieties in future.