Enhanced tolerance to salt stress in highland barley seedlings (Hordeum vulgare ssp vulgare) by gamma irradiation pretreatment

Salinity toxicity has become a major threat to the yield of highland barley in Tibet due to severe soil salinization. This research disclosed the effects of low-dose gamma-irradiation on the physio-biochemical and transcriptional responses to NaCl stress in highland barley seedlings. The results revealed that 50-Gy gamma irradiation pretreatment could markedly stimulate highland barley growth under NaCl stress and alleviate the salt-induced oxidative stress (evidenced by lower malondialdehyde and hydrogen peroxide contents in irradiated seedlings) through elevating the antioxidant enzyme activities and proline level. Moreover, transmission electron microscopy results revealed that irradiation pretreatment could alleviate the salt damage to chloroplasts ultrastructure. Notably, transcriptional analysis showed that gamma-irradiation pretreatment could enhance the expression of salt stress related genes. Overall, our results show that gamma ray pretreatment can improve the salt tolerance of barley seedlings.