Evaluating Salinity Effects On Transgenic Soybean Harboring A Cytokinin Dehydrogenase Gene At Germination And Vegetative Growth Stage

Abstract

Soil salinization, along with drought, is a natural threat that has a great impact on agricultural production in many locations throughout the world. The cytokinin oxidase/dehydrogenase (CKX) plays an essential role in regulating plant CK levels to develop abiotic-tolerant plants. This study aimed to find out whether there were differential effects of salinity on GmCKX-transgenic and wild-type (WT) soybean (Glycine max L.) plants. The effects of salt stress were monitored by deploying different concentrations of NaCl. According to the obtained results, the transgenic plants could maintain a better germination rate (77.5%) than the WT (60%) after 4-day treatment of 200 mM NaCl. In addition, as the level and duration of salinity stress increased, there was a decrease in relative water content in the soybean shoots and an increase in peroxidation of the membrane lipid. At a concentration of 100 mM NaCl, the malondialdehyde (MDA) content of the WT was significantly higher compared to the GmCKX13-transgenic plants by 21.37%, as recorded on day 12th of salt stress treatment, indicating a higher stressinduced damage level in the former genotype. Taking these findings together, it is suggested that modulating the expression of CKX13 could contribute to better salt tolerance in soybean, providing a novel strategy for developing new salinity-tolerant varieties.