Induction Of Salt Tolerance In Transgenic Alfalfa (Medicago Sativa) Through Overexpression Of The Mserecta Gene

Alfalfa is an important crop for large-scale improvement of saline-alkali land and development of modern animal husbandry in China. However, the mild salt tolerance of alfalfa limits further promotion of planting. Therefore, it is of great significance to cultivate alfalfa varieties with high salt tolerance. With the aim to improve the tolerance of alfalfa to high levels of salt stress, a receptor-like kinase gene, MsERECTA, was analyzed for homology, isolated from alfalfa (Medicago sativa L.) cv. Zhongmu No. 1, and transferred back to alfalfa Zhongmu No. 1. Expression of the MsERECTA gene can be induced by salt and ABA, and the most responsive expression was found in immature leaves of wild-type plants. Subsequently, the transgenic lines were compared with the wild type (WT) plants without any introduced genes for salt tolerance after being treated with 250 mM NaCl for 26 d. Transgenic alfalfa plants over-expressing MsERECTA, OXERECTA-2, -6, and -1 0, showed slower water loss rates and lower malondialdehyde and Na+ contents in the leaves and roots compared to the WT. However, these lines showed higher levels of chlorophyll and free proline. These results suggest that over-expression of the MsERECTA gene could efficiently improve salt tolerance of alfalfa Zhongmu No. 1 at a high salt level (250 mM NaCl). The present study provides a solid foundation for transgenic breeding of super salt-tolerant alfalfa. (C) 2020 Friends Science Publishers