Overexpression of the ISiLEA5/I Gene in ISaussurea involucrata/I Increases the Low-Temperature Tolerance of Transgenic Tomatoes

The late embryonic development abundant protein (LEA) is a family of proteins widely present in the body and related to osmoregulation. Saussurea involucrata is an extremely cold-tolerant plant. In our previous studies, we found that the LEAs gene in Saussurea involucrata has up-regulated expression under low temperature. To evaluate the biological function of SiLEA5 protein under low-temperature stress and its potential in agricultural breeding, we isolated the SiLEA5 gene from Saussurea involucrata, constructed a plant overexpression vector, and transformed tomato. We found that SiLEA5 protein significantly increased the yield of transgenic tomatoes by increasing their photosynthetic capacity, including net photosynthetic rate, stomatal conductance, and intercellular CO[sub.2] concentration. Under low-temperature stress, the SiLEA5 protein can regulate proline metabolism and oxidative stress, which confers transgenic tomatos with cold resistance. Thus, our work provided evidence for the role of SiLEA5 protein in low-temperature stress resistance in plants, as well as potential applications in crop breeding and cold stress resistance research.