Cold tolerance gene SiLEA B19.3 of Saussurea involucrata increases the yield of transgenic tomato

Late embryogenesis abundant proteins are a widely occurring class of osmoregulation-related proteins found in various organisms. Saussurea involucrata is an extremely low-temperature tolerant plant with valuable germplasm resources. Transcriptomic sequencing revealed that cold stress upregulated the expression of SiLEA B19.3 in S. involucrata. In this study, SiLEA B19.3 was isolated from S. involucrata, and a plant overexpression vector was constructed to transform SiLEA B19.3 into tomato. Our results demonstrate that transgenic tomato plants exhibited greater stability and recovery ability than wild-type plants when exposed to cold stress. Physiological and biochemical data showed that transgenic tomatoes exhibited lower electrolyte leakage and malondialdehyde content, higher relative water content and antioxidant enzyme activity, and accumulated more osmoregulatory substances than wild-type plants. Meanwhile, the semi-lethal low temperatures of the transgenic and wild-type tomatoes were 2.52 ℃ and 3.99 ℃, respectively. These results indicate that SiLEA B19.3 plays a protective role in cells under low-temperature stress. The results of the field experiment showed that the transgenic tomato plants had higher photosynthetic capacity and higher yield than the wild-type tomato plants. Thus, SiLEA B19.3 has the potential to be a candidate gene for genetic improvement of crop stress resistance in the future and has valuable potential applications.