Overexpression of the tomato SlLEA_2-26 gene enhances the tolerance to drought and salt stresses in Arabidopsis thaliana

Late embryogenesis abundant (LEA) proteins are pivotal in conferring cellular tolerance to abiotic stresses and sustaining plant growth and development. However, systematic functional characterization of the tomato SlLEA_2 gene family remains limited. To elucidate the role of tomato SlLEA_2–26 in abiotic stress responses, this study cloned its full-length cDNA. Quantitative real-time PCR (qRT-PCR) analysis revealed that SlLEA_2–26 exhibits predominant expression in flowers and fruits, and is strongly induced by drought, salt, Cu ²⁺ , and Pb ²⁺ stresses. Three homozygous Arabidopsis T ₃ SlLEA_2-26 -overexpression lines were generated and confirmed via genomic PCR. Under drought and salt stress, T ₃ Arabidopsis SlLEA_2-26 -overexpressing lines demonstrated significantly enhanced seed germination rates, root elongation, and fresh weights wild type (WT) plants, indicating improved stress tolerance during early seedling development. Furthermore, transgenic plants accumulated higher levels of soluble sugar and proline, and displayed elevated antioxidant enzyme activity compared to the WT, whereas contents of malondialdehyde (MDA) and reactive oxygen species (ROS) were markedly reduced relative to WT. qRT-PCR analysis confirmed the significant upregulation of SlLEA_2–26 in transgenic lines under drought and salt stress conditions, accompanied by elevated expression of AtP5CS1 , AtCSD1 , AtRD29A , AtRD26 , and AtNCED3 . Collectively, these results demonstrate that SlLEA_2–26 overexpression enhances drought and salt stress tolerance in Arabidopsis by promoting the accumulation of osmoregulatory substances, augmenting antioxidant defense capacity, and activating stress-responsive genes expression. This study provides a theoretical foundation and valuable genetic resources for breeding stress-tolerant tomatoes and other crops.