Saussurea involucrata SiLEA5 Enhances Tolerance to Drought Stress in Solanum lycopersicum

Drought adversely affects plant growth, which leads to reduced crop yields and exacerbates food insecurity. Late embryogenesis abundant (LEA) proteins are crucial for plants' responses to abiotic stresses. This research further investigates the role of <i>SiLEA5</i> by utilizing transgenic tomatoes under drought stress. The expression of <i>SiLEA5</i> was upregulated under drought and abscisic acid (ABA) treatment, resulting in decreased electrolyte leakage and malondialdehyde content, alongside increased levels of osmotic regulators and antioxidant enzyme activity. These biochemical alterations reduce oxidative damage and enhance drought resistance. qRT-PCR analysis revealed the upregulation of ABA signaling genes and key enzymes involved in proline biosynthesis (P5CS) and dehydrin (DHN) synthesis under drought stress. Additionally, overexpression of <i>SiLEA5</i> increased the net photosynthetic rate (Pn) and fruit yield of tomatoes by regulating stomatal density and aperture. These findings suggest that <i>SiLEA5</i> may be a potential target for improving drought tolerance in tomatoes and other crops.