Abstract:

The trehalose-6-phosphate phosphatase (TPP) gene family plays a critical role in plant metabolism, growth, and stress resilience by regulating trehalose biosynthesis. Despite its significance, research on TPP genes in tomato (Solanum lycopersicum L.) under hormonal and abiotic stress conditions remains limited. Here, we identified eight SlTPP genes distributed across five chromosomes in the tomato genome. Phylogenetic, synteny, and structural analyses classified the SlTPP genes into three subfamilies, revealing conserved intron structures similar to those in Arabidopsis thaliana and grape. Cis-acting element analysis suggested that SlTPP genes are responsive to plant hormones, stress, and light. Reverse transcription quantitative PCR (RT-qPCR) demonstrated tissue-specific expression patterns, with SlTPP2 and SlTPP3 highly expressed in leaves, flowers, and fruits, whereas SlTPP8 was predominantly expressed in flowers and green fruits. In contrast, SlTPP4 exhibited low expression in aboveground tissues. Notably, SlTPP3, SlTPP5, SlTPP6, and SlTPP8 were significantly upregulated by abscisic acid (ABA) and methyl jasmonate (MeJA) treatments. Most SlTPP genes also showed increased expression under drought, salt, heat, and cold stress. Subcellular localization confirmed SlTPP3 presence in chloroplast. Virus-induced gene silencing (VIGS) experiments suggested that trehalose may enhance TPP activity and accumulation by upregulating SlTPP3 under NaCl stress, leading to improved leaf Fv/Fm, chlorophyll content, root vitality, and overall salt tolerance in tomato plants. Furthermore, SlTPP3 overexpression enhanced antioxidant capacity, reduced ROS accumulation, alleviated growth inhibition, and improved salt tolerance in tomato plants under NaCl stress. The findings highlight the crucial role of SlTPP3 in trehalose-mediated salt tolerance. In summary, SlTPP genes are essential for tomato development and stress responses; our findings offer valuable insights into trehalose regulation and serving as reference for similar studies in other perennial plants.