SlTPP4 participates in ABA-mediated salt tolerance by enhancing root architecture in tomato

Salinity tolerance is an important physiological index for crop breeding. Roots are typically the first plant tissue to withstand salt stress. In this study, we found that the tomato (Solanum lycopersicum) trehalose-6-phosphate phosphatase (SlTPP4) gene is induced by abscisic acid (ABA) and salt, and is mainly expressed in roots. Overexpression of SlTPP4 in tomato enhanced tolerance to salt stress, resulting in better growth performance. Under saline conditions, SlTPP4 overexpression plants demonstrated enhanced sucrose metabolism, as well as increased expression of genes related to salt tolerance. At the same time, expression of genes related to ABA biosynthesis and signal transduction was enhanced or altered, respectively. In-depth exploration demonstrated that SlTPP4 enhances Casparian band development in roots to restrict the intake of Na+. Our study thus clarifies the mechanism of SlTPP4-mediated salt tolerance, which will be of great importance for the breeding of salt-tolerant tomato crops.

Automated summary

This study identified a gene called SlTPP4 in tomato that is involved in sucrose metabolism and salt tolerance. Overexpression of SlTPP4 enhanced tomato's tolerance to salt stress and improved growth performance. The study also revealed that SlTPP4 restricts the uptake of salt ions by enhancing the development of Casparian bands in roots, and alters the expression of genes related to ABA biosynthesis and signal transduction.