Strigolactone-Mediated Trehalose Enhances Salt Resistance in Tomato Seedlings

Strigolactones (SLs) are newly discovered plant hormones that modulate a variety of physiological and biochemical processes and plant stress responses. In this study, SLs' synthetic analog, GR24, significantly improved the growth of tomato seedlings under salt stress, while SLs' synthesis inhibitor, TIS108, inversed the positive role of SLs, indicating that SLs could effectively enhance salt-stress resistance in tomato. To further explore the mechanism of SL-modulated trehalose (Tre) in response to salt stress, Tre metabolism was analyzed during this process. GR24 increased the endogenous Tre and starch contents and decreased the glucose (Glu) level under salt-stress conditions. Additionally, the TPS and TPP activities were enhanced by GR24 and the activity of THL was inhibited by GR24 under salt stress; thereafter, Tre biosynthesis-related genes, including TPS1, TPS2, TPP1, and TPP2, were also upregulated by GR24 under salt stress. However, the function of GR24 in Tre metabolism was inhibited by TIS108. Thus, the results indicated that GR24 improved the expression levels or activities of Tre biosynthesis-related genes or enzymes and inhibited the transcript level or activity of genes or enzymes related to Tre degradation, respectively, resulting in an increase in the endogenous Tre level and, therefore, weakening the salt toxicity of tomato seedlings.

Automated summary

Strigolactones (SLs), a newly discovered plant hormone, can modulate physiological and biochemical processes and plant stress responses. Synthetic analog GR24 improves the growth of tomato seedlings under salt stress, while synthesis inhibitor TIS108 reverses this effect, indicating that SLs effectively enhance salt-stress resistance in tomato. Mechanistically, GR24 increases endogenous Trehalose (Tre) levels and activates Tre biosynthesis-related genes and enzymes, resulting in weakened salt toxicity; whereas, TIS108 inhibits GR24's effects on Tre metabolism.