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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. [ABSTRACT FROM AUTHOR]

Trehalose (Tre) plays a vital role in response to drought stress in plants but its regulatory mechanism remains unclear. Here, this study explores the mechanism of re-regulated drought tolerance during cucumber adventitious root formation. Our results indicate that 2 mM Tre displays remarkable drought alleviation in the aspect of root number, root length, fresh weight, and dry weight. Under drought stress, Tre could inhibit greatly the MDA, H 2 O 2 , and O 2 − accumulation, enhance obviously the activities of SOD, POD, and CAT enzymes and up-regulate significantly the transcript levels of SOD , POD , and CAT genes. Furthermore, Tre treatment also promotes Tre metabolism during drought stress: significantly increases starch and Tre contents and decreases glucose content, the biosynthesis enzymatic activity of the Tre metabolic pathway including TPS and TPP are enhanced and the activity of degradation enzyme THL is decreased, and corresponding genes TPS1 , TPS2 , TPPA , and TPPB are up-regulated. Tre significantly reversed the decrease caused by PEG in IAA, ethylene, ABA, and BR contents and the increase caused by PEG in GA 3 and KT contents. Collectively, Tre appears to be the effective treatment in counteracting the negative effects of drought stress during adventitious root formation by regulating ROS, Tre metabolisms and plant hormones. • Trehalose enhances drought stress resistance in cucumber during adventitious rooting. • Trehalose-medicated ROS improves drought stress resistance. • Trehalose alleviates cucumber drought stress by regulating trehalose metabolism. [ABSTRACT FROM AUTHOR]