The essential role of jasmonate signaling in Solarium habrochaites rootstock -mediated cold tolerance in tomato grafts

Tomato (Solanum lycopersicum) is among the most important vegetables across the world, but cold stress usually affects its yield and quality. The wild tomato species Solanum habrochaites is commonly utilized as rootstock for enhancing resistance against abiotic stresses in cultivated tomato, especially cold resistance. However, the underlying molecular mechanism remains unclear. In this research, we confirmed that S. habrochaites rootstock can improve the cold tolerance of cultivated tomato scions, as revealed by growth, physiological, and biochemical indicators. Furthermore, transcriptome profiling indicated significant differences in the scion of homoand heterografted seedlings, including substantial changes in jasmonic acid (JA) biosynthesis and signaling, which were validated by RT-qPCR analysis. S. habrochaites plants had a high basal level of jasmonate, and cold stress caused a greater amount of active JAisoleucine in S. habrochaites heterografts. Moreover, exogenous JA enhanced while JA inhibitor decreased the cold tolerance of tomato grafts. The JA biosynthesis -defective mutant spr8 also showed increased sensitivity to cold stress. All of these results demonstrated the significance of JA in the cold tolerance of grafted tomato seedlings with S. habrochaites rootstock, suggesting a future direction for the characterization of the natural variation involved in S. habrochaites rootstock -mediated cold tolerance.

Automated summary

This research confirms that wild tomato rootstock can improve the cold tolerance of cultivated tomato scions, as demonstrated by growth, physiological, and biochemical indicators. Transcriptome profiling reveals significant differences in jasmonic acid (JA) biosynthesis and signaling, with wild tomato having higher levels of JA. Exogenous JA enhances the cold tolerance of tomato grafts, highlighting the importance of JA in wild tomato rootstock-mediated cold tolerance.