JA-Mediated Regulation of Amino Acid Homeostasis Adjusts Metabolic Flux and Enhances Spider Mite Tolerance via the SlJAZ8-SlWRKY57-SlAVT6s Module in Tomato.

Abstract

A crucial strategy employed by plants to enhance insect resistance is allocating amino acids into secondary metabolic pathways, ensuring the synthesis of specialized metabolites that confer resistance. The storage and redistribution of amino acids primarily occur in vacuole; therefore, transport mechanisms must exist to facilitate the directed extravasation of amino acids from vacuole to cytosol and feed them into secondary metabolism in response to stress. However, the specific amino acid transporter located in the vacuole responsible for amino acid distribution remains unclear. Here, we identify two tomato vacuolar amino acid transporters, SlAVT6A and SlAVT6B. SlAVT6A functions as the primary exporter, while SlAVT6B modulates transport capacity through SlAVT6A/SlAVT6B heterodimer formation. This system redirects amino acids to boost trichome density, terpene accumulation, and gibberellin synthesis, thereby strengthening defense against spider mites. Furthermore, SlWRKY57 coordinates both transporters by forming a complex with SlJAZ8, linking jasmonic acid (JA) signaling to amino acid homeostasis through metabolic reprogramming from primary to specialized pathways. The findings reveal a SlJAZ8-SlWRKY57-SlAVT6A/SlAVT6B module that enhances growth and resistance by allocating amino acid to secondary metabolic pathways, offering insights for improving resistance in metabolic-assisted breeding.