A Tocopherol-Related Methyltransferase SlVTE3(2) Regulates Tomato Fruit Ripening and Tocopherol Accumulation.

Tomato fruit ripening is a critical developmental process that determines the fruit quality. However, the regulatory mechanisms underlying the ripening initiation remain incompletely understood. Here, we characterized SlVTE3(2), a tocopherol-biosynthesis-related methyltransferase, and investigated its role in tomato fruit ripening. CRISPR/Cas9-mediated mutation of SlVTE3(2) accelerated ripening initiation, resulting in earlier ethylene production, faster softening, and an earlier color transition, whereas overexpression delayed these processes. Transcriptome analysis showed that SlVTE3(2) affected multiple ripening-related pathways, including ethylene biosynthesis and signaling, carotenoid metabolism, and cell wall modification. Although SlVTE3(2) significantly altered the tocopherol composition in tomato fruits, exogenous tocopherol treatment did not affect ripening initiation. These findings provide new insights into the regulation of tomato fruit ripening by the metabolic enzymes.