摘要：SummaryFruit softening indicated by firmness determines the texture, transportability, and shelf life of tomato products. However, the regulatory mechanism underlying firmness formation in tomato fruit is poorly understood. Here, we report the regulatory role of SlBES1, an essential component of brassinosteroid hormone signaling, in tomato fruit softening. We found that SlBES1 promotes fruit softening during tomato fruit ripening and postharvest storage. RNA-seq analysis suggested thatPMEU1, which encodes a pectin methylesterase, might participate in SlBES1-mediated softening. Biochemical and immunofluorescence assays indicated that SlBES1 inhibited PMEU1-related pectin de-methylesterification. Further molecular and genetic evidence verified that SlBES1 directly binds to the E-box ofPMEU1to repress its expression, leading to fruits softening. Loss-of-functionSlBES1mutant generated by CRISPR-Cas9 showed firmer fruits and longer shelf life during postharvest storage without other quality alteration. Collectively, our results indicated the potential of manipulating SlBES1 to regulate firmness without negative consequence on visual and nutrition quality.Graphical abstractDisplay OmittedHighlights•SlBES1 promotes tomato fruit softening without affecting nutritional quality•SlBES1 inhibits PMEU1-related fruit pectin de-methylesterification•SlBES1 repressesPMEU1expression through directly binding to the E-box•Knockout ofSlBES1by CRISPR-Cas9 enhances fruit firmness and extends shelf lifeBiological sciences; Molecular biology; Plant biology; Plant development
