26S Proteasome Subunit SlPBB2 Regulates Fruit Development and Ripening in Tomato

Proteasomes are protein complexes responsible for degrading unneeded or damaged proteins through proteolysis and play critical roles in regulating plant development and response to environmental stresses. However, it is still unclear whether proteasomes regulate fruit development and ripening. In this study, we investigated the function of a core proteasome subunit, SlPBB2, in tomato fruit. We found that silencing the SlPPB2 gene through virus-induced gene silencing resulted in tomato seedling death, while SlPPB2 RNA interference (RNAi-SlPBB2) plants driven by a fruit-specific promoter PP2C present normal development. Further observation reveals that silencing SlPBB2 in fruits impaired the chloroplast development and chlorophyll metabolism of fruits, increased the fruit size, and delayed fruit ripening. These findings provide novel insights into the role of proteasomes in regulating fruit development and ripening.