The basic helix-loop-helix transcription factor MdbHLH3 modulates leaf senescence in apple via the regulation of .

Basic helix-loop-helix (bHLH) domain-containing transcription factors are known for their roles in regulating various plant growth and developmental processes. Previously, we showed that MdbHLH3 from apple () has multiple functions, modulating both anthocyanin biosynthesis and cell acidification. Here, we show that MdbHLH3 also regulates ethylene biosynthesis and leaf senescence by promoting the expression of (). Therefore, we propose a model whereby MdbHLH3 acts as a crucial factor that modulates anthocyanin biosynthesis and cell acidification in addition to fruit ripening and leaf senescence by regulating distinct target genes.