SiNAC2 accelerates leaf senescence and modulates yield traits in Setaria italica by activating SiJAR1-mediated jasmonate signaling

The objective of this study was to identify the regulatory mechanisms underlying leaf senescence in foxtail millet ( Setaria italica ). We identified and functionally characterized a NAC transcription factor, SiNAC2, whose expression increased along a developmental senescence gradient and which bound to and activated the jasmonate-conjugating enzyme gene SiJAR1 , with a TIFY/JAZ protein, SiTIFY3, attenuating this activation. We propose that SiNAC2 promotes leaf senescence via transcriptional activation of SiJAR1 , attenuated by SiTIFY3. These findings reveal a transcriptional mechanism by which SiNAC2 modulates jasmonate signaling during leaf senescence and provide broader insight into the relationship between senescence regulation and agronomic traits in cereals