Wheat NAC transcription factor is a positive regulator of senescence.

Wheat ( L.) is an important source of both calories and protein in global diets, but there is a trade-off between grain yield and protein content. The timing of leaf senescence could mediate this trade-off as it is associated with both declines in photosynthesis and nitrogen remobilization from leaves to grain. NAC transcription factors play key roles in regulating senescence timing. In rice, expression is correlated with increased protein content and upregulated in senescing leaves, but the role of the wheat ortholog in senescence had not been characterized. We verified that is the ortholog of and that it is expressed in senescing flag leaves in wheat. To characterize , we combined missense mutations in and from a TILLING mutant population and overexpressed in wheat. Mutation in was associated with delayed onset of flag leaf senescence, while overexpression of was associated with slightly earlier onset of leaf senescence. DAP-seq was performed to locate transcription factor binding sites of . Analysis of DAP-seq and comparison with other studies identified putative downstream target genes of which could be associated with senescence. This work showed that is a positive transcriptional regulator of leaf senescence in wheat. Further research is needed to test the effect of on yield and protein content in field trials, to assess the potential to exploit this senescence regulator to develop high-yielding wheat while maintaining grain protein content.