Direct links between the vernalization response and other key traits of cereal crops

Abstract

Transcription of the ​VERNALIZATION1 gene (​VRN1) is induced by prolonged cold (vernalization) to trigger flowering of cereal crops, such as wheat and barley. ​VRN1 encodes a MADS box transcription factor that promotes flowering by regulating the expression of other genes. Here we use transcriptome sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) to identify direct targets of ​VRN1. Over 500 genomic regions were identified as potential ​VRN1-binding targets by ChIP-seq. ​VRN1 binds the promoter of ​FLOWERING LOCUS T-like 1, a promoter of flowering in vernalized plants. ​VRN1 also targets VERNALIZATION2 and ​ODDSOC2, repressors of flowering that are downregulated in vernalized plants. RNA-seq identified additional ​VRN1 targets that might play roles in triggering flowering. Other targets of ​VRN1 include genes that play central roles in low-temperature-induced freezing tolerance, spike architecture and hormone metabolism. This provides evidence for direct regulatory links between the vernalization response pathway and other important traits in cereal crops.