H3K4 demethylase SsJMJ11 promotes flowering in sugarcane

Abstract

Flowering in sugarcane (Saccharum spp.), a vital industrial crop for the production of sugar and energy, have always imposed a challenge for its agricultural productivity and breeding. Despite this, the molecular mechanisms controlling sugarcane flowering, particularly the roles of epigenetic regulators, remain largely unknown. Here, we demonstrate that SsJMJ11, a S. spontaneum KDM5/JHDM1 subfamily JmjC protein, promotes flowering by acting as a H3K4me3 demethylase. Ectopic overexpression of SsJMJ11 in Arabidopsis accelerated flowering possibly by downregulating the expression of AtFLC and AtCDF1, which are well-known flowering repressors. SsJMJ11 directly bound to AtFLC and AtCDF1, and decreased their H3K4me3 levels. In S. spontaneum, long day photoperiod enhanced the transcription of SsJMJ11, associated with the elevated SsCO, SsFT3 and reduced SsCDF1&2 transcript levels. Transient overexpression of SsJMJ11 in S. spontaneum protoplasts inhibited the expression of SsCDF1&2, in parallel with decreased H3K4me3 levels at its loci. The findings suggest that the dynamic deposition of H3K4me3 mediated by SsJMJ11 is required for proper flowering time in sugarcane.