The Arabidopsis H3K27me3 demethylase JUMONJI 13 is a temperature and photoperiod dependent flowering repressor

Shuzhi Zheng,Huimin Ren,Daye Sun,Qi Qiu,Hongmiao Hu,Xiaomei Chen,Xiekui Cui,Bing Zhou,Zhenlin Yang,Xinye Liu,Jiamu Du,Weiwei Qi,Xiaofeng Cao,Sisi Li

doi:10.1038/s41467-019-09310-x

Abstract

In plants, flowering time is controlled by environmental signals such as day-length and temperature, which regulate the floral pathway integrators, including FLOWERING LOCUS T (FT), by genetic and epigenetic mechanisms. Here, we identify an H3K27me3 demethylase, JUMONJI 13 (JMJ13), which regulates flowering time in Arabidopsis. Structural characterization of the JMJ13 catalytic domain in complex with its substrate peptide reveals that H3K27me3 is specifically recognized through hydrogen bonding and hydrophobic interactions. Under short-day conditions, the jmj13 mutant flowers early and has increased FT expression at high temperatures, but not at low temperatures. In contrast, jmj13 flowers early in long-day conditions regardless of temperature. Long-day condition and higher temperature induce the expression of JMJ13 and increase accumulation of JMJ13. Together, our data suggest that the H3K27me3 demethylase JMJ13 acts as a temperature- and photoperiod-dependent flowering repressor.

Highlights

In plants, flowering time is controlled by environmental signals such as day-length and temperature, which regulate the floral pathway integrators, including FLOWERING LOCUS T (FT), by genetic and epigenetic mechanisms
JMJ13 is a homolog of EARLY FLOWERING 6 (ELF6)/JMJ11 and RELATIVE OF EARLY FLOWERING 6 (REF6)/JMJ12, the two Arabidopsis KDM4 subfamily H3K27me[3] demethylases (Supplementary Table 1)[25,26]
In most eukaryotic genomes, a large proportion of chromatin is enriched with H3K27me[3]

Summary

Introduction

In plants, flowering time is controlled by environmental signals such as day-length and temperature, which regulate the floral pathway integrators, including FLOWERING LOCUS T (FT), by genetic and epigenetic mechanisms. Under short-day conditions, the jmj[13] mutant flowers early and has increased FT expression at high temperatures, but not at low temperatures. These authors contributed : Varying day-length (photoperiod) and ambient temperature are two environmental cues that play central roles in plant development, including the regulation of flowering time. Higher ambient temperature promotes flowering and there is considerable crosstalk between the photoperiodic pathway and the ambient temperature pathway These environmental cues regulate the expression of key flowering integrators such as FLOWERING LOCUS T (FT)[1]. Histone methylation, which has important roles in transcriptional regulation and genome integrity[17], is written by histone methyltransferases and erased by histone demethylases[18]

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Conclusion