Histone demethylases JMJ19 and JMJ20 interact with LUX2 to mediate flowering time and adaptation in soybean [CHIP-seq]
Flowering time is a critical trait to determine regional adaptation and yield of crops including soybean. Evening Complex (EC) components soybean LUX1, LUX2, and ELF3a are critical for flowering and adaptation to lower latitudes. However, the mechanisms of EC in regulating flowering time remain largely unclear in soybean. Here, we identified GmJMJ19 and GmJMJ20 gene paralogs encoding JmjC-domain containing proteins, which co-express and interact with GmLUX2. In vitro and in vivo assays demonstrate that GmJMJ19 and GmJMJ20 bind to histone, but lack histone demethylase activity. Notably, simultaneous mutation of GmJMJ19 and GmJMJ20 causes delayed flowering time. Further transcriptomic, CUT&Tag and ChIP-seq analyses show that GmJMJ19/20 and GmLUX2 primarily co-repress transcription of 168 genes, which are not associated with the alternation of examined histone methylation state. Strikingly, we identify that the direct repression of GmSVP by GmJMJ19/20-GmLUX2 module is independent of the classical EC-E1 pathway. Interestingly, haplotype analyses support the idea that GmJMJ19 might undergo selection during soybean expansion to lower latitude. In summary, our findings reveal a mechanistic insight of GmJMJ19/20-GmLUX2 into flowering time control beyond EC complex in plants and also provide resources for improving soybean adaptability through molecular breeding. Overall design: Genomic occupancy of JMJ20 in soybean leaves at ZT12 in JMJ20-OE transgenic plants