A specific gene needed for the winter growth habit in Arabidopsis plants

An ATXR3 lesion suppressed the enhanced FLC expression and delayed flowering caused by an active allele of FRI in non-vernalized plants.

• Active alleles of flowering locus C (FLC) and FRIGIDA (FRI) are essential for the winter-annual habit of Arabidopsis thaliana.
• FLC activation by FRI is linked to increased levels of specific histone modifications, including tri-methylation of histone H3 at lysine 4 (H3K4me3).
• Three known H3K4 methyltransferases are involved in FLC activation, but they do not fully suppress FLC expression when mutated.
• ATXR3, a member of a novel class of H3K4 methyltransferases, also contributes to FLC activation.
• The decrease in FLC expression in atxr3 mutants correlates with reduced H3K4me3 levels at the FLC gene.
• ATXR3 is involved in activating other FLC clade members, contributing to the delay in flowering under non-inductive photoperiods.

Simplified