Regulation of temperature-responsive flowering by MADS-box transcription factor repressors.

Changes in ambient temperature affect flowering time in plants; understanding this phenomenon will be crucial for buffering agricultural systems from the effects of climate change. Here, we show that levels of FLM-β, an alternatively spliced form of the flowering repressor FLOWERING LOCUS M, increase at lower temperatures, repressing flowering. FLM-β interacts with SHORT VEGETATIVE PHASE (SVP); SVP is degraded at high temperatures, reducing the abundance of the SVP-FLM-β repressor complex and, thus, allowing the plant to flower. The svp and flm mutants show temperature-insensitive flowering in different temperature ranges. Control of SVP-FLM-β repressor complex abundance via transcriptional and splicing regulation of FLM and posttranslational regulation of SVP protein stability provides an efficient, rapid mechanism for plants to respond to ambient temperature changes.