Florigen and Florigen-Like Genes Regulate Temperature-Responsive Flowering in Tomato.

Seasonal temperature fluctuations serve as crucial environmental cues that regulate plant reproductive timing, yet the mechanisms underlying thermoresponsive flowering regulation in tomato remain poorly understood. The study uncovers a temperature-sensing mechanism in the tomato shoot apical meristem coordinated through antagonistic interactions between a florigen-like protein FLOWERING LOCUS T-Like 2 (FTL2) and florigen protein SINGLE-FLOWER TRUSS (SFT). Under short day conditions, FTL2 expression is specifically upregulated at the shoot apex by high temperature and functions as a flowering repressor. FTL2 physically interacts with the floral inducer SFT, directly suppressing its transcriptional activity to delay floral transition. This FTL2-SFT regulatory circuit enables tomato precise integration of photoperiodic and thermal signals at the shoot apex, providing a molecular framework for seasonal flowering adaptation. The findings elucidate a fundamental mechanism of temperature perception in tomato flowering control and provide broader insights into how florigen-based networks contribute to adaptive flowering control across plant species.