A J-Domain Protein J3 Antagonizes ABI5-BINDING PROTEIN2 to Regulate CONSTANS Stability and Flowering Time.

CONSTANS (CO) plays a vital role in activating the expression of the florigen FT during photoperiod-dependent flowering. The diurnal oscillation of CO protein abundance is strictly controlled by daylength and the circadian clock. We showed previously that ABI5-BINDING PROTEIN2 (AFP2) represses CO expression to delay flowering.

HFR1 antagonizes ABI4 to coordinate cytosolic redox status for seed germination under high-temperature stress.

Seed germination and dormancy represent critical phases in the life cycle of plants, tightly regulated by endogenous phytochrome levels and environment signals. High temperatures (HT) induce the overaccumulation of reactive oxygen species (ROS) and increase abscisic acid (ABA), thereby inhibiting seed germination. Our previous findings showed that HT induced the burst of reactive nitrogen species (RNS), increasing the S-nitrosylation modification of HFR1, which effectively blocks seed germination.