High Ambient Temperatures Inhibit Ghd7-Mediated Flowering Repression in Rice.

Area of Science:

• Plant biology
• Molecular genetics
• Agricultural science

Background:

• Seasonal changes are vital for plant reproduction.
• The influence of ambient temperature on photoperiodic flowering in rice remains largely uncharacterized.
• Rice is a globally significant crop.

Purpose of the Study:

• To investigate the effects of temperature and photoperiod on rice flowering time.
• To elucidate the molecular mechanisms underlying temperature-mediated photoperiodic flowering in rice.
• To identify key genes involved in temperature sensing and flowering regulation.

Main Methods:

• Phenotypic analysis of flowering time in rice under diverse temperature and photoperiod conditions.
• Gene expression analysis of key flowering-time genes (e.g., Hd1, Ghd7, Ehd1, Hd3a, RFT1).
• Utilized rice cultivars, near-isogenic lines, and mutants.

Main Results:

• Low temperatures enhance photoperiodic flowering, mediated by Hd1 and Ghd7.
• PhyB functions as a temperature sensor, inhibiting flowering-related genes (Ehd1, Hd3a, RFT1) at low temperatures via post-transcriptional regulation of Ghd7.
• High temperatures rapidly decrease Ghd7 mRNA, leading to increased RFT1 mRNA and floral induction.

Conclusions:

• Multiple temperature-sensing pathways regulate photoperiodic flowering in rice.
• Rising ambient temperatures, like in early summer, may inhibit Ghd7 repressor activity, facilitating timely floral induction in temperate regions.
• Understanding these mechanisms is crucial for optimizing rice cultivation and yield.