GIGANTEA accelerates wheat heading time through gene interactions converging on FLOWERING LOCUS T1

Area of Science:

• Plant Biology
• Molecular Genetics
• Crop Science

Background:

• Flowering time regulation is crucial for cereal crop yield, synchronizing reproduction with optimal environmental conditions.
• The GIGANTEA (GI) gene is a key regulator of flowering time, circadian rhythms, and stress responses in plants.

Purpose of the Study:

• To investigate the role of GIGANTEA (GI) in controlling flowering time in tetraploid wheat.
• To elucidate the interaction between GI, photoperiod, and other flowering time regulatory genes in wheat.

Main Methods:

• Analysis of GI loss-of-function mutants in tetraploid wheat under different photoperiods.
• Genetic crosses between GI mutants and mutants/transgenics of key flowering pathway genes (PPD1, ELF3, FT1, VRN2, CO, AP2).
• Assessment of heading time and gene expression analysis at transcriptional and protein levels.

Main Results:

• GI loss-of-function mutants showed delayed heading, with stronger effects under long days, dependent on functional PPD1 and ELF3.
• GI accelerates wheat heading by promoting FLOWERING LOCUS T1 (FT1) expression through interactions with ELF3, VRN2, CO, and the miR172-AP2 pathway.
• Identified conserved and specific interactions of GI in wheat's photoperiod and vernalization pathways.

Conclusions:

• Normal circadian regulation of PPD1 is essential for GI's photoperiod-dependent effects on wheat heading time.
• GI integrates photoperiod, vernalization, and age pathways to control flowering via FT1.
• Findings offer insights for improving wheat heading time and developing climate-resilient varieties.