OsCOL16, encoding a CONSTANS-like protein, represses flowering by up-regulating Ghd7 expression in rice

Area of Science:

• Plant Biology
• Genetics
• Agronomy

Background:

• Flowering time is a crucial agronomic trait in cereal crops, directly impacting yield.
• The CONSTANS (CO)-like gene family is key in regulating flowering time.
• While CO-like genes in groups I, III, and IV are studied, group II remains largely unknown in rice.

Purpose of the Study:

• To functionally characterize OsCOL16, a group-II CO-like protein in rice.
• To investigate the role of OsCOL16 in regulating flowering time, plant architecture, and yield.
• To elucidate the molecular mechanism by which OsCOL16 influences flowering.

Main Methods:

• Gene expression analysis under different photoperiods.
• Overexpression studies of OsCOL16 in rice.
• Analysis of downstream gene targets and transcription factor activity.
• Genetic diversity and phylogeographic analyses of OsCOL16 alleles.

Main Results:

• OsCOL16 acts as a constitutive floral inhibitor, delaying heading under both long-day and short-day conditions.
• Overexpression of OsCOL16 increases plant height and grain yield.
• OsCOL16 functions as a transcription factor that up-regulates Ghd7, consequently down-regulating Ehd1, Hd3a, and RFT1.
• Genetic diversity analysis revealed correlations between OsCOL16 alleles and flowering time variations.

Conclusions:

• OsCOL16 plays a significant role in regulating rice photoperiodic flowering.
• OsCOL16 contributes to the environmental adaptation of rice through flowering time regulation.
• Understanding OsCOL16 provides insights into improving rice yield and adaptability.