The E3 Ubiquitin Ligase HAF1 Modulates Circadian Accumulation of EARLY FLOWERING3 to Control Heading Date in Rice Under Long-day Conditions

Interacting genes control when rice flowers

2 April 2019

The molecular mechanisms that determine how day length affects when rice plants flower have been clarified, revealing differences in flowering time between varieties.

The Hd1 gene causes rice to flower under short-day conditions and prevents flowering on long days. Its accumulation is controlled by another gene, HAF1. Long-day flowering is promoted by the gene OsELF3, but the effect of HAF1 on it has remained unclear.

A team at China’s Huazhong Agricultural University have studied the link between HAF1 and OsELF3 by using mutants and in vitro assays. Their experiments revealed that HAF1 controls the accumulation of OsELF3 by physically binding to it and thereby marking it for degradation.

Furthermore, genomic analysis revealed that many varieties have a mutation in OsELF3 that prevents the gene from interacting with HAF1, causing the plants to flower later.

These findings improve our understanding of rice biology and offer a tool to target this pivotal trait through breeding.

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References

1. The Plant Cell 30, 2352–2367 (2018). doi: 10.1105/tpc.18.00653