ID1 promotes flowering in Brachypodium distachyon

What is it about?

The timing of flowering is a critical developmental process in the plant life cycle, and many species adapted to temperate climates use seasonal cues such as day-length and temperature for proper timing. In many plant species, a prolonged period of winter cold (vernalization) is required for plants to flower in the spring. Some plants can also sense the short day lengths (SD) of winter as another seasonal cue that can confer competence to flower in spring through a process called SD vernalization. A screen for mutants in SD vernalization in Brachypodium distachyon identified INDETERMINATE1 (ID1) as a regulator of FT and FT-like genes involved in the cold and SD vernalization flowering pathways.

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Photo by Jack Blueberry on Unsplash

Photo by Jack Blueberry on Unsplash

Why is it important?

Temperate grasses, such as B. distachyon, wheat, barley, rye, and oat, also have a SD vernalization response. However, only in B. distachyon have any components of the SD vernalization pathway been identified. Specifically, SD expression of FTL9 (FT-like 9) is necessary for FT1 to be induced after shifting to inductive LD to trigger flowering. In this study, we identified ID1 as involved in SD vernalization because it is required for proper FTL9 expression. Furthermore, ID1 regulates the expression of FT1 and several other FT-like genes, making it an essential component in various flowering pathways. Thus, this study provides a phenotypic and molecular characterization of ID1 in temperature grasses.