A new class of plant-specific genes required for flowering control in temperate grasses

Establishment of a vernalization requirement in Brachypodium distachyon requires REPRESSOR OF VERNALIZATION1.

The Science

To better understand flowering time control in temperate grasses, we sought to identify which genes prevent a grass from flowering until it has undergone prolonged cold exposure. After screening for and identifying mutants in the grass species Brachypodium distachyon, we identified a mutant that flowers rapidly without cold exposure and described and characterized a new gene we named REPRESSOR OF VERNALIZATION1 (RVR1).

The Impact

Increasing biomass yield could improve the economics of biomass as an energy source. By furthering the molecular-level understanding of the flowering regulatory network in the model grass Brachypodium distachyon, we are advancing the potential to manipulate flowering time in bioenergy grass crops to increase biomass yield.

Summary

The timing of flowering is a key trait for biomass yield. A requirement for vernalization, the process by which prolonged cold exposure provides competence to flower, is an important adaptation to temperate climates that ensures flowering does not occur prior to the onset of winter. In temperate grasses, vernalization results in the up-regulation of VERNALIZATION1 (VRN1) to establish competence to flower; however, little is known about the mechanism underlying repression of VRN1 in the fall season, which is necessary to establish a vernalization requirement. Here we report that a plant-specific gene containing a bromo adjacent homology (BAH) and transcriptional elongation factor S-II(TFIIS) domain, which we named REPRESSOR OF VERNALIZATION1 (RVR1), represses VRN1 prior to vernalization in Brachypodium distachyon. Thus, RVR1 plays a role in establishing a vernalization requirement in B. distachyon and is likely to play the same role in other vernalization-requiring pooid grasses. Interestingly, RVR1 is a plant-specific gene that is conserved across the plant kingdom, and this study provides the first example of a role for this class of plant specific-genes.

Contacts (BER PM)

N. Kent Peters
Program Manager, Office of Biological and Environmental Research
kent.peters@science.doe.gov, 301-903-5549

(PI Contact)

Richard M. Amasino
University of Wisconsin - Madison
amasino@biochem.wisc.edu

Funding

This work was funded in part by the National Science Foundation (grant no. IOS-1258126), the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-FCO2-07ER64494), a National Institutes of Health-sponsored predoctoral training fellowship to the University of Wisconsin Genetics Training program, and the Gordon and Betty Moore Foundation and the Life Sciences Research Foundation for their postdoctoral fellowship, and the Wallonie-Bruxelles International for their postdoctoral fellowships.

Publications

Woods, D.P. et al. “Establishment of a vernalization requirement in Brachypodium distachyon requires REPRESSOR OF VERNALIZATION1.” Proc. Natl. Acad. Sci. USA (2017) [DOI: 10.1073/pnas.1700536114].

Related Links

http://www.pnas.org/content/early/2017/05/31/1700536114.abstract