Poster: Temperature responses

Abs # 140: Role of the CBF Cold Response Pathway in Configuring the Low Temperature Metabolome of Arabidopsis

Presenter:	Cook, Daniel D, dcook@ars.usda.gov
Authors	Cook, Daniel D (A) (B)  Fiehn, Oliver  (C)   Fowler, Sarah  (B)   Thomashow, Michael F (B) (D)
Affiliations:	(A): USDA, ARS, Natural Products Utilization Research Unit (B): MSU-DOE Plant Research Laboratory (C): Max Planck Institute of Molecular Plant Physiology (D): Department of Crop and Soil Sciences, Michigan State University

The Arabidopsis CBF cold response pathway has a central role in cold acclimation, the process whereby plants increase their freezing tolerance in response to low nonfreezing temperatures. Here we examined the changes that occur in the Arabidopsis metabolome in response to low temperature and the role of the CBF cold response pathway in bringing about these modifications. The results indicate that extensive changes occur in the metabolome of plants exposed to low temperature and that these alterations can be largely mimicked by overexpression of the CBF3 transcriptional activator. However, a dichotomy was evident regarding the effects that CBF3 overexpression had on the levels of polar and nonpolar metabolites. Of the 328 polar metabolites that were identified as increasing in response to cold acclimation in Arabidopsis Ws-2 plants, 259 (79%) were found to increase in response to CBF3 overexpression. In contrast, of the 22 nonpolar metabolites that were found to increase in cold-treated plants, only 1 (5%) increased in response to CBF3 overexpression. Additional experiments established that the Cvi-1 ecotype of Arabidopsis was less freezing tolerant than the Ws-2 ecotype, that the low temperature-induced expression of the CBF genes was much lower in Cvi-1 plants than in Ws-2 plants, and that the low temperature metabolome of Cvi-1 plants was depleted in metabolites affected by CBF3 overexpression. Taken together, the results indicate a prominent role for the CBF cold response pathway in configuring the low temperature metabolome of Arabidopsis. This research was supported in part by grants to Michael F. Thomashow from NSF plant genome project pdbi 0110124, in addition to DOE DEFG0291ER20021 and the Michigan Agricultural Experiment Station.