Minisymposium 24: Temperature Response

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Abs # M2404: Light-responsiveness of CBF transcriptional activators and involvement of the CBF regulon in the photoinhibitory responses of Arabidopsis

Presenter:	Hulm, Jacqueline L       Contact Presenter
Authors	Hulm, Jacqueline L (A)   McIntosh, Kerri B (A)   Khanal, Nityananda  (B)   Kriger, Jillian N (B)   Bonham-Smith, Peta C (A)   Gray, Gordon R (B)
Affiliations:	(A): University of Saskatchewan, Department of Biology (B): University of Saskatchewan, Department of Plant Sciences

When cold tolerant plants, such as Arabidopsis, are exposed to low, non-freezing temperatures, they become more freezing tolerant as a result of a multifaceted process known as cold acclimation. Central to this area of research has been the isolation and characterization of genes that are induced during cold acclimation. A transcriptional regulatory system based on a C-repeat (CRT)/dehydration-responsive element (DRE) cis-acting element and a trans-acting DNA-binding protein CBF/DREB1 (CRT-binding factor or DRE-binding protein) has previously been identified. A family of transcriptional activators that bind to the CRT/DRE, designated as CBF1, CBF2, and CBF3, control the expression of a regulon of cold-regulated (COR) genes that are thought to contribute to freezing tolerance. Since growth a low temperatures predisposes plants to photoinhibition of photosynthesis, we decided to examine the effects of light on the CBF transcriptional activators and the cold-regulated genes COR6.6, COR 15a, COR 47 and COR 78. We assessed the transcript levels of these genes by RT-PCR in response to low temperature shifts at the growth irradiance, as well as photoinhibitory treatments at both low and room temperature. The role of light in the cold acclimation process and potential role of the CBF regulon under photoinhibitory conditions will be discussed.