Regulation of the Arabidopsis CBF regulon by a complex low‐temperature regulatory network

• Published in: The Plant journal : for cell and molecular biology Vol. 82; no. 2; pp. 193 - 207
• Main Authors: Park, Sunchung, Lee, Chin‐Mei, Doherty, Colleen J, Gilmour, Sarah J, Kim, YongSig, Thomashow, Michael F
• Format: Journal Article
• Language: English
• Published: England Blackwell Scientific Publishers and BIOS Scientific Publishers in association with the Society for Experimental Biology 01-04-2015; Blackwell Publishing Ltd; Wiley-Blackwell
• Subjects: acclimation; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Botany; CBF regulatory pathway; Cold; Cold Temperature; cold tolerance; DNA; DNA-binding proteins; freezing tolerance; Gene expression; Gene Expression Regulation, Plant; gene overexpression; genetically modified organisms; low‐temperature regulatory network; regulon; Regulon - genetics; Temperature; Transcription factors; Arabidopsis thaliana; freezing tolerance; low-temperature regulatory network; CBF regulatory pathway
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.12796

Exposure of Arabidopsis thaliana plants to low non‐freezing temperatures results in an increase in freezing tolerance that involves action of the C‐repeat binding factor (CBF) regulatory pathway. CBF1, CBF2 and CBF3, which are rapidly induced in response to low temperature, encode closely related AP2/ERF DNA‐binding proteins that recognize the C‐repeat (CRT)/dehydration‐responsive element (DRE) DNA regulatory element present in the promoters of CBF‐regulated genes. The CBF transcription factors alter the expression of more than 100 genes, known as the CBF regulon, which contribute to an increase in freezing tolerance. In this study, we investigated the extent to which cold induction of the CBF regulon is regulated by transcription factors other than CBF1, CBF2 and CBF3, and whether freezing tolerance is dependent on a functional CBF–CRT/DRE regulatory module. To address these issues we generated transgenic lines that constitutively overexpressed a truncated version of CBF2 that had dominant negative effects on the function of the CBF–CRT/DRE regulatory module, and 11 transcription factors encoded by genes that were rapidly cold‐induced in parallel with the ‘first‐wave’ CBF genes, and determined the effects that overexpressing these proteins had on global gene expression and freezing tolerance. Our results indicate that cold regulation of the CBF regulon involves extensive co‐regulation by other first‐wave transcription factors; that the low‐temperature regulatory network beyond the CBF pathway is complex and highly interconnected; and that the increase in freezing tolerance that occurs with cold acclimation is only partially dependent on the CBF–CRT/DRE regulatory module.