CsbZIP6 is a negative regulator of cold response in transgenic arabidopsis

The tea plant CsbZIP6 transcription factor functions as a negative regulator of the cold stress response in Arabidopsis thaliana, potentially by down-regulating cold-responsive genes.

Changes in air temperature and CsbZIP6 expression levels in the leaves of six tea plant cultivars during cold acclimation. (A) Changes in the air temperature from November 2015 to February 2016. The maximum (Max), minimum (Min) and average (Avg) daily temperatures recorded are shown. Leaf sampling time points are indicated with red circles on the x-axis. The Avg temperatures on sampling days were 22·9 °C (6 November), 6·1 °C (25 November), 8·4 °C (15 December), 3·9 °C (13 January) and 7·3 °C (25 February). (B) Expression analysis of CsbZIP6 and CsCBF1 transcript abundance in the leaves of six tea plant cultivars during cold acclimation. Transcript abundance was determined by qRT-PCR. Data are shown as the mean ± s.e.m. (n = 3). All values are expressed relative to the CsPTB expression level.

Wang et al. find that constitutive overexpression of CsbZIP6 in Arabidopsis lowered tolerance to freezing stress during seedling growth, exhibiting increased levels of electrolyte leakage and malondialdehyde contents, and reduced levels of total soluble sugars under cold stress conditions. Microarray analysis revealed that CsbZIP6 overexpression repressed most of the cold- and drought-responsive genes as well as the starch metabolism under cold stress conditions.