Identification of a novel bZIP transcription factor in Camellia sinensis as a negative regulator of freezing tolerance in transgenic arabidopsis.
Basic region/leucine zipper (bZIP) transcription factors play vital roles in the abiotic stress response of plants. However, little is known about the function of bZIP genes in Camellia sinensis .



CsbZIP6 was overexpressed in Arabidopsis thaliana . Effects of CsbZIP6 overexpression on abscisic acid (ABA) sensitivity, freezing tolerance and the expression of cold-responsive genes in arabidopsis were studied.



CsbZIP6 was induced during cold acclimation in tea plant. Constitutive overexpression of CsbZIP6 in arabidopsis lowered the plants' tolerance to freezing stress and ABA exposure during seedling growth. Compared with wild-type (WT) plants, CsbZIP6 overexpression (OE) lines exhibited increased levels of electrolyte leakage (EL) and malondialdehyde (MDA) contents, and reduced levels of total soluble sugars (TSS) under cold stress conditions. Microarray analysis of transgenic arabidopsis revealed that many differentially expressed genes (DEGs) between OE lines and WT plants could be mapped to 'response to cold' and 'response to water deprivation' terms based on Gene Ontology analysis. Interestingly, CsbZIP6 overexpression repressed most of the cold- and drought-responsive genes as well as starch metabolism under cold stress conditions.



The data suggest that CsbZIP6 functions as a negative regulator of the cold stress response in A. thaliana , potentially by down-regulating cold-responsive genes.
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.|Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou 310008, China.
Lu
L
Wang
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.
Hongli
H
Cao
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.|College of Horticulture, Northwest Agriculture and Forestry University, Yangling, 712100, China.
Wenjun
W
Qian
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.
Lina
L
Yao
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.|Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou 310008, China.
Xinyuan
X
Hao
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.
Nana
N
Li
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.|Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou 310008, China.
Yajun
Y
Yang
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.|Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou 310008, China.
Xinchao
X
Wang
D000040:Abscisic Acid; D000064:Acclimatization / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics*; D028241:Camellia sinensis / Q000235:genetics* / Q000502:physiology; D003080:Cold Temperature; D005615:Freezing; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000235:genetics; D013312:Stress, Physiological
D050976:Basic-Leucine Zipper Transcription Factors; D010940:Plant Proteins; D000040:Abscisic Acid
CsbZIP6; cold stress; tea plant (Camellia sinensis); transcription factor; transgenic arabidopsis