Cloning And Expression Analysis Of BZIP Transcription Factor Family Genes In Tea Plant (Camellia Sinensis)

Chilling stress is one of the vital abiotic stresses which limits the growth and geographicaldistribution of plants on the earth. And it impedes the development of global agriculture productions.However, the cold tolerance of plant could be increased through cold acclimation. Tea plant (Camelliasinensis) is an important economic crop around the world, originated from tropical or subtropical ofsouthwest China and been sensitive to chilling. The tea plant breeding for cold hardiness hertherto iscrucial but unsolved. This study aimed at analyzing the relationship between bZIPs transcription factorsand cold resistance of tea plant.12full length cDNA sequences of bZIP transcription factors werecloned utilizing RACE PCR combined with reverse transcription PCR (RT-PCR) methods from resultsof cold acclimation transcriptome sequencing, and their bioinformatic characteristics were also analyzed.The expression patterns of CsbZIPs under natural cold acclimation and artificial cold acclimation weredetected by real-time quantitative PCR (qRT-PCR), respectively.1. The full-length cDNA sequences of12genes named CsbZIP1-12were isolated through RACEPCR and RT-PCR techniques, and had been already submitted to GenBank. The bioinformatics analysisshowed that the12CsbZIPs were divided into seven groups (A-G) according to Arabodopsisclassification methods. And subcellular localization prediction results showed that the CsbZIPs proteinare more inclined to nuclear protein; Phosphorylation sites prediction results showed CsbZIPs proteincontain multiple phosphorylation sites, especially in the majority of tryptophan locus, which confirmedthat the actiities of CsbZIPs protein regulated by phosphorylation. Protein tertiary structure predictionshowed that CsbZIPs protein shared consensus domains of bZIP transcription factor family contained,alpha helix structure domain and leucine zipper structure.2. The expression profiles of12groups of CsbZIPs under natural cold acclimation by qRT-PCRindicated that the expression level of G group was weaker than others and no fluctuation, and nothingthat this group related to cold resistance in tea plant. However, the all other of6groups were detected,and their expression level showed “low-high-low” variation according with progress of “beforeacclimation-after acclimation-removing acclimation” and cold-hardness of “weak-strong-weak” of teaplant. The expression patterns between cold resistence varieties of tea plants were different, whichdemonstrated that CsbZIPs expression may related to genetic traits of tea plants. And the expressionpatterns of CsbZIPs displayed differences in the same cultivar, this may due to the structure diversity ofCsbZIPs. The further experiments showed the cultivars which had stronger cold hardiness had higherexpression level of CsbZIPs than that of the cultivars which had weaker cold hardiness during the sameacclimation stage.3. The expression patterns of CsbZIPs under artifical cold acclimation had a similarity with undernatural cold acclimation. And the expression level of G still remained low, but the rest6groups weredetected. The expression pattern of different groups of CsbZIPs showed that all the highest level wasafter reaching the critical temperature of cold acclimation and expression fluctuation of “low-high-low” reflected with the temperature treatment. The results verificated the effects of CsbZIPs on coldhardiness of tea plant under natural cold acclimation.