Genome-wide identification and expression pattern analysis of WRKY transcription factors in response to biotic and abiotic stresses in tea plants (Camellia sinensis).

Plants would encounter various biotic and abiotic stresses during the growth and development. WRKY transcription factors (TFs) as plant-specific TFs, play an important role in responding to various adverse circumstances. Despite some advances were achieved in functional studies of WRKY TFs in tea plants, systematic analysis of the involvement of CsWRKY TFs when facing cold, salt, drought stresses and pathogen and insect attack was lacked. In present study, a total of 78 CsWRKY TFs were identified following the genomic and transcript databases. The expression patterns of CsWRKYs in various organs of tea plants and the expression profiles in response to biotic and abiotic stresses were investigated by examining representative RNA-seq data. Moreover, the effects of hormone treatments (SA and MeJA) on the transcription levels of WRKY TFs were also investigated. The phylogenetic tree of CsWRKY TFs from different species indicated the functional diversity of WRKY TFs was not closely related to their protein classification. Concurrently, CsWRKY70-2 TF was identified as a positive regulator in response to drought stress. This study provided solid and valuable information, helping us better understand the functional diversity of CsWRKY TFs, and laid the foundation for further research on the function of key WRKY genes in tea plants. In this study, 78 WRKY transcription factors had been identified in tea plants as accurately as possible based on the transcriptome and genomic data. At the transcriptomic level, the expression patterns of CsWRKYs in various organs of tea plants and the expression profiles in response to biotic (Ectropis oblique, tea leafhopper and gray-blight attack), abiotic stresses (Cold, drought, salt) and exogenous hormones (SA and MeJA) were investigated. Expression pattern analysis showed that most Cs WRKYs were involved in the process of tea plants resisting biotic and abiotic stresses. Phylogenetic analysis indicated that the functional diversity of CsWRKY TFs was not closely related to their protein classification. In addition, CsWRKY70-2 TF had been proved to play a positive regulatory role in drought stress tolerance. This study provided solid and valuable information, helping better understand the functional diversity of CsWRKY TFs, and laid the foundation for further research on the function of key WRKY genes in tea plants. [ABSTRACT FROM AUTHOR]