Abstract: WRKY transcription factors, a super family of plant transcription factors, play an essential role in the regulation of plant defense responses to herbivores. While the roles of herbivore-related WRKY transcription factors are well established in grass plants, their roles in woody plants are still largely unknown. Here, we cloned a WRKY transcription factor, named CsWRKY17. CsWRKY17 has a full length of 1 141 bp, contains a 987 bp open reading frame, and encodes 328 amino acids. Based on the conserved domain analysis, CsWRKY17 belongs to the WRKY Ⅱ subfamily, containing one conserved WRKY domain and a typical C₂H₂-type zinc finger motif. Homology alignment and phylogenetic tree analysis show that CsWRKY17 has the closest relationship with AtWKRY11 and AtWRKY17 in Arabidopsis thaliana. Moreover, CsWRKY17 exhibited a tissue specific expression, and was also induced by mechanical wounding, tea geometrid (Ectropis oblique) attack, simulated herbivory, and exogenous phytohormone treatments like JA. Transient expression experiments indicate that it might play a role in the nucleus. Taken together, we proposed that CsWRKY17 is a potential regulator of herbivore-induced defense responses against herbivores in tea plants through JA, ABA, GA and BR signaling. Our study paved the way for molecular analysis of herbivore-related WRKY genes in tea plants, and provided a good genetic resource and theoretical basis for future studies of pest-resistant genes and breeding of tea plants.

Key words: Camellia sinensis, WRKY transcription factors, CsWRKY17, expression analysis, herbivore resistance