Analysis of thaumatin-like protein (TLP) gene family in tea plant revealed that CsTLP8 contributes to tea blister blight resistance.

BACKGROUND: Thaumatin-like proteins (TLPs) belong to the PR-5 family of the pathogenesis-related (PR) proteins, and have been widely reported in plants for their important role in resisting pathogenic bacteria. However, people know very little about the function it plays in helping tea plants resist tea blister blight. RESULTS: In the tea plant, a total of 43 CsTLPs were detected. According to the evolutionary tree analysis, these genes can be divided into 9 subfamilies. Through promoter analysis, a substantial quantity of elements associated with stress, hormone response, as well as growth and development were identified. The collinearity analysis indicates that the sequences of multiple CsTLPs genes have high homology in tea plants. The combination of transcriptome analysis and qRT-PCR demonstrated that the expression of CsTLP8, CsTLP23, CsTLP28 and CsTLP34 were significantly up-regulated after tea blister blight infection. In addition, we have verified the functionality of CsTLP8. CsTLP8 is localized in cytoplasm, and has β-1,3-glucanase activity. Transient overexpression of CsTLP8 in tobacco can significantly increase POD and CAT activities and decrease hydrogen peroxide content. CONCLUSIONS: The results will help to better understand the role of CsTLPs gene family in tea blister blight, and provide theoretical support for improving disease resistance of tea trees and breeding new varieties resistant to disease.