TRANSPARENT TESTA GLABRA1 (TTG1) regulates leaf trichome density in tea Camellia sinensis

• Published in: Nordic journal of botany Vol. 38; no. 1
• Main Authors: Sun, Binmei, Zhu, Zhangsheng, Liu, Renjian, Wang, Limei, Dai, Fengling, Cao, Fanrong, Liu, Shaoqun
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.2020; Wiley Subscription Services, Inc
• Subjects: Camellia sinensis; CsTTG1; Cultivars; Cytoplasm; Diagnostic systems; Genetic control; Herbivores; Leaves; Molecular modelling; Plant resistance; Planting density; Proteins; Taxonomy; Tea; Transcription; trichome formation; Trichomes; WD-repeat protein
• ISSN: 0107-055X; 1756-1051
• DOI: 10.1111/njb.02592

Plant leaf trichomes are both essential for taxonomy and participate in plant resistance to biotic and abiotic stresses. In the tea plant, teaf trichomes vary significantly among different varieties, ranging from leaves with high trichome density to relatively glabrous leaves. Leaf trichomes provides crucial diagnostic characters for tea identification and taxonomy. In addition, trichomes are a valued trait in tea production; leaf trichomes are generally considered to be associated with improved taste. However, the molecular mechanisms of trichome formation and the genetic control of trichome density in tea plants remain unknown. In this study, we identified a gene named TRANSPARENT TESTA GLABRA1 (CsTTG1), which encodes a WD‐repeat protein and is associated with trichome formation in tea. The results also showed that CsTTG1 is particularly highly expressed in the top bud, which is consistent with trichome formation in this tissue. CsTTG1 encodes a protein localized in both the nucleus and the cytoplasm. In addition, the transcription level of CsTTG1 was related to the length and/or density of the trichomes in different tea cultivars with diverse leaf trichome densities and overexpressing CsTTG1 increased the number of trichomes in Arabidopsis thaliana. Collectively, our results indicate that CsTTG1 is involved in regulating trichome formation in general and that the expression level of CsTTG1 is related to trichome density in tea plants. Our results may facilitate research on tea taxonomy and the adaptation of tea to its habitats.