Tea Science Research Institute, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing, 210095, China.
Mol Biotechnol. 2024 Nov;66(11):3311-3322. doi: 10.1007/s12033-023-00942-5. Epub 2023 Oct 28.
Tea plants (Camellia sinensis (L.) O. Kuntze) belong to Theaceae family, in the section Thea. Tea plants are widely distributed in subtropical and tropical regions in the word. α-carotene and β-carotene in the tea leaves belong to carotenoids, which are associated with the aroma and color of the tea. Phytoene synthase (PSY) is a rate-limiting enzyme in carotenoids biosynthesis. We identified three CsPSY genes in 'Shuchazao', named CsPSY1, CsPSY2, and CsPSY3. Structural analysis of three CsPSY genes showed that CsPSY1 had a longer intro structure. The cis-acting elements of CsPSYs promoter were mainly associated with light-responsiveness, abiotic stress-responsiveness, and hormone-responsiveness. CsPSY1 exhibited expression in all tissues of the tea plants, whereas CsPSY2 and CsPSY3 were trace expression levels in all tissues. The positive expression of CsPSY1 under hormonal and abiotic stresses suggested its role in plant development and defense responses. The amino acid sequence of CsPSY1 was highly conserved in eight tea cultivars. The recombinant vector pCAMBIA1301-CsPSY1 was constructed to stabilize the overexpression of CsPSY1 in carrot. The contents of α-carotene and β-carotene in transgenic carrot callus were significantly increased. This study provides a foundational basis for further research on the function of CsPSYs and carotenoids accumulation in tea plants.
茶树（Camellia sinensis (L.) O. Kuntze）属于山茶科，茶属。茶树广泛分布于世界亚热带和热带地区。茶叶中的α-胡萝卜素和β-胡萝卜素属于类胡萝卜素，与茶叶的香气和颜色有关。八氢番茄红素合成酶（PSY）是类胡萝卜素生物合成的限速酶。我们在‘树茶早’中鉴定了三个 CsPSY 基因，分别命名为 CsPSY1、CsPSY2 和 CsPSY3。三个 CsPSY 基因的结构分析表明，CsPSY1 具有更长的内含子结构。CsPSYs 启动子的顺式作用元件主要与光响应、非生物胁迫响应和激素响应有关。CsPSY1 在茶树的所有组织中均有表达，而 CsPSY2 和 CsPSY3 在所有组织中的表达水平均较低。CsPSY1 在激素和非生物胁迫下的阳性表达表明其在植物发育和防御反应中的作用。CsPSY1 的氨基酸序列在八个茶树品种中高度保守。构建了重组载体 pCAMBIA1301-CsPSY1，以稳定地过表达胡萝卜中的 CsPSY1。转基因胡萝卜愈伤组织中α-胡萝卜素和β-胡萝卜素的含量显著增加。本研究为进一步研究 CsPSYs 功能和茶树中类胡萝卜素积累提供了基础。
