不同遮阴处理对茶树叶片主要植物激素生物合成的影响

Effects of different shade treatments on the biosynthesis of main phytohormones in the leaves of tea plants

采用遮阳网覆盖是常见的农艺措施之一,已广泛应用于抹茶生产中。本研究以‘福鼎大白茶’为研究对象,采用黑网、红网、蓝网和黄网遮阴处理茶树以改变茶树生长的光环境(光照强度和光谱组成),以在自然光照条件下生长的茶树为对照组(CK),检测不同遮阴处理下茶树叶片的植物激素水平和转录组谱。结果表明:相较于CK,蓝网遮阴处理可以显著提高茶树叶片中脱落酸、赤霉素类、生长素类、细胞分裂素类、茉莉酸和水杨酸等激素含量,其次为黄网、黑网和红网遮阴处理。转录组测序结果表明,相较于CK,黑网遮阴处理茶样的差异表达基因条数最多(上调3 422条,下调4 074条),然后依次是蓝网(上调476条,下调1 271条)、黄网(上调663条,下调994条)、红网(上调723条,下调810条)。京都基因与基因组百科全书通路富集结果表明,蓝网遮阴处理组与CK比较组中,光合作用-天线蛋白和植物激素信号转导2条通路被显著富集,主要体现在捕光复合物和植物激素信号合成通路相关基因表达明显上调。由此可见,覆盖遮阴可以改变茶树生长的光环境并调节茶树叶片植物激素合成,从而影响茶树新梢生育。

Shade net covering is a conventional agronomic practice, which has been widely applied in the production of matcha. The present study used different shade treatments(black, red, blue, and yellow shade net treatments) to alter the light conditions(including light intensity and spectral composition) for the growth of tea plants, and investigated the effects of different shade treatments on the phytohormone levels and transcriptome profiles of the leaves of ‘Fuding white tea’ plants, with taking the tea plants grown under the natural light conditions as the control group(CK). The results showed that blue shade net treatment significantly increased the contents of abscisic acid, gibberellins, auxins, cytokinins, jasmonic acid, and salicylic acid in the tea leaves compared with CK, followed by yellow, black, and red shade net treatments. The transcriptome sequencing results showed that the most abundant number of differentially expressed genes(DEGs) was observed under the black shade net treatment(3 422 up-regulation, and 4 074 down-regulation) compared with CK, subsequently followed by blue shade net treatment(476 up-regulation, and 1 271 down-regulation), and yellow shade net treatment(663up-regulation, and 994 down-regulation), while the lowest DEGs number was observed under the red shade net treatment(723 up-regulation, and 810 down-regulation). The results of Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis indicated that photosynthesis-antenna proteins as well as plant hormone signal transduction were the significantly enriched pathways in the pair of blue shade net treatment and CK. Especially, the expressions of light-harvesting complex and phytohormone biosynthesis-related genes were greatly up-regulated. Thus, shade net treatments could regulate the biosynthesis of phytohormones in tea plants through altering the light condition underneath, and further affect the growth of tea young shoots.