State Key Laboratory of Tea Plant Biology and Utilization/Key Laboratory of Tea Biology and Processing, Ministry of Agriculture, Anhui Agricultural University, West 130 Changjiang Road, Hefei, 230036, Anhui, People's Republic of China.
Department of Genetics, University of Georgia, 120 E Green Street, Athens, GA, 30602, USA.
BMC Plant Biol. 2018 Nov 6;18(1):266. doi: 10.1186/s12870-018-1497-9.
Alternative splicing (AS) regulates mRNA at the post-transcriptional level to change gene function in organisms. However, little is known about the AS and its roles in tea plant (Camellia sinensis), widely cultivated for making a popular beverage tea.
In our study, the AS landscape and dynamics were characterized in eight tissues (bud, young leaf, summer mature leaf, winter old leaf, stem, root, flower, fruit) of tea plant by Illumina RNA-Seq and confirmed by Iso-Seq. The most abundant AS (~ 20%) was intron retention and involved in RNA processes. The some alternative splicings were found to be tissue specific in stem and root etc. Thirteen co-expressed modules of AS transcripts were identified, which revealed a similar pattern between the bud and young leaves as well as a distinct pattern between seasons. AS events of structural genes including anthocyanidin reductase and MYB transcription factors were involved in biosynthesis of flavonoid, especially in vegetative tissues. The AS isoforms rather than the full-length ones were the major transcripts involved in flavonoid synthesis pathway, and is positively correlated with the catechins content conferring the tea taste. We propose that the AS is an important functional mechanism in regulating flavonoid metabolites.
Our study provides the insight into the AS events underlying tea plant's uniquely different developmental process and highlights the important contribution and efficacy of alternative splicing regulatory function to biosynthesis of flavonoids.
选择性剪接（AS）在转录后水平上调节 mRNA，从而改变生物体中的基因功能。然而，对于茶树（Camellia sinensis），即广泛用于制作流行饮品茶的植物，其 AS 及其作用知之甚少。
在我们的研究中，通过 Illumina RNA-Seq 对茶树的八个组织（芽、嫩叶、夏季成熟叶、冬季老叶、茎、根、花、果）中的 AS 景观和动态进行了描述，并通过 Iso-Seq 进行了验证。最丰富的 AS（~20%）是内含子保留，参与 RNA 过程。在茎和根等组织中发现了一些组织特异性的选择性剪接。鉴定出 13 个共表达的 AS 转录本模块，其揭示了芽和嫩叶之间的相似模式以及季节之间的明显模式。包括类黄酮还原酶和 MYB 转录因子在内的结构基因的 AS 事件参与了类黄酮的生物合成，特别是在营养组织中。AS 异构体而不是全长异构体是参与类黄酮合成途径的主要转录本，并且与儿茶素含量呈正相关，赋予茶的味道。我们提出，AS 是调节类黄酮代谢物的重要功能机制。
本研究深入了解了茶树独特发育过程中的 AS 事件，并强调了选择性剪接调节功能对类黄酮生物合成的重要贡献和功效。
