Zhang Liping, Wang Donghui, Zhang Lan, Fu Jianyu, Yan Peng, Ge Shibei, Li Zhengzhen, Ahammed Golam Jalal, Han Wenyan, Li Xin
Key Laboratory of Tea Quality and Safety Control, Ministry of Agriculture and Rural Affairs, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, China.
College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, China.
Front Plant Sci. 2022 Aug 22;13:977086. doi: 10.3389/fpls.2022.977086. eCollection 2022.
Alternative splicing (AS) is a process by which several functional splice variants are generated from the same precursor mRNA. In our recent study, five splice variants with various numbers of ATTTA motifs in the untranslated regions (UTRs) were cloned. Meanwhile, their transient expression, as well as the expression and functional analysis in the two shoot branching processes were studied. Here, we examined how these splice variants regulate the other three important shoot branching processes, including the spring tea development, the distal branching of new shoots, and the shoot branching induced by 2,3,5-triiodobenzoic acid (TIBA) spraying, and thus unraveling the key transcripts which play the most important roles in the shoot branching of tea plants. The results showed that the increased expression of 5' UTR AS3, 3' UTR AS1 and 3' UTR AS2 could contribute to the increased synthesis of Z/iP-type cytokinins (CKs), thus promoting the spring tea development. Meanwhile, in the TIBA-induced shoot branching or in the distal branching of the new shoots, transcripts regulated the synthesis of CsA-IPT5 protein and CKs through transcriptional regulation of the ratios of its splice variants. Moreover, 3' UTR AS1 and 3' UTR AS2 both play key roles in these two processes. In summary, it is revealed that 3' UTR AS1 and 3' UTR AS2 of might act as the predominant splice variants in shoot branching of the tea plant, and they both can serve as gene resources for tea plant breeding.
可变剪接（AS）是一个从同一前体mRNA产生多个功能剪接变体的过程。在我们最近的研究中，克隆了五个在非翻译区（UTR）具有不同数量ATTTA基序的剪接变体。同时，研究了它们的瞬时表达以及在两个枝条分枝过程中的表达和功能分析。在此，我们研究了这些剪接变体如何调节其他三个重要的枝条分枝过程，包括春茶发育、新梢的远端分枝以及2,3,5-三碘苯甲酸（TIBA）喷施诱导的枝条分枝，从而揭示在茶树枝条分枝中起最重要作用的关键转录本。结果表明，5'UTR AS3、3'UTR AS1和3'UTR AS2表达的增加有助于Z/iP型细胞分裂素（CKs）合成的增加，从而促进春茶发育。同时，在TIBA诱导的枝条分枝或新梢的远端分枝中，转录本通过对其剪接变体比例的转录调控来调节CsA-IPT5蛋白和CKs的合成。此外，3'UTR AS1和3'UTR AS2在这两个过程中都起关键作用。总之，研究表明 的3'UTR AS1和3'UTR AS2可能是茶树枝条分枝中的主要剪接变体，它们都可作为茶树育种的基因资源。
