Institute of Plant Biology and Department of Life Science, National Taiwan University, Taipei 10617, Taiwan.
Institute of Plant Biology and Department of Life Science, National Taiwan University, Taipei 10617, Taiwan; Academy of Agricultural Sciences, Sanming 365000, Fujian, China.
Plant Sci. 2020 Mar;292:110391. doi: 10.1016/j.plantsci.2019.110391. Epub 2019 Dec 27.
Plant microRNAs (miRNAs) are non-coding RNAs, which are composed of 20-24 nucleotides. MiRNAs play important roles in plant growth and responses to biotic and abiotic stresses. Wounding is one of the most serious stresses for plants; however, the regulation of miRNAs in plants upon wounding is not well studied. In this study, miR2111, a wound-repressed miRNA, identified previously in sweet potato (Ipomoea batatas cv Tainung 57) by small RNA deep sequencing was chosen for further analysis. Based on sweet potato transcriptome database, F-box/kelch repeat protein (IbFBK), a target gene of miR2111, was identified. IbFBK is a wound-inducible gene, and the miR2111-induced cleavage site in IbFBK mRNA is between the 10th and 11th nucleotides of miR2111. IbFBK is a component of the E3 ligase SCF (SKP1-Cullin-F-box) complex participating in protein ubiquitination and degradation. The results of yeast two-hybrid and bimolecular fluorescence complementation assays demonstrate that IbFBK was conjugated with IbSKP1 through the F-box domain in IbFBK N-terminus to form SCF complex, and interacted with IbCNR8 through the kelch-repeat domain in IbFBK C-terminus. The interaction of IbFBK and IbCNR8 may lead to the ubiquitination and degradation of IbCNR8. In conclusion, the suppression of miR2111 resulted in the increase of IbFBK, and may regulate protein degradation of IbCNR8 in sweet potato responding to wounding.
植物 microRNAs (miRNAs) 是一类非编码 RNA，由 20-24 个核苷酸组成。miRNAs 在植物生长和应对生物及非生物胁迫中发挥重要作用。创伤是植物面临的最严重胁迫之一；然而，miRNAs 在植物受到创伤后的调控机制还没有得到很好的研究。在本研究中，我们选择了先前在甘薯（Ipomoea batatas cv Tainung 57）中通过小 RNA 深度测序鉴定的受创伤抑制的 miRNA miR2111 进行进一步分析。基于甘薯转录组数据库，鉴定到 IbFBK（miR2111 的一个靶基因）是一个 F-box/kelch 重复蛋白。IbFBK 是一个受创伤诱导的基因，miR2111 在 IbFBK mRNA 上的切割位点位于 miR2111 的第 10 和第 11 个核苷酸之间。IbFBK 是参与蛋白质泛素化和降解的 E3 连接酶 SCF（SKP1-Cullin-F-box）复合物的一个组成部分。酵母双杂交和双分子荧光互补实验的结果表明，IbFBK 通过其 N 端的 F-box 结构域与 IbSKP1 连接形成 SCF 复合物，并通过 C 端的 kelch 重复结构域与 IbCNR8 相互作用。IbFBK 和 IbCNR8 的相互作用可能导致 IbCNR8 的泛素化和降解。总之，miR2111 的抑制导致 IbFBK 的增加，可能调节甘薯对创伤反应中 IbCNR8 的蛋白质降解。
