Jin Hongmiao, Yang Zhengfu, Luo Jia, Li Caiyun, Chen Junhao, Lim Kean-Jin, Wang Zhengjia
State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, Zhejiang, China.
Front Plant Sci. 2023 Jan 4;13:1000489. doi: 10.3389/fpls.2022.1000489. eCollection 2022.
Flower bud differentiation represents a crucial transition from vegetative growth to reproductive development. (hickory) is an important economic species in China, with a long juvenile period that hinders its commercial development. In recent years, circular RNAs (circRNAs) have been widely studied and identified as sponges for miRNA regulation of mRNA expression. However, little is known regarding the role of circRNAs in flower buds. In this study, we sequenced circRNAs at three developmental stages (undifferentiated, differentiating, and fully differentiated) in both female and male buds. A total of 6,931 circRNAs were identified in the three developmental stages and 4,449 and 2,209 circRNAs were differentially expressed in female and male buds, respectively. Gene ontology demonstrated that many circRNA host genes participated in various processes, for example, cellular and intracellular pH regulation. Function annotation identified 46 differentially expressed circRNAs involved in flowering regulation, with 28 circRNAs found only in female buds, 4 found only in male buds, and 11 found in both female and male buds. A circRNA-miRNA-mRNA network was predicted based on 13 flowering-related circRNAs and their seven putative interacting miRNAs to describe the regulatory mechanism. Our preliminary results demonstrated a potential involvement of circRNA in bud differentiation. They provided a preliminary theoretical basis for how circRNA might participate in flower development in hickory, perhaps in woody plants.
花芽分化代表了从营养生长到生殖发育的关键转变。山核桃是中国一种重要的经济树种，但其幼年期较长，这阻碍了它的商业开发。近年来，环状RNA（circRNA）已得到广泛研究，并被确定为调控mRNA表达的miRNA海绵。然而，关于circRNA在花芽中的作用却知之甚少。在本研究中，我们对雌花和雄花在三个发育阶段（未分化、分化中和完全分化）的circRNA进行了测序。在这三个发育阶段共鉴定出6931个circRNA，其中雌花和雄花中分别有4449个和2209个circRNA差异表达。基因本体论表明，许多circRNA宿主基因参与了各种过程，例如细胞和细胞内pH调节。功能注释鉴定出46个参与开花调控的差异表达circRNA，其中28个仅在雌花中发现，4个仅在雄花中发现，11个在雌花和雄花中均有发现。基于13个与开花相关的circRNA及其7个假定的相互作用miRNA预测了一个circRNA-miRNA-mRNA网络，以描述其调控机制。我们的初步结果表明circRNA可能参与了芽分化。这些结果为circRNA可能如何参与山核桃以及或许木本植物的花发育提供了初步的理论基础。
