Ji Chuanya, Song Fang, He Chuan, An Jianyong, Huang Shengyu, Yu Huimin, Lu Hang, Xiao Shunyuan, Bucher Marcel, Pan Zhiyong
National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, China.
Institute of Fruit and Tea, Hubei Academy of Agricultural Sciences, Wuhan, China.
Plant Cell Environ. 2023 Jun;46(6):1805-1821. doi: 10.1111/pce.14564. Epub 2023 Feb 19.
Over 70% land plants live in mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi, and maintenance of symbiosis requires transcriptional and post-transcriptional regulation. The former has been widely studied, whereas the latter mediated by symbiotic microRNAs (miRNAs) remains obscure, especially in woody plants. Here, we performed high-throughput sequencing of the perennial woody citrus plant Poncirus trifoliata and identified 3750 differentially expressed genes (DEGs) and 42 miRNAs (DEmiRs) upon AM fungal colonization. By analyzing cis-regulatory elements in the promoters of the DEGs, we predicted 329 key AM transcription factors (TFs). A miRNA-mRNA regulatory network was then constructed by integrating these data. Several candidate miRNA families of P. trifoliata were identified whose members target known symbiotic genes, such as miR167h-AMT2;3 and miR156e-EXO70I, or key TFs, such as miR164d-NAC and miR477a-GRAS, thus are involved in AM symbiotic processes of fungal colonization, arbuscule development, nutrient exchange and phytohormone signaling. Finally, analysis of selected miRNA family revealed that a miR159b conserved in mycorrhizal plant species and a Poncirus-specific miR477a regulate AM symbiosis. The role of miR477a was likely to target GRAS family gene RAD1 in citrus plants. Our results not only revealed that miRNA-mRNA network analysis, especially miRNA-TF analysis, is effective in identifying miRNA family regulating AM symbiosis, but also shed light on miRNA-mediated post-transcriptional regulation of AM symbiosis in woody citrus plants.
超过70%的陆地植物与丛枝菌根（AM）真菌形成互利共生关系，而共生关系的维持需要转录和转录后调控。前者已得到广泛研究，而由共生微小RNA（miRNA）介导的后者仍不清楚，尤其是在木本植物中。在这里，我们对多年生木本柑橘植物枳进行了高通量测序，鉴定出3750个差异表达基因（DEG）和42个miRNA（DEmiR）在AM真菌定殖后出现差异。通过分析DEG启动子中的顺式调控元件，我们预测了329个关键的AM转录因子（TF）。然后通过整合这些数据构建了一个miRNA-mRNA调控网络。鉴定出了枳的几个候选miRNA家族，其成员靶向已知的共生基因，如miR167h-AMT2;3和miR156e-EXO70I，或关键TF，如miR164d-NAC和miR477a-GRAS，因此参与了真菌定殖、丛枝发育、养分交换和植物激素信号传导的AM共生过程。最后，对选定的miRNA家族的分析表明，在菌根植物物种中保守的miR159b和枳特异性的miR477a调节AM共生。miR477a的作用可能是靶向柑橘植物中的GRAS家族基因RAD1。我们的结果不仅表明miRNA-mRNA网络分析，尤其是miRNA-TF分析，在鉴定调节AM共生的miRNA家族方面是有效的，而且还揭示了木本柑橘植物中miRNA介导的AM共生转录后调控机制。
