Wang Xiangyu, Yu Guangchao, Zhao Junyue, Cui Na, Yu Yang, Fan Haiyan
College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China.
College of Horticulture, Shenyang Agricultural University, Shenyang, China.
Front Plant Sci. 2019 May 31;10:668. doi: 10.3389/fpls.2019.00668. eCollection 2019.
Target leaf spot (TLS), which is caused by (), is one of the most important diseases in cucumber ( L.). Our previous research identified several -responsive miRNAs in cucumber by high-throughput sequencing, including two known miRNAs and two novel miRNAs. The target genes of these miRNAs were related to secondary metabolism. In this study, we verified the interaction between these miRNAs and target genes by histochemical staining and fluorescence quantitative assays of GUS. We transiently expressed the candidate miRNAs and target genes in cucumber cotyledons to investigate the resistance to . Transient expression of miR164d, miR396b, Novel-miR1, and Novel-miR7 in cucumber resulted in decreased resistance to , while transient expression of (inhibited by miR164d), (inhibited by miR396b), (inhibited by Novel-miR1), and (inhibited by Novel-miR7) led to enhanced resistance to . In addition, overexpression of and downregulated lignin synthesis, and overexpression of Novel-miR1 and Novel-miR7 also downregulated lignin synthesis, indicating that the regulation of and by Novel-miR1 and Novel-miR7 could affect lignin content. The tobacco rattle virus (TRV) induced short tandem target mimic (STTM)-miRNA silencing vector was successfully constructed, and target miRNAs were successfully silenced. The identification of disease resistance and lignin content showed that silencing candidate miRNAs could improve cucumber resistance to .
靶斑病（TLS）由（）引起，是黄瓜（L.）最重要的病害之一。我们之前的研究通过高通量测序在黄瓜中鉴定了几种响应（）的miRNA，包括两种已知miRNA和两种新miRNA。这些miRNA的靶基因与次生代谢有关。在本研究中，我们通过组织化学染色和GUS荧光定量分析验证了这些miRNA与靶基因之间的相互作用。我们在黄瓜子叶中瞬时表达候选miRNA和靶基因以研究对（）的抗性。黄瓜中miR164d、miR396b、新miR1和新miR7的瞬时表达导致对（）的抗性降低，而（受miR164d抑制）、（受miR396b抑制）、（受新miR1抑制）和（受新miR7抑制）的瞬时表达导致对（）的抗性增强。此外，（）和（）的过表达下调了木质素合成，新miR1和新miR7的过表达也下调了木质素合成，表明新miR1和新miR7对（）和（）的调控可能影响木质素含量。成功构建了烟草脆裂病毒（TRV）诱导的短串联靶标模拟（STTM）-miRNA沉默载体，并且靶标miRNA被成功沉默。抗病性和木质素含量鉴定表明，沉默候选miRNA可以提高黄瓜对（）的抗性。
