香蕉枯萎病已严重威胁香蕉产业的发展，为了分析香蕉枯萎病菌尖孢镰刀菌古巴专化型4号生理小种（Fusarium oxysporum F. sp. cubense race 4，Foc4）中miRNA-like（milRNA）及其调控功能，本研究构建了3个Foc4菌丝小RNA测序文库，测序得到原始数据11783990条，其中可用于后续milRNA鉴定的有效数据3351578条，通过与miRbase中植物miRNA和已报道的真菌milRNA进行比对，共预测出7个保守的和3个新型的milRNA。进而利用降解组测序预测milRNA靶基因，共预测出53对milRNA-mRNA。通过对靶基因进行GO和KEGG富集分析，发现milRNA与多个代谢通路有关，包括嘌呤代谢，甘油磷脂代谢，硫胺素代谢和三羧酸循环通路等，对真菌生长发育有重要影响；同时发现milRNA靶向ABC转运器CDR4和孢子壁成熟蛋白DIT1，可能对Foc4致病过程具有重要影响。本研究在高通量测序获得milRNA的基础上，首次在香蕉枯萎病致病菌Foc4中利用降解组测序分析了milRNA靶基因，对研究真菌milRNA调控提供了重要参考，也为香蕉枯萎病的防治提供了新的思路。

Fusarium wilt has seriously threatened the development of the banana industry. In order to analyze the miRNA-like (milRNA) and its regulatory function in the Fusarium oxysporum F. sp. cubense race 4 (Foc4), three Foc4 mycelia small RNA sequencing libraries were constructed. Totally 11,783,990 raw reads were obtained by sequencing, of which 3,351,578 valid reads can be used for subsequent milRNA identification. Through the comparison with the plant miRNAs in miRbase and the reported fungal milRNAs, seven conservative milRNAs and three novel milRNAs were identified. A total of 53 pairs of milRNA-mRNAs were identified through degradome sequencing to predict milRNA target genes. Through GO and KEGG enrichment analysis of target genes, milRNA was found in association with multiple metabolic pathways, including purine metabolism, glycerophospholipid metabolism, thiamine metabolism, and tricarboxylic acid cycle pathways, and would have an important impact on fungal growth and development. In the meantime, milRNA targeted the ABC transporter CDR4 and spore wall mature protein DIT1, thereby probably influencing the pathogenic process of Foc4. This study is the first to analyze milRNA-targeted genes in the pathogen Foc4 via degradome sequencing after milRNA was obtained by high-throughput sequencing, which provides an important reference for studying the regulatory functions of fungal milRNA and new ideas for the prevention and treatment of Fusarium wilt.

广东省公益研究与能力建设专项资金项目（2015B020202005）；广州市科技计划项目基础与应用基础研究项目(202002030051)