Table_2_Dicer-Like Proteins Regulate Sexual Development via the Biogenesis of Perithecium-Specific MicroRNAs in a Plant Pathogenic Fungus Fusarium graminearum.XLSX

Ascospores act as the primary inoculum of Fusarium graminearum, which causes the destructive disease Fusarium head blight (FHB), or scab. MicroRNAs (miRNAs) have been reported in the F. graminearum vegetative stage, and Fgdcl2 is involved in microRNA-like RNA (milRNA) biogenesis but has no major impact on vegetative growth, abiotic stress or pathogenesis. In the present study, we found that ascospore discharge was decreased in the Fgdcl1 deletion mutant, and completely blocked in the double-deletion mutant of Fgdcl1 and Fgdcl2. Besides, more immature asci were observed in the double-deletion mutant. Interestingly, the up-regulated differentially expressed genes (DEGs) common to ΔFgdcl1 and ΔFgdcl1/2 were related to ion transmembrane transporter and membrane components. The combination of small RNA and transcriptome sequencing with bioinformatics analysis predicted 143 novel milRNAs in wild-type perithecia, and 138 of these milRNAs partly or absolutely depended on Fgdcl1, while only 5 novel milRNAs were still obtained in the Fgdcl1 and Fgdcl2 double-deletion mutant. Furthermore, 117 potential target genes were predicted. Overall, Fgdcl1 and Fgdcl2 genes were partly functionally redundant in ascospore discharge and perithecium-specific milRNA generation in F. graminearum, and these perithecium-specific milRNAs play potential roles in sexual development.

担子孢子作为禾谷镰刀菌（Fusarium graminearum）的主要接种体，引起具有毁灭性的病害——穗腐病（FHB）或黑粉病。在F. graminearum的繁殖阶段中，已发现存在微RNA（miRNA）。Fgdcl2参与类似miRNA的RNA（milRNA）的生物发生，但对繁殖生长、非生物胁迫或致病性没有显著影响。在本研究中，我们发现Fgdcl1缺失突变体中担子孢子释放减少，而Fgdcl1和Fgdcl2双重缺失突变体中担子孢子释放则完全被阻断。此外，在双重缺失突变体中还观察到更多的未成熟子囊。有趣的是，ΔFgdcl1和ΔFgdcl1/2中共同上调的差异表达基因（DEGs）与离子跨膜转运蛋白和膜组分相关。结合小RNA和转录组测序以及生物信息学分析，在野生型子囊中预测出143个新的milRNA，其中138个部分或完全依赖于Fgdcl1，而在Fgdcl1和Fgdcl2双重缺失突变体中仅获得5个新的milRNA。此外，还预测出117个潜在靶基因。总体而言，Fgdcl1和Fgdcl2基因在禾谷镰刀菌担子孢子释放和子囊特异性milRNA生成方面部分功能冗余，这些子囊特异性milRNA在性发育中可能发挥潜在作用。