Table_3_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的主要接种体，是引起毁灭性的病害——禾谷镰刀菌头腐病（FHB）或黑粉病的病原。在禾谷镰刀菌的生殖阶段中，已报道存在微RNAs（miRNAs），其中Fgdcl2参与类miRNA（milRNA）的生物发生，但对营养生长、非生物胁迫或致病性并无显著影响。在本研究中，我们发现Fgdcl1缺失突变体中的担子孢子排放减少，而在Fgdcl1和Fgdcl2双缺失突变体中，担子孢子排放被完全阻断。此外，在双缺失突变体中还观察到更多未成熟的子囊。有趣的是，ΔFgdcl1和ΔFgdcl1/2共同上调的差异表达基因（DEGs）与离子跨膜转运蛋白和膜成分相关。结合小RNA和转录组测序以及生物信息学分析，预测了野生型子囊座中的143个新的milRNA，其中138个milRNA部分或完全依赖于Fgdcl1，而在Fgdcl1和Fgdcl2双缺失突变体中，仅获得5个新的milRNA。此外，还预测了117个潜在靶基因。总体而言，Fgdcl1和Fgdcl2基因在禾谷镰刀菌的担子孢子排放和子囊座特异性milRNA生成方面部分功能冗余，这些子囊座特异性milRNA在性发育中可能发挥潜在作用。