MicroRNAs (miRNAs) are about 22 nucleotides regulatory non-coding RNAs that play versatile roles in reprogramming plant responses to biotic and abiotic stresses. However, it remains unknown whether miRNAs confer the resistance to necrotrophic fungus Rhizoctonia solani in rice. To investigate whether miRNAs regulate the resistance to R. solani, we constructed 12 small RNA libraries from susceptible and resistant rice cultivars treated with water/pathogen at 5 h post inoculation (hpi), 10 hpi and 20 hpi, respectively. By taking the advantage of next-generation sequencing, we totally collected 400–450 known miRNAs and 450–620 novel miRNAs from the libraries. Expression analysis of miRNAs demonstrated different patterns for known and novel miRNAs upon R. solani challenge. Thirty-four miRNA families were identified to be expressed specifically in rice, and most of them were involved in plant disease resistance. A particular Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis result revealed that a great majority of target genes of regulated miRNAs belonged to the pathway of plant-pathogen interaction. Moreover, miR444b.2, miR531a, mir1861i, novel_miR1956 and novel_miR135 conferred response to R. solani infection confirmed by Northern blot. Our global understanding of miRNA profiling revealed that the regulation of miRNAs may be implicated in the control of rice immunity to R. solani. Analysis of the expression of miRNAs will offer the community with a direction to generate appropriate strategies for controlling rice sheath blight disease.

微小RNA（miRNA）是约22个核苷酸的调节性非编码RNA，在重新编程植物对生物和非生物胁迫的反应中起多种作用。然而，尚不清楚miRNA是否赋予水稻抗坏死性真菌Rhozoctonia solani的抗性。为了研究miRNA是否调节对R. solani的抗性，我们分别在接种后5 h，10 hpi和20 hpi的水/病原体处理的敏感和抗性水稻品种中构建了12个小RNA文库。利用下一代测序的优势，我们从文库中共收集了400–450个已知的miRNA和450–620个新颖的miRNA。对miRNA的表达分析表明，在solani细菌中已知和新颖的miRNA的模式不同挑战。已鉴定出34个miRNA家族在水稻中特异性表达，其中大多数与植物抗病性有关。特定的《京都基因与基因组百科全书》（KEGG）途径分析结果显示，受调控的miRNA的大多数靶基因都属于植物-病原体相互作用的途径。此外，通过Northern印迹证实，miR444b.2，miR531a，mir1861i，novel_miR1956和novel_miR135赋予了对茄红痢疾杆菌感染的响应。我们对miRNA分析的全球了解表明，miRNA的调控可能与水稻对solani solani的免疫控制有关。。分析miRNA的表达将为社区提供指导，以产生控制水稻鞘枯病的适当策略。