MG引起的鸡慢性呼吸道病是降低养禽业经济效益的重大疾病，迄今未找到理想的防治措施。研究表明，miRNA在病原致病中发挥着重要的作用，而在MG致病中miRNA的研究尚未见报道。本项目以MG-HS感染鸡为对象，拟利用Illumina深度测序技术鉴定感染前后气管中差异表达的miRNAs，并用real time-PCR、Northern blot、原位杂交等技术进行验证；采用生物信息学技术预测及分析差异表达miRNA潜在的靶基因，利用miRNA-mRNA复合物分析及pGL3 Luciferase报告基因载体等方法对靶基因进行鉴定；通过反义寡核苷酸及超表达miRNA技术对特异miRNA进行功能研究；利用逆转录病毒介导超表达和RNAi技术研究靶基因的功能，阐明miRNAs在MG-HS感染中的分子调控机制。项目的完成将诠释MG的致病机理，为分子抗病育种和miRNA疗法提供理论基础和科学方法。

Chronic respiratory disease（CRD）infected by Mycoplasma gallisepticum（MG）is the most important factor depressing the economic benefit of poultry industry. However, there isn't active prevention measure nowaday. Although miRNA take contribution to the pathopoiesis of most etiological agent, the research of miRNA contribution on the effect of MG infection is still unknown. miRNAs differentially expressed in broiler trachea and lung infected by MG-HS strain will be screened with Illumina extensive sequencing technology, and further identified with real time PCR, Northern blot and hybridization in situ. The potential target genes of miRNA will be forecasted with bioinformatics, and assessed with analytical method of miRNA-mRNA compound and report gene pGL3Luciferase. miRNA contribution will be investigated with antisense oligonucleotide and miRNA overexpresssion technique. Moreover, the function of target genes will be demonstrated with the target gene silencing by RNA interference. According to the above results,The molecular regulating mechanism of miRNAs in broilers to Mycoplasma gallisepticum infection could be illuminated. This research will be beneficial to explain the molecular mechanism of CRD etiopathogenesis，and contribute theory and technological foundation to CRD prevention, treatment and molecular breeding for CRD resistance.