【摘要】 为探讨黑斑原■（Glyptosternum maculatum）水霉病的致病机理，采用组织学、分子生物学以及转录组学方法研究体质量为（58.16±26.65)g的黑斑原感染水霉病后皮肤组织形态结构变化、Tolling-like受体及其相关信号通路基因在皮肤中的表达。结果表明，人工感染水霉菌后，黑斑原体表伤口处可明显观察到菌丝，随着感染时间的增长，病灶迅速扩大，菌丝体的长度不断增长，呈棉絮状；菌丝周围裸露的真皮出现红肿甚至溃烂，感染个体大量死亡。基于转录组数据，共获得黑斑原Tolls样受体基因7种，分属于不同的Tlr家族。实时荧光定量PCR结果显示，感染水霉菌48 h后，皮肤中tlr3和tlr13基因的表达量显著上调，tlr2和tlr6基因的表达量则显著下调，Toll-like受体信号转导通路中关键细胞因子myd88、asc、rac1、traf6、fadd、mip和il8等基因的表达量降低。综上所述，黑斑原感染水霉菌可导致皮肤损伤和炎性病变，水霉菌通过下调tlr2、tlr6、myd88等基因的表达，使TLR/Myd88/NF-κB信号通路传递受限，皮肤免疫功能降低，增加水霉菌的易感性。更多还原

【Abstract】 To explore the pathogenic mechanism of saprolegniasis Saprolegnia parasitica in Glyptosternum maculatum, the changes in histological structure and the expression levels of tolling-like receptor and its related signal pathway genes were detected in skin of G.maculatum by histological, molecular biological and transcriptomic methods. The results showed that the water mold damaged the fish body in a single or aggregated manner, and then invaded the fish skin and germinated the hyphae inward and outward to absorb nutrients and release the spores, after the artificial infection of G. maculatum with S. parasitica. The focal infection expanded rapidly with the increase in infection time, with the long mycelium like cotton. The naked leather around hyphae became swelling and ulceration, even massive fish death. Seven Tolls-like unigenes were found in RNA-Seq data base on the data of transcriptome, belong to different kind of Tlr family. Tlr3 m RNA and Tlr13 m RNA were found to be significantly increased 48 h post S. parasitica infection.S. parasitica infection induced lower expression of Tlr2 m RNA and Tlr6 m RNA in skin, while it mainly decreased the key genes expression related to Tolling-like signaling pathway, including myd88, asc, rac1, traf6, fadd, mip, and il8. Therefore, our results suggest that S. parasitica infection can cause skin damage and inflammatory lesions in G. maculatum. During the S. parasitica infection, tlr2, tlr6 and myd88 possessed important defensive roles in skin, made the TLR/Myd88/NF-κB signaling pathway transmission limitation, decreased the skin immune function, and increased susceptibility to S. parasitica infection in skin of G.maculatum.更多还原