Dual RNA-seq provides novel insight into the roles of <i>dksA</i> from <i>Pseudomonas plecoglossicida</i> in pathogen-host interactions with large yellow croakers (<i>Larimichthys crocea</i>)
Luying Wang, 集美大学水产学院，福建 厦门 361021，中国, Zixu Liu, Lingmin Zhao, Lixing Huang, Yingxue Qin, Yongquan Su, Weiqiang Zheng, Fan Wang, Qingpi Yan, 宁德富发水产有限公司大黄鱼育种国家重点实验室,，福建 宁德 352000，中国, 福建水产技术推广中心，福建 福州 350003，中国
Abstract
<i>Pseudomonas plecoglossicida</i> is a rod-shaped, gram-negative bacterium with flagella. It causes visceral white spot disease and high mortality in <i>Larimichthys crocea</i> during culture, resulting in serious economic loss. Analysis of transcriptome and quantitative real-time polymerase chain reaction (PCR) data showed that <i>dksA</i> gene expression was significantly up-regulated after 48 h of infection with <i>Epinephelus coioides</i> (log<sub>2</sub>FC=3.12, <i>P</i><0.001). RNAi of five shRNAs significantly reduced the expression of <i>dksA</i> in <i>P. plecoglossicida</i>, and the optimal silencing efficiency was 96.23%. Compared with wild-type strains, the symptoms of visceral white spot disease in <i>L. crocea</i> infected with RNAi strains were reduced, with time of death delayed by 48 h and mortality reduced by 25%. The <i>dksA</i> silencing led to a substantial down-regulation in cellular component-, flagellum-, and ribosome assembly-related genes in <i>P. plecoglossicida</i>, and the significant up-regulation of <i>fliC</i> may be a way in which virulence is maintained in <i>P. plecoglossicida</i>. The GO and KEGG results showed that RNAi strain infection in <i>L. crocea</i> led to the down-regulation of inflammatory factor genes in immune-related pathways, which were associated with multiple immune response processes. Results also showed that <i>dksA</i> was a virulence gene in <i>P. plecoglossicida</i>. Compared with the wild-type strains, RNAi strain infection induced a weaker immune response in <i>L. crocea</i>.