en Genetics Genetics پژوهشي Orginal research papers <span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">Proliferative kidney disease (PKD), caused by </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">Tetracapsuloides bryosalmonae</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">, is a major challenge in rainbow trout (<i>Oncorhynchus</i> <i>mykiss</i>) aquaculture. To better understand the host response at the molecular level, eight microarray datasets from erythrocytes of healthy and infected fish (GSE198859) were analyzed to identify differentially expressed genes (DEGs) using the GEO2R tool. The results revealed that upregulated genes such as </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">SNRPE</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">, </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">miR-301b</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">, </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">TNFRSF10B</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">, </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">Bckdha</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">, and </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">Aqp1</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black"> are associated with RNA processing, post-transcriptional regulation, osmoregulation, energy metabolism, and apoptosis, highlighting their essential roles in compensatory responses to kidney damage. Conversely, downregulated genes including </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">Degs1</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">, </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">Flt1</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">, </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">BATF3</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">, and </span></span></span><em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">RALY</span></span></span></em><span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black"> suggested suppression of angiogenesis, inhibition of dendritic cell responses, disruption of immune signaling, and impairment of lipid metabolism and RNA processing, which may represent part of the parasite&rsquo;s strategy to evade host immunity. GO analysis showed significant enrichment in cellular components such as the nucleus, nucleosome,</span></span></span> <span lang="TR" style="font-size:11.5pt"><span calibri="" style="font-family:"><span style="color:black">plasma membrane, exosomes, and extracellular regions. In parallel, molecular functions related to kinase activity and protein binding emphasized the importance of signaling and intercellular communication during infection. Overall, these findings suggest that the rainbow trout response to PKD involves a combination of activated defense pathways and simultaneous suppression of some critical immune components by the parasite, which contributes to its survival. The identified genes and pathways may serve as potential molecular markers and support future efforts in selective breeding to improve resistance against PKD.</span></span></span> Differentially expressed genes (DEGs), Gene network analysis, Microarray, Proliferative kidney disease (PKD), Rainbow trout (Oncorhynchus mykiss) 301 315 http://jifro.ir/browse.php?a_code=A-10-4285-1&slc_lang=en&sid=1 R. Pasandideh Rezapasandideh63@gmail.com 100319475328460058796 100319475328460058796 Yes Shrimp Research Center, Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization (AREEO), Bushehr, Iran M. Pasandideh Majidpasandideh@gmail.com 100319475328460058797 100319475328460058797 No Department of Animal Science, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran