Transcriptome analysis and discovery of genes involved in immune pathways from coelomocytes of Onchidium struma after bacterial challenge

Authors: ZHANG, MINGMING - Yancheng Institute Of Technology; QIAO, GUO - Yancheng Institute Of Technology; LI, QIANG - Yancheng Institute Of Technology; Xu, Dehai; QI, ZHITAO - Yancheng Institute Of Technology; WANG, AIMING - Yancheng Institute Of Technology; XU, CHEN - Yancheng Institute Of Technology; HUANG, JINTIAN - Yancheng Institute Of Technology

Submitted to: Fish and Shellfish Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2017
Publication Date: 11/15/2017
Citation: Zhang, M., Qiao, G., Li, Q., Xu, D., Qi, Z., Wang, A., Xu, C., Huang, J. 2017. Transcriptome analysis and discovery of genes involved in immune pathways from coelomocytes of Onchidium struma after bacterial challenge. Fish and Shellfish Immunology. 72:528-543.

Interpretive Summary: Onchidium struma is a shellfish with a high economical value and widely cultured in Southeast Asia countries. The population of O. struma has been declined rapidly due to diseases caused by virus, bacteria and parasites. Diseases remain a limiting factor for aquaculture production and there is no effective method available to prevent or control some serious diseases of O. struma. To gain better understanding how O. struma against bacterial infection, this study compared transcriptomic profiles of coelomocytes between uninfected and bacteria infected O. struma to explore the molecular immune mechanism against bacterial infection. Following bacterial infection, 10,623 differently expressed unigenes (DEGs) were identified, including 7,644 up-regulated and 2,979 down-regulated unigenes. Further analysis annotated those DEGs to 42 pathways, and 11 pathways were identified to be related with diseases and immune system. Results of this study will be helpful for improving the efficiency of breeding, establishing genetic linkage map, and enhancing disease control for this species.

Technical Abstract: Onchidium struma widely distributes in subtidal and low-tidal zones, which is considered to be an economical species with rich nutrition, a valuable biomonitor for heavy metal pollution and a representative species for evolution from ocean to land. However, there is limited genetic information available for O. struma development. This study compared transcriptomic profiles of coelomocytes between uninfected and bacteria infected O. struma by Illumina-based paired-end sequencing to explore the molecular immune mechanism of O. struma against bacterial infection. After assembly, a total of 92,450 unigenes with an average length of 1019 bp were obtained. Approximately 34,964 (37.82%) unigenes were annotated in the Nr NCBI database and 40.1% of unigenes were similar with that of Aplysia californica. Among them, 7,609 unigenes were classified into three Gene Ontology (GO) categories: biological process (3,250 unigenes, 42.7%), cellular component (2,281, 30.0%) and molecular function (2,078 unigenes, 27.3%). A total of 22,776 unigenes were aligned to the Clusters of Orthologous Groups (COG) of proteins and classified into 25 functional categories. Following bacterial infection, 10,623 differently expressed unigenes (DEGs) were identified, including 7,644 up-regulated and 2,979 down-regulated unigenes. Further KEGG analysis annotated 11,681 DEGs to 42 pathways, and 11 pathways were identified to be related with diseases and immune system. To our knowledge, it was first time to analyze transcriptome profiles of O. struma. Results of the present study will provide valuable theoretical resources for future genetic and genomic research on O. struma. The research result will be helpful for improving the efficiency and quality of artificial breeding, establishing genetic linkage map, and enhancing health management for O. struma.