Transcriptome analysis of digestive diverticula of Crassostrea hongkongesis infected with Vibrio harveyi

The Hong Kong oyster (Crassostrea hongkongesis), as the main marine aquaculture shellfish in the South China Sea, not only has high economic and ecological value, but also is an ideal model for conducting research on pathogen host interaction. Vibrio harveyi, a Gram negative luminescent marine bacterium, is widely distributed in coastal water environments, surface tissues and internal organs of marine animals, and can cause large-scale death of C. hongkongesis. However, little in formation is available on the immune response molecular mechanisms of C. hongkongesis infected with V. harveyi. Therefore, we performed transcriptome analysis of digestive diverticula of C. hongkongesis infected with V. harveyi. A total of 977689912 high quality reads and 955208562 valid reads were obtained. 6520 differentially expressed genes (DEGs) were identified, of which 3657 DEGs were up-regulated and 3255 DEGs were down-regulated during the time of infection. GO enrichment analysis showed that DEGs were mainly enriched in Cellular processes, Single-organism process, Binding, Catalytic activity, Cell, Cell part and other terms. KEGG enrichment analysis revealed that these DEGs were mainly associated with Notch signaling pathway, Necroptosis, RIG-I-like receptor signaling pathway, PPAR signaling pathway ECM-receptor interaction, Hematopoietic cell lineage, p53 signaling pathway, NF-kappa B signaling pathway, Toll-like receptor signaling pathway and other pathways are related. The results of WGCNA analysis indicated that THBS1, CA10, Svep1, Trpm2, WWOX, THAP12, PTPRT, HSPA12A, CHIA, and ADAM10 were the hub genes in the gene co-expression network. This study will provide new ideas at the transcriptome level for the immune regulatory mechanisms and adaptability of the C. hongkongesis to V. infection, as well as for achieving selective breeding for Vibrio resistance in the C. hongkongesis.

香港牡蛎（Crassostrea hongkongesis）作为我国南海海域主要的海水养殖贝类，不仅兼具极高的经济与生态价值，同时也是开展病原体-宿主互作研究的理想模型。哈维氏弧菌（Vibrio harveyi）是一类革兰氏阴性发光海洋细菌，广泛分布于近岸水环境、海洋动物体表组织与内脏器官中，可引发香港牡蛎出现大规模死亡现象。然而目前针对香港牡蛎感染哈维氏弧菌后的免疫应答分子机制的相关研究仍较为匮乏。为此，本研究对感染哈维氏弧菌的香港牡蛎消化盲囊开展了转录组分析，共获得977689912条高质量读段与955208562条有效读段。研究共鉴定得到6520个差异表达基因（differentially expressed genes, DEGs），其中感染过程中上调表达的DEGs有3657个，下调表达的DEGs有3255个。基因本体（Gene Ontology, GO）富集分析结果显示，差异表达基因主要富集于细胞过程、单有机体过程、结合功能、催化活性、细胞、细胞组分等条目。京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）富集分析表明，这些差异表达基因主要与Notch信号通路、细胞坏死性凋亡、RIG-I样受体信号通路、过氧化物酶体增殖物激活受体（PPAR）信号通路、细胞外基质-受体互作、造血细胞谱系、p53信号通路、NF-κB信号通路、Toll样受体信号通路等通路相关。加权基因共表达网络分析（Weighted Gene Co-expression Network Analysis, WGCNA）结果显示，THBS1、CA10、Svep1、Trpm2、WWOX、THAP12、PTPRT、HSPA12A、CHIA与ADAM10为该基因共表达网络中的核心枢纽基因。本研究可为解析香港牡蛎应对哈维氏弧菌感染的免疫调控机制与适应性，以及开展抗哈维氏弧菌的香港牡蛎选择育种工作，提供转录组层面的全新研究思路。