Microbiome Chen Songlin/Ning Kang reveals the regulatory mechanism of intestinal microbiota in the formation of anti-vibriomycosis traits in semi-slippery tongue rays

iNature

Infectious diseases cause huge economic losses and food security problems for
the fish farming industry.
Current management and breeding strategies rely heavily on knowledge
of the modulating mechanisms of potential disease resistance.
While the gut microbiome is associated with disease infections, little
is known about the role of gut microbes in fish disease resistance.
Semi-slippery tongue fish is an important marine aquaculture fish in China, is one of the nine major varieties of the national marine fish industry technology system, its taste is delicious, nutritious and high
economic value.
However, it suffers from an outbreak of vibriobacterial disease, which leads to huge mortality and economic losses
.
On September 23, 2022, the team of academician Chen Songlin of the Yellow Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences and the team of Professor Ning Kang of the School of Life Science and Technology of Huazhong University of Science and Technology jointly published an online publication entitled "Intestinal microbiome-mediated resistance against vibriosis for Cynoglossus semilaevis" online at Microbiome (IF=17" A research paper in which the semi-slippery tongue fish is used as a research model to study the role
of host-microbiome interactions in regulating Vibrioplasmosis resistance.
The resistance of the intestinal flora to vibriomycosis is reflected in two levels
: classification and function.
This difference also affects the expression
of host genes in resistant families.
The gut microbiome may control host immune homeostasis and inflammatory responses through the microbiome-gut-immune axis, enhancing resistance
to vibrinosis.
For example, in disease-resistant families, Phaeobacter reduces the inflammatory response of disease-resistant families by upregulating its own hdhA gene and host bile acid biosynthesis pathway cyp27a1 gene, as well as the expression of its own trxA gene and host pro-inflammatory cytokine biosynthesis pathway akt gene, thereby improving the ability
of semi-slippery tongue to resist Vibrio infection.
In addition, binding gut microbes and host genes as biomarkers allows for an accurate distinction between disease-resistant families and susceptibility families
.
In summary, the study revealed regulatory patterns of the microbiome-gut-immune axis, which may help to understand Vibrioplasmosis resistance in semi-slippery tongue rays
.
These findings can inform the control of diseases and the selection of high-quality disease-resistant germplasms in aquaculture
.
The world is currently facing increasing challenges in nutrition and food security issues
.
Aquaculture provides aquatic food and plays an increasingly important role
in the global food supply.
According to FAO, aquaculture production is expected to reach 109 million tonnes by 2030, which requires sustainable development
of agricultural practices.
However, the frequent occurrence of infectious diseases has had a devastating impact on
the aquaculture industry worldwide.
Vibriomycosis, caused by Vibrio bacteria, is one of the most important threats in aquaculture, resulting in huge mortality and economic losses
for many aquatic animals such as crustaceans, molluscs and fish.
The gut microbiome is a key and direct regulator of fish physiology, immunity and health
.
Recently, the relevance of the microbiome to the host has been recognized as one of the most promising scientific breakthroughs that could have a significant positive impact on
food and agriculture.
Understanding the differences in microbiota between resistant and non-resistant germplasms in fish farming, as well as the interaction between fish and microbiota, provides important knowledge for disease control, probiotic development, genetic modification, and ultimately improves disease resistance and yield
.
In addition, there are currently very few
biomarkers available to screen for disease-resistant germplasm in fish.
Through the study of the intestinal flora and the host-flora relationship in fish, it can provide biomarkers for the identification of resistant germplasms and provide a basis
for breeding.
Overview of the workflow of integrating multi-omics (including host genes, gut microbiomes, gut microbiome genes) and model animal zebrafish and economic species Atlantic salmon (Salmo salar), grass carp (Ctenopharyngodon idellus), and semi-slippery tongue scorpion (Cynoglossus semilaevis) all reported changes in
gut microbial communities with disease infection status 。 Gaulke et al.
confirmed that Pseudocapillaria tomentosa infection destroys the composition of the zebrafish gut microbiome, and the degree of microbiome disruption during infection varies
with the severity of the infection.
Gong et al.
found that after Vibrio vulnificus infection, the composition of the microbial community in semi-slippery tongue fish changed significantly, and at high doses of infection, the host could stimulate innate immunosuppressive Vibrio vulnificus growth
.
However, this scattered evidence focuses on characterizing the composition and variation of the gut microbiome in pathogenic infections using the 16S rRNA sequencing method, while the regulatory patterns and underlying mechanisms of the gut microbiome on fish against vibrinosis remain a mystery
.
On the other hand, the resistance of fish to infectious diseases is a highly complex trait
.
Previous studies have shown differences
in immune parameters for disease-resistant and susceptible carp to Aeromonas hydrophila infection, including lysozyme activity, phagocytosis and antibody levels.
Several studies point to differences in transcriptome responses to different pathogenic infections
.
For example, disease-resistant Atlantic salmon exhibits a moderate and effective inflammatory response
when infected with pancreatic necrosis virus.
Current research on disease resistance in fish has focused on physiological and transcriptome responses after infection, while less research has been done on the anti-disease infection function of gut microorganisms
.
Semi-slippery tongue fish disease resistance and susceptibility system multiple markers (figure from Microbiome) semi-slippery tongue fish (scientific name: Cynoglossus semilaevis), also known as mammoth, dragon li, stingray, rice and tongue fish, is an important marine aquaculture fish in China, is one of the nine major varieties of the national marine fish industry technology system, its taste is delicious, nutritious and high
economic value 。 However, in the process of breeding, infectious diseases caused by Vibrio pathogens occur frequently, resulting in a survival rate of as low as 30%, which seriously limits the healthy and sustainable development of the semi-slippery tongue fish breeding industry and causes huge economic losses
。 Based on the multigenerational selection of the disease-resistant family of Academician Chen Songlin's team, the structural function differences, host gene expression patterns and flora-host interactions of the intestinal flora, host gene expression patterns and microflora-host interactions of disease-resistant and susceptible families were analyzed through multi-omics analysis, and it was found that the microbial community structure of disease-resistant and susceptible families was significantly different: disease-resistant families enhanced their anti-Vibrio infection ability by recruiting beneficial bacteria (such as Phaeobacter, Propionibacterium).
Susceptible families, on the other hand, affect disease resistance due to the enrichment of pro-inflammatory bacteria such as Alicyclobacillus
.
Further analysis found that the gut microbiome affects the ability
of semi-slippery tongue rays to resist Vibrio infection by regulating host metabolism (including steroids, steroids, bile acid synthesis and unsaturated fatty acid metabolism pathways) and immune signaling pathways (including DNA-sensing, Toll-like, and RIG-I-like receptor signaling pathways).
。 In addition, it was found that the intestinal flora may regulate the immune homeostasis and inflammatory response of the host through the "bacteria-intestine-immune axis", such as Phaeobacter by regulating its own hdhA gene and host bile acid biosynthesis pathway cyp27a1 gene upregulation, while regulating the expression of its own trxA gene and host pro-inflammatory cytokine biosynthesis pathway akt gene down-regulation, to reduce the inflammatory response of the anti-disease family, thereby improving the ability
of semi-slippery tongue fish to fight Vibrio infection 。 On this basis, this study further screens for biomarkers based on the combination of gut microbiota and host genes, which can be used for disease-resistant germplasm screening
in semi-slippery tongue rays 。 This study first reveals the molecular mechanism of intestinal microbiome regulating the anti-Vibriomyceous traits of semi-slippery tongue fish by regulating host immune homeostasis and reducing inflammation, and the "bacteria-intestine-immune axis" regulatory model revealed will help to understand the role of intestinal flora in the formation of fish disease resistance traits, and provide a new perspective for the study of fish disease resistance traits.
The research results have laid an important foundation
for opening up new ways for fish disease control and fine seed breeding.
The first author of the paper is Zhou Qian, associate researcher of the Yellow Sea Fisheries Research Institute and Zhu Xue, doctoral student of Huazhong University of Science and Technology, and the corresponding authors are academician Chen Songlin and Professor
Ning Kang.
The above work was completed with the support of the National Natural Science Foundation of China, the National Key Research and Development Program, the Taishan Scholars Climbing Program of Shandong Province, and the Innovation Team of the Chinese Academy of
Fishery Sciences.

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