Transcriptomic analysis of Pacific white shrimp (Litopenaeus vannamei, Boone 1931) in response to acute hepatopancreatic necrosis disease caused by Vibrio parahaemolyticus

Abstract

Acute hepatopancreatic necrosis disease (AHPND), caused by marine bacteria Vibrio Parahaemolyticus , is a huge problem in shrimp farms. The V . parahaemolyticus infecting material is contained in a plasmid which encodes for the lethal toxins PirAB Vp , whose primary target tissue is the hepatopancreas, causing sloughing of epithelial cells, necrosis, and massive hemocyte infiltration. To get a better understanding of the hepatopancreas response during AHPND, juvenile shrimp Litopenaeus vannamei were infected by immersion with V . parahaemolyticus . We performed transcriptomic mRNA sequencing of infected shrimp hepatopancreas, at 24 hours post-infection, to identify novel differentially expressed genes a total of 174,098 transcripts were examined of which 915 transcripts were found differentially expressed after comparative transcriptomic analysis: 442 up-regulated and 473 down-regulated transcripts. Gene Ontology term enrichment analysis for up-regulated transcripts includes metabolic process, regulation of programmed cell death, carbohydrate metabolic process, and biological adhesion, whereas for down-regulated transcripts include, microtubule-based process, cell activation, and chitin metabolic process. The analysis of protein- protein network between up and down-regulated genes indicates that the first gene interactions are connected to oxidation-processes and sarcomere organization. Additionally, protein-protein networks analysis identified 20-top highly connected hub nodes. Based on their immunological or metabolic function, ten candidate transcripts were selected to measure their mRNA relative expression levels in AHPND infected shrimp hepatopancreas by RT-qPCR. Our results indicate a close connection between the immune and metabolism systems during AHPND infection. Our RNA-Seq and RT-qPCR data provide the possible immunological and physiological scenario as well as the molecular pathways that take place in the shrimp hepatopancreas in response to an infectious disease.

The implication of metabolically active Vibrio spp. in the digestive tract of Litopenaeus vannamei for its post-larval development

“…in shrimp intestines is higher than its metabolic activity. This is in agreement with previous studies, where innate immune system activation of shrimp, such as Marsopenaeus japonicus and L. vannamei , was evaluated in response to V. alginolyticus and V. parahaemolyticus infections, demonstrating that they could modulate host signalling proteins and activate their defence system in the presence of potentially pathogenic microorganisms, activating genes that have activities related to immune response mechanisms, such as prophenoloxidase and superoxide dismutase activities, and apoptosis in the hepatopancreas tissue 36 , 37 as well as in the intestinal epithelium 38 . Therefore, a selective biological pressure exerted by the host on the metabolic activity of this bacteria could be occurring, while stimulating the shrimp's immune system by functioning as a natural probiotic necessary for the life cycle of the host.…”

Differentially Expressed Genes in Hepatopancreas of Acute Hepatopancreatic Necrosis Disease Tolerant and Susceptible Shrimp (Penaeus vannamei)

“…Recently, it has been reported that the PirA VP -and PirB VP binary toxin encoded by V. parahaemolyticus can be neutralized by either hemocyanin or anti-lipopolysaccharide factor (16). In addition, the interaction between immune and metabolism appears to play a role in AHPND response in hepatopancrease in shrimp (17,18). Until now, due to the lack of AHPND-tolerant lines of shrimp, no effort could be made to examine the gene expression profiles of AHPND-susceptible and tolerant lines of shrimp.…”

Transcriptome analysis of Macrobrachium rosenbergii hepatopancreas in response to Vibrio harveyi infection

“…These mostly include studies on host–viral mechanisms in shrimps for the identification of immune gene repertoire (Xue et al., 2013; Zeng et al., 2013). Some studies pertaining to host antibacterial mechanisms have also been recorded that understands the molecular pathways responsible for shrimp defence in response to infectious diseases (Qin et al., 2018; Velazquez‐Lizarraga et al., 2019; Zeng et al., 2020). From the Illumina sequencing data sets obtained in the present study, we found a total of 1,911 differentially expressed genes in between the Mr_VH and Mr_C transcriptome libraries, out of which a significant proportion of the contig sequences (1,805) were downregulated.…”