Profiling of Up-Regulated Genes Response to Acute Hypo-Osmotic Stress in Hepatopancreas and Gill of the Pacific White Shrimps (Litopenaeus vannamei)

Yuan-you Li,Hong-yu Liu,Qi-hui Yang,Bei-ping Tan,Wu-wei Sun,Xiao-hui Dong,Shu-yan Chi

doi:10.5539/ijb.v8n2p43

Abstract

Suppression subtractive hybridization (SSH) was applied to screen responsively up-regulation genes in hepatopancreas and gill of Litopenaeus vannamei induced by acute hypo-osmotic stress. In the hepatopancreas, 196 clones were randomly selected and sequenced. 131 non-redundant transcripts, corresponding to 41 genes, were found with elevated expressions. They were functionally clustered into eight biological processes which were protein synthesis and processing, carbohydrate metabolism and energy production, transport, cell growth, apoptosis, cytoskeletal component, cell defense and homeostasis, signal transduction, accounting for 26.2%, 14.3%, 16.7%, 4.7%, 4.7%, 2.3%, 11.9% and 7.1%, respectively. When confirmed by real time qRT-PCR, the gene expression levels of MnSOD, glutathione and glutamine synthetase showed significant increases (2.64-folds, 3.44-folds and 2.16-folds, respectively) in hepatopancreas (P&lt;0.05). Totally 81 expressed sequence tags (ESTs) were obtained by random sequencing from the gill SSH cDNA library, and 52 unigenes, including 15 contigs and 37 singlets, after CP3 online matching were gained by clustering and assembling. The sequence alignment results revealed that 30 of them had significant homology to previously identified Genbank database sequences, while 22 unigenes did not match any sequence in the datebase and presumably represented unidentified cDNAs. Functionally, the unigenes were classified into six clusters, including ion channels and transport proteins (1); protein synthesis, translation and transcription factor (2); stress resistance and antioxidant factors (3); energy metabolism (4); signal receptor and transduction (5); cell fibrin and cytoskeletal proteins (6) with proportion of 23.3%, 20.0%, 20.0%, 16.7%, 10.0% and 10.0% respectively. Real time qRT-PCR confirmation revealed significant elevation of Arginine kinase, Carbonic anhydrase and NaK-ATPase-α-subunit expressions (3.73-folds, 2.55-folds and 5.83-folds, respectively) in the gill after acute low-osmotic stress (P &lt; 0.05). These results provided insight into critical physiology processes and pathways constituting the hypo-osmotic stress adaption program in hepatopancreas and gill of L. vannamei.

Highlights

Litopenaeus vannamei, has been cultured widely in many parts of the world, such as the US (Cuzon, Lawrence, Gaxiola, Rosas, & Guillaume, 2004), Thailand (Thongsawad et al, 2007), China (Bi, Huang, Gu, Wang, & Wang, 2008), Brazil and Indonesia
Shrimps produced more B cells in hepatopancreas tubules at salinity 3 ppt than at salinity 17.0 ppt, which indicated that the high rate of synthesis and release of digestive and antioxidant enzymes accelerated the mobilization of nutrients in hepatopancreas tubules, by which more energy is supplied for omosregulation of shrimps at low salinity, and to adapt to environment stress
196 clones were sequenced in hepatopancreas Suppression subtractive hybridization (SSH) cDNA library. 131 potential transcripts included 21 contigs and 110 singlets were identified by assembling and clustering. 41 with significant homologies to known genes were obtained and categorized according to their putative functions (Table 2), out of which ribosomal protein S15, ribosomal protein S2, ATP/ADP translocase, vesicle-associated membrane protein 2, cytochrome P450 and glutamine synthetase were firstly uncovered in L.vannamei

Summary

Introduction

Litopenaeus vannamei, has been cultured widely in many parts of the world, such as the US (Cuzon, Lawrence, Gaxiola, Rosas, & Guillaume, 2004), Thailand (Thongsawad et al, 2007), China (Bi, Huang, Gu, Wang, & Wang, 2008), Brazil (dos Santos Braz, Reis, Martins, de Sales, & Meissner, 2009) and Indonesia. The tolerance of shrimps to acute salinity change dependent on their capability of osmotic physiological regulation, such as improvements of ion-transport enzymes activities The osmoregulatory mechanism of L. vannamei in low salinity stress is accomplished through the coordination of a number of functional genes, usually accompanied by the modulation of mRNA expression levels of a series of osmoticrelated genes (Zhao, Pan, Ren, & Hu, 2015). The gill epithelial cells are the primary sites of shrimps for ion exchange with the environment. Shrimps produced more B cells in hepatopancreas tubules at salinity 3 ppt than at salinity 17.0 ppt, which indicated that the high rate of synthesis and release of digestive and antioxidant enzymes accelerated the mobilization of nutrients in hepatopancreas tubules, by which more energy is supplied for omosregulation of shrimps at low salinity, and to adapt to environment stress Shrimps produced more B cells in hepatopancreas tubules at salinity 3 ppt than at salinity 17.0 ppt, which indicated that the high rate of synthesis and release of digestive and antioxidant enzymes accelerated the mobilization of nutrients in hepatopancreas tubules, by which more energy is supplied for omosregulation of shrimps at low salinity, and to adapt to environment stress (E. Li et al, 2008)

Objectives

Methods

Results

Conclusion