White Prawn Research Articles

Paospora carinifang n. gen., n. sp. (Microsporidia: Spragueidae), a parasite of the ridgetail white prawn, Palaemon carinicauda

A new microsporidian disease of the pond-reared ridgetail white prawn, Palaemon carinicauda, was found in China. Light microscopy, pathology, and scanning electron microscopy showed that the parasite infected the host’s skeletal muscle tissue and formed spherical sporophorous vesicles (SPOVs). Electron microscopy revealed that its merogonic life stages developed in direct contact with the host cytoplasm. The sporogonic life stages underwent octosporoblastic sporogony with the formation of eight uninucleate spores in each SPOV. Fresh SPOVs were 5.4 ± 0.55 µm in diameter. The octospores were oval and measured 2.3 × 1.5 μm (fresh) and 1.96 × 1.17 μm (fixed). The isofilar polar filament was coiled with 9–10 turns and arranged in two rows. Phylogenetic analysis based on the SSU rRNA gene suggests that this microsporidium has close affinities with members of the genera Potaspora and Apotaspora, but represents an independent generic taxon. We therefore propose the establishment of a new genus and species (Paospora carinifang n. gen., n. sp.) within the family Spragueidae. We also propose a taxonomic revision to transfer Potaspora macrobrachium to this new genus and reclassify it as Paospora macrobrachium comb. nov.

Genetic diversity and population structure of wild and artificially selected populations of the ridgetail white prawn (Exopalaemon carinicauda) using consolidated mitochondrial cytochrome b and microsatellite markers

The ridgetail white prawn (Exopalaemon carinicauda) belongs to the family Palaemonidae and genus Exopalaemon. Owing to its significant economic value and excellent nutritional properties, it is an important species for the development of saltwater aquaculture models in China. In this study, 160 individuals were collected from four wild populations and one artificially selected population using consolidated mitochondrial cytochrome b (mt-cyt b), and microsatellite molecular markers. The results showed that the hatcheries had lower genetic diversity than the wild samples, both at the levels of mt-cyt b (haplotype diversity: 0.123 VS 0.572; nucleotide diversity: 0.0003 VS 0.0014) and microsatellite (expected heterozygosity: 0.672 VS 0.752). Among the four wild populations, the Ningbo population sampled from the East China Sea showed higher genetic diversity in both mt-cyt b and microsatellites. A pairwise comparison of genetic differentiation coefficients revealed that the artificially selected population had not genetically diverged from the Cangzhou and Rizhao populations. However, the Ningbo population exhibited moderate to high genetic differentiation (compared to other populations), whereas the Zhanjiang population showed a high level of genetic differentiation, indicating a distinct geographical distribution pattern. Structural analysis revealed the presence of three lineage clusters in all current populations, and the artificially selected population predominantly consisted of lineage 3, accounting for 71.68 % of the population. Currently, the effective population size of hatcheries was <50, rendering them susceptible to the genetic threat of inbreeding depression. These findings provide a scientific basis for the conservation of wild germplasm resources of E. carinicauda and inform future breeding and management strategies for improved varieties.

The mannose-binding lectin (MBL) gene cloned from Exopalaemon carinicauda plays a key role in resisting infection by Vibrio parahaemolyticus

Mannose-binding lectin (MBL) is a vital member of the lectin family, crucial for mediating functions within the complement lectin pathway. In this study, following the cloning of the mannose-binding lectin (MBL) gene in the ridgetail white prawn, Exopalaemon carinicauda, we examined its expression patterns across various tissues and its role in combating challenges posed by Vibrio parahaemolyticus. The results revealed that the MBL gene spans 1342 bp, featuring an open reading frame of 972 bp. It encodes a protein comprising 323 amino acids, with a predicted relative molecular weight of 36 kDa and a theoretical isoelectric point of 6.18. The gene exhibited expression across various tissues including the eyestalk, heart, gill, hepatopancreas, stomach, intestine, ventral nerve cord, muscle, and hemolymph, with the highest expression detected in the hepatopancreas. Upon challenge with V. parahaemolyticus, RT-PCR analysis revealed a trend of MBL expression in hepatopancreatic tissues, characterized by an initial increase followed by a subsequent decrease, peaking at 24 h post-infection. Employing RNA interference to disrupt MBL gene expression resulted in a significant increase in mortality rates among individuals challenged with V. parahaemolyticus. Furthermore, we successfully generated the Pet32a-MBL recombinant protein through the construction of a prokaryotic expression vector for conducting in vitro bacterial inhibition assays, which demonstrated the inhibitory effect of the recombinant protein on V. parahaemolyticus, laying a foundation for further exploration into its immune mechanism in response to V. parahaemolyticus challenges.

Anesthetic effects of eugenol on adult ridgetail white prawn (Exopalaemon carinicauda) and its protective effects under simulated transportation

Anesthesia is a common practice used to improve animal welfare and reduce the negative impacts of stress factors in aquaculture settings. However, few studies have been conducted to investigate the application of anesthetics in ridgetail white prawn (Exopalaemon carinicauda). In the present study, the anesthetic efficacy and protective effects of eugenol in adults of this species were evaluated. When the prawns (n = 5) were immersed in different concentrations of eugenol in the range of 0–240 μL/L for 30 min, the results showed that 180 and 240 μL/L could lead to quick sedative and anesthesia effects with 100% mortality after 30 min exposure, while 30 μL/L failed to induce any sedative and anesthesia effects. Further tests showed that adult individuals were quickly anesthetized by eugenol at a concentration of 60–90 μL/L with a 30 min immersion, while half of the prawns were sedated in 30 μL/L eugenol after 4 h exposure, then recovered at 2 h without any mortality. Furthermore, we checked the water quality parameters after the adult prawns were immersed in four eugenol concentrations (0, 10, 20, 30 μL/L) for 8 h of simulated transportation followed by a 96 h recovery, we found that 30 μL/L eugenol treatment could significantly decrease the ammonia nitrogen concentration, and increased the survival rate at 96 h post recovery. The oxidative responses of the prawns during the 8 h transportation at 30 μL/L eugenol followed by 96 h recovery period were analyzed. The results showed that eugenol administration significantly decreased the malonaldehyde (MDA) concentration and the activities of most antioxidant-related enzymes immediately. The present data indicated that eugenol was an efficient anesthetic, which could be used for long-distance transportation of this species. It exhibited excellent protective effects to improve the animal's welfare by improving water quality and alleviating oxidative stress.

Capability of Amla Extract on Quality Retardation of Chilled Stored Indian White Prawn (Fenneropenaeus Indicus Milne Edwards, 1837)

Capability of Amla Extract on Quality Retardation of Chilled Stored Indian White Prawn (Fenneropenaeus Indicus Milne Edwards, 1837)

Retracted: Effects of lemon and pomelo peel extracts on quality and melanosis of Indian white prawn during chilled storage

Retracted: Effects of lemon and pomelo peel extracts on quality and melanosis of Indian white prawn during chilled storage

Assessing the Institutional Domain: A Comprehensive Analysis of White Prawn (Penaeus merguiensis) Fisheries Management in Cilacap Regency through Ecosystem Approach and Multi-criteria Analysis

The concept of fisheries management in coastal and marine areas refers to the concept of sustainable development, which emphasizes the balance between economic growth, environmental quality, and the quality of natural resources. Data were collected using observation, questionnaires, and in-depth interviews with 20 respondents. This study aims to determine the condition of the management of white prawn (Penaeus merguiensis) resources from the institutional domain which has 6 indicators based on the score criteria in EAFM. This research uses a simple composite approach with flag modeling technique. The flag modeling technique is done by analyzing a multi-criteria analysis (MCA) approach in which a set of criteria is built as a basis for analyzing the state of fisheries management areas seen from the ecosystem approach in fisheries management (EAFM) through the development of composite indices. Based on the results of the research, the condition of the institutional domain in the management of white prawn in Cilacap Regency obtained a composite index value of 75.80, this fig. indicates that the condition is in the good category. Each indicator in the institutional domain obtained different valuesand conditions. For the Fisheries Management Plan indicator, it received a score of 1, which means it is in the poor category. For the indicators of the completeness of the rules of the game and the decision- making mechanism, each received a score of 2, which is a moderate category. Then, the indicator of compliance with the principles of responsible fisheries in fisheries management, the indicator of the level of synergy of fisheries management policies and institutions, and the indicator of stakeholder capacity received a score of 3, meaning that each of these indicators was in a good category. The conclusion that can be drawn is that the condition of the institutional domain in the management of white prawn in Cilacap Regency has a good category and still needs a strategy for improvement.

FOXO is involved in antimicrobial peptides expression during WSSV infection in Exopalaemon carinicauda

The forkhead box transcription factor O family protein (FOXO) acts as a transcription factor that regulates biological processes regarding DNA repair, immunity, cell cycle regulation, and other biological processes. In this study, EcFOXO was identified from the ridgetail white prawn, Exopalaemon carinicauda. EcFOXO protein contains multiple low-complexity regions and a forkhead (FH) domain. Phylogenetic tree showed that EcFOXO is clustered with crustacean FOXOs. The amino acid sequences of its FH domain are highly similar to the FH domain of FOXOs from other crustaceans. The expression of EcFOXO is altered after white spot syndrome virus (WSSV) stimulation in hepatopancreas and gills. The relationship between EcFOXO and EcRelish was explored by RNA interference (RNAi). Results showed that EcFOXO and EcRelish could positively regulate each other’s expression. The expression levels of various antimicrobial peptides (AMPs) significantly reduced after interfering with EcFOXO or EcRelish. These results suggest a positive regulatory loop between EcFOXO and EcRelish, which participates in the innate immunity of ridgetail white prawn by regulating the expression of AMPs during WSSV infection. This study enriches the knowledge about the regulatory mechanism of FOXO in the innate immunity of crustaceans.

CRISPR/Cas9-mediated gene mutation of EcIAG leads to sex reversal in the male ridgetail white prawn Exopalaemon carinicauda.

In the culture of crustaceans, most species show sexual dimorphism. Monosex culture is an effective approach to achieve high yield and economic value, especially for decapods of high value. Previous studies have developed some sex control strategies such as manual segregation, manipulation of male androgenic gland and knockdown of the male sexual differentiation switch gene encoding insulin-like androgenic gland hormone (IAG) in decapods. However, these methods could not generate hereditable changes. Genetic manipulation to achieve sex reversal individuals is absent up to now. In the present study, the gene encoding IAG (EcIAG) was identified in the ridgetail white prawn Exopalaemon carinicauda. Sequence analysis showed that EcIAG encoded conserved amino acid structure like IAGs in other decapod species. CRISPR/Cas9-mediated genome editing technology was used to knock out EcIAG. Two sgRNAs targeting the second exon of EcIAG were designed and microinjected into the prawn zygotes or the embryos at the first cleavage with commercial Cas9 protein. EcIAG in three genetic males was knocked out in both chromosome sets, which successfully generated sex reversal and phenotypic female characters. The results suggest that CRISPR/Cas9-mediated genome editing technology is an effective way to develop sex manipulation technology and contribute to monosex aquaculture in crustaceans.

The Pathogenic Yeast Metschnikowia bicuspidata var. bicuspidata in the Aquacultured Ecosystem and Its Biocontrol.

M. bicuspidata var. bicuspidata is a pathogenic yeast which can affect aquacultured and marine-cultured animals such as brine shrimp, ridgetail white prawn, chinook salmon, giant freshwater prawn, the Chinese mitten crab, marine crab, the mud crab, the mangrove land crab, the Chinese grass shrimp, sea urchins, sea urchins, Daphnia dentifera and even snails, causing a milky disease, and it has caused big economic losses in aquacultural and marine-cultural industries in the past. However, the detailed mechanisms and the reasons for the milky disease in the diseased aquatic animals are still completely unknown. So far, only some antimycotics, killer toxins and Massoia lactone haven been found to be able to actively control and kill its growth. The ecofriendly, green and renewable killer toxins and Massoia lactone have high potential for application in controlling the milky disease.

Impact of Diethylstilbestrol on the Growth Characteristics of White Prawn, &lt;i&gt;Penaeus indicus (M. edwards)&lt;/i&gt;

The effect of dietary diethylstibestrol (DES) on the growth performance of white prawn, Penaeus indicus, was investigated for a period of 85 days in earthen ponds. DES at 4 mg/kg produced significantly superior growth (p &lt; 0.01), high feed converson efficiency and nutrient digestibility. The total and specific digestive enzyme activities were maximum in the prawns fed with 4 mg/kg DES. Carcass protein content was increasd due to DES treatment. Residual DES content of the treated prawns on the final day of the experiment had been metabolised and reduced to that of the normal level of the control groups on the 20th day after cessation of hormone diets. DES had stimulated the growth of P. indicus through enhanced feed intake, high digestive enzymes activity, better nutrient digestibility and protein synthesis.

Characterization of a crustin-like peptide involved in shrimp immune response to bacteria and Enterocytozoon hepatopenaei (EHP) infection in Palaemon carinicauda.

Crustins represent one type of antimicrobial peptides (AMPs) that are key components of the innate immune process of crustaceans. This study successfully identified a novel crustin-like peptide, EcCrustin2, in ridgetail white prawn, Palaemon carinicauda (formerly Exopalaemon carinicauda). EcCrustin2 was found to be 1082 bp in length, with a 378 bp open reading frame (ORF) encoding 125 amino acids. The deduced amino acid sequence of EcCrustin2 exhibited characteristics of crustins in crustacean, including a Cys-rich region at the N-terminus as well as a whey acidic protein domain at the C-terminus. Phylogenetic analysis revealed that the EcCrustin2 was first clustered with Type I crustins, then with other crustins. Expression of EcCrustin2 was mainly detected in immune tissues, including hemocytes, gill and stomach. The expression level of EcCrustin2 was also significantly up-regulated after being exposed to lipopolysaccharide (LPS), lipoteichoic acid (LTA), Vibrio parahaemolyticus and Staphylococcus aureus. EHP infection could also induce EcCrustin2 expression in P. carinicauda. Knockdown of EcCrustin2 with siRNA increased the mortality of V. parahaemolyticus challenged shrimp. Finally, the recombinant EcCrustin2 protein was obtained and demonstrated a wide spectrum of antibacterial activity in vitro. These results indicated that EcCrustin2 takes part in the immune response against bacteria and EHP infection.

Reproductive quality evaluation of male Indian white prawn Penaeus indicus broodstock fed diets supplemented with polychaete extracts (Marphysa sp.)

ABSTRACT The present study determined the effect of different polychaete extracts, namely, total soluble fraction (TSF), neutral lipid fraction (NLF) and polar lipid fraction (PLF), in the maturation and sperm quality of male Penaeus indicus. Three levels (0.25, 0.50 and 1.00%) of extracts were included using a 3 × 3 factorial design. Groups fed the basal diet (BD) and fresh-frozen diet served as controls. Extracts in varying doses and control groups did not have a significant effect on broodstock survival (67–87%; p = 0.960), maturation rate (42–68%; p = 0.615), inter-spermatophore period (8–10 days; p = 0.505) or sperm viability (97–100%; p = 0.819). However, sperm counts of broodstock fed BD (11.70 × 106 ±1.05 × 106 per spermatophore) and those fed diets supplemented with polychaete extracts were significantly higher compared to that fed with control fresh diet at 0.73 × 106± .09 × 106 (p = 0.001). Spermatophore crude lipid was highest in groups fed 0.25% TSF and 0.25% PLF of broodstock (p =1.0 x10−6 ). Inclusion of TSF (0.25–1.00%) significantly increased the spermatophore crude protein content of broodstock compared to those fed with other diets (p = 1.20 × 10−5). These results demonstrate that NLF and TSF extracts are bioactive components of polychaete which when fed to male P. indicus, can stimulate aspects of sperm production.

Pokkali Rice Cultivation: A Review on the Indigenous Rice Cultivation Method in Kerala

Kerala state's rice consumption is predicted to be between 3.5 and 4 million tons per year, but production is just a sixth of this. In order to boost the state's rice production, attention must be paid to traditional rice growing techniques. Thus, there is a need to understand the Pokkali rice cultivation method used in Kerala. The Pokkali style of rice farming in Kerala's acidic, saline soil is a distinctive way of rice cultivation. A native historic salt-tolerant type of rice called Pokkali, with a 120-day growing season, can withstand flooding by growing up to a height of 1.5 meters. Chettivirippu, Vyttila 1, Vyttila 2, Vyttila 3, Vyttila 4 and Vyttila 5 are the other rice varieties cultivated using the Pokkali rice cultivation method. With this technique, a single rice crop is harvested on mounds during the low salinity part of the production cycle (June to mid-October), with prawn aquaculture taking place during the high salinity phase (November to April). Pokkali cultivation only produce 2000 kg of rice per hectare, making it slightly unprofitable. The rice plant residue after harvesting is left to rot in the water which subsequently acts as prawn feed. Prawn farming takes place from November to April. Sluice gates help in prawn culture filtering by maximizing the amount of saline water that enters the field and preventing the prawns from escaping. The two main cultivated prawns species are Penaeus monodon (Tiger prawn) and Penaeus indicus (White prawn). Prawns are typically collected in mid-April, especially two to three days before new full moon days, as tidal activity affects their movement. Prawn excreta serve as a natural fertilizer for rice cultivation; prawns feeding on rice cultivation stubbles help to minimize the occurrence of illness in rice to a minimum. It is an organic rice production approach with less cost than commercial rice farming because chemical fertilizers and pesticides are not used.

Complete genome analysis of pathogenic Metschnikowia bicuspidata strain MQ2101 isolated from diseased ridgetail white prawn, Exopalaemon carinicauda

BackgroundMetschnikowia bicuspidata is a pathogenic yesst that can cause disease in many different economic aquatic animal species. In recent years, there was a new disease outbreak in ridgetail white prawn (Exopalaemon carinicauda) in coastal areas of Jiangsu Province China that was referred to as zombie disease by local farmers. The pathogen was first isolated and identified as M. bicuspidata. Although the pathogenicity and pathogenesis of this pathogen in other animals have been reported in some previous studies, research on its molecular mechanisms is still very limited. Therefore, a genome-wide study is necessary to better understand the physiological and pathogenic mechanisms of M. bicuspidata.ResultIn this study, we obtained a pathogenic strain, MQ2101, of M. bicuspidata from diseased E. carinicauda and sequenced its whole genome. The size of the whole genome was 15.98 Mb, and it was assembled into 5 scaffolds. The genome contained 3934 coding genes, among which 3899 genes with biological functions were annotated in multiple underlying databases. In KOG database, 2627 genes were annotated, which were categorized into 25 classes including general function prediction only, posttranslational modification, protein turnover, chaperones, and signal transduction mechanisms. In KEGG database, 2493 genes were annotated, which were categorized into five classes, including cellular processes, environmental information processing, genetic information processing, metabolism and organismal systems. In GO database, 2893 genes were annotated, which were mainly classified in cell, cell part, cellular processes and metabolic processes. There were 1055 genes annotated in the PHI database, accounting for 26.81% of the total genome, among which 5 genes were directly related to pathogenicity (identity ≥ 50%), including hsp90, PacC, and PHO84. There were also some genes related to the activity of the yeast itself that could be targeted by antiyeast drugs. Analysis based on the DFVF database showed that strain MQ2101 contained 235 potential virulence genes. BLAST searches in the CAZy database showed that strain MQ2101 may have a more complex carbohydrate metabolism system than other yeasts of the same family. In addition, two gene clusters and 168 putative secretory proteins were predicted in strain MQ2101, and functional analysis showed that some of the secretory proteins may be directly involved in the pathogenesis of the strain. Gene family analysis with five other yeasts revealed that strain MQ2101 has 245 unique gene families, including 274 genes involved in pathogenicity that could serve as potential targets.ConclusionGenome-wide analysis elucidated the pathogenicity-associated genes of M. bicuspidate while also revealing a complex metabolic mechanism and providing putative targets of action for the development of antiyeast drugs for this pathogen. The obtained whole-genome sequencing data provide an important theoretical basis for transcriptomic, proteomic and metabolic studies of M. bicuspidata and lay a foundation for defining its specific mechanism of host infestation.

Proteomic analysis of the hepatopancreas of Exopalaemon carinicauda in response to Metschnikowia bicuspidate infection

The ridge-tail white prawn, Exopalaemon carinicauda, is an important economic shrimp in the mariculture of China, especially in Jiangsu Province. The “zombie disease” of ridge-tail prawn is a new epidemic that is a highly transmissible and pathogenic fungal disease caused by Metschnikowia bicuspidate infection. To understand the response mechanism of E. carinicauda after M. bicuspidate infection, the hepatopancreas of shrimp injected with M. bicuspidate MQ2101 and normal saline solution were used for proteomics analysis. A total of 5078 proteins were identified, of which 1708 proteins were identified as differentially expressed proteins (DEPs, 1311 upregulated and 397 downregulated) using a 1.2-fold change in expression as a physiologically significant benchmark. These DEPs were mainly involved in cellular processes, single-organism processes, and metabolic processes in the GO enrichment analysis and metabolism, translation, signal transduction, cell growth and death, and immune system pathways in the KEGG enrichment analysis. The DEPs related to immunity and metabolism were significantly changed, such as CTSB, CPs, DSP1, GDP, and ADH3, and these proteins might be potential determinants of E. carinicauda responses to M. bicuspidata infection. qRTPCR was used to detect changes in the expression of nine DEP-related genes at the transcriptional level to validate the proteomics analysis results, and the results of the transcription tendencies in qRTPCR were consistent with proteomics analysis. The results of this study might provide an important theoretical basis for the response mechanism of ridge-tail white prawns to M. bicuspidate infection and scientific prevention and control of this fungus in ridge-tail white prawn aquaculture. Availability of data and materialsThe data that support the results of this present study are available from the corresponding author upon reasonable request.

The ubiquitin-like, containing PHD and RING finger domains 1 (uhrf1) gene promotes ovarian development in Exopalaemon carinicauda

Ridgetail white prawn, Exopalaemon carinicauda, with high reproductive capacity can reproduce up to three or four generations a year. In exploring the genetic factors affecting the gonadal development of E. carinicauda, we cloned and studied the function of the ubiquitin-like, containing PHD and RING finger domains 1 (uhrf1) gene. The open reading frame of uhrf1 gene was 2286 bp, encoding a total of 761 amino acids. The Uhrf1 has UBL, TTD, PhD, SRA, and ring finger domains that are associated with genome methylation, histone recognition and chromatin modification. According to the phylogenetic analysis, the amino acid sequence of Ec-uhrf1 has the highest similarity with Litopenaeus vannamei uhrf1, and it is a branch of Penaeus monodon and L. vannamei. The real-time quantitative PCR showed that the expression level of uhrf1 was highest in ridgetail white prawn ovarian tissue, which was significantly higher than that of other tissues (P < 0.05). In addition, the expression level gradually increased in stages I-IV of ovarian development, with its expression level in stage IV being significantly higher than that in other stages (P < 0.05). RNAi results showed that a knockdown of uhrf1 gene expression significantly reduced the expression of the cell proliferation-related gene pcna, the DNA methylation-related gene dnmt1 and yolk synthesis related genes vg, indicating that uhrf1 regulates the expression of pcna and dnmt1. The in situ hybridization tests further indicated that the uhrf1 gene plays an important role in oocyte proliferation and accumulation of exogenous nutrients.

Phylogenetics of Sea Lice (Cymothoa spp) Infesting the Indian White Prawn, Penaeus indicus, along the Kenyan Coast

Phylogenetics of Sea Lice (Cymothoa spp) Infesting the Indian White Prawn, Penaeus indicus, along the Kenyan Coast

The Responses of the Ovary and Eyestalk in Exopalaemon carinicauda under Low Salinity Stress

As a euryhaline shrimp, the ridgetail white prawn Exopalaemon carinicauda is strongly adaptable to salinity. Exploring the effect of long-term low salinity stress on ovarian development in E. carinicauda is essential to promote its culture in a non-marine environment. In this study, we performed biochemical assays and ovary histology analysis, finding that the E. carinicauda can adapt to low salinity stress through osmotic adjustment, and there was no substantial damage to the ovary of E. carinicauda under low salinity stress. Then, the ovarian development of E. carinicauda under low salt stress was further explored by RNA sequencing of eyestalk and ovarian tissues. A total of 389 differentially expressed genes (DEGs) in ovary tissue were identified under low salinity stress, and the 16 important DEGs were associated with ovarian development. The majority of the DEGs were enriched in ECM-receptor interaction, folate biosynthesis, arginine biosynthesis, insect hormone biosynthesis and lysosome which were involved in the ovarian development of E. carinicauda. A total of 1223 DEGs were identified in eyestalk tissue under low salinity stress, and the 18 important DEGs were associated with ovarian development. KEGG enrichment analysis found that ECM-receptor interaction, folate biosynthesis, lysosome, arginine biosynthesis and retinol metabolism may be involved in the ovarian development under low salinity stress. Our results provided new insights and revealed new genes and pathways involved in ovarian development of E. carinicauda under long-term low salinity stress.

Identification and functional characterization of WNT5 in the ovarian maturation of Exopalaemon carinicauda (Holthuis, 1950) (Caridea, Palaemonidae)

Abstract The Wnt family, the ligand of the Wnt signal pathway, is highly conserved and plays an important role in various cellular processes including reproduction and development. In this study, wnt5 was cloned from the ridgetail white prawn Exopalaemon carinicauda (Ec-wnt5) and its function in ovarian maturation was investigated. The results showed that the Ec-wnt5 cDNA was 2422 bp, including an ORF with 1116 bp encoding a polypeptide with 371 amino acids. Ec-WNT5 had the highest homology with WNT5 from Penaeus vannamei (93.1%). Ec-wnt5 was expressed in 9 tissues with the most expression in ovary and increased significantly () along with ovarian maturation, while decreased significantly () with vitellogenin and cathepsin L in E. carinicauda ovary post Ec-wnt5 RNA interference. All gonadosmatic indices of the RNAi group were significantly lower than those of the control (). The results suggest that Ec-WNT5 might be the key member of the Wnt family involved in ovarian maturation.