Molecular characterization of shrimp harbinger transposase derived 1 (HARBI1)-like and its role in white spot syndrome virus and Vibrio alginolyticus infection

The Role of microRNA-133 in Hemocyte Proliferation and Innate Immunity of Scylla paramamosain

MicroRNAs (miRNAs) are important signaling regulators that are involved in regulating the innate immunity of crustacean. However, few studies focus on the role of crustacean miRNAs in the cellular immunity have been reported. In this study, we showed that the expression of miR-133 was significantly up-regulated in the mud crab Scylla paramamosain after infection by white spot syndrome virus (WSSV) or Vibrio parahaemolyticus. The anti-miRNA oligonucleotide AMO-miR-133 was used to knock down miR-133 expression in S. paramamosain. The number of WSSV copies increased significantly in WSSV-infected crabs after miR-133 knockdown. Knockdown of miR-133 also enhanced the mortality rates of WSSV-infected and V. parahaemolyticus-infected mud crabs, and it significantly enhanced the expression of the astakine, which was confirmed by real-time quantitative PCR and western blot analysis. The data also indicate that miR-133 may affect hemocyte proliferation in S. paramamosain by regulating astakine expression. miR-133 Knockdown enhanced the apoptosis or phagocytosis of crab hemocytes, and increased the mortality of mud crabs after WSSV or V. parahaemolyticus infection. These results indicate that miR-133 is involved in the host immune response to WSSV and V. parahaemolyticus infection in mud crabs. Taken together, our research provides new insights for the control of viral or vibrio diseases in S. paramamosain.

Genome-Wide Identification, Characterization, and Expression Analysis of DDE_Tnp_4 Family Genes in Eriocheir sinensis

DDE transposase 4 (DDE_Tnp_4) family is a large endonuclease family involved in a wide variety of biological processes. However, little information is available about this family in crustaceans. In this study, we used HMMER to identify 39 DDE_Tnp_4 family genes in Eriocheir sinensis genome, and the genes were classified into four subfamilies according to phylogenetic analysis. Gene expansions occurred among E. sinensis genome, and synteny analysis revealed that some DDE_Tnp_4 family genes were caused by tandem duplication. In addition, the expression profiles of DDE_Tnp_4 family genes in E. sinensis indicated that subfamily I and II genes were up-regulated in response to acute high salinity and air exposure stress. E. sinensis is a kind of economical crustacean with strong tolerance to environmental stress. We confirmed the expansion of DDE_Tnp_4 family genes in E. sinensis and speculated that this expansion is associated with strong tolerance of E. sinensis. This study sheds light on characterizations and expression profiles of DDE_Tnp_4 family genes in E. sinensis and provides an integrated framework for further investigation on environmental adaptive functions of DDE_Tnp_4 family in crustaceans.

MdHARBI1, a MdATG8i-interacting protein, plays a positive role in plant thermotolerance

Autophagy is a major degradation pathway in plants for maintaining cellular homeostasis in response to various environmental stressors. ATG8 is one of a series of autophagy-related (ATG) proteins and plays a central role in both bulk and selective autophagy. Previously, we characterized MdATG8i in apple and demonstrated that it has a positive role in apple stress resistance. Although many ATG8-interacting proteins have been found in Arabidopsis, no protein has been reported to interact with MdATG8 in apple. Here, we identified MdHARBI1 as a MdATG8i-interacting protein in apple, however, the functions of HARBI1-like proteins have not been explored in plants. Expression analysis of MdHARBI1 and pro-MdHARBI1-GUS staining of transgenic Arabidopsis exposed to high temperature demonstrated that MdHARBI1 was significantly induced by heat stress. Moreover, heat-treated MdHARBI1-trangenic tomato plants maintained higher autophagic activity, accumulated fewer ROS, and displayed stronger chlorophyll fluorescence than wild-type plants. Because these phenotypes were consistent with those displayed by MdATG8i-overexpressing apple plants under high temperature, we concluded that the MdATG8i-interacting protein MdHARBI1 plays a critical role in the basal thermotolerance of plants, mainly by influencing autophagy pathways.

The role of Astakine in Scylla paramamosain against Vibrio alginolyticus and white spot syndrome virus infection

Astakine is a crucial factor in the proliferation and differentiation of hematopoietic stem cells and is directly involved in hematopoiesis in crustaceans. To assess the role of Astakine in the innate immune system of Scylla paramamosain, the immune responses in healthy and Astakine-inhibited S. paramamosain were investigated in the present study. The RNA transcripts of Astakine were widely distributed in all examined tissues, with significantly higher levels of expression in hemocytes of both healthy and challenged S. paramamosain with Vibrio alginolyticus and WSSV. When Astakine was knocked down by RNA interference technology, immune-related genes, including Janus kinase, prophenoloxidase, hemocyanin, β-actin, myosin II essential light chain-like protein, signal transducer and activator of transcription, Relish, and C-type-lectin, were significantly down-regulated in hemocytes. The levels of phenoloxidaseactivity (PO), total hemocyte counts (THC) and hemocyte proliferation decreased significantly in hemocytes of Astakine-dsRNA treated S. paramamosain. After being challenged with V. alginolyticus and WSSV, the THC decreased significantly and the levels of hemocyte apoptosis increased significantly in Astakine-dsRNA treated S. paramamosain in comparison with those in infected groups without Astakine-dsRNA treatment. After being challenged with WSSV, the WSSV copies were significantly lower in Astakine-dsRNA treated groups than those in the WSSV infection group, which suggested that knockdown of Astakine was not conductive to WSSV replication and this might be associated with the decreasing THC. The results of survival analysis showed that the survival rate of V. alginolyticus or WSSV infected S. paramamosain decreased significantly following Astakine knockdown. These results suggested that RNA interference of Astakine might weaken the resistance of S. paramamosain to V. alginolyticus or WSSV infection. The weaken resistivity after knockdown Astakine might be related to the changes of important immune-related gene expression, THC, PO activity, proliferation and apoptosis of hemocytes.

miRNAs induced by white spot syndrome virus involve in immunity pathways in shrimp Litopenaeus vannamei

White shrimp Litopenaeus vannamei are widely cultured in the world and white spot syndrome virus (WSSV) led to huge economic losses in the shrimp industry every year. In the present study, miRNAs involved in the response of shrimp L. vannamei to WSSV infection were obtained through the Illumina HiSeq 2500 high-throughput next-generation sequencing technique. A total number of 7 known miRNAs and 54 putative novel miRNAs were obtained. Among them, 14 DEMs were identified in the shrimp infected with WSSV. The putative target genes of these DEMs were related to host immune response or signaling pathways, indicating the importance of miRNAs in shrimp against WSSV infection. The results will provide information for further research on shrimp response to virus infection and contribute to the development of new strategies for effective protection against WSSV infections.

Differentially expressed genes of the shrimp Marsupenaeus japonicus in response to infection by white spot syndrome virus or Vibrio alginolyticus

This is the first study to use a next-generation high-throughput DNA sequencing technique, the Illumina Hiseq2000 method, to analyze the transcriptome from hemocytes of Marsupenaeus japonicus. A total of 80,929,652 Illumina reads, including 79,525,942 high quality reads were obtained in this study. From these, 40,231 unigenes with a mean length of 1557 bp were assembled using Trinity de novo software and 28,746 cDNA were matched in the NCBI database. Then we compared the transcriptome changes after white spot syndrome virus (WSSV) or Vibrio alginolyticus infection. A total of 19,872 putative proteins were classified functionally into 25 molecular families in the cluster of orthologous groups. KEGG pathway analysis identified that the metabolic pathway possessed more unigenes (1358 unigenes), followed by biosynthesis of secondary metabolites, Huntington's disease and RNA transport. Important immune functions like apoptosis, phagocytosis, and lysosomes were in response to WSSV and V. alginolyticus early infection. Only 26 transcripts were significantly up-regulated or down-regulated after WSSV infection showed compared with V. alginolyticus. Crustin-like protein, endonuclease-reverse transcriptase, putative nuclease HARBI1-like, diphthamide biosynthesis protein 7 and hormone receptor 3 were involved in the immune response to WSSV or V. alginolyticus infection. These transcriptome datasets accelerate our understanding of the innate immune mechanisms in M. japonicus and other crustaceans.

Genome survey, high-resolution genetic linkage map construction, growth-related quantitative trait locus (QTL) identification and gene location in Scylla paramamosain

Scylla paramamosain is one of the most economically important crabs in China. In this study, the first genome survey sequencing of this crab was performed, and the results revealed that the estimated genome size was 1.21 Gb with high heterozygosity (1.3%). Then, RAD technology was used to construct a high-resolution linkage map for this species. A total of 24,444 single nucleotide polymorphism (SNP) makers were grouped into 47 linkage groups. The total length of the linkage groups was 3087.53 cM with a markers interval of 0.92 cM. With the aid of transcriptome and genome scaffold data, 4,271 markers were linked to genes, including several important growth-related genes such as transforming growth factor-beta regulator I, immune related-gene C-type lectin and ecdysone pathway gene broad-complex-like protein. Further, 442 markers, representing 279 QTLs, associated with 24 traits were identified, and of these markers, 78 were linked to genes. Some interesting genes, such as dedicator of cytokinesis protein 3, tenascin-X and DNA helicase MCM8, were believed to have important relationship with specific traits and merit further exploration. The results of this study will accelerate the genetic improvement and genome sequencing analysis of the mud crab.