Triploid Pacific Oysters Research Articles

Comparative analysis of growth and metabolism in diploid and triploid Pacific oysters Crassostrea gigas under different temperature and salinity

Comparative analysis of growth and metabolism in diploid and triploid Pacific oysters Crassostrea gigas under different temperature and salinity

Overexpression of CDC42 causes accumulation of DNA damage leading to failure of oogenesis in triploid Pacific oyster Crassostrea gigas

Triploid Pacific oyster Crassostrea gigas exhibits notable differences in fecundity, with the majority being sterile individuals, referred to as female β, which produce few oocytes, while a minority are fertile individuals, referred to as female α, which produce abundant oocytes. However, the molecular mechanisms underlying these differences in triploid fecundity remain poorly understood. CDC42 has been implicated in processes related to increased DNA damage and genomic instability. Here, we investigate the crucial role of CDC42 in DNA damage repair during oogenesis in triploid C. gigas. Immunofluorescence analysis of γH2AX, a marker for DNA double-stranded breaks, showed significantly higher levels of DNA damage in gonadal cells of triploids compared to diploids, particularly in female β. Histological and ultrastructural analyses revealed abnormal germ cells, termed β gonia, characterized by giant nuclei condensed into irregular chromosome-like chromatin, present in triploid gonadal follicles. RNAseq and proteomic analyses revealed significantly elevated CDC42 expression in triploid gonads compared to the diploids. Inhibition of CDC42 activity in triploids using ZCL278, a CDC42-specific inhibitor, resulted in a significant reduction in DNA damage, increased oocyte numbers, and a decrease in β gonia count. Transcriptome profiling revealed that CDC42 inhibition upregulated the PI3K-AKT signaling pathway along with DNA repair activation. Overall, our findings suggest that overexpression of CDC42 during oogenesis in triploid C. gigas impedes DNA repair, leading to the accumulation of DNA damage, and consequently, oogenesis blockade and abnormal germ cell differentiation. Conversely, inhibition of CDC42 activity activates the PI3K-AKT signaling pathway and promotes DNA repair, thereby mitigating DNA damage and facilitating oogenesis in triploids. This study provides new insights into the molecular mechanisms of sterility in female triploid C. gigas.

Characterization of piRNAs in Diploid and Triploid Pacific Oyster Gonads: Exploring Their Potential Roles in Triploid Sterility.

PIWI-interacting RNAs (piRNAs) are crucial for silencing transposable elements, germ cell development, and gametogenesis. Triploid Pacific oysters (Crassostrea gigas) are vital in the oyster aquaculture industry due to reduced fertility and rapid growth. This study integrates piRNA and mRNA expression analyses to elucidate their potential contributions to the sterility of triploid C. gigas. Bioinformatics analysis reveals a distinct U-bias at the 5' terminal of oyster piRNAs. The abundance of piRNA clusters is reduced in triploid gonads compared to diploid gonads, particularly in sterile gonads, with a significant decrease in piRNA numbers. A specific piRNA cluster is annotated with the PPP4R1 gene, which is downregulated in infertile female triploids and exhibits a negative correlation with three piRNAs within the cluster. Differential expression analysis identified 46 and 88 piRNAs in female and male comparison groups, respectively. In female sterile triploids, the expression of three target genes of differentially expressed piRNAs associated with cell division showed downregulation, suggesting the potential roles of piRNAs in the regulation of cell division-related genes, contributing to the gonad arrest observed in female triploid oysters. In male triploid oysters, piRNAs potentially interact with the target genes associated with spermatogenesis, including TSSK4, SPAG17, and CCDC81. This study provides a concise overview of piRNAs expression in oyster gonads, offering insights into the regulatory role of piRNAs in triploid sterility.

A comparative study of the survival, growth, and gonad development of the diploid and triploid Pacific oyster, “Haida No.2” strain

A comparative study of the survival, growth, and gonad development of the diploid and triploid Pacific oyster, “Haida No.2” strain

Investigating the molecular mechanism of sterility in female triploid Pacific oyster (Crassostrea gigas)

The emergence of triploid oysters has freed the oyster market from the problem of interruptions in the breeding season, allowing for year-round availability. However, according to recent statistics, the phenomenon of fertility in triploid oysters has been increasing yearly, perhaps eventually leading to the loss of the sterility characteristic. This has in turn affected the oyster farming industry. Therefore, we attempted to mine key genes through transcriptomics to find the causes of triploid fertility. During our surveys and sampling, we found that most of the fertile triploid Crassostrea gigas were females, with a much smaller percentage of males. Therefore, the main objective of this study was to analyze the differences between fertile and sterile triploid female C. gigas. We performed transcriptome analysis of fertile female triploid C. gigas and sterile female triploid C. gigas and identified 2361 up-regulated differentially expressed genes (DEGs) and 1541 down-regulated DEGs, respectively. Enrichment analysis of these DEGs revealed that most GO terms and KEGG pathways were associated with mitosis. We then created a protein–protein interaction (PPI) network using genes enriched in mitosis-associated KEGG pathways. Finally, we screened and validated 26 key genes by quantitative RT-PCR and all were found to be downregulated in expression in sterile female triploids. The main cause of sterility is the suppression of the expression of genes that control the process of germ cell proliferation, the failure of the mitotic cycle to proceed smoothly, and the inability to produce an oogonium. These results can be used to explore ways to reduce the fertility of triploid C. gigas and to promote the breeding of higher quality triploid oysters.

Stable Differences in Growth Rates of Juvenile Triploid Oysters <i>Crassostrea gigas</i>

The three groups of mollusks of the triploid Pacific oyster Crassostrea gigas from the Liman Donuzlav (Black Sea), differing in morphometric characteristics: fast growing (FG) – shell height (H) 40 mm, medium growing (MG) – 15 mm H 40 mm and slow growing (SG) – H 15 mm, were studied. The stable differences in the growth rates of juveniles of the same age were revealed. Mollusks of the FG group were the leaders in terms of weight gain and linear size throughout the study. The average daily increase in shell height in the studied mollusks ranged from 0.1 to 0.35 mm/day, with maximum values in June and September. Weight gain occurred with different intensity, on average in SG – 0.051 g/day, in MG – 0.168 g/day, in FG – 0.287 g/day. The peaks of this indicator were in August and September, reaching 0.12, 0.26 and 0.43 g/day, respectively. A negative allometry of the shell in height was obtained in slow–growing polyploid oysters (b = 2.17), in the other two other groups – a clear positive (for MG b = 3.23, for FG b = 3.80), i.e., the increase in mass was faster than linear growth in juveniles of the species. Polyploidy (triploidy) is suggested as the reason for the differences in the growth rates of the same-aged mollusks. The allometry indicator b can be used to identify growth features in the early stages of oyster development.

Marine heatwaves impact mortality of triploid Pacific oysters.

Studies of heatwave impacts on marine organisms are needed to understand biological tolerance to heat stress. Such studies should include integrative analyses across different levels of biological organization, which often reveal that predictions are non‐linear (e.g., gene–protein–physiology–organism). Further insights into potential evolutionary responses of organisms to rapid environmental change can be gained from formal genetic studies of multigenerational pedigreed families.

Triploid Pacific oysters exhibit stress response dysregulation and elevated mortality following heatwaves.

Polyploidy has been suggested to negatively impact environmental stress tolerance, resulting in increased susceptibility to extreme climate events. In this study, we compared the genomic and physiological response of diploid (2n) and triploid (3n) Pacific oysters (Crassostrea gigas) to conditions present during an atmospheric heatwave that impacted the Pacific Northwestern region of the United States in the summer of 2021. Climate stressors were applied either singly (single stressor; elevated seawater temperature, 30°C) or in succession (multiple stressor; elevated seawater temperature followed by aerial emersion at 44°C), replicating conditions present within the intertidal over a tidal cycle during the event. Oyster mortality rate was elevated within stress treatments with respect to the control and was significantly higher in triploids than diploids following multiple stress exposure (36.4% vs. 14.8%). Triploids within the multiple stressor treatment exhibited signs of energetic limitation, including metabolic depression, a significant reduction in ctenidium Na+ /K+ ATPase activity, and the dysregulated expression of genes associated with stress response, innate immunity, glucose metabolism, and mitochondrial function. Functional enrichment analysis of ploidy-specific gene sets identified that biological processes associated with metabolism, stress tolerance, and immune function were overrepresented within triploids across stress treatments. Our results suggest that triploidy impacts the transcriptional regulation of key processes that underly the stress response of Pacific oysters, resulting in downstream shifts in physiological tolerance limits that may increase susceptibility to extreme climate events that present multiple environmental stressors. The impact of chromosome set manipulation on the climate resilience of marine organisms has important implications for domestic food security within future climate scenarios, especially as triploidy induction becomes an increasingly popular tool to elicit reproductive control across a wide range of species used within marine aquaculture.

Transcriptome profiling explores the immune defence mechanism of triploid Pacific oyster (Crassostrea gigas) blood against Vibrio alginolyticus based on protein interaction networks.

Triploid oysters have provided the oyster industry with many benefits, such as fast growth rates, meat quality improvement, and increased oyster production and economic benefits, since the first report on triploid oysters was published. The development of polyploid technology has remarkably increased the output of triploid oysters to meet the increasing demand of consumers for Crassostrea gigas in the past decades. At present, research on triploid oyster has mainly focused on breeding and growth, but studies on the immunity of triploid oysters are limited. According to recent reports, Vibrio alginolyticus is a highly virulent strain that can cause disease and death in shellfish, shrimp, as well as serious economic losses. V. alginolyticus may be a reason why oysters die during summer. Therefore, using V. alginolyticus to explore the resistance and immune defense mechanisms of triploid oysters against pathogens presents practical significance. Transcriptome analysis of gene expression was performed in triploid C. gigas at 12 and 48h after infection with V. alginolyticus, and the respective 2257 and 191 differentially expressed genes (DEGs) were identified. The results of GO and KEGG enrichment analyses showed that multiple significantly enriched GO terms and KEGG signaling pathways are associated with immunity. A protein-protein interaction network was constructed to investigate the interaction relationship of immune-related genes. Finally, we verified the expression situation of 16 key genes using quantitative RT-PCR. This study is the first to use the PPI network in exploring the immune defense mechanism of triploid C. gigas blood to fill the gap in the immune mechanism of triploid oysters and other mollusks, and provide valuable reference for future triploid farming and pathogen prevention and control.

Comparative study between triploid and diploid oysters (Crassostrea gigas) on non-volatile and volatile compounds

The quality of diploid oyster (crassostrea gigas) decreased significantly during the breeding period, which reflected the quality advantage of triploid oyster. However, there were few comparative studies on flavor quality characteristics between diploid and triploid oysters. This study compared the non-volatile compounds and volatile compounds between triploid and diploid oysters. These results showed that the percentage of eicosapentaenoic acid (EPA) in diploid oysters (18.68 ± 0.26%) was significantly higher than that in triploid oysters (16.16 ± 1.61%). The content of inosincacid (IMP) in diploid oysters (16.13 ± 0.03 mg/100 g) was significantly lower than that in triploid oysters (22.27 ± 0.41 mg/100 g). Adenosine monophosphate (AMP) content (364.08 ± 0.48 mg/100 g), succinic acid content (1244.51 ± 24.81 mg/100 g), and total free amino acid content (638.34 ± 17.32 mg/100 g) were significantly higher than those of triploid oysters (248.85 ± 2.32 mg/100 g, 420.99 ± 8.76 mg/100 g, 552.71 ± 17.32 mg/100 g, respectively). The main volatile compounds in diploid and triploid Pacific oysters were alcohols, aldehydes, ketones and esters. The volatile compounds content in triploid oysters were higher than those in diploid oysters. This study will provide basic data of Pacific oyster flavor and essential for the flavor pattern of seafood.

Relationship between Condition Index Values and Expression Levels of Gene and Protein in the Adductor Muscle of Diploid and Triploid Oysters Crassostrea gigas

Three proteins [myosin heavy chain (MHC), filamin-C fragment (FIL-C), and actin 2 (ACT2)] were identified in adductor muscle from diploid and triploid Pacific oysters (Crassostrea gigas) and the relationship between the condition index (CI) and mRNA expression of these genes was investigated, together with the mRNA expression of molluscan insulin-related peptide (MIP), C. gigas insulin receptor-related receptor (CIR), and insulin-like growth factor binding protein complex acid labile subunit (IGFBP-ALS). Monthly changes in the CI were similar to the changes in the tissue weight rate in both groups. ACT2 and MHC mRNA expression was statistically higher in the triploid than the diploid, while FIL-C mRNA expression was significantly higher in the diploid (p<0.05). The MIP, CIR, and IGFBP-ALS mRNA expression of the diploid oysters were all significantly higher in July than in other months (p<0.05). The MIP, CIR, and IGFBP-ALS mRNA expression in the triploid oysters was high in July, but there were no significant differences (p>0.05). Changes in the expression levels of the genes investigated in this study could be used as intrinsic indicators of the annual growth, maturity, and spawning period of cultured diploid and triploid C. gigas in Tongyeong, Korea.

Physiological and gene expression responses of diploid and triploid Pacific oyster ( Crassostrea gigas ) to heat acclimation

High temperature is considered to be one of the important causes of mass mortality of diploid and triploid oysters in summer. In order to compare the tolerance adaptability of diploid and triploid oysters to heat stress, the activities of superoxide dismutase activity (SOD), catalase activity (CAT) and contents of malondialdehyde (MDA) and the expression of Hsp70 and metallothionein (MT) genes in diploid and triploid oysters under acute and chronic heat stress were studied. The results showed that the survival rate of diploid oysters was significantly higher than that of triploid oysters under acute and chronic heat stress (p < 0.05). Under acute heat stress, the SOD levels in gills of both diploid and triploid oysters increased significantly from hour 3 (p < 0.05), but there was no significant difference in SOD levels between diploid and triploid oysters at all time points. The SOD level in hepatopancreas of triploid oysters was significantly higher than that of diploid oysters at all time points except 48 h (p < 0.05). The CAT level of diploid and triploid oysters decreased sharply at 48 h and that of diploid oysters was significantly higher than that of triploid oysters (p < 0.05). Under acute heat stress, the increase in MDA content in triploid oysters was significantly higher than that in diploid oysters (p < 0.05). Under acute heat stress, the expression levels of Hsp70 in the gills and hepatopancreas were significantly increased in diploid and triploid oysters (p < 0.05), but increased varies between gills and hepatopancreas. The expression levels of MT in the gills and hepatopancreas were significantly decreased in diploid and triploid oysters (p < 0.05). The results obtained in this study provide physiological and immunological evidence to explain differences in high-temperature tolerance between diploid and triploid oysters and help us better understand the mass mortality of oysters that occurs during high temperatures in summer.

Investigation of the role of endogenous miRNAs in determining sterility in triploid Pacific oysters (Crassostrea gigas)

Triploid oysters generate fewer gametes than diploid oysters and exhibit varying degrees of gonad development. The expression of related genes, such as those involved in gametogenesis and energy metabolism, may influence reproductive potential. In addition, microRNAs (miRNAs) are important regulators of gene expression. However, the contribution of miRNAs has not yet been assessed in sterile triploid Pacific oysters (Crassostrea gigas). We therefore obtained extensive miRNA and gene expression data to identify potentially critical miRNA-mRNA interactions that are linked to sterility in triploid C. gigas. Here, we found miR-263-x to be significantly downregulated in the gonads of sterile females. The upregulated target genes were associated with lipid droplet formation, which revealed the likely involvement of nutrient accumulation during gonadal development as regulated by miR-263-x in female sterile triploids. In males, the upregulated miRNAs (miR-1992-y and miR-2001-x) were shown to regulate spermatogenesis-related gene expression, including flagellar formation, and cell proliferation and migration. Our results suggest that energy redistribution regulated by miRNAs may be critical for gonad development in females, indicating that sterile triploids undergo a significant reduction in gamete number and show an increased accumulation of nutrients in the gonads. Our findings further indicate that decreased expression of genes related to spermatogenesis regulated by miRNAs is important in gonadal dysgenesis in sterile triploids. These results shed light on the epigenetic regulatory mechanisms governing sterility in triploid bivalves.

Dynamic simulation of diploid vs. triploid Pacific oyster (Crassostrea gigas) productive performance in northwestern Mexico

The Pacific oyster Crassostrea gigas was introduced in northwestern Mexico for aquaculture purposes. Although its cultivation has been successful, this species has shown high mortalities during summer. To mitigate this problem, producers have resorted to biotechnology (triploidy), whose performance -regarding diploid seedling- depends on site conditions and stocking time. Hence, uncertainty exists on its benefits under real production conditions. This research evaluates triploidy performance by implementing a dynamic simulation model considering environmental effects (temperature and chlorophyll) on culture production. The dynamic simulation was based on systems theory, dividing the productive system into two sub-models (environmental and biological), including temperature and chlorophyll effects, growth, mortality, and condition index parameterized in the function of the environmental parameters. The dynamic simulation results suggest that implementing triploid culture is advantageous in zones under high stress associated with high temperature and low productivity; likewise, triploid spat tends to show better performance independently of the site. Nevertheless, performance by ploidy varies depending on the environmental conditions of the sites.

Disruption of cell division prevents gametogenesis in triploid Pacific oysters (Crassostrea gigas)

Triploid oysters with their large size and consistent meat quality have become a major component of the oyster aquaculture industry worldwide. It has been observed that triploid Pacific oysters (Crassostrea gigas) showed high levels of variation and sex-specific differences in sterility. Here, we analyzed mitosis and meiosis during gametogenesis in triploid Pacific oysters and the expression of key cell cycle regulatory proteins, namely members of the cyclin family (A, B, D, E). We found that in female C. gigas, expression of cyclin D and E in gonad of triploids were higher than those in diploids, while expression of cyclin A and B were significantly suppressed in the gonads of triploids. To test whether mitosis of gonia might be arrested at G1/S or S/G2 phase in triploids, we compared EdU labeling in gonadal cells of triploid and diploid oysters. The results showed a similar number of EdU-labelled cells in gonads of triploid and diploid females, indicating that gonia in triploids successfully entered the S-phase as diploids. In male triploids, gonadal expression of the four cyclin genes at the mature stage were similar to that in male diploids at the growth stage with numerous spermatogenic cells. The number of EdU-labelled cells in triploid male gonads at the mature stage was significantly more than that in diploids, suggesting more proliferating cells in triploid gonads in males. Collectively, these data inidate that the sterility of triploid females is likely caused by the failure of germ cells to enter G2-phase during mitosis. In addition, we speculate that gonadal development of triploid males was arrested at the growth stage and defective spermatogenesis might be associated with disruption of meiosis.

Comparative transcriptomic analyses reveal differences in the responses of diploid and triploid Pacific oysters (Crassostrea gigas) to thermal stress

Triploid oysters often have higher growth rates and survival rates than diploid oysters. However, some studies have observed the opposite patterns. Triploid oysters have also been observed to show reduced resistance to stress and disease compared with diploid oysters. We compared the transcriptional patterns of diploid and triploid Pacific Oysters (Crassostrea gigas) in response to acute and prolonged thermal stress. The survival rate of triploid C. gigas was lower than that of diploid oysters after prolonged heat stress at 28 °C. A total of 779 and 396 differentially expressed genes (DEGs) were detected in diploid and triploid oysters exposed to acute heat stress, respectively, and the number of DEGs was 418 in diploids and 483 in triploids after prolonged heat stress. Functional enrichment analysis revealed that the DEGs were significantly enriched in protein processing in the endoplasmic reticulum pathway, NF-kappa B signaling pathway, NOD-like receptor signaling pathway, and TNF signaling pathway in both diploid and triploid C. gigas under heat stress. Genes encoding translation initiation factors, including MKNK1, eIF4G3, eIF2a kinase 1, and eIF2a kinase 3, were differentially expressed under acute heat stress in diploid oysters. The number of differentially expressed HSP and IAP genes was greater in diploids than in triploids under acute heat stress, and the expression levels of most of these HSP and IAP genes were higher in diploid oysters than in triploid oysters. Overall, our findings revealed differences in the response of diploid and triploid C. gigas to thermal stress. Triploid C. gigas might be less capable of rapidly modifying the inflammatory response and apoptosis in response to heat stress compared with diploid C. gigas. Different genetic lines of diploid and tetraploid oysters should be used to produce triploid oysters with increased stress resistance.

Refinement of a classification system for gonad development in the triploid oyster Crassostrea gigas

Breakthroughs in polyploidy technologies have enabled the scaling-up of the commercial utilization of phenotypically-sterile triploid Crassostrea gigas . Compared with diploid oysters, gonad development in triploids is retarded, but not absent. Although histological methods of characterizing gonadal development in triploid C. gigas has been reported, the selection of sampling sites and densities might lead to bias when taking seasonal variations into consideration. Moreover, previously-employed classification systems were found to be incompatible with our long-term observations. In this study, by sampling Pacific oysters at different seasons, over several years and from different locations, we were able to establish a new classification system for gonadal development in triploid Pacific oyster based on histological analysis. Based on the types of germ cells, triploids were grouped into female (divided into female α and female β), male and hermaphrodites during the reproductive season. Surprisingly, female α was partially sterile, showing active gametogenesis and few abnormal germ cells, which were defined as β gonia. Unlike female α, triploid female β had the most severely retarded gonad along with abnormal morphological features in the gonia. We inferred that β gonia were correlated with female triploid sterility. Despite the presence of numerous gametes in triploid male gonads, the fecundity of triploid males was still severely reduced compared with that of diploids. In addition, maturation arrest of spermatogenesis in triploid males was detected histologically. Based on the types of germ cells and the presence of β gonia, hermaphrodites were further divided into hermaphrodite I and hermaphrodite II. An almost male-like triploid was redefined as a hermaphrodite triploid. The gonadal development of triploids from different sites was mostly similar. As shown via annual histological analysis, the increase in the percentage of female α and the decrease in the percentage of female β matched the seasonal development of the oyster gonad. Hence, we speculated that gonad development in female triploid oysters was delayed. • A new classification system for triploid C. gigas was established. • The sex of triploid C. gigas could be identified at early gametogenesis. • The fecundity of triploid males was overestimated. • Some male-like triploids were hermaphrodite. • We hypothesized β gonia lead to sterility of female triploids, whose gonad development delayed.

Genome-Wide Differential DNA Methylomes Provide Insights into the Infertility of Triploid Oysters.

Chromosomal incompatibility and gene expression changes would affect the development of polyploid gonad and gamete formation. The role of epigenetics like DNA methylation in reproductive development is fully demonstrated in diploid animals. The lack of polyploid species and the infertility of polyploid animals, especially the odd ploidy, limit the study of epigenetic regulation mechanism of polyploid reproduction. Fertile and infertile individuals exist in triploid Pacific oyster Crassostrea gigas, which provide an interesting model for studies on the effect of epigenetic regulation on gonadal development. The whole genome single base resolution DNA methylomes in gonads of triploid females α (F-3nα), triploid females β (F-3nβ), triploid males α (M-3nα), triploid hermaphrodite predominantly males (HPM-3n), diploid females (F-2n), and diploid males (M-2n) were generated by using bisulfite-sequencing. The overall DNA methylation profiles in gene regions and transposable regions of fertile and infertile triploid oysters were consistent with those of diploid oysters. The DNA methylation level of CG context decreased in infertile triploid oysters, with more hypomethylated than hypermethylated regions, and the opposite is true in fertile triploid oysters. Genes harbored with differentially methylated regions (DMRs) in infertile triploids were mainly related to the metabolism pathways and the signal pathways. Correlation analysis indicated that the expression of gene transcriptions was generally positively associated with DNA methylation in gene body regions, and DMRs in infertile triploid oysters played significant roles in gonadal development as a possible critical epigenetic regulator of gonadal development gene transcriptional activity. These findings indicate a potential relationship between DNA methylation variability and gene expression plasticity in newly formed polyploidy. As far as we know, this is the first study revealing the epigenetic regulation of gonadal development in invertebrates based on fertile and infertile models, meanwhile providing a new mentality to explore the regulatory mechanisms of infertility in triploids.

Physiological and Gene Expression Responses of Diploid and Triploid Pacific Oyster (Crassostrea Gigas) to Heat Acclimation

Physiological and Gene Expression Responses of Diploid and Triploid Pacific Oyster (Crassostrea Gigas) to Heat Acclimation

Integrated Proteomic and Transcriptomic Analysis of Gonads Reveal Disruption of Germ Cell Proliferation and Division, and Energy Storage in Glycogen in Sterile Triploid Pacific Oysters (Crassostrea gigas)

Triploid oysters have poor gonadal development, which can not only bring higher economic benefits but also have a potential application in the genetic containment of aquaculture. However, the key factors that influence germ cell development in triploid oysters remain unclear. In this study, data-independent acquisition coupled to transcriptomics was applied to identify genes/proteins related to sterility in triploid Crassostrea gigas. Eighty-four genes were differentially expressed at both the protein and mRNA levels between fertile and sterile females. For male oysters, 207 genes were differentially expressed in the transcriptomic and proteomic analysis. A large proportion of downregulated genes were related to cell division, which may hinder germ cell proliferation and cause apoptosis. In sterile triploid females, a primary cause of sterility may be downregulation in the expression levels of certain mitotic cell cycle-related genes. In sterile triploid males, downregulation of genes related to cell cycle and sperm motility indicated that the disruption of mitosis or meiosis and flagella defects may be linked with the blocking of spermatogenesis. Additionally, the genes upregulated in sterile oysters were mainly associated with the biosynthesis of glycogen and fat, suggesting that sterility in triploids stimulates the synthesis of glycogen and energy conservation in gonad tissue.