Genetic characteristics and growth patterns of the hybrid grouper derived from the hybridization of Epinephelus fuscoguttatus (female) × Epinephelus polyphekadion (male).

Hybridization is one of the primary methods used to cultivate farmed grouper species. The hybrid grouper derived from crossing Epinephelus fuscoguttatus (♀) and E. polyphekadion (♂) exhibits growth superiority over its parents. The genetic characteristics and growth patterns of the hybrid grouper have not yet been defined. This study confirms the ploidy level of the hybrid grouper (2n = 48) using chromosome count analysis and flow cytometry. The 5S rDNA family was used to evaluate genetic diversity. Only one 5S class (~400 bp) was detected in the hybrid grouper, which could be used to distinguish between two different types based on nucleotide sequences, likely representing homologous unit classes from the female and male parental species. Growth patterns of 5-8-month-old hybrid groupers were also monitored. In this phase, a positive allometric growth pattern in body mass with total length was found. Body height and body mass were significantly correlated based on correlation and path coefficient, suggesting that body height could serve as an excellent index to increase body mass. These results aid our understanding of the genetic evolution of the hybrid grouper and inform the development of improved rearing techniques.

Label free proteomics and systematic analysis of secretome reveals effector candidates regulated by SGE1 and FTF1 in the plant pathogen Fusarium oxysporum f. sp. cubense tropical race 4.

BACKGROUND: Phytopathogens secreted effectors during host colonization to suppress or trigger plant immunity. Identification of new effectors is one of the research focuses in recent years. There is only a limited knowledge about effectors of Fusarium oxysporum f. sp. Cubense tropical race 4 (Foc TR4), the causal agent of wilt disease in Cavendish banana. RESULTS: Two transcription factors, SGE1 and FTF1, were constitutively over-expressed in Foc TR4 to partially mimic the in-planta state. Secreted proteins with high purity were prepared through a two-round extraction method. Then the secretome were analyzed via label free proteomics method. A total of 919 non-redundant proteins were detected, of which 74 proteins were predicted to be effector candidates. Among these candidates, 29 were up-regulated and 13 down-regulated in the strain over-expressing SGE1 and FTF1, 8 were up-regulated and 4 down-regulated in either SGE1 or FTF1 over expression strain. CONCLUSIONS: Through label free proteomics analysis, a series of effector candidates were identified in secretome of Foc TR4. Our work put a foundation for functional research of these effectors.

Can genes modulate anchoring effect?

The anchoring effect is a well-known decision bias, referring that initial irrelevant number (anchor) can impact late estimation. Anchoring effect can be explained as people starting from the anchor and stopping incremental adjustment too early-in other words, jumping into the conclusion impulsively. High impulsivity is associated with AA genotype of rs806379. Therefore, we hypothesized that rs806379 polymorphism can exert an influence on the anchoring effect. The subjects completed an experimental task of anchoring effect and provided saliva for genotyping. As expected, we found that subjects with AA genotype of rs806379 demonstrated stronger anchoring effect. This is the first article that explores the anchoring effect from the gene perspective. Our finding suggests that nature plays a role in anchoring effect.

SGE1 is involved in conidiation and pathogenicity of Fusarium oxysporum f.sp. cubense.

The ascomycete fungus Fusarium oxysporum f.sp. cubense race 4 (Foc TR4) causes vascular wilt diseases in banana (Musa spp.). In the present study, the role of SGE1 in regulating growth, conidiation, and pathogenicity of Foc TR4 was investigated. Deletion of SGE1 did not influence vegetative growth but impaired the conidiation of Foc TR4. Besides, the SGE1 deletion mutant basically lost pathogenicity on banana plantlets. Observation under the microscope indicated that the penetration and colonization processes were severely impaired in the SGE1 deletion mutant. Proteomics analysis suggested that SGE1 regulated the production of a series of proteins of Foc TR4. Taken together, our results suggest that SGE1 plays an important role in regulating conidiation and pathogenicity in fungal pathogen Foc TR4.

rDNA and mtDNA analysis for the identification of genetic characters in the hybrid grouper derived from hybridization of Cromileptes altivelis (female) × Epinephelus lanceolatus (male).

BACKGROUND: Hybridization is a useful strategy to produce offspring with more desirable phenotypic characteristics than those of parents. The hybrid grouper derived from the cross of Cromileptes altivelis (♀, 2n = 48) with Epinephelus lanceolatus (♂, 2n = 48) exhibits improved growth compared with its female parent, which makes it valuable to aquaculture. However, the genetic traits of the hybrid grouper are poorly understood. RESULTS: The observations showed that the hybrid grouper was diploid (2n = 48) and displayed intermediate morphology with the parent's measurable characteristics. The ribosomal DNA (rDNA) and mitochondria DNA (mtDNA) were characterized at molecular and phylogenetic level. High similarity and low genetic distance of 5S rDNA and mtDNA sequences between the hybrid grouper and C. altivelis showed that the hybrid grouper had a closer genetic relationship with female parents. The reconstructed phylogenetic tree based on COI gene and D-loop region of mtDNA recovered that mtDNA was maternally inherited in the hybrid grouper. Additionally, the DNA methylation level of 5S rDNA intergenic spacers (IGS) sequence was tested in here. The results showed that the DNA methylation status of the hybrid grouper was significantly lower than that of C. altivelis. CONCLUSION: Results of this study provide important data on the genetic characteristics of the hybrid derived from the cross of C. altivelis and E. lanceolatus, and contribute the knowledge of both evolution and marine fish breeding.

Exploring the influence of DNA methylation and single nucleotide polymorphisms of the Myostatin gene on growth traits in the hybrid grouper (Epinephelus fuscoguttatus (female) × Epinephelus polyphekadion (male)).

Investigations into the correlation between growth characteristics and DNA methylation levels, along with genetic variations, can provide fundamental insights to enhance growth performance in groupers. The Myostatin (mstn) gene plays a vital role in regulating skeletal muscle development and growth. This study scrutinized the DNA methylation levels of the mstn gene across hybrid groupers (E. fuscoguttatus (♀) × E. polyphekadion (♂)) and their parental species, to evaluate its impact on growth attributes in grouper fish. The nucleotide sequence of the mstn gene was directly sequenced in the hybrid grouper, exhibiting different growth performance to identify the single nucleotide polymorphisms (SNPs) of the mstn gene and explore their correlation with growth characteristics. The findings revealed no significant differences in global DNA methylation levels within muscle tissue among the hybrid grouper and parents. However, significant differences in DNA methylation sites were discovered between the hybrid grouper and E. polyphekadion at sites 824 and 1521 (located at exon 2 and intron 2, respectively), and between E. fuscoguttatus and E. polyphekadion at site 1521. These variations could potentially influence the mRNA expression of the mstn gene. The study also identified that SNP g.1003 T > C in exon 2 of the mstn gene was significantly associated with various growth traits including body weight, total length, body length, head length, caudal peduncle height, and body height (p < 0.01). Specimens with the TT genotype at site 1003 demonstrated superior growth performance compared to those with the TC genotype. Furthermore, microstructural analyses of muscle tissue showed that the average area and diameter of muscle fibers in TT genotype individuals were significantly greater than those in TC genotype individuals. Therefore, this research provides robust evidence linking the DNA methylation level and polymorphisms of the mstn gene with growth traits, which could be beneficial for grouper breeding programs.

Do Genes Play a Role in the Decoy Effect?

The decoy effect arises when the ratio of choosing B from A and B options is lower than the ratio of choosing B from A, B, and D options, wherein D is dominated by B. This decision pattern is obviously unreasonable but quite common. Previous research suggested that impulsive people have stronger decoy effect. Rs806379, as a single-nucleotide polymorphism (SNP) locus of cannabis receptor 1 gene (CNR1), has significant effect on impulsivity-people of A/A genotype are more impulsive than others. Therefore, rs806379 may relate to the decoy effect, which was tested in this study. Participants (359 Han Chinese college students) finished a task of the decoy effect, in which they made decisions between two or three mobile hard disks with various prices and provided saliva for genotyping. The results revealed the existence of the decoy effect. Furthermore, we found that participants with A/A genotype (251 Han Chinese college students) showed stronger decoy effect than others, when the prices were not high. This is the first attempt to study the decoy effect from a gene perspective. The result shows that even an SNP of a gene can have a significant association with complex human economic decision-making activities.

The effector SIX8 is required for virulence of Fusarium oxysporum f.sp. cubense tropical race 4 to Cavendish banana.

Plant pathogens employ effectors as molecular weapons to manipulate host immunity and facilitate colonization. Fusarium oxysporum f. sp. cubense is the agent of wilt disease in banana plantlets and four races of the pathogen have been identified based on the cultivar specificity. A total of 9 SIX genes have been detected in the genome of Foc TR4 and 6 genes detected in Foc1. Among these SIX genes, SIX2 and SIX8 are only detected in Foc TR4, not identified in Foc1. Expression profiles analysis revealed that SIX genes of Foc TR4 are highly induced after inoculation to Cavendish banana plantlets. Virulence analysis of the SIX2 and SIX8 knock-out mutants showed that SIX8 is required for the virulence of Foc TR4 while SIX2 has no obvious functions. Over expression of SIX8-FLAG proteins in the SIX8 knock-out mutant partly restored the virulence. Western blot analysis suggested that SIX8 could be secreted into the extracellular space and a signal peptide resided the N-terminal polypeptide sequence. This study provides some clues for further research on mechanism of SIX8 in regulating virulence of Foc TR4.

Dicer-like Proteins Regulate the Growth, Conidiation, and Pathogenicity of Colletotrichum gloeosporioides from Hevea brasiliensis.

Colletotrichum gloeosporioides from Hevea brasiliensis is the hemibiotrophic fungi which could cause anthracnose in rubber trees. Dicer like proteins (DCL) were the core enzymes for generation of small RNAs. In the present study, the knocking-out mutants of two dicer like proteins encoding genes of C. gloeosporioides were constructed; and functions of two proteins were investigated. The results showed that DCL play important roles in regulating the growth, conidiation and pathogenicity of C. gloeosporioides; and there is a functional redundancy between DCL1 and DCL2. Microscopy analysis and DAB staining revealed that loss of penetration ability into the host cells, instead of the decreased growth rate, was the main cause for the impaired pathogenicity of the ΔDcl1ΔDcl2 double mutant. Proteomics analysis suggested that DCL proteins affected the expression of functional proteins to regulating multiple biological processes of C. gloeosporioides. These data lead to a better understanding of the functions of DCL proteins in regulating the development and pathogenesis of C. gloeosporioides.