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Human norovirus (HuNoV) is a non-enveloped, single-stranded, positive-stranded RNA virus belonging to the family Caliciviridae. HuNoVs are important pathogenic microorganisms responsible for causing food safety incidents. Numerous species of shellfish are characterized by their abundant nutritional value, excellent healthcare function, and a high economic value. As a filter-feeding animal, shellfish filter the seawater at a rate of 4–20 L per hour and ingest microalgae to meet their physiological needs. Additionally, shellfish are able to continuously accumulate viruses from seawater into their bodies, resulting in a concentration ten or even thousand times higher in their tissues than in the environment. In recent years, more attention has been paid to HuNoV contamination in shellfish in China, and related monitoring studies have been conducted in different areas. However, most of these studies focused on a certain region in a certain period of time, and some species, which are not conducive to a comprehensive understanding of the overall prevalence of HuNoVs in shellfish in China. Meta-analysis refers to the methods which focus on contrasting and combining results from different studies for identifying patterns among the study results or other interesting relationships that may come to light in the context of multiple studies. This study aimed to collect cross-sectional data on the studies conducted on shellfish contamination in China. The search terms used were Norwalk virus, norovirus, shellfish, bivalves, oysters, mussels, clams, cockles, and scallops in all the databases (CNKI, VIP, CBM, WanFang Data, PubMed, Web of Science, Embase, and Cochrane Library). A total of 600 studies on HuNoV contamination of shellfish were initially included in the data. First, 303 duplicate studies were removed, leaving 297 studies remaining. One meta-analysis, 11 reviews, and 16 meeting abstracts were excluded from the first analysis. In the second analysis, abstracts of the remaining 269 studies were read by two independent reviewers, further excluding 221 studies in which experimental designs did not meet the inclusion criteria. After carefully reading the full text of the 48 studies, 11 of them were excluded. Ultimately, 37 studies were included in the final analysis. The total sample size in these 37 studies was 17 162 among which the maximum number of samples in a single study was 2 955, and the minimum was 52, and the total number of HuNoV-contaminated samples was 1 970. The meta-analysis was conducted using Stata 14.0, and the effect size was defined as the prevalence of HuNoVs (percentage). Moreover, the heterogeneity of the studies was examined using Q test (P-value) and I2. The pooled prevalence of HuNoVs in shellfish was found to be 15% with an I2 value of 97.22%, which indicated a strong heterogeneity among the 37 studies. We then grouped them based on genogroups, area, season, and species using a random effect model. As a result, GⅠ and GⅡ were found as the two most prevalent genogroups. As revealed by the results, the prevalence of contamination of GⅠ alone, contamination of GⅡ alone, and the combined contamination of GⅠ and GⅡwas found to be 3%, 10%, and 1%, respectively; both Beijing and Guangdong contributed the most with seven studies, followed by Zhejiang with five studies. In addition, there were four studies conducted each in Jiangsu and Shandong, and Fujian contributed with three studies. Two studies were conducted in Gansu, Guangxi, Hebei, Liaoning, and Shanghai. Only one study has been conducted in Hainan. The geographical location exhibited a significant impact on the prevalence of HuNoVs (P < 0.01), and its prevalence in South China (Guangdong, Guangxi, Hainan), North China (Beijing, Hebei), and East China (Fujian, Jiangsu, Shandong, Shanghai, and Zhejiang) reached 19%, 17%, and 11%, respectively, while those in Northeast China (Liaoning) and Northwest China (Gansu), which were not coastal areas, were 4% and 9%, respectively. HuNoVs contamination in shellfish was found to be significantly correlated with the season. At low temperatures, the virus is more persistent, and shellfish metabolism may be inhibited. Our results showed that the prevalence of HuNoVs was the highest in winter (25%), only 10% in summer, and 16% and 12% in spring and autumn, respectively. HuNoVs may contaminate a wide variety of species during the pre-harvest or post-harvest stages. Oysters, clams, and mussels have been recognized as the most common seafood on the table and therefore these are the most investigated. The results of this meta-analysis revealed that the prevalence of HuNoVs in oysters, mussels, and clams was 16%, 10%, and 9%, respectively. The possible reasons why oysters showed the highest prevalence among all shellfish are as follows. One, the oyster farming area is located in shallow bays, which are easily contaminated by domestic sewage. Second, different oyster tissues contain HuNoV receptors (human histo-blood group antigens (HBGAs)-like carbohydrates) and protein-ligands (oyster heat shock protein 70), which can specifically bind to HuNoVs. In summary, HuNoV contamination in shellfish is common in China, and the region, season, and species exhibit significant effects on the prevalence of HuNoVs. The results of this study are beneficial for gaining insights into the HuNoV contamination in shellfish, demonstrating the importance of continuous HuNoV monitoring. Future studies should establish some effective control measures to ensure the sound growth of the shellfish industry in China.

Norovirus, commonly found on shellfish and vegetables, is a foodborne virus with GII.4 as the dominant genotype responsible for widespread outbreaks since 1995. Continuous variation of major capsid protein VP1 can lead to changes in the immunogenicity and host receptor binding ability of norovirus, which is an important evolutionary mechanism. Therefore, analyzing the immunogenicity of VP1 and its binding ability to various HBGAs in GII.4 variants could improve our understanding of the persistent prevalence of GII.4. Here, the results suggest that GII.4 has gradually enhanced its HBGAs binding ability over time for various types of receptors. Variants exhibit significantly stronger immune response to homologous mouse antiserum than heterologous ones, highlighting the importance of variation of antigenic and histo-blood group binding sites in driving the evolution of GII.4. These synergistic forces constantly lead to antigenic drift and changes in receptor binding, resulting in continuous emergence of new variant strains and sustained prevalence.

Fertilizer application is a decisive measure for the productivity of medicinal chrysanthemum plants. Therefore, determining the optimal doses of nutrients required for the growth and yield is crucial. In this study, we set out to investigate the effect of various nutrients on the growth, yield, and functional components of chrysanthemum under eight different fertilization levels at seedling, branching, and flowering growth periods. The results show that plant height, stem diameter, and leaf area under the balance fertilization treatment were the highest (82 cm, 0.78 cm, and 38.50 cm2, respectively), while the flower size and yield under the high potassium treatment were significantly increased compared to using balance fertilization. Chlorophyll content was also highest under the high potassium treatment. Moreover, plant defensive antioxidant peroxidase (POD) was responsive to low nitrogen treatment and low phosphorus treatment, while high potassium treatment enhanced the phenylalanine aminolase (PAL) activity and increased the content of flavonoids and chlorogenic acid in Chrysanthemum morifolium. In addition, low phosphorus treatment promoted the accumulation of flavonoids and chlorogenic acid content. Convincingly, the results show that growth, flowering, and functional indicators of chrysanthemum may thrive best under high potassium and balanced fertilization dosages, which will contribute to the development of a new economical chrysanthemum fertilizer ratio.

Begonia × benariensis series varieties have high ornamental and economic value and are excellent varieties for large-area group planting in gardens and green areas. At present, the B. × benariensis series varieties grown in China rely on foreign imports, and the price of imported germplasm resources is expensive, which greatly increases the cost of flower enterprises. In view of this, B. × benariensis (2n = 2x = 34) was used as the material, the callus was treated with colchicine to induce polyploid plants, and the polyploid plants were subjected to morphology, DNA content identification, and stomatal identification, as well as comparisons of the morphophysiological indexes of the plants. The results showed that the polyploid was better induced with the treatment of 0.05% colchicine for 4 h, and the induction rate was 46.67%. Among the mutagenized plants, there were 42 triploids (2n = 3x = 51) and 98 tetraploids (2n = 4x = 68). The stomatal density of diploid leaves was about 1.09 times that of the triploid and 1.67 times that of the tetraploid, the defense cells of the leaves increased gradually, and the stomatal density decreased; with the increase in ploidy, the height of the plants increased, while the crown width decreased; the maximum length and width of the leaves decreased, the color of the leaves became darker, and the chlorophyll content increased. This study provides abundant variation materials and technical support for the selection and breeding of new varieties of B. × benariensis in the future.

Abstract The emergence of the novel GII.17 Kawasaki 2014 norovirus variant raising the interest of the public, has replaced GII.4 as the predominant cause of noroviruses outbreaks in East Asia during 2014–2015. Antigenic variation of the capsid protein is considered as one of the key mechanisms of norovirus evolution. In this study, we screened a panel of GII.17 mutants. First, we produced norovirus P proteins using cell-free protein synthesis (CFPS) system, comparing the results to pure proteins expressed in a cell-based system. Next, we determined the binding capability of specific monoclonal antibody (mAb) 2D11 using a unique set of wild-type GII.17 strains. Results of the EIA involving a panel of mutant cell-free proteins indicated that Q298 was the key residue within loop 1. These data highlighted the essential residues in the linear antibody binding characteristics of novel GII.17. Furthermore, it supported the CFPS as a promising tool for rapidly screening mutants via the scalable expression of norovirus P proteins.

Filter-feeding oyster is an important food transmission vector for the foodborne norovirus. To investigate the contamination level and genetic diversity of norovirus in commercial oysters in Guangzhou and better assess the risk of consumption, oyster samples were collected from local aquatic market from June 2020 to May 2021 in this study. The contamination content and genotype distribution of virus in shellfish were detected by protease K treatment coupled with polyethylene glycol precipitation small system previously established in the laboratory，including the real-time reverse transcription polymerase chain reaction and the nested RT-PCR. 110 oyster samples were detected, the positive rate of norovirus genogroup II(GII) was 52.7% (58/110), and the contents of virus was 1.56×103~1.09×106 copies/g (digestive gland). The positive rate of norovirus in oysters collected in spring and summer (March to August) was 35.7% (20/56), which was lower than the positive rate of 70.4% (38/54) in autumn and winter (September to February). However, there was no significant difference in content of virus detected in all seasons, in spring, content of virus was (2.69±1.46)×105 copies/g (digestive gland), in summer, content of virus was (1.97±2.16)×105 copies/g (digestive gland), in autumn, content of virus was (6.91±6.16)×104 copies/g (digestive gland), and winter was (4.83±2.99)×104 copies/g (digestive gland). Positive samples were sequenced and analyzed, the result showed that except for one was GII.17 genotype, the rest were all GII.4 genotypes (n=13), which was consistent with the local clinical epidemic genotypes. The results of this study showed that the level of norovirus contamination in commercial oysters of Guangzhou was severe, it is necessary to strengthen control work of prevention for virus, especially to remind consumers to fully process when eating oysters.

With the continuous growth of the human population, the demand for fiber is also rising sharply. As one of the main fiber plants available globally, cotton fiber yield (Gossypium hirsutum) is affected by boll abscission, which is related to the formation of the abscission layer. Therefore, we explored the formation of the abscission layer in cotton. The formation of the abscission layer in the cotton boll stalk was promoted by exogenous ethylene. It was found that both the number of the Golgi apparatus and the number of stacking layers increased in the dissociated cells. The GhArfGAP gene family in cotton was screened by the bioinformatics method, and the species and evolutionary relationship of the GhArfGAP gene family were analyzed. qRT-PCR showed that GhArfGAP13, GhArfGAP15, GhArfGAP25, and GhArfGAP34 in cotton had spatiotemporal-specific expression patterns. Subcellular localization suggested that GhArfGAP25 played a role in the Golgi apparatus. The expression of GhArfGAP25 in transgenic Arabidopsis thaliana is increased in the roots, stems, and leaves. Finally, we found that ethylene could induce the formation of the abscission layer in cotton. GhArfGAP13, GhArfGAP15, GhArfGAP25, and GhArfGAP34 might regulate the changes in the Golgi apparatus in the abscission layer. Taken together, the findings provide new ideas for the study of the formation of cotton abscission.

Abstract Background Human noroviruses are one of the main causes of foodborne illnesses and represent a serious public health concern. Rapid and sensitive assays for human norovirus detection are undoubtedly necessary for clinical diagnosis, especially in regions without more sophisticated equipment. Method The rapid reverse transcription recombinase-aided amplification (RT-RAA) is a fast, robust and isothermal nucleic acid detection method based on enzyme reaction. This method can complete the sample detection at 39 °C in 30 min. In this study, we successfully established a rapid reverse transcription recombinase-aided amplification (RT-RAA) assay for the detection of human norovirus GII.4 and applied this assay to clinical samples, as well as comparison with commercial reverse transcription real-time fluorescence quantitative PCR (RT-qPCR). Results At 95% probability, the detection sensitivity of RT-RAA was 3.425 log10 genomic copies (LGC)/reaction. Moreover, no cross-reaction was observed with other norovirus genogroups and other common foodborne viruses. Stool samples were examined by RT-RAA and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). Compared of RT-qPCR, kappa values for human norovirus detection with RT-RAA were 0.894 (p

Although noroviruses are the causative agents of most non-bacterial foodborne disease outbreaks, effective antivirals are currently unavailable. Certain probiotic strains have been reported as active antivirals for norovirus infections, but their mechanisms have not been fully elucidated. Herein, we examined the antiviral potential of 122 lactic acid bacteria isolates against murine norovirus (MNV), a human norovirus surrogate. A centenarian gut-derived strain, Limosilactobacillus fermentum PV22, exhibited the strongest MNV antagonism and reduced the viral titer by 2.23 ± 0.38 (log-value) in 5 min with stable activity at 25°C (P < 0.01). Genome mining revealed that its antiviral activity can be attributed to the synthesis of γ-aminobutyric acid, and this finding was experimentally verified. Furthermore, we demonstrated the safety of the isolate and its high intestinal colonization ability. In conclusion, we discovered a centenarian gut-derived L. fermentum strain with strong anti-norovirus activity and identified its antiviral metabolite. Our results will offer new solutions for the prevention and treatment of food-related norovirus infections.

Foodbone norovirus (NoV) is the leading cause of acute gastroenteritis worldwide. Candidate vaccines are being developed, however, no licensed vaccines are currently available for managing NoV infections. Screening for stimulated antibodies with broad-spectrum binding activities can be performed for the development of NoV polyvalent vaccines. In this study, we aimed to develop an indirect enzyme-linked immunosorbent assay (ELISA) for testing the broad spectrum of anti-NoV antibodies. Capsid P proteins from 28 representative NoV strains (GI.1–GI.9 and GII.1–GII.22 except GII.11, GII.18, and GII.19) were selected, prepared, and used as coating antigens on one microplate. Combined with incubation and the horseradish peroxidase chromogenic reaction, the entire process for testing the spectrum of unknown antibodies required 2 h for completion. The intra-assay and inter-assay coefficients of variation were less than 10%. The new method was successfully performed with monoclonal antibodies and polyclonal antibodies induced by multiple antigens. In conclusion, the indirect ELISA assay developed in this study had a good performance of reliability, convenience, and high-throughput screening for broad-spectrum antibodies.

Tetrahydrobiopterin (BH4) is a vital coenzyme for several enzymes involved in diverse enzymatic reactions in animals, and BH4 deficiency can lead to metabolic and neurological disorders due to dysfunction in its metabolism. In the silkworm natural homozygous mutant leml, the key enzyme sepiapterin reductase (BmSPR) in the de novo synthesis pathway of BH4 is inactivated, resulting in severe deficiency of BH4 synthesis. However, it is not known why the leml larvae can survive to the second-instar stage and which pathways lead to their death when BH4 is deficient. Here, we quantified BH4 and found that the fertilized eggs contained large amounts of BH4 transferred from the mother to the offspring, maintaining its normal development in the embryo and the first instar. Subsequently, we investigated the multiple pathways in which BH4 is involved as a cofactor. The results showed that BH4 deficiency in silkworms blocked the melanin synthesis pathway, caused an insufficient degree of epidermal sclerosis, disordered tyrosine metabolism, and damaged mitochondria. On the other hand, BH4 deficiency led to the uncoupling of nitric oxide synthase (BmNOS), a reduced NO production, and a significantly reduced fat in fat body catalyzation by phospholipase A2, resulting in an impaired immune system. Meanwhile, the uncoupling of BmNOS increased the O2− content, damaged the DNA, and caused the apoptosis of the body cells. Taken together, BH4 is critical for the life and death of leml mutants. This study lays a foundation for the further exploration of lepidopteran insects and provides an important basis for the treatment of human BH4 deficiency-related diseases.

Human norovirus is a common cause of acute gastroenteritis worldwide, and oysters have been found to be the main carriers for its spread. The lack of efficient pre-treatment methods has been a major bottleneck limiting the detection of viruses in oysters. In this study, we established a novel immunomagnetic enrichment method using polyamidoamine (PAMAM) dendrimer/SA-biotin-mediated cascade amplification for reverse transcriptase quantitative real-time polymerase chain reaction (RT-qPCR) detection. We compared the capture efficiency of traditional immunomagnetic enrichment, biotin-amplified immunomagnetic enrichment, and PAMAM dendrimer/SA-biotin-mediated cascade-amplification immunomagnetic enrichment. The optimal capture efficiency of the novel method was 44.26 ± 1.45%, which increased by 183.17% (P < 0.01) and 18.09% (P < 0.05) compared with the first two methods, respectively. Three methods were all applied in detecting norovirus in 44 retail oysters, the detection rate of the PAMAM dendrimer/SA-biotin-mediated method was 25.0%, which was higher than those of traditional IME (15.90%) and SA-biotin-amplified IME (18.80%) by 9.1 and 6.2%, respectively. In conclusion, the novel method can be applied for the rapid detection of norovirus in oysters, which can help reduce the cost and time of detection and improve detection rates.

Abstract Background Human norovirus is regarded as the leading cause of nonbacterial acute diarrhea in developing and developed countries. Among all genotypes, GII.4 has been the predominant genotype, but in East Asia, it was replaced by the GII.17 in 2014/2015. However, after the prevalence of new GII.17 variant in South China, a sharply increase in the number of norovirus infections associated with sporadic acute diarrhea was detected. In this study, we would investigate the prevalence and genetic diversity of noroviruses in the sporadic acute gastroenteritis cases in the post-GII.17 period in South China. Methods Norovirus was screened from 217 patients with sporadic acute gastroenteritis from August 2015 to October 2017 by reverse transcription-polymerase chain reaction. Then, two regions including the partial RNA polymerase and the capsid gene of positive samples were amplified and sequenced. Phylogenetic analyses were performed to determine norovirus genotypes. Complete VP1 sequences of GII.4 strains detected in this study were also amplified and subjected into evolutionary tracing analyses. Results A total of 43 (19.82%) norovirus samples were confirmed from 217 stool specimens, and it was found that GII.4 resurged as the new predominant variant, accounting for 76.74% (33/43) of positive samples. Only one local strain GZ2015-L550 was clustered with the contemporary GII.P16/GII.4–2012 recombinant variant, and other 32 local strains belonged to the clade with the GII.Pe/GII.4–2012 variant. Other genotypes including GII.17 (n = 4), GII.3 (n = 4), GII.8 (n = 1) and GI. 6 (n = 1) were also detected. Furthermore, all GII.4 strains were phylogenetic analyzed based on their capsid P2 subdomains. Combined with other reported 754 strains, the GII.4–2012 variant could be divided into two clades. Most GII.4 strains collected in 2016 and 2017 in this study (7/8) formed a new cluster A in Clade II with additional 103 contemporaneous strains. In addition, evolutionary tracing of the capsid P2 subdomain of this variant was also analyzed, and one specific amino acid substitutions (N373) was identified for Cluster A. Conclusion In summary, this study confirmed a norovirus infection peak in the post-GII.17 period in South China, which was caused by the resurgence of the GII.4 variant.

Abstract Background Previously, we demonstrated that pollen chamber formation (PCF) in G. biloba ovules was a process of programmed cell death (PCD) within the nucellar cells at the micropylar end. However, the signal triggering the cascades of the programmed events in these nucellar cells remains unexplored. Results A transcriptomic strategy was employed to unravel the mechanism underlying the nucellar PCD via the comparative profiles of RNA-seq between pre-PCF and post-PCF ovules. A total of 5599 differentially expressed genes (DEGs) with significance was identified from G. biloba ovules and classified into three main categories of GO annotation, including 17 biological processes, 15 cellular components and 17 molecular functions. KEGG analysis showed that 72 DEGs were enriched in “Plant hormone signal transduction”. Furthermore, 99 DEGs were found to be associated with the PCD process, including the genes involved in ethylene signaling pathway, PCD initiation, and PCD execution. Moreover, calcium-cytochemical localization indicated that calcium could play a role in regulating PCD events within the nucellar cells during pollen chamber formation in G. biloba ovules. Conclusions A putative working model, consisting of three overlapping processes, is proposed for the nucellar PCD: at the stage of PCD preparation, ethylene signaling pathway is activated for transcriptional regulation of the downstream targets; subsequently, at the stage of PCD initiation, the upregulated expression of several transcription factors, i.e., NAC, bHLH, MADS-box, and MYB, further promotes the corresponding transcript levels of CYTOCHROME C and CALMODULINs, thereby, leads to the PCD initiation via the calcium-dependent signaling cascade; finally, at the stage of PCD execution, some proteases like metacaspases and vacuolar processing enzyme for hydrolysis, together with the process of autophagy, play roles in the clearance of cellular components. Afterwards, a pollen chamber is generated from the removal of specific nucellar cells in the developing ovule.

Human norovirus is regarded as the leading cause of epidemic acute gastroenteritis with GII.4 being the predominant genotype during the past decades. In the winter of 2014/2015, the GII.17 Kawasaki 2014 emerged as the predominant genotype, surpassing GII.4 in several East Asian countries. Hence, the influence of host immunity response on the continuous evolution of different GII.17 variants needs to be studied in depth. Here, we relate the inferences of evolutionary mechanisms of different GII.17 variants with the investigation of cross-reactivity and cross-protection of their respective antisera using the expression of norovirus P particles in Escherichia coli. The cross-reactivity assay showed that the antisera of previous strains (GII.17 A and GII.17 B) reacted with recent variants (GII.17 C and GII.17 D) at high OD values from 0.8 to 1.16, while recent variant antisera cross-reacting with previous strains were weak with OD values between 0.26 and 0.56. The cross-protection assay indicated that the antisera of previous strains had no inhibitory effect on recent variants. Finally, mutations at amino acids 353–363, 373–384, 394–404, and 444–454 had the greatest impact on cross-reactivity. These data indicate that the recent pandemic variants GII.17 C and GII.17 D avoided the herd immunity effect of previous GII.17 A and GII.17 B strains through antigenic variation.

Abscisic acid (ABA) is an important plant hormone that plays multiple roles in regulating growth and development as well as in stress responses in plants. The NCED gene family includes key genes involved in the process of ABA synthesis. This gene family has been found in many species; however, the function of the NCED gene family in cotton is unclear. Here, a total of 23 NCED genes (designated as GhNCED1 to GhNCED23) were identified in cotton. Phylogenetic analysis indicated that the identified NCED proteins from cotton and Arabidopsis could be classified into 4 subgroups. Conserved motif analysis revealed that the gene structure and motif distribution of proteins within each subgroup were highly conserved. qRT-PCR and ABA content analyses indicated that NCED genes exhibited stage-specific expression patterns at tissue development stages. GhNCED5, GhNCED6 and GhNCED13 expression was similar to the change in ABA content, suggesting that this gene family plays a role in ABA synthesis. These results provide a better understanding of the potential functions of GhNCED genes.

The silk-spinning and Lepidopteran model insect Bombyx mori (Bombycidae) is a mulberry specialist. The BmSuc1 gene is the first β-fructofuranosidase (β-FFase) encoding gene identified in animals, and β-FFase acts as an essential sucrase for glycometabolism modulation in the silkworm larvae, involved in resistance to mulberry alkaloids. Glyphodes pyloalis Walker (Lepidoptera: Pyralidae) is an important mulberry pest leading to heavy economic loss of sericulture. However, no molecular or biochemical information is available about G. pyloalis β-FFase homologs. In this study, five β-FFase homologous genes in G. pyloalis were obtained. The genes GpSuc1a and GpSuc2c were expressed in the midgut; GpSuc2c encodes a truncated polypeptide. The expression and the localization of GpSUC1a in the midgut was characterized. Whereas recombinant GpSUC1a expressed in both Escherichia coli and BmN cells displayed little activity as compared with higher activity of BmSUC1, β-FFase activity in the larval midgut of G. pyloalis and GpSUC1a purified from the midgut were both confirmed. The data suggested that the activation of GpSUC1a is probably controlled by a more complicated post-translational regulation system in G. pyloalis larvae than that of BmSUC1 in B. mori. To study post-translational modifications (PTMs), GpSUC1a and BmSUC1 were purified from larval midguts using immunoprecipitation and subjected to LC-MS to perform PTMs analysis. Some putative N-glycosylated sites were found in GpSUC1a but none in BmSUC1, while there was more methylation in BmSUC1 than in GpSUC1a, indicating that such PTMs were supporting the differential β-FFases activities in these two mulberry feeding caterpillars.

Human norovirus (HuNoV), which is the major causative agent of acute gastroenteritis, has broad antigenic diversity; thus, the development of a broad-spectrum vaccine is challenging. To establish the relationship between viral genetic diversity and antigenic diversity, capsid P proteins and antisera of seven GI and 16 GII HuNoV genotypes were analyzed. Enzyme-linked immunosorbent assays showed that HuNoV antisera strongly reacted with the homologous capsid P proteins (with titers > 5 × 104). However, 17 (73.9%) antisera had weak or no cross-reactivity with heterologous genotypes. Interestingly, the GII.5 antiserum cross-reacted with seven (30.4%) capsid P proteins (including pandemic genotypes GII.4 and GII.17), indicating its potential use for HuNoV vaccine development. Moreover, GI.2 and GI.6 antigens reacted widely with heterologous antisera (n ≥ 5). Sequence alignment and phylogenetic analyses of the P proteins revealed conserved regions, which may be responsible for the immune crossover reactivity observed. These findings may be helpful in identifying broad-spectrum epitopes with clinical value for the development of a future vaccine.

The most common type of RNA editing in metazoans is the deamination of adenosine into inosine (A-to-I) catalyzed by the adenosine deaminase acting on the RNA (ADAR) family of proteins. The deletion or dysfunction of ADAR enzymes in higher eukaryotes can affect the efficiency of substrate editing and cause neurological disorders. However, the information concerning A-to-I RNA editing and ADAR members in the silkworm, Bombyx mori (BmADAR), is limited. In this study, a first molecular comprehensive cloning and sequence analysis of BmADAR transcripts was presented. A complete open reading frame (ORF) (BmADARa) was obtained using RT-PCR and RACE and its expression pattern, subcellular localization and A-to-I RNA-editing function on the silkworm synaptotagmin I (BmSyt I) were investigated. Subcellular localization analysis observed that BmADARa was mainly localized in the nucleus. To further study the A-to-I RNA-editing function of BmADARa, BmSyt I-pIZ-EGFP was constructed and co-transfected with BmADARa-pIZ-EGFP into BmN cells. The result demonstrates that BmADARa can functionally edit the specific site of BmSyt I. Taken together, this study not only provides insight into the function of the first ADAR enzyme in B. mori, but also lays foundations for further exploration of the functional domain of BmADARa and its editing substrates and target sites.

Zinc finger-homeodomain (ZHD) genes encode a family of plant-specific transcription factors that not only participate in the regulation of plant growth and development but also play an important role in the response to abiotic stress. The ZHD gene family has been studied in several model plants, including Solanum lycopersicum, Zea mays, Oryza sativa, and Arabidopsis thaliana. However, a comprehensive study of the genes of the ZHD family and their roles in fiber development and pigmentation in upland cotton has not been completed. To address this gap, we selected a brown fiber cultivar for our study; brown color in cotton is one of the most desired colors in the textile industry. The natural colored fibers require less processing and little dying, thereby eliminating dye costs and chemical residues. Using bioinformatics approaches, we identified 37 GhZHD genes from Gossypium hirsutum and then divided these genes into seven groups based on their phylogeny. The GhZHD genes were mostly conserved in each subfamily with minor variations in motif distribution and gene structure. These genes were largely distributed on 19 of the 26 upland cotton chromosomes. Among the Gossypium genomes, the paralogs and orthologs of the GhZHD genes were identified and further characterized. Furthermore, among the paralogs, we observed that the ZHD family duplications in Gossypium genomes (G. hirsutum, G. arboreum, and G. raimondii) were probably derived from segmental duplication or genome-wide duplication (GWD) events. Through a combination of qRT-PCR and proanthocyanidins (PA) accumulation analyses in brown cotton fibers, we concluded that the candidate genes involved in early fiber development and fiber pigment synthesis include the following: GhZHD29, GhZHD35, GhZHD30, GhZHD31, GhZHD11, GhZHD27, GhZHD18, GhZHD15, GhZHD16, GhZHD22, GhZHD6, GhZHD33, GhZHD13, GhZHD5, and GhZHD23. This study delivers insights into the evolution of the GhZHD genes in brown cotton, serves as a valuable resource for further studies, and identifies the conditions necessary for improving the quality of brown cotton fiber.

The SQUAMOSA promoter binding protein (SBP)-box proteins are plant-specific transcriptional factors in plants. SBP TFs are known to play important functions in a diverse development process and also related in the process of evolutionary novelties. SBP gene family has been characterized in several plant species, but little is known about molecular evolution, functional divergence and comprehensive study of SBP gene family in Rosacea. We carried out genome-wide investigations and identified 14, 32, 17, and 17 SBP genes from four Rosacea species (Fragaria vesca, Pyrus bretschneideri, Prunus persica and Prunus mume, respectively). According to phylogenetic analysis arranged the SBP protein sequences in seven groups. Localization of SBP genes presented an uneven distribution on corresponding chromosomes of Rosacea species. Our analyses designated that the SBP genes duplication events (segmental and tandem) and divergence. In addition, due to highly conserved structure pattern of SBP genes, recommended that highly conserved region of microsyneteny in the Rosacea species. Type I and II functional divergence was detected among various amino acids in SBP proteins, while there was no positive selection according to substitutional model analysis using PMAL software. These results recommended that the purifying selection might be leading force during the evolution process and dominate conservation of SBP genes in Rosacea species according to environmental selection pressure analysis. Our results will provide basic understanding and foundation for future research insights on the evolution of the SBP genes in Rosacea.

Plant type III polyketide synthase (PKS) can catalyse the formation of a series of secondary metabolites with different structures and different biological functions; the enzyme plays an important role in plant growth, development and resistance to stress. At present, the PKS gene has been identified and studied in a variety of plants. Here, we identified 11 PKS genes from upland cotton (Gossypium hirsutum) and compared them with 41 PKS genes in Populus tremula, Vitis vinifera, Malus domestica and Arabidopsis thaliana. According to the phylogenetic tree, a total of 52 PKS genes can be divided into four subfamilies (I–IV). The analysis of gene structures and conserved motifs revealed that most of the PKS genes were composed of two exons and one intron and there are two characteristic conserved domains (Chal_sti_synt_N and Chal_sti_synt_C) of the PKS gene family. In our study of the five species, gene duplication was found in addition to Arabidopsis thaliana and we determined that purifying selection has been of great significance in maintaining the function of PKS gene family. From qRT-PCR analysis and a combination of the role of the accumulation of proanthocyanidins (PAs) in brown cotton fibers, we concluded that five PKS genes are candidate genes involved in brown cotton fiber pigment synthesis. These results are important for the further study of brown cotton PKS genes. It not only reveals the relationship between PKS gene family and pigment in brown cotton, but also creates conditions for improving the quality of brown cotton fiber.

As an environmental factor, light influences the physiological functions and secondary metabolism of plants. However, the role of light in cotton fiber development and pigment biosynthesis has not yet been thoroughly explored. In this study, ovules of green cotton were cultured in vitro under dark and light conditions, and fiber and ovule growth parameters as well as fiber carbohydrate and cellulose contents and the expression of genes related to fiber development were investigated to elucidate the effect of light on fiber development. In addition, to investigate the effect of light on fiber pigment biosynthesis, the fiber flavonoid content and related gene expression were determined. The results demonstrated that the fiber length and the expression levels of fiber elongation genes under light culture were significantly lower than under dark culture, however, the ovule and fiber weight were significantly higher than under dark culture. The fiber developed under light culture had higher carbohydrate concentrations and carbohydrate transformation rate than under dark culture. Additionally, light culture exhibited higher cellulose contents and expression levels of cellulose biosynthesis genes compared with dark culture. In contrast, the pattern of the effect of light on flavonoid biosynthesis differed from that for cellulose biosynthesis. At 10 DAC (days after culture) and 20 DAC, the flavonoid contents and the expression levels of genes related to flavonoid biosynthesis were lower than under dark culture. However, the flavonoid contents and gene expression levels observed at 30 DAC and 40 DAC were higher in the light culture than in the dark culture. These results suggested that light hindered fiber elongation, but promoted carbohydrate accumulation and carbohydrate transformation, which resulted in fiber weight gain and increased cellulose accumulation in fibers. In addition, light inhibited flavonoid biosynthesis at early stage of fiber development, but promoted it at later stages. These findings provide the basis for intensive study of fiber development and flavonoids biosynthesis in green cotton.

Sucrose synthase (SS) is a key enzyme involved in sucrose metabolism that is critical in plant growth and development, and particularly quality of the fruit. Sucrose synthase gene families have been identified and characterized in plants various plants such as tobacco, grape, rice, and Arabidopsis. However, there is still lack of detailed information about sucrose synthase gene in pear. In the present study, we performed a systematic analysis of the pear (Pyrus bretschneideri Rehd.) genome and reported 30 sucrose synthase genes. Subsequently, gene structure, phylogenetic relationship, chromosomal localization, gene duplications, promoter regions, collinearity, RNA-Seq data and qRT-PCR were conducted on these sucrose synthase genes. The transcript analysis revealed that 10 PbSSs genes (30%) were especially expressed in pear fruit development. Additionally, qRT-PCR analysis verified the RNA-seq data and shown that PbSS30, PbSS24, and PbSS15 have a potential role in the pear fruit development stages. This study provides important insights into the evolution of sucrose synthase gene family in pear and will provide assistance for further investigation of sucrose synthase genes functions in the process of fruit development, fruit quality and resistance to environmental stresses.

β-fructofuranosidase (β-FFase) belongs to the glycosyl-hydrolase family 32 (GH32), which can catalyze both the release of β-fructose from β-d-fructofuranoside substrates to hydrolyze sucrose and the synthesis of short-chain fructooligosaccharide (FOS). BmSuc1 has been cloned and identified from the silkworm Bombyx mori as a first animal type of β-FFase encoding gene. It was hypothesized that BmSUC1 plays an important role in the silkworm-mulberry adaptation system. However, there is little information about the enzymatic core sites of BmSUC1. In this study, we mutated three amino acid residues (D63, D181, and E234) that represent important conserved motifs for β-FFase activity in GH32 to alanine respectively by using site-directed mutagenesis. Recombinant proteins of three mutants and wild type BmSUC1 were obtained by using a Bac-to-Bac/BmNPV expression system and BmN cells. Enzymatic activity, kinetic properties, and substrate specificity of the four proteins were analyzed. High Performance Liquid Chromatography (HPLC) was used to compare the hydrolyzing and transfructosylating activities between D181A and wtBmSUC1. Our results revealed that the D63A and E234A mutations lost activity, suggesting that D63 and E234 are key amino acid residues for BmSUC1 to function as an enzyme. The D181A mutation significantly enhanced both hydrolyzing and transfructosylating activities of BmSUC1, indicating that D181 may not be directly involved in catalyzation. The results provide insight into the chemical catalyzation mechanism of BmSUC1 in B. mori. Up-regulated transfructosylating activity of BmSUC1 could provide new ideas for using B. mori β-FFase to produce functional FOS.