Search

The golden-needle mushroom Flammulina filiformis is one of the bulk mushroom products in the world. This study obtained complete mitogenomes of 44 wild isolates collected from nine provinces and two artificially bred cultivars of F. filiformis, together with three Flammulina rossica isolates and one Flammulina fennae isolate for comparison. The mitogenome of F. filiformis ranged from 83,540 bp to 90,938 bp, consisting of 14 conserved protein-coding genes (PCGs), two rRNA genes, and 25 tRNA genes. To the best of our knowledge, it contained the highest proportion of intergenic regions compared to the other known Basidiomycota mitogenomes. Introns and intergenic regions were two major contributing factors to the total size of the F. filiformis mitogenome. The conserved PCG cox3 is located in an intron of another conserved PCG, nad5. This is a unique phenomenon in all known fungal mitogenomes. Gain/loss of introns was observed in cox1, nad5, and rnl. Length polymorphism was widely observed in intergenic regions. Accordingly, primers were designed as useful markers for rapid identification of F. filiformis isolates with differentiated mitogenomes. Our findings provide a basis for further studies related to variety identification and population genetics of this economically important mushroom.

During 2018-2020, we isolated 32 Eurasian avian-like swine influenza A(H1N1) viruses and their reassortant viruses from pigs in China. Genomic testing identified a novel reassortant H3N1 virus, which emerged in late 2020. Derived from G4 Eurasian H1N1 and H3N2 swine influenza viruses. This virus poses a risk for zoonotic infection.

The diversity of Asian horned toads is considered highly underestimated and to contain a large number of undescribed cryptic species. In this work, we describe three new species of Boulenophrys from south China, namely, Boulenophrys yaoshanensis sp. nov. from central Guangxi, Boulenophrys yingdeensis sp. nov. from northern Guangdong, and Boulenophrys yunkaiensis sp. nov. from western Guangdong. These three new species can be distinguished from all recognized congeners by a combination of morphological characteristics and significant genetic divergences. These descriptions increase the number of recognized species of Boulenophrys to 61. In addition, an updated checklist of the Asian horned toads of the subfamily Megophryinae is provided in this study.

In this work, a new species of the genus Tylototriton is described from Guangdong, southern China. Tylototriton sini sp. nov. was recorded as T. asperrimus for decades, and was indicated to represent an independent lineage based on recent molecular phylogenetic analyses. After detailed molecular analysis and morphological comparisons, Tylototriton sini sp. nov. is recognized as a distinct species which can be clearly distinguished from all known congeners by a combination of morphological characteristics and the significant divergence in the mitochondrial gene. Because the genus Tylototriton is of high conservation concern and all formally described members are protected by law, we also provide first data on the conservation status and recommendations for IUCN categorization for Tylototriton sini sp. nov. A suggestion on the species groups division of the genus Tylototriton is also provided based on their morphological differences and phylogenetic relationships.

Microbial sulfate reduction is largely associated with anaerobic methane oxidation and alkane degradation in sulfate-methane transition zone (SMTZ) of deep-sea cold seeps. How the sulfur cycling is mediated by microbes near SMTZ has not been fully understood. In this study, we detected a shallow SMTZ in three of eight sediment cores sampled from two cold seep areas in the South China Sea. One hundred ten genomes representing sulfur-oxidizing bacteria (SOB) and sulfur-reducing bacteria (SRB) strains were identified from three SMTZ-bearing cores. In the layers above SMTZ, SOB were mostly constituted by Campylobacterota, Gammaproteobacteria and Alphaproteobacteria that probably depended on nitrogen oxides and/or oxygen for oxidation of sulfide and thiosulfate in near-surface sediment layers. In the layers below the SMTZ, the deltaproteobacterial SRB genomes and metatranscriptomes revealed CO2 fixation by Wood-Ljungdahl pathway, sulfate reduction and nitrogen fixation for syntrophic or fermentative lifestyle. A total of 68% of the metagenome assembled genomes were not adjacent to known species in a phylogenomic tree, indicating a high diversity of bacteria involved in sulfur cycling. With the large number of genomes for SOB and SRB, our study uncovers the microbial populations that potentially mediate sulfur metabolism and associated carbon and nitrogen cycles, which sheds light on complex biogeochemical processes in deep-sea environments.

Microbially mediated nitrogen cycling in carbon-dominated cold seep environments remains poorly understood. So far anaerobic methanotrophic archaea (ANME-2) and their sulfate-reducing bacterial partners (SEEP-SRB1 clade) have been identified as diazotrophs in deep sea cold seep sediments. However, it is unclear whether other microbial groups can perform nitrogen fixation in such ecosystems. To fill this gap, we analyzed 61 metagenomes, 1428 metagenome-assembled genomes, and six metatranscriptomes derived from 11 globally distributed cold seeps. These sediments contain phylogenetically diverse nitrogenase genes corresponding to an expanded diversity of diazotrophic lineages. Diverse catabolic pathways were predicted to provide ATP for nitrogen fixation, suggesting diazotrophy in cold seeps is not necessarily associated with sulfate-dependent anaerobic oxidation of methane. Nitrogen fixation genes among various diazotrophic groups in cold seeps were inferred to be genetically mobile and subject to purifying selection. Our findings extend the capacity for diazotrophy to five candidate phyla (Altarchaeia, Omnitrophota, FCPU426, Caldatribacteriota and UBA6262), and suggest that cold seep diazotrophs might contribute substantially to the global nitrogen balance.

Porcine reproductive and respiratory syndrome virus (PRRSV) is an important pathogen that causes huge economic losses to the swine industry worldwide. Here, a novel variant of PRRSV strain named TJnh2021 was isolated from nursery piglets with morbidity rate (75%) and mortality rate (40%) in Tianjin Province of China in 2021. Phylogenetic and molecular evolutionary analyses revealed that TJnh2021 was highly similar to NADC34-like (lineage 1.5, isolated in North America in 2014) in the ORF1ab-ORF2 and ORF6-ORF7 coding regions, as well as to QYYZ-like (lineage 3, isolated in China in 2010) in the ORF3-ORF5, suggestive of a natural recombination event. Recombination analyses revealed that recombination events occurred in two interlineage recombination events between lineages 1.5 and 3, and two breakpoints in ORF2 (nt12196) and ORF5 (nt13628) (with reference to the VR-2332 strain). Animal experiments demonstrated that TJnh2021 caused mortality rates of 40% and exhibited higher pathogenicity in piglets compared to other lineage 1.5 strains reported in China. Taken altogether, NADC34-like PRRSV has undergone genetic exchange with Chinese local PRRSV strains and recombination might be responsible for the variations in pathogenicity and highlight the importance of surveillance of this lineage in China.

Carotenoids are natural functional pigments produced by plants and microorganisms and play essential roles in human health. Cabbage (Brassica oleracea L. var. capitata L.) is an economically important vegetable in terms of production and consumption. It is highly nutritious and contains β-carotene, lutein, and other antioxidant carotenoids. Here, we systematically analyzed carotenoid biosynthetic genes (CBGs) on the whole genome to understand the carotenoid biosynthetic pathway in cabbage. In total, 62 CBGs were identified in the cabbage genome, which are orthologs of 47 CBGs in Arabidopsis thaliana. Out of the 62 CBGs, 46 genes in cabbage were mapped to nine chromosomes. Evolutionary analysis of carotenoid biosynthetic orthologous gene pairs among B. oleracea, B. rapa, and A. thaliana revealed that orthologous genes of B. oleracea underwent a negative selection similar to that of B. rapa. Expression analysis of the CBGs showed functional differentiation of orthologous gene copies in B. oleracea and B. rapa. Exogenous phytohormone treatment suggested that ETH, ABA, and MeJA can promote some important CBGs expression in cabbage. Phylogenetic analysis showed that BoPSYs exhibit high conservatism. Subcellular localization analysis indicated that BoPSYs are located in the chloroplast. This study is the first to study carotenoid biosynthesis genes in cabbage and provides a basis for further research on carotenoid metabolic mechanisms in cabbage.

Hulless barley (Hordeum vulgare L. var. nudum), also called naked barley, is a unique variety of cultivated barley. The genome-wide specific length amplified fragment sequencing (SLAF-seq) method is a rapid deep sequencing technology that is used for the selection and identification of genetic loci or markers. In this study, we collected 300 hulless barley accessions and used the SLAF-seq method to identify candidate genes involved in plant height (PH) and tiller number (TN). We obtained a total of 1407 M paired-end reads, and 228,227 SLAF tags were developed. After filtering using an integrity threshold of >0.8 and a minor allele frequency of >0.05, 14,504,892 single-nucleotide polymorphisms (SNP) loci were screened out. The remaining SNPs were used for the construction of a neighbour-joining phylogenetic tree, and the three subcluster members showed no obvious differentiation among regional varieties. We used a genome wide association study approach to identify 1006 and 113 SNPs associated with TN and PH, respectively. Based on best linear unbiased predictors (BLUP), 41 and 29 SNPs associated with TN and PH, respectively. Thus, several of genes, including Hd3a and CKX5, may be useful candidates for the future genetic breeding of hulless barley. Taken together, our results provide insight into the molecular mechanisms controlling barley architecture, which is important for breeding and yield.

Infections caused by SARS-CoV-2 have brought great harm to human health. After transmission for over two years, SARS-CoV-2 has diverged greatly and formed dozens of different lineages. Understanding the trend of its genome evolution could help foresee difficulties in controlling transmission of the virus. In this study, we conducted an extensive monthly survey and in-depth analysis on variations of nucleotide, amino acid and codon numbers in 311,260 virus samples collected till January 2022. The results demonstrate that the evolution of SARS-CoV-2 is toward increasing U-content and reducing genome-size. C, G and A to U mutations have all contributed to this U-content increase. Mutations of C, G and A at codon position 1, 2 or 3 have no significant difference in most SARS-CoV-2 lineages. Current viruses are more cryptic and more efficient in replication, and are thus less virulent yet more infectious. Delta and Omicron variants have high mutability over other lineages, bringing new threat to human health. This trend of genome evolution may provide a clue for tracing the origin of SARS-CoV-2, because ancestral viruses should have lower U-content and probably bigger genome-size.

Domestication of the helmeted guinea fowl (HGF; Numida meleagris) in Africa remains elusive. Here we report a high-quality de novo genome assembly for domestic HGF generated by long- and short-reads sequencing together with optical and chromatin interaction mapping. Using this assembly as the reference, we performed population genomic analyses for newly sequenced whole-genomes for 129 birds from Africa, Asia, and Europe, including domestic animals (n = 89), wild progenitors (n = 34), and their closely related wild species (n = 6). Our results reveal domestication of HGF in West Africa around 1,300-5,500 years ago. Scanning for selective signals characterized the functional genes in behavior and locomotion changes involved in domestication of HGF. The pleiotropy and linkage in genes affecting plumage color and fertility were revealed in the recent breeding of Italian domestic HGF. In addition to presenting a missing piece to the jigsaw puzzle of domestication in poultry, our study provides valuable genetic resources for researchers and breeders to improve production in this species.

Although interplays between plant and coevolved microorganisms are believed to drive landscape formation and ecosystem services, the relationships between the mycobiome and phytochemical evolution and the evolutionary characteristics of plant-mycobiome interaction patterns are still unclear. The present study explored fungal communities from 405 multiniche samples of three Holarctic disjunct Panax species. The overall mycobiomes showed compartment-dominated variations and dynamic universality. Neutral models were fitted for each compartment at the Panax genus (I) and species (II) levels to infer the community assembly mechanism and identify fungal subgroups potentially representing different plant-fungi interaction results, i.e., the potentially selected, opposed, and neutral taxa. Selection contributed more to the endosphere than to external compartments. The nonneutral taxa showed significant phylogenetic clustering. In Model I, the opposed subgroups could best reflect Panax saponin diversities (r = 0.69), and genera with highly positive correlations to specific saponins were identified using machine learning. Although mycobiomes in the three species differed significantly, subgroups in Model II were phylogenetically clustered based on potential interaction type rather than plant species, indicating potentially conservative plant-fungi interactions. In summary, the finding of strong links between invaders and saponin diversity can help explore the underlying mechanisms of saponin biosynthesis evolution from microbial insights, which is important to understanding the formation of the current landscape. The potential conservatism of plant-fungi interaction patterns suggests that the related genetic modules and selection pressures were convergent across Panax species, advancing our understanding of plant interplay with biotic environments.

To understand the epidemic status of feline bocavirus (FBoV) in Anhui Province, eastern China, FBoV was successfully extracted from fecal samples of domestic cats, and five complete genomes were amplified in this study. Phylogenetic analysis showed that these five strains belong to three different FBoV genotypes. Recombination analysis showed that inter- and intra-genotype recombination events occurred. Selection pressure and codon usage bias analyses indicated that FBoV-1 and FBoV-3 continuously evolve toward adaptation, and selection pressure is the main factor for codon usage bias during evolution. This study provides the first molecular evidence of FBoV prevalence in eastern China, further enriching the available information on its genetics and evolutionary characteristics and providing a basis for further research on its evolution.