scholarly journals Comparative Genomics of the Rhodococcus Genus Shows Wide Distribution of Biodegradation Traits

2020 ◽  
Vol 8 (5) ◽  
pp. 774 ◽  
Author(s):  
Daniel Garrido-Sanz ◽  
Miguel Redondo-Nieto ◽  
Marta Martín ◽  
Rafael Rivilla

The genus Rhodococcus exhibits great potential for bioremediation applications due to its huge metabolic diversity, including biotransformation of aromatic and aliphatic compounds. Comparative genomic studies of this genus are limited to a small number of genomes, while the high number of sequenced strains to date could provide more information about the Rhodococcus diversity. Phylogenomic analysis of 327 Rhodococcus genomes and clustering of intergenomic distances identified 42 phylogenomic groups and 83 species-level clusters. Rarefaction models show that these numbers are likely to increase as new Rhodococcus strains are sequenced. The Rhodococcus genus possesses a small “hard” core genome consisting of 381 orthologous groups (OGs), while a “soft” core genome of 1253 OGs is reached with 99.16% of the genomes. Models of sequentially randomly added genomes show that a small number of genomes are enough to explain most of the shared diversity of the Rhodococcus strains, while the “open” pangenome and strain-specific genome evidence that the diversity of the genus will increase, as new genomes still add more OGs to the whole genomic set. Most rhodococci possess genes involved in the degradation of aliphatic and aromatic compounds, while short-chain alkane degradation is restricted to a certain number of groups, among which a specific particulate methane monooxygenase (pMMO) is only found in Rhodococcus sp. WAY2. The analysis of Rieske 2Fe-2S dioxygenases among rhodococci genomes revealed that most of these enzymes remain uncharacterized.

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Jianchao Ying ◽  
Jun Ye ◽  
Teng Xu ◽  
Qian Wang ◽  
Qiyu Bao ◽  
...  

Rhodococcus equi, a member of the Rhodococcus genus, is a gram-positive pathogenic bacterium. Rhodococcus possesses an open pan-genome that constitutes the basis of its high genomic diversity and allows for adaptation to specific niche conditions and the changing host environments. Our analysis further showed that the core genome of R. equi contributes to the pathogenicity and niche adaptation of R. equi. Comparative genomic analysis revealed that the genomes of R. equi shared identical collinearity relationship, and heterogeneity was mainly acquired by means of genomic islands and prophages. Moreover, genomic islands in R. equi were always involved in virulence, resistance, or niche adaptation and possibly working with prophages to cause the majority of genome expansion. These findings provide an insight into the genomic diversity, evolution, and structural variation of R. equi and a valuable resource for functional genomic studies.


2015 ◽  
Vol 65 (Pt_10) ◽  
pp. 3507-3510 ◽  
Author(s):  
Christopher A. Dunlap

‘Bacillus vanillea’ XY18 ( = CGMCC 8629 = NCCB 100507) was isolated from cured vanilla beans and involved in the formation of vanilla aroma compounds. A draft genome of this strain was assembled and yielded a length of 3.71 Mbp with a DNA G+C content of 46.3 mol%. Comparative genomic analysis with its nearest relatives showed only minor differences between this strain and the genome of the Bacillus siamensis KCTC 13613T ( = BCC 22614T = KACC 16244T), with a calculated DNA–DNA hybridization (DDH) value of 91.2 % and an average nucleotide identity (ANI) of 98.9 %. This DDH value is well above the recommended 70 % threshold for species delineation, as well as the ANI threshold of 95 %. In addition, the results of morphological, physiological, chemotaxonomic and phylogenetic analyses indicate that the type strains of these two taxa are highly similar with phenotype coherence. A core genome multi-locus sequencing analysis was conducted for the strains and the results show that ‘Bacillus vanillea’ XY18 clusters closely to the type strain of Bacillus siamensis. Therefore, it is proposed that the species ‘Bacillus vanillea’ XY18 ( = CGMCC 8629 = NCCB 100507) should be reclassified as a later heterotypic synonym of Bacillus siamensis KCTC 13613T ( = BCC 22614T = KACC 16244T). An emended description of Bacillus siamensis is provided.


2021 ◽  
Vol 22 (11) ◽  
pp. 5723
Author(s):  
Yuan-Yuan Xu ◽  
Sheng-Rui Liu ◽  
Zhi-Meng Gan ◽  
Ren-Fang Zeng ◽  
Jin-Zhi Zhang ◽  
...  

A high-density genetic linkage map is essential for genetic and genomic studies including QTL mapping, genome assembly, and comparative genomic analysis. Here, we constructed a citrus high-density linkage map using SSR and SNP markers, which are evenly distributed across the citrus genome. The integrated linkage map contains 4163 markers with an average distance of 1.12 cM. The female and male linkage maps contain 1478 and 2976 markers with genetic lengths of 1093.90 cM and 1227.03 cM, respectively. Meanwhile, a genetic map comparison demonstrates that the linear order of common markers is highly conserved between the clementine mandarin and Poncirus trifoliata. Based on this high-density integrated citrus genetic map and two years of deciduous phenotypic data, two loci conferring leaf abscission phenotypic variation were detected on scaffold 1 (including 36 genes) and scaffold 8 (including 107 genes) using association analysis. Moreover, the expression patterns of 30 candidate genes were investigated under cold stress conditions because cold temperature is closely linked with the deciduous trait. The developed high-density genetic map will facilitate QTL mapping and genomic studies, and the localization of the leaf abscission deciduous trait will be valuable for understanding the mechanism of this deciduous trait and citrus breeding.


Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 483
Author(s):  
Wen-Juan Ma ◽  
Paris Veltsos

Frogs are ideal organisms for studying sex chromosome evolution because of their diversity in sex chromosome differentiation and sex-determination systems. We review 222 anuran frogs, spanning ~220 Myr of divergence, with characterized sex chromosomes, and discuss their evolution, phylogenetic distribution and transitions between homomorphic and heteromorphic states, as well as between sex-determination systems. Most (~75%) anurans have homomorphic sex chromosomes, with XY systems being three times more common than ZW systems. Most remaining anurans (~25%) have heteromorphic sex chromosomes, with XY and ZW systems almost equally represented. There are Y-autosome fusions in 11 species, and no W-/Z-/X-autosome fusions are known. The phylogeny represents at least 19 transitions between sex-determination systems and at least 16 cases of independent evolution of heteromorphic sex chromosomes from homomorphy, the likely ancestral state. Five lineages mostly have heteromorphic sex chromosomes, which might have evolved due to demographic and sexual selection attributes of those lineages. Males do not recombine over most of their genome, regardless of which is the heterogametic sex. Nevertheless, telomere-restricted recombination between ZW chromosomes has evolved at least once. More comparative genomic studies are needed to understand the evolutionary trajectories of sex chromosomes among frog lineages, especially in the ZW systems.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Miao-Miao Zhang ◽  
Jun-Wei Zhao ◽  
Zhan-Qiang Sun ◽  
Jun Liu ◽  
Xiao-Kui Guo ◽  
...  

Comparative genomic studies have identified severalMycobacterium tuberculosis-specific genomic regions of difference (RDs) which are absent in the vaccine strains ofMycobacterium bovisBCG and which may be useful in the specific diagnosis of tuberculosis (TB). In this study, all encoded proteins from DNA segment RD5 ofMycobacterium tuberculosis, that is, Rv3117–Rv3121, were recombined and evaluated by enzyme-linked immunosorbent assays for antibody reactivity with sera from HIV-negative pulmonary TB patients (n=60) and healthy controls (n=32). The results identified two immunodominant antigens, that is, Rv3117 and Rv3120, both of which revealed a statistically significant antigenic distinction between healthy controls and TB patients (P<0.05). In comparison with the well-known early-secreted antigen target 6 kDa (ESAT-6) (sensitivity 21.7%, specificity 90.6%), the higher detection sensitivity and higher specificity were achieved (Rv3117: sensitivity 25%, specificity 96.9%; Rv3120: sensitivity 31.7%, specificity 96.9%). Thus, the results highlight the immunosensitive and immunospecific nature of Rv3117 and Rv3120 and indicate promise for their use in the serodiagnosis of TB.


2018 ◽  
Author(s):  
Benjamin J Tully

AbstractDespite their discovery over 25 years ago, the Marine Group IIEuryarchaea(MGII) have remained a difficult group of organisms to study, lacking cultured isolates and genome references. The MGII have been identified in marine samples from around the world and evidence supports a photoheterotrophic lifestyle combining phototrophy via proteorhodopsins with the remineralization of high molecular weight organic matter. Divided between two clades, the MGII have distinct ecological patterns that are not understood based on the limited number of available genomes. Here, I present the comparative genomic analysis of 250 MGII genomes, providing the most detailed view of these mesophilic archaea to-date. This analysis identified 17 distinct subclades including nine subclades that previously lacked reference genomes. The metabolic potential and distribution of the MGII genera revealed distinct roles in the environment, identifying algal-saccharide-degrading coastal subclades, protein-degrading oligotrophic surface ocean subclades, and mesopelagic subclades lacking proteorhodopsins common in all other subclades. This study redefines the MGII and provides an avenue for understanding the role these organisms play in the cycling of organic matter throughout the water column.


2021 ◽  
Vol 288 (1963) ◽  
Author(s):  
Iker Irisarri ◽  
Tatyana Darienko ◽  
Thomas Pröschold ◽  
Janine M. R. Fürst-Jansen ◽  
Mahwash Jamy ◽  
...  

Streptophytes are one of the major groups of the green lineage (Chloroplastida or Viridiplantae). During one billion years of evolution, streptophytes have radiated into an astounding diversity of uni- and multicellular green algae as well as land plants. Most divergent from land plants is a clade formed by Mesostigmatophyceae, Spirotaenia spp. and Chlorokybophyceae. All three lineages are species-poor and the Chlorokybophyceae consist of a single described species, Chlorokybus atmophyticus. In this study, we used phylogenomic analyses to shed light into the diversity within Chlorokybus using a sampling of isolates across its known distribution. We uncovered a consistent deep genetic structure within the Chlorokybus isolates, which prompted us to formally extend the Chlorokybophyceae by describing four new species. Gene expression differences among Chlorokybus species suggest certain constitutive variability that might influence their response to environmental factors. Failure to account for this diversity can hamper comparative genomic studies aiming to understand the evolution of stress response across streptophytes. Our data highlight that future studies on the evolution of plant form and function can tap into an unknown diversity at key deep branches of the streptophytes.


2019 ◽  
Vol 63 (8-9-10) ◽  
pp. 359-369 ◽  
Author(s):  
Yoshinori Kawabe ◽  
Qingyou Du ◽  
Christina Schilde ◽  
Pauline Schaap

The well-orchestrated multicellular life cycle of Dictyostelium discoideum has fascinated biologists for over a century. Self-organisation of its amoebas into aggregates, migrating slugs and fruiting structures by pulsatile cAMP signalling and their ability to follow separate differentiation pathways in well-regulated proportions continue to be topics under investigation. A striking aspect of D. discoideum development is the recurrent use of cAMP as chemoattractant, differentiation inducing signal and second messenger for other signals that control the developmental programme. D. discoideum is one of >150 species of Dictyostelia and aggregative life styles similar to those of Dictyostelia evolved many times in eukaryotes. Here we review experimental studies investigating how phenotypic complexity and cAMP signalling co-evolved in Dictyostelia. In addition, we summarize comparative genomic studies of multicellular Dictyostelia and unicellular Amoebozoa aimed to identify evolutionary conservation and change in all genes known to be essential for D. discoideum development.


2020 ◽  
Vol 33 (5) ◽  
pp. 718-720
Author(s):  
Karthi Natesan ◽  
Ji Yeon Park ◽  
Cheol-Woo Kim ◽  
Dong Suk Park ◽  
Young-Seok Kwon ◽  
...  

Peronospora destructor is an obligate biotrophic oomycete that causes downy mildew on onion (Allium cepa). Onion is an important crop worldwide, but its production is affected by this pathogen. We sequenced the genome of P. destructor using the PacBio sequencing platform, and de novo assembly resulted in 74 contigs with a total contig size of 29.3 Mb and 48.48% GC content. Here, we report the first high-quality genome sequence of P. destructor and its comparison with the genome assemblies of other oomycetes. The genome is a very useful resource to serve as a reference for analysis of P. destructor isolates and for comparative genomic studies of the biotrophic oomycetes.


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