scholarly journals Legionella becoming a mutualist: adaptive processes shaping the genome of symbiont in the louse Polyplax serrata

2017 ◽  
Author(s):  
Jana Říhová ◽  
Eva Nováková ◽  
Filip Husník ◽  
Václav Hypša

AbstractLegionellaceae are intracellular bacteria known as important pathogens of man. In the environment, they are mainly found in biofilms associated with amoebas. In contrast to another gammaproteobacterial family Enterobacteriaceae which established a broad spectrum of symbioses with many insect taxa, the only instance of legionella-like symbiont has been reported from lice of the genus Polyplax. Here, we sequenced the complete genome of this symbiont and compared its main characteristics to other Legionella species and insect symbionts. Based on rigorous multigene phylogenetic analyses, we confirm this bacterium as a member of the genus Legionella and propose the name Candidatus Legionella polyplacis, sp.n. We show that the genome of Ca. Legionella polyplacis underwent massive degeneration, including considerable size reduction (529.746 bp, 484 protein coding genes) and a severe decrease in GC content (23%). We identify several possible constraints underlying the evolution of this bacterium. On one hand, Ca. Legionella polyplacis and the louse symbionts Riesia and Puchtella experienced convergent evolution, perhaps due to adaptation to similar hosts. On the other hand, some metabolic differences are likely to reflect different phylogenetic positions of the symbionts and hence availability of particular metabolic function in the ancestor. This is exemplified by different arrangements of thiamine metabolism in Ca. Legionella polyplacis and Riesia. Finally, horizontal gene transfer is shown to play a significant role in the adaptive and diversification process. Particularly, we show that Ca. L. polyplacis horizontally acquired a complete biotin operon (bioADCHFB) that likely assisted this bacterium when becoming an obligate mutualist.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yingying Zhao ◽  
Xiaochen Zhu ◽  
Yingdong Li ◽  
Zhibin Han ◽  
Weibin Xu ◽  
...  

AbstractThe mitogenome of Chinese grass shrimp, Palaemonetes sinensis, was determined through Illumina sequencing, and the basic characteristics and gene arrangement were analyzed. The mitogenome of P. sinensis was 15955 bp in length, consisting of 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes and one control region, with tightly packed. 33 of these genes were encoded on the heavy strand, and the remainders encoded on the light strand. The composition of P. sinensis mitogenome presented a strong A + T bias, which account for 66.7%. All PCGs were initiated by a canonical ATN codon, except nad5, which was initiated by GTG. The termination codons of the PCGs were TAA, TAG and T–. The secondary structures of 22 tRNAs of P. sinensis had the typical clover structure, except of trnS1 owing to the lack of dihydroxyuridine (DHU) arm. Gene order comparison of P. sinensis and previously-sequenced Palaemoninae revealed a unique translocation between trnT and trnP in Macrobrachium. The phylogenetic analyses showed that three Exopalaemon species formed a monophyletic group and then clustered with two Palaemon species and P. sinensis successively whereas Macrobrachium clustered with Palaemon capensis in the other clade.


Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1497
Author(s):  
Cai-Yun Zhang ◽  
Tong-Jian Liu ◽  
Xiao-Lu Mo ◽  
Hui-Run Huang ◽  
Gang Yao ◽  
...  

Pogostemon Desf., the largest genus of the tribe Pogostemoneae (Lamiaceae), consists of ca. 80 species distributed mainly from South and Southeast Asia to China. The genus contains many patchouli plants, which are of great economic importance but taxonomically difficult. Therefore, it is necessary to characterize more chloroplast (cp) genomes for infrageneric phylogeny analyses and species identification of Pogostemon, especially for patchouli plants. In this study, we newly generated four cp genomes for three patchouli plants (i.e., Pogostemon plectranthoides Desf., P. septentrionalis C. Y. Wu et Y. C. Huang, and two cultivars of P. cablin (Blanoco) Benth.). Comparison of all samples (including online available cp genomes of P. yatabeanus (Makino) Press and P. stellatus (Lour.) Kuntze) suggested that Pogostemon cp genomes are highly conserved in terms of genome size and gene content, with a typical quadripartite circle structure. Interspecific divergence of cp genomes has been maintained at a relatively low level, though seven divergence hotspot regions were identified by stepwise window analysis. The nucleotide diversity (Pi) value was correlated significantly with gap proportion (indels), but significantly negative with GC content. Our phylogenetic analyses based on 80 protein-coding genes yielded high-resolution backbone topologies for the Lamiaceae and Pogostemon. For the overall mean substitution rates, the synonymous (dS) and nonsynonymous (dN) substitution rate values of protein-coding genes varied approximately threefold, while the dN values among different functional gene groups showed a wider variation range. Overall, the cp genomes of Pogostemon will be useful for phylogenetic reconstruction, species delimitation and identification in the future.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Meng-Yuan Zhao ◽  
Qing-Bo Huo ◽  
Yu-Zhou Du

AbstractIn this study, the mitochondrial genome of the stonefly, Oyamia nigribasis Banks, 1920 (Plecoptera: Perlidae), was sequenced and compared with the mtDNA genomes of 38 other stoneflies and two Ephemerae. The O. nigribasis mitogenome is a circular 15,923 bp molecule that encodes a large, noncoding control region (CR) and 37 typical mtDNA genes; these include 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs), respectively. Most of the PCGs initiated with ATN and terminated with TAN. The dihydrouridine (DHU) arm of tRNASer (AGN) was missing, whereas the other 21 tRNAs all exhibited the typical cloverleaf secondary structure. Stem-loop (SL) structures and tandem repeats were identified in the CR. Phylogenetic analyses using Bayesian inference and maximum likelihood were undertaken to determine relationships between stoneflies. Results indicated that the Antarctoperlaria, which contains Gripopterygidae, was absolutely separated from Arctoperlaria; this finding agrees with morphology. Finally, the overall relationships could be summarized as follows ((((Notonemouridae + Nemouridae) + Leuctridae) + (Scopuridae + (Capniidae + Taeniopterygidae))) + (((Perlodidae + Chloroperlidae) + Perlidae) + (Pteronarcyidae + (Peltoperlidae + Styloperlidae))) + ((Diamphipnoidae + Eustheniidae) + Gripopterygidae)).


2021 ◽  
Vol 9 ◽  
Author(s):  
Peng Tian ◽  
Jiaguang Xiao ◽  
Zhiyu Jia ◽  
Feng Guo ◽  
Xiaolei Wang ◽  
...  

Complete mitochondrial DNA sequence data have played a significant role in phylogenetic and evolutionary studies of scleractinian corals. In this study, the complete mitogenome of Psammocora profundacella Gardiner, 1898, collected from Guangdong Province, China, was sequenced by next-generation sequencing for the first time. Psammocora profundacella is the first species for which a mitogenome has been sequenced in the family Psammocoridae. The length of its assembled mitogenome sequence was 16,274 bp, including 13 protein-coding genes, two tRNAs and two rRNAs. Its gene content and gene order were consistent with the other Scleractinia species. All genes were encoded on the H strand and the GC content of the mitochondrial genome was 30.49%. Gene content and order were consistent with the other Scleractinia species. Based on 13 protein-coding genes, Maximum Likelihood phylogenetic analysis showed that P. profundacella belongs to the “Robust” clade. Mitochondrial genome data provide important molecular information for understanding the phylogeny of stony corals. More variable markers and additional species should be sequenced to confirm the evolutionary relationships of Scleractinia in the future.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6386 ◽  
Author(s):  
Dan Zong ◽  
Anpei Zhou ◽  
Yao Zhang ◽  
Xinlian Zou ◽  
Dan Li ◽  
...  

Species of the genus Populus, which is widely distributed in the northern hemisphere from subtropical to boreal forests, are among the most commercially exploited groups of forest trees. In this study, the complete chloroplast genomes of five Populus species (Populus cathayana, P. kangdingensis, P. pseudoglauca, P. schneideri, and P. xiangchengensis) were compared. The chloroplast genomes of the five Populus species are very similar. The total chloroplast genome sequence lengths for the five plastomes were 156,789, 156,523, 156,512, 156,513, and 156,465 bp, respectively. A total of 130 genes were identified in each genome, including 85 protein-coding genes, 37 tRNA genes and eight rRNA genes. Seven genes were duplicated in the protein-coding genes, whereas 11 genes were duplicated in the RNA genes. The GC content was 36.7% for all plastomes. We analyzed nucleotide substitutions, small inversions, simple sequence repeats and long repeats in the chloroplast genomes and found nine divergence hotspots (ccsA+ccsA-ndhD, ndhC-trnV, psbZ-trnfM, trnG-atpA, trnL-ndhJ, trnR-trnN, ycf4-cemA, ycf1, and trnR-trnN), which could be useful molecular genetic markers for future population genetic and phylogenetic studies. We also observed that two genes (rpoC2 and rbcL) were subject to positive selection. Phylogenetic analysis based on whole cp genomes showed that P. schneideri had a close relationship with P. kangdingensis and P. pseudoglauca, while P. xiangchengensis was a sister to P. cathayana.


Zootaxa ◽  
2021 ◽  
Vol 4952 (2) ◽  
pp. 331-353
Author(s):  
CHAO YANG ◽  
LE ZHAO ◽  
QINGXIONG WANG ◽  
HAO YUAN ◽  
XUEJUAN LI ◽  
...  

To gain a better understanding of mitogenome features and phylogenetic relationships in Sylvioidea, a superfamily of Passerida, suborder Passeri, Passeriformes, the whole mitogenome of Alaudala cheleensis Swinhoe (Alaudidae) was sequenced, a comparative mitogenomic analysis of 18 Sylvioidea species was carried out, and finally, a phylogeny was reconstructed based on the mitochondrial dataset. Gene order of the A. cheleensis mitogenome was similar to that of other Sylvioidea species, including the gene rearrangement of cytb-trnT-CR1-trnP-nad6-trnE-remnant CR2-trnF-rrnS. There was slightly higher A+T content than that of G+C in the mitogenome, with an obvious C skew. The ATG codon initiated all protein-coding genes, while six terminating codons were used. The secondary structure of rrnS contained three domains and 47 helices, whereas rrnL included six domains and 60 helices. All tRNAs could be folded into a classic clover-leaf secondary structure except for trnS (AGY). The CR1 could be divided into three domains, including several conserved boxes (C-string, F, E, D, C and B-box, Bird similarity box, CSB1). Comparative analyses within Sylvioidea mitogenomes showed that most mitochondrial features were consistent with that of the A. cheleensis mitogenome. The basal position of the Alaudidae within the Sylvioidea in our phylogenetic analyses is consistent with other recent studies. 


2021 ◽  
Author(s):  
VISHNU PRASOODANAN P K ◽  
Shruti S. Menon ◽  
Rituja Saxena ◽  
Prashant Waiker ◽  
Vineet K Sharma

Discovery of novel thermophiles has shown promising applications in the field of biotechnology. Due to their thermal stability, they can survive the harsh processes in the industries, which make them important to be characterized and studied. Members of Anoxybacillus are alkaline tolerant thermophiles and have been extensively isolated from manure, dairy-processed plants, and geothermal hot springs. This article reports the assembled data of an aerobic bacterium Anoxybacillus sp. strain MB8, isolated from the Tattapani hot springs in Central India, where the 16S rRNA gene shares an identity of 97% (99% coverage) with Anoxybacillus kamchatkensis strain G10. The de novo assembly and annotation performed on the genome of Anoxybacillus sp. strain MB8 comprises of 2,898,780 bp (in 190 contigs) with a GC content of 41.8% and includes 2,976 protein-coding genes,1 rRNA operon, 73 tRNAs, 1 tm-RNA and 10 CRISPR arrays. The predicted protein-coding genes have been classified into 21 eggNOG categories. The KEGG Automated Annotation Server (KAAS) analysis indicated the presence of assimilatory sulfate reduction pathway, nitrate reducing pathway, and genes for glycoside hydrolases (GHs) and glycoside transferase (GTs). GHs and GTs hold widespread applications, in the baking and food industry for bread manufacturing, and in the paper, detergent and cosmetic industry. Hence, Anoxybacillus sp. strain MB8 holds the potential to be screened and characterized for such commercially relevant enzymes.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10364
Author(s):  
Natalia I. Abramson ◽  
Fedor N. Golenishchev ◽  
Semen Yu. Bodrov ◽  
Olga V. Bondareva ◽  
Evgeny A. Genelt-Yanovskiy ◽  
...  

In this article, we present the nearly complete mitochondrial genome of the Subalpine Kashmir vole Hyperacrius fertilis (Arvicolinae, Cricetidae, Rodentia), assembled using data from Illumina next-generation sequencing (NGS) of the DNA from a century-old museum specimen. De novo assembly consisted of 16,341 bp and included all mitogenome protein-coding genes as well as 12S and 16S RNAs, tRNAs and D-loop. Using the alignment of protein-coding genes of 14 previously published Arvicolini tribe mitogenomes, seven Clethrionomyini mitogenomes, and also Ondatra and Dicrostonyx outgroups, we conducted phylogenetic reconstructions based on a dataset of 13 protein-coding genes (PCGs) under maximum likelihood and Bayesian inference. Phylogenetic analyses robustly supported the phylogenetic position of this species within the tribe Arvicolini. Among the Arvicolini, Hyperacrius represents one of the early-diverged lineages. This result of phylogenetic analysis altered the conventional view on phylogenetic relatedness between Hyperacrius and Alticola and prompted the revision of morphological characters underlying the former assumption. Morphological analysis performed here confirmed molecular data and provided additional evidence for taxonomic replacement of the genus Hyperacrius from the tribe Clethrionomyini to the tribe Arvicolini.


2021 ◽  
Vol 10 (16) ◽  
Author(s):  
Zhenhua Yu ◽  
Sergio de los Santos-Villalobos ◽  
Yansheng Li ◽  
Jian Jin ◽  
Fannie Isela Parra Cota ◽  
...  

ABSTRACT Here, we present the draft genome of Bacillus sp. strain IGA-FME-2. This strain was isolated from the bulk soil of soybean (Glycine max L.). Its genome consists of 3,810 protein-coding genes, 44 tRNAs, two 16S rRNAs, and a single copy of 23S rRNA, with a GC content of 46.4%.


2018 ◽  
Vol 7 (11) ◽  
Author(s):  
Huy Quang Nguyen ◽  
Nguyen Thi-Hanh Vu ◽  
Ha Hoang Chu ◽  
Son Ky Chu ◽  
Ha Hoang ◽  
...  

This study reports the draft genome sequence of the endophytic Streptomyces cavourensis strain YBQ59, produces the antibiotics bafilomycin D, nonactic acid, prelactone B, and 5,11-epoxy-10-cadinanol. The draft genome sequence comprises ∼10.2 Mb, with a GC content of 64% and 8,958 predicted protein-coding genes, of which 14 gene clusters were found to associate with antibiotic biosynthetic pathways.


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