scholarly journals Taxonomic scheme of the order Chaetophorales (Chlorophyceae, Chlorophyta) based on Chloroplast genomes

2020 ◽  
Author(s):  
Benwen Liu ◽  
Yu Xin Hu ◽  
Zheng Yu Hu ◽  
Guo Xiang Liu ◽  
Huan Zhu

Abstract Background: Order Chaetophorales currently includes six families, namely Schizomeridaceae, Aphanochaetaceae, Barrancaceae, Uronemataceae, Fritschiellaceae, and Chaetophoraceae. The phylogenetic relationships of Chaetophorales have been inferred primarily based on short and less informative rDNA sequences. This study aimed to phylogenetically reconstruct order Chaetophorales and determine the taxonomic scheme and to further the current understanding of the evolution of order Chaetophorales.Results: In the present study, seven complete and five fragmentary chloroplast genomes were harvested. Phylogenomic and comparative genomic analysis were performed to determine the taxonomic scheme within Chaetophorales. Consequently, Oedogoniales was found to be a sister to a clade linking Chaetophorales and Chaetopeltidales. Schizomeriaceae, and Aphanochaetaceae clustered into a well-resolved basal clade in Chaetophorales, inconsistent with the results of phylogenetic analysis based on rDNA sequences. Comparative genomic analyses revealed that the chloroplast genomes of Schizomeriaceae and Aphanochaetaceae were highly conserved and homologous, highlighting the closest relationship in this order. Germination types of zoospores precisely correlated with the phylogenetic relationships.Conclusions: chloroplast genome structure analyses, synteny analyses, and zoospore germination analyses were concurrent with phylogenetic analyses based on the chloroplast genome, and all of them robustly determined the unique taxonomic scheme of Chaetophorales and the relationships of Oedogoniales, Chaetophorales, and Chaetopeltidales.

2020 ◽  
Author(s):  
Benwen Liu ◽  
Yu Xin Hu ◽  
Zheng Yu Hu ◽  
Guo Xiang Liu ◽  
Huan Zhu

Abstract Background Order Chaetophorales currently includes six families, namely Schizomeridaceae, Aphanochaetaceae, Barrancaceae, Uronemataceae, Fritschiellaceae, and Chaetophoraceae. Most studies have primarily focused on intergeneric phylogenetic relationships within this order and the phylogenetic relationships with four other Chlorophycean orders (Chaetophorales, Chaetopeltidales and Oedogoniales, and Volvocales). This study aimed to phylogenetically reconstruct order Chaetophorales and determine the taxonomic scheme and to further the current understanding of the evolution of order Chaetophorales. The taxonomic scheme of Chaetophorales has been inferred primarily through phylogenetic analysis based on rDNA sequences and phylogenetic relationships among families in order Chaetophorales remain unclear. Results In present study, seven complete and five fragmentary chloroplast genomes were harvested. Phylogenomic and comparative genomic analysis were performed to determine the taxonomic scheme within Chaetophorales. Consequently, Oedogoniales was found to be a sister to a clade linking Chaetophorales and Chaetopeltidales, Schizomeriaceae, and Aphanochaetaceae clustered into a well-resolved basal clade in Chaetophorales, inconsistent with the results of phylogenetic analysis based on rDNA sequences. Comparative genomic analyses revealed that the chloroplast genomes of Schizomeriaceae and Aphanochaetaceae were highly conserved and homologous, highlighting the closest relationship in this order. Germination types of zoospores precisely correlated with the phylogenetic relationships. Conclusions In conclusion, chloroplast genome structure analyses, synteny analyses, and zoospore germination analyses were concurrent with phylogenetic analyses based on the chloroplast genome, and all of them robustly determined the unique taxonomic scheme of Chaetophorales and the relationships of Oedogoniales, Chaetophorales, and Chaetopeltidales.


2020 ◽  
Author(s):  
Benwen Liu(Former Corresponding Author) ◽  
Yu Xin Hu ◽  
Zheng Yu Hu ◽  
Guo Xiang Liu ◽  
Huan Zhu(New Corresponding Author)

Abstract Background: Order Chaetophorales currently includes six families, namely Schizomeridaceae, Aphanochaetaceae, Barrancaceae, Uronemataceae, Fritschiellaceae, and Chaetophoraceae. The phylogenetic relationships of Chaetophorales have been inferred primarily through phylogenetic analysis based on rDNA sequences. Most studies have primarily focused on intergeneric phylogenetic relationships within this order and the phylogenetic relationships with four other Chlorophycean orders (Chaetophorales, Chaetopeltidales and Oedogoniales, and Volvocales). The phylogenetic relationships among families in order Chaetophorales remain unclear. This study aimed to phylogenetically reconstruct order Chaetophorales and determine the taxonomic scheme and to further the current understanding of the evolution of order Chaetophorales . Results: In the present study, seven complete and five fragmentary chloroplast genomes were harvested. Phylogenomic and comparative genomic analysis were performed to determine the taxonomic scheme within Chaetophorales. Consequently, Oedogoniales was found to be a sister to a clade linking Chaetophorales and Chaetopeltidales. Schizomeriaceae, and Aphanochaetaceae clustered into a well-resolved basal clade in Chaetophorales, inconsistent with the results of phylogenetic analysis based on rDNA sequences. Comparative genomic analyses revealed that the chloroplast genomes of Schizomeriaceae and Aphanochaetaceae were highly conserved and homologous, highlighting the closest relationship in this order. Germination types of zoospores precisely correlated with the phylogenetic relationships. Conclusions: chloroplast genome structure analyses, synteny analyses, and zoospore germination analyses were concurrent with phylogenetic analyses based on the chloroplast genome, and all of them robustly determined the unique taxonomic scheme of Chaetophorales and the relationships of Oedogoniales, Chaetophorales, and Chaetopeltidales.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10687
Author(s):  
Joonhyung Jung ◽  
Hoang Dang Khoa Do ◽  
JongYoung Hyun ◽  
Changkyun Kim ◽  
Joo-Hwan Kim

Background Carduus, commonly known as plumeless thistles, is a genus in the Asteraceae family that exhibits both medicinal value and invasive tendencies. However, the genomic data of Carduus (i.e., complete chloroplast genomes) have not been sequenced. Methods We sequenced and assembled the chloroplast genome (cpDNA) sequences of three Carduus species using the Illumina Miseq sequencing system and Geneious Prime. Phylogenetic relationships between Carduus and related taxa were reconstructed using Maximum Likelihood and Bayesian Inference analyses. In addition, we used a single nucleotide polymorphism (SNP) in the protein coding region of the matK gene to develop molecular markers to distinguish C. crispus from C. acanthoides and C. tenuiflorus. Results The cpDNA sequences of C. crispus, C. acanthoides, and C. tenuiflorus ranged from 152,342 bp to 152,617 bp in length. Comparative genomic analysis revealed high conservation in terms of gene content (including 80 protein-coding, 30 tRNA, and four rRNA genes) and gene order within the three focal species and members of subfamily Carduoideae. Despite their high similarity, the three species differed with respect to the number and content of repeats in the chloroplast genome. Additionally, eight hotspot regions, including psbI-trnS_GCU, trnE_UUC-rpoB, trnR_UCU-trnG_UCC, psbC-trnS_UGA, trnT_UGU-trnL_UAA, psbT-psbN, petD-rpoA, and rpl16-rps3, were identified in the study species. Phylogenetic analyses inferred from 78 protein-coding and non-coding regions indicated that Carduus is polyphyletic, suggesting the need for additional studies to reconstruct relationships between thistles and related taxa. Based on a SNP in matK, we successfully developed a molecular marker and protocol for distinguishing C. crispus from the other two focal species. Our study provides preliminary chloroplast genome data for further studies on plastid genome evolution, phylogeny, and development of species-level markers in Carduus.


Gene ◽  
2021 ◽  
pp. 145715
Author(s):  
Ying Zhang ◽  
Zhengfeng Wang ◽  
Yanan Guo ◽  
Sheng Chen ◽  
Xianyi Xu ◽  
...  

2020 ◽  
Author(s):  
Ying-min Zhang ◽  
Li-jun Han ◽  
Ying-Ying Liu ◽  
Cong-wei Yang ◽  
Xing Tian ◽  
...  

Abstract Background: Veratrum is a genus of perennial herbs that are widely used as traditional Chinese medicine for emetic, resolving blood stasis and relieve pain. However, the species classification and the phylogenetic relationship of the genus Veratrum have long been controversial due to the complexity of morphological variations. Knowledge on the infrageneric relationships of the genus Veratrum can be obtained from their chloroplast genome sequences and increase the taxonomic and phylogenetic resolution.Methods: Total DNA was extracted from ten species of Veratrum and subjected to next-generation sequencing. The cp genome was assembled by NOVOPlasty. Genome annotation was conducted using the online tool DOGMA and subsequently corrected by Geneious Prime. Then, genomic characterization of the Veratrum plastome and genome comparison with closely related species was analyzed by corresponding software. Moreover, phylogenetical trees were reconstructed, based on the 29 plastomes by maximum likelihood (ML) and Bayesian inference (BI) methods.Results: The whole plastomes of Veratrum species possess a typical quadripartite structure, ranging from 151,597 bp to 153,711 bp in size and comprising 135 genes. The gene order, content, and genome structure were nearly identical with a few exceptions across the Veratrum chloroplast genomes. The total number of simple sequence repeats (SSRs) ranged from 31 to 35, and of large sequence repeats (LSRs) ranged from 65 to 71. Seven highly divergent regions (rpoB-trnC, trnT-trnL, trnS-trnG, psbC-psbZ, psbI, ycf1, and ndhF) were identified that can be used for DNA barcoding in the genus of Veratrum. Phylogenetic analyses based on 29 plastomes strongly supported the monophyly of Veratrum. The circumscription and relationships of infrageneric taxa of Veratrum were well evaluated with high resolutions. Conclusions: Our study identified and analyzed the cp genome features of ten Veratrum species, and suggested high effectivity of chloroplast complete genome in resolving generic circumscription in Veratrum. These results will facilitate the identification, taxonomy, and utilization of Veratrum plants as well as the phylogenetic study of Melanthiaceae simultaneously.


2020 ◽  
Author(s):  
Pieter De Maayer ◽  
Talia Pillay ◽  
Teresa A Coutinho

Abstract Background: Flagellar motility is an efficient means of movement that allows bacteria to successfully colonize and compete with other microorganisms within their respective environments. The production and functioning of flagella is highly energy intensive and therefore flagellar motility is a tightly regulated process. Despite this, some bacteria have been observed to possess multiple flagellar systems which allow distinct forms of motility. Results: Comparative genomic analyses showed that, in addition to the previously identified primary peritrichous (flag-1) and secondary, lateral (flag-2) flagellar loci, three novel types of flagellar loci, varying in both gene content and gene order, are encoded on the genomes of members of the order Enterobacterales. The flag-3 and flag-4 loci encode predicted peritrichous flagellar systems while the flag-5 locus encodes a polar flagellum. In total, 798/4,028 (~20%) of the studied taxa incorporate dual flagellar systems, while nineteen taxa incorporate three distinct flagellar loci. Phylogenetic analyses indicate the complex evolutionary histories of the flagellar systems among the Enterobacterales. Conclusions: Supernumerary flagellar loci are relatively common features across a broad taxonomic spectrum in the order Enterobacterales. Here, we report the occurrence of five (flag-1 to flag-5) flagellar loci on the genomes of enterobacterial taxa, as well as the occurrence of three flagellar systems in select members of the Enterobacterales. Considering the energetic burden of maintaining and operating multiple flagellar systems, they are likely to play a role in the ecological success of members of this family and we postulate on their potential biological functions.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3919 ◽  
Author(s):  
Hui Cheng ◽  
Jinfeng Li ◽  
Hong Zhang ◽  
Binhua Cai ◽  
Zhihong Gao ◽  
...  

Compared with other members of the family Rosaceae, the chloroplast genomes ofFragariaspecies exhibit low variation, and this situation has limited phylogenetic analyses; thus, complete chloroplast genome sequencing ofFragariaspecies is needed. In this study, we sequenced the complete chloroplast genome ofF. × ananassa‘Benihoppe’ using the Illumina HiSeq 2500-PE150 platform and then performed a combination ofde novoassembly and reference-guided mapping of contigs to generate complete chloroplast genome sequences. The chloroplast genome exhibits a typical quadripartite structure with a pair of inverted repeats (IRs, 25,936 bp) separated by large (LSC, 85,531 bp) and small (SSC, 18,146 bp) single-copy (SC) regions. The length of theF. × ananassa‘Benihoppe’ chloroplast genome is 155,549 bp, representing the smallestFragariachloroplast genome observed to date. The genome encodes 112 unique genes, comprising 78 protein-coding genes, 30 tRNA genes and four rRNA genes. Comparative analysis of the overall nucleotide sequence identity among ten complete chloroplast genomes confirmed that for both coding and non-coding regions in Rosaceae, SC regions exhibit higher sequence variation than IRs. The Ka/Ks ratio of most genes was less than 1, suggesting that most genes are under purifying selection. Moreover, the mVISTA results also showed a high degree of conservation in genome structure, gene order and gene content inFragaria, particularly among three octoploid strawberries which wereF. × ananassa‘Benihoppe’,F.chiloensis(GP33) andF.virginiana(O477). However, when the sequences of the coding and non-coding regions ofF. × ananassa‘Benihoppe’ were compared in detail with those ofF.chiloensis(GP33) andF.virginiana(O477), a number of SNPs and InDels were revealed by MEGA 7. Six non-coding regions (trnK-matK,trnS-trnG,atpF-atpH,trnC-petN,trnT-psbDandtrnP-psaJ) with a percentage of variable sites greater than 1% and no less than five parsimony-informative sites were identified and may be useful for phylogenetic analysis of the genusFragaria.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6320 ◽  
Author(s):  
Zhen Yang ◽  
Guixi Wang ◽  
Qinghua Ma ◽  
Wenxu Ma ◽  
Lisong Liang ◽  
...  

Background Previous phylogenetic conclusions on the family Betulaceae were based on either morphological characters or traditional single loci, which may indicate some limitations. The chloroplast genome contains rich polymorphism information, which is very suitable for phylogenetic studies. Thus, we sequenced the chloroplast genome sequences of three Betulaceae species and performed multiple analyses to investigate the genome variation, resolve the phylogenetic relationships, and clarify the divergence history. Methods Chloroplast genomes were sequenced using the high-throughput sequencing. A comparative genomic analysis was conducted to examine the global genome variation and screen the hotspots. Three chloroplast partitions were used to reconstruct the phylogenetic relationships using Maximum Likelihood and Bayesian Inference approaches. Then, molecular dating and biogeographic inferences were conducted based on the whole chloroplast genome data. Results Betulaceae chloroplast genomes consisted of a small single-copy region and a large single copy region, and two copies of inverted repeat regions. Nine hotspots can be used as potential DNA barcodes for species delimitation. Phylogenies strongly supported the division of Betulaceae into two subfamilies: Coryloideae and Betuloideae. The phylogenetic position of Ostryopsis davidiana was controversial among different datasets. The divergence time between subfamily Coryloideae and Betuloideae was about 70.49 Mya, and all six extant genera were inferred to have diverged fully by the middle Oligocene. Betulaceae ancestors were probably originated from the ancient Laurasia. Discussions This research elucidates the potential of chloroplast genome sequences in the application of developing molecular markers, studying evolutionary relationships and historical dynamic of Betulaceae.It also reveals the advantages of using chloroplast genome data to illuminate those phylogenies that have not been well solved yet by traditional approaches in other plants.


BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Pieter De Maayer ◽  
Talia Pillay ◽  
Teresa A. Coutinho

Abstract Background Flagellar motility is an efficient means of movement that allows bacteria to successfully colonize and compete with other microorganisms within their respective environments. The production and functioning of flagella is highly energy intensive and therefore flagellar motility is a tightly regulated process. Despite this, some bacteria have been observed to possess multiple flagellar systems which allow distinct forms of motility. Results Comparative genomic analyses showed that, in addition to the previously identified primary peritrichous (flag-1) and secondary, lateral (flag-2) flagellar loci, three novel types of flagellar loci, varying in both gene content and gene order, are encoded on the genomes of members of the order Enterobacterales. The flag-3 and flag-4 loci encode predicted peritrichous flagellar systems while the flag-5 locus encodes a polar flagellum. In total, 798/4028 (~ 20%) of the studied taxa incorporate dual flagellar systems, while nineteen taxa incorporate three distinct flagellar loci. Phylogenetic analyses indicate the complex evolutionary histories of the flagellar systems among the Enterobacterales. Conclusions Supernumerary flagellar loci are relatively common features across a broad taxonomic spectrum in the order Enterobacterales. Here, we report the occurrence of five (flag-1 to flag-5) flagellar loci on the genomes of enterobacterial taxa, as well as the occurrence of three flagellar systems in select members of the Enterobacterales. Considering the energetic burden of maintaining and operating multiple flagellar systems, they are likely to play a role in the ecological success of members of this family and we postulate on their potential biological functions.


Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 737 ◽  
Author(s):  
Abdullah ◽  
Claudia L. Henriquez ◽  
Furrukh Mehmood ◽  
Iram Shahzadi ◽  
Zain Ali ◽  
...  

The chloroplast genome provides insight into the evolution of plant species. We de novo assembled and annotated chloroplast genomes of four genera representing three subfamilies of Araceae: Lasia spinosa (Lasioideae), Stylochaeton bogneri, Zamioculcas zamiifolia (Zamioculcadoideae), and Orontium aquaticum (Orontioideae), and performed comparative genomics using these chloroplast genomes. The sizes of the chloroplast genomes ranged from 163,770 bp to 169,982 bp. These genomes comprise 113 unique genes, including 79 protein-coding, 4 rRNA, and 30 tRNA genes. Among these genes, 17–18 genes are duplicated in the inverted repeat (IR) regions, comprising 6–7 protein-coding (including trans-splicing gene rps12), 4 rRNA, and 7 tRNA genes. The total number of genes ranged between 130 and 131. The infA gene was found to be a pseudogene in all four genomes reported here. These genomes exhibited high similarities in codon usage, amino acid frequency, RNA editing sites, and microsatellites. The oligonucleotide repeats and junctions JSB (IRb/SSC) and JSA (SSC/IRa) were highly variable among the genomes. The patterns of IR contraction and expansion were shown to be homoplasious, and therefore unsuitable for phylogenetic analyses. Signatures of positive selection were seen in three genes in S. bogneri, including ycf2, clpP, and rpl36. This study is a valuable addition to the evolutionary history of chloroplast genome structure in Araceae.


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