Phylogenetic analysis guided by intragenomic SSU rDNA polymorphism refines classification of “Alexandrium tamarense” species complex

Harmful Algae ◽  
2012 ◽  
Vol 16 ◽  
pp. 35-48 ◽  
Author(s):  
Lilibeth N. Miranda ◽  
Yunyun Zhuang ◽  
Huan Zhang ◽  
Senjie Lin
Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 241
Author(s):  
Joon Moh Park ◽  
Jachoon Koo ◽  
Se Won Kang ◽  
Sung Hee Jo ◽  
Jeong Mee Park

Rhodococcus fascians is an important pathogen that infects various herbaceous perennials and reduces their economic value. In this study, we examined R. fascians isolates carrying a virulence gene from symptomatic lily plants grown in South Korea. Phylogenetic analysis using the nucleotide sequences of 16S rRNA, vicA, and fasD led to the classification of the isolates into four different strains of R. fascians. Inoculation of Nicotiana benthamiana with these isolates slowed root growth and resulted in symptoms of leafy gall. These findings elucidate the diversification of domestic pathogenic R. fascians and may lead to an accurate causal diagnosis to help reduce economic losses in the bulb market.


2021 ◽  
Vol 7 (3) ◽  
pp. 171
Author(s):  
Reannon L. Smith ◽  
Tom W. May ◽  
Jatinder Kaur ◽  
Tim I. Sawbridge ◽  
Ross C. Mann ◽  
...  

The Podosphaera tridactyla species complex is highly variable morphologically and causes powdery mildew on a wide range of Prunus species, including stone fruit. A taxonomic revision of the Po. tridactyla species complex in 2020 identified 12 species, seven of which were newly characterised. In order to clarify which species of this complex are present in Australia, next generation sequencing was used to isolate the fungal ITS+28S and host matK chloroplast gene regions from 56 powdery mildew specimens of stone fruit and ornamental Prunus species accessioned as Po. tridactyla or Oidium sp. in Australian reference collections. The specimens were collected in Australia, Switzerland, Italy and Korea and were collected from 1953 to 2018. Host species were confirmed using matK phylogenetic analysis, which identified that four had been misidentified as Prunus but were actually Malusprunifolia. Podosphaera species were identified using ITS+28S phylogenetic analysis, recognising three Podosphaera species on stone fruit and related ornamental Prunus hosts in Australia. These were Po.pannosa, the rose powdery mildew, and two species in the Po. tridactyla species complex: Po. ampla, which was the predominant species, and a previously unidentified species from peach, which we describe here as Po. cunningtonii.


Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 41
Author(s):  
Marcos Godoy ◽  
Daniel A. Medina ◽  
Rudy Suarez ◽  
Sandro Valenzuela ◽  
Jaime Romero ◽  
...  

Piscine orthoreovirus (PRV) belongs to the family Reoviridae and has been described mainly in association with salmonid infections. The genome of PRV consists of about 23,600 bp, with 10 segments of double-stranded RNA, classified as small (S1 to S4), medium (M1, M2 and M3) and large (L1, L2 and L3); these range approximately from 1000 bp (segment S4) to 4000 bp (segment L1). How the genetic variation among PRV strains affects the virulence for salmonids is still poorly understood. The aim of this study was to describe the molecular phylogeny of PRV based on an extensive sequence analysis of the S1 and M2 segments of PRV available in the GenBank database to date (May 2020). The analysis was extended to include new PRV sequences for S1 and M2 segments. In addition, subgenotype classifications were assigned to previously published unclassified sequences. It was concluded that the phylogenetic trees are consistent with the original classification using the PRV genomic segment S1, which differentiates PRV into two major genotypes, I and II, and each of these into two subgenotypes, designated as Ia and Ib, and IIa and IIb, respectively. Moreover, some clusters of country- and host-specific PRV subgenotypes were observed in the subset of sequences used. This work strengthens the subgenotype classification of PRV based on the S1 segment and can be used to enhance research on the virulence of PRV.


Author(s):  
Andrea Highfield ◽  
Angela Ward ◽  
Richard Pipe ◽  
Declan C. Schroeder

Abstract Twelve hyper-β carotene-producing strains of algae assigned to the genus Dunaliella salina have been isolated from various hypersaline environments in Israel, South Africa, Namibia and Spain. Intron-sizing of the SSU rDNA and phylogenetic analysis of these isolates were undertaken using four commonly employed markers for genotyping, LSU rDNA, ITS, rbcL and tufA and their application to the study of Dunaliella evaluated. Novel isolates have been identified and phylogenetic analyses have shown the need for clarification on the taxonomy of Dunaliella salina. We propose the division of D. salina into four sub-clades as defined by a robust phylogeny based on the concatenation of four genes. This study further demonstrates the considerable genetic diversity within D. salina and the potential of genetic analyses for aiding in the selection of prospective economically important strains.


2018 ◽  
Vol 49 (2) ◽  
pp. 103-129 ◽  
Author(s):  
Rogério Botion Lopes ◽  
Fernando Barbosa Noll

Zethus is the largest genus in Eumeninae, with over 250 species. Currently, it is divided in four subgenera: Z. (Zethus), Z. (Zethusculus), Z. (Zethoides) and Z. (Madecazethus). Z. (Zethoides), with 42 species, is subdivided in eight species groups, each considered a phylogenetic unit, that were created without any phylogenetic analysis. Eighteen species of Z. (Zethoides) corresponding to different groups were examined, altogether with terminals from distinct lineages of Zethus, Zethini and Eumenini, to perform a cladistics analysis to verify the proposed divisions. Zethus (Zethoides) and all of its species groups, except for the Z. biglumis group, were monophyletic. Zethus s.s. was paraphyletic in relation to Z. (Madecazethus), Z. (Zethoides) and Ctenochilus. Z. (Zethusculus) was also retrieved paraphyletic. Despite the subgeneric incongruences, the outgroups were too poorly represented to carry a taxonomic modification. Thus, the only alteration was the inclusion of the Z. clypearis group in the Z. biglumis group.


Author(s):  
Viola Kurm ◽  
Ilse Houwers ◽  
Claudia E. Coipan ◽  
Peter Bonants ◽  
Cees Waalwijk ◽  
...  

AbstractIdentification and classification of members of the Ralstonia solanacearum species complex (RSSC) is challenging due to the heterogeneity of this complex. Whole genome sequence data of 225 strains were used to classify strains based on average nucleotide identity (ANI) and multilocus sequence analysis (MLSA). Based on the ANI score (>95%), 191 out of 192(99.5%) RSSC strains could be grouped into the three species R. solanacearum, R. pseudosolanacearum, and R. syzygii, and into the four phylotypes within the RSSC (I,II, III, and IV). R. solanacearum phylotype II could be split in two groups (IIA and IIB), from which IIB clustered in three subgroups (IIBa, IIBb and IIBc). This division by ANI was in accordance with MLSA. The IIB subgroups found by ANI and MLSA also differed in the number of SNPs in the primer and probe sites of various assays. An in-silico analysis of eight TaqMan and 11 conventional PCR assays was performed using the whole genome sequences. Based on this analysis several cases of potential false positives or false negatives can be expected upon the use of these assays for their intended target organisms. Two TaqMan assays and two PCR assays targeting the 16S rDNA sequence should be able to detect all phylotypes of the RSSC. We conclude that the increasing availability of whole genome sequences is not only useful for classification of strains, but also shows potential for selection and evaluation of clade specific nucleic acid-based amplification methods within the RSSC.


2017 ◽  
Vol 10 (1) ◽  
pp. 53-91 ◽  
Author(s):  
Thomas Arndt ◽  
Michael Wink

Introduction: The relationships within the Pyrrhura species complex are partly unresolved. In this study, a comprehensive phylogenetic analysis of the Pyrrhura picta-leucotis complex was carried out, covering all species except P. subandina. Material and Methods: We made a morphological analysis of 745 preserved specimens of all the taxa in different museums. Nucleotide sequences of the mitochondrial cytochrome gene were generated and used to reconstruct a molecular phylogeny of Pyrrhura. Results and Discussion: Our results show that the complex is divided into 6 main groups comprising 15 species. P. dilutissima, regarded up to now as a subspecies of P. peruviana, acquires species status and three new subspecies are described. We also provide evidence that P. roseifrons is a paraphyletic group, indicating the existence of probably 3 lineages of which 2 deserve species status.


1994 ◽  
Vol 119 (5) ◽  
pp. 1073-1082 ◽  
Author(s):  
Antonio Figueira ◽  
Jules Janick ◽  
Morris Levy ◽  
Peter Goldsbrough

Genetic similarities among eight Theobroma and two Herrania species, including 29 genotypes of T. cacao, were estimated by rDNA polymorphism. A phenogram based on these genetic similarities significantly separated two clusters: one cluster included all Herrania and Theobroma species, except T. cacao, while the second contained 28 of 29 T. cacao genotypes. There was no clear distinction between Herrania and Theobroma species. Separation of 29 T. cacao genotypes, representing all races and various origins, had no congruency with the conventional classification into three horticultural races: Criollo, Forastero, and Trinitario. Genetic similarities in T. cacao, estimated with RAPD markers, indicated continuous variation among the generally similar but heterogeneous genotypes. The wild genotypes formed an outgroup distinct from the cultivated genotypes, a distinction supported by the rDNA data. The phenograms constructed from RAPD and rDNA data were not similar within the wild and cultivated cacao subsets.


2018 ◽  
Vol 156 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Dinaíza A. Rocha-Reis ◽  
Karina de Oliveira Brandão ◽  
Lurdes F. de Almeida-Toledo ◽  
Rubens Pazza ◽  
Karine F. Kavalco

The genus Hypostomus has a broad geographic distribution in Brazilian rivers and comprises armored catfishes with a very complicated taxonomy due to the absence of morphological autapomorphies. The existence of nearly 10 allopatric populations with different karyotypes suggests that Hypostomusancistroides represents a species complex in the Upper Paraná River basin. In this paper, an unusual karyotype of an isolated H. aff. ancistroides population was investigated. All specimens of this sample have 2n = 66 chromosomes except for 1 male with 2n = 67, most likely due to a supernumerary chromosome. In this population, the sexes are dimorphic, the males are heterogametic, and an XX/XY sex chromosome system is present. Phylogenetic analysis using mitochondrial and nuclear DNAs indicated that this population forms a monophyletic group separate from the other populations of H.ancistroides and may represent an incipient species.


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