Molecular systematics of Australian Podolepis (Asteraceae: Gnaphalieae): evidence from DNA sequences of the nuclear ITS region and the chloroplast matK gene

2000 ◽  
Vol 13 (5) ◽  
pp. 709 ◽  
Author(s):  
N. Konishi ◽  
K. Watanabe ◽  
K. Kosuge

The generic circumscription and intra-generic relationships of the genus Podolepis Labill., with various chromosome numbers from n = 12 to n = 3, were examined by sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA and the matK gene of chloroplast DNA. The topology of the ITS tree for 17 species and the matK tree for 18 species of the genus Podolepis sensu Davis (1957) and Anderberg (1991) and 15 taxa from eight related genera (Anderberg 1989, 1991, 1994) are basically concordant. Except for P. georgei Diels andP. kendallii F.Muell., parsimony analyses support the monophyly of the genus Podolepis sensu Davis (1957) and Anderberg (1991). The genera of Asteridea Lindl. and Pterochaeta Steetz are sisters toPodolepis in the combined tree based on the ITS and matK sequences. Within the monophyletic clade of the genus Podolepis, three lineages are identified. The chromosome base number of x = 12 may be ancestral in the genus Podolepis. The dysploidal reduction in chromosome number from n = 12 to n = 10 and 9, from n = 12 to n = 8 and 7, and from n = 12 to n = 11 and 3 in three lineages, respectively, is the primary mode of chromosomal evolution in this genus. Total karyotypic length (= genome size) is much greater in perennials than in annuals within the genus Podolepis. The number of pappus bristles on outer female florets tends to decrease and they are absent in some annuals of this genus, while myxogenic cells on the pericarp become prominent.

Horticulturae ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 19
Author(s):  
Patricia Coughlan ◽  
James C. Carolan ◽  
Ingrid L. I. Hook ◽  
Lisa Kilmartin ◽  
Trevor R. Hodkinson

Taxus is a genus of trees and shrubs with high value in horticulture and medicine as a source of the anticancer drug paclitaxel. The taxonomy of the group is complex due to the lack of diagnostic morphological characters and the high degree of similarity among species. Taxus has a wide global geographic distribution and some taxonomists recognize only a single species with geographically defined subgroups, whereas others have described several species. To address these differences in taxonomic circumscription, phylogenetic analyses were conducted on DNA sequences using Maximum Likelihood, Bayesian Inference and TCS haplotype networks on single and combined gene regions obtained for the nuclear ribosomal ITS region and the plastid trnL intron and trnL-F intergenic spacer. Evidence is presented for the sister group status of Pseudotaxus to Taxus and the inclusion of Amentotaxus, Austrotaxus, Cephalotaxus and Torreya within Taxaceae. Results are consistent with the taxonomic recognition of nine species: T. baccata, T. brevifolia, T. canadensis, T. cuspidata, T. floridana, T. fuana, T. globosa, T. sumatrana and T. wallichiana, but evidence is found for less species distinction and considerable reticulation within the T. baccata, T. canadensis and T. cuspidata group. We compare the results to known taxonomy, biogeography, present new leaf anatomical data and discuss the origins of the hybrids T. ×media and T. ×hunnewelliana.


2006 ◽  
Vol 19 (2) ◽  
pp. 155 ◽  
Author(s):  
K. Watanabe ◽  
K. Kosuge ◽  
R. Shimamura ◽  
N. Konishi ◽  
K. Taniguchi

The intra-generic relationships of the Australian genus Calotis, with various chromosome base numbers from x = 8 to x = 4, were examined by the comparison of nucleotide sequences of the complete ITS region of nuclear rDNA and of the matK gene of chloroplast DNA. Within a monophyletic Calotis, four lineages were identified. Reconstruction of ancestral states suggests that the chromosome base number for Calotis is x = 8. Dysploidal reductions in chromosome base number from x = 8 to x = 7 and from x = 8 to x = 5 or 4 have occurred independently at least three times. Lower base numbers of x = 7, 5, and 4 are found predominantly in the arid and semi-arid zone species of Central and Western Australia. Total karyotypic length (genome size) is greater in perennials than in annuals within the genus Calotis. The elaborated pappus and surface structures of cypsela, and life form of species seem to be homoplasous with multiple origins in the evolutionary history of the lineage.


2003 ◽  
Vol 16 (1) ◽  
pp. 19 ◽  
Author(s):  
Daniel J. Murphy ◽  
Joseph T. Miller ◽  
Randall J. Bayer ◽  
Pauline Y. Ladiges

The largest monophyletic group within Acacia is subgenus Phyllodineae, with more than 950 predominately Australian species, the majority characterised by adult foliage consisting of phyllodes. Molecular sequence data from the internal transcribed spacers (ITS) of the nuclear ribosomal DNA repeat were used to investigate the monophyly of seven sections within the subgenus. A nested PCR approach was used to amplify the ITS region. Fifty-one species representative of all sections were sequenced together with one outgroup taxon Lysiloma divaricata (Ingeae).Phylogenetic parsimony analysis suggested that there are two main clades within Phyllodineae but that only one section, Lycopodiifoliae, is apparently monophyletic. In one of the main clades, Lycopodifoliae is related to some taxa in sections Alatae and Pulchellae and some members of section Phyllodineae. In the second main clade, sections Juliflorae, Plurinerves and Botrycephalae cluster with other members of section Phyllodineae. The two sections that are characterised by bipinnate foliage, Botrycephalae and Pulchellae, are nested within phyllodinous clades, indicating that at least two separate reversals to bipinnate leaves have occurred. Botrycephalae is paraphyletic with respect to taxa from section Phyllodineae that have single-nerved phyllodes and racemose inflorescences.


2005 ◽  
Vol 17 (3) ◽  
pp. 377-384 ◽  
Author(s):  
M.L. SKOTNICKI ◽  
A.M. MACKENZIE ◽  
M.A. CLEMENTS ◽  
P.M. SELKIRK

We have sequenced the 18S–26S nuclear ribosomal DNA ITS region from the genome of nine different moss species from the Ross Sea region of Antarctica. This relatively quick and simple technique enables these species to be readily distinguished, facilitating their taxonomic identification. Only a single moss shoot is required, and for identification of these bryophytes it is only necessary to determine a few hundred nucleotides of the DNA sequence in a single sequencing reaction. Several previously unidentified Antarctic moss specimens were readily characterized by comparison with ITS sequences of known moss species. The relationships between species and locations previously detected by the RAPD (Random Amplified Polymorphic DNA) technique were confirmed by DNA sequencing, demonstrating that the two techniques can be complementary for molecular analysis of the ecology of mosses in Antarctica.


Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 87
Author(s):  
Kumpei Shiragaki ◽  
Shuji Yokoi ◽  
Takahiro Tezuka

The genus Capsicum is comprised of 5 domesticated and more than 30 wild species. The region of nuclear ribosomal DNA internal transcribed spacers (rDNA-ITS) has widely been used for species identification, but has rarely been used in Capsicum. In this study, the evaluation of genetic diversity and a phylogenetic analysis were conducted using rDNA-ITS of 28 Capsicum accessions, including five domesticated and two wild species. We surveyed six conventional keys of domesticated species and another five traits in Capsicum accessions. Specific morphological characteristics were found in C. annuum, C. baccatum, and C.pubescens. Three subclones of each accession were sequenced, and rDNA-ITS polymorphisms were detected in all accessions excluding C. annuum, suggesting that incomplete concerted evolution occurred in rDNA-ITS of Capsicum. The genetic diversity was evaluated using nucleotide polymorphism and diversity. C. annuum had the lowest genetic diversity of all species in this study. The phylogenetic tree formed a species-specific clade for C. annuum, C. baccatum, and C. pubescens. The C. chinense clade existed in the C. frutescens clade, implying that it was a cultivated variant of C. frutescens. C. chacoense likely belonged to the C. baccatum complex according to its morphologic and genetic features. This study indicated that the rDNA-ITS region can be used for simple identification of domesticated Capsicum species.


MycoKeys ◽  
2019 ◽  
Vol 56 ◽  
pp. 33-47 ◽  
Author(s):  
Arooj Naseer ◽  
Abdul Nasir Khalid ◽  
Rosanne Healy ◽  
Matthew E. Smith

The genus Hygrophorus is poorly studied from Asia. From Pakistan, only one species has been reported so far. Two new species in the genus have been collected from Himalayan oak forests of Pakistan. Hygrophorusalboflavescens (section Pudorini, subgenus Colorati) is characterised by its pure white, centrally depressed pileus, occurrence of white stipe with yellow patches at lower half and broader (4.98 μm) basidiospores. Hygrophorusscabrellus (section Hygrophorus, subgenus Hygrophorus) is characterised by its yellowish-green stipe with white apex that has fine scales on the entire stipe, an off-white pileus with dark green and greyish fibrils, ovoid to ellipsoid basidiospores and clavate 4-spored basidia. Macro- and micromorphological descriptions have revealed that both these taxa are not yet described. Phylogenetic estimation based on DNA sequences from the internal transcribed spacer (ITS) region and large subunit (LSU) of the nuclear ribosomal DNA (rDNA) genes, is congruent with the morphological characters that help to delimit these as new species of Hygrophorus. Allied taxa are also compared.


2016 ◽  
Vol 8 (4) ◽  
pp. 444-450 ◽  
Author(s):  
Emre SEVİNDİK ◽  
Veysel UZUN ◽  
Fatih COŞKUN

In the current study, sequence analysis of some Turkish Lactuca L. species using nrITS DNA and trnL-F cpDNA sequences were performed to elucidate phylogenetic relationships among the taxa under study. Hieracium umbellatum was used as an outgroup. Different plant materials of Lactuca were collected from different parts of Turkey during excursions of summer 2013. Plant materials were either kept in silica gel or kept fresh for immediate DNA isolation. Both phenol chloroform-isoamyl alcohol method and commercial kits were used to extract genomic DNA for PCR reactions. ITS4 and ITS5A primers were utilized for ITS region, while trnLe and trnLf primers were used to amplify the trnL-F region. Obtained DNA sequences were edited both manually and by using BioEdit 7.0.4.1. Sequencing data were aligned via ClustalW program and analyzed using PAUP 4.01b10 software. nrITS sequences varied from 639 nucleotides to 735 nucleotides. Average nucleotide composition for nrITS was 22.1% (T), 27.9% (C), 23.2% (A) and 26.8% (G). It was also found that divergence values differed between 0.0000 and 0.10290. The trnL-F sequences varied from 296 nucleotides to 385 nucleotides. Average nucleotide composition of trnL-F sequences was 34.1% (T), 18.4% (C), 31.6% (A) and 16.0% (G). It was also found that divergence values differed between 0.0000 and 0.09674. Neighbour Joining (NJ) trees were constructed in order to identify the relationships among Lactuca species. Phylogenetic trees based on ITS region were found to be more useful than phylogenetic trees based on trnL-F region. After analysis of the results obtained, the data suggest that Lactuca contains 2 clades, with clade 1 having 2 subclades. These results support the prior phylogenetic studies on Lactuca and hence provide an up to date review of Turkish Lactuca species.


Zootaxa ◽  
2010 ◽  
Vol 2647 (1) ◽  
pp. 1 ◽  
Author(s):  
GUO-QING LI ◽  
XIAO-FENG XUE ◽  
KAI-JUN ZHANG ◽  
XIAO-YUE HONG

Tetranychid mites are serious agricultural pests. Identification of species in the Tetranychidae is hampered by their close morphological similarities, especially for species within the genus Tetranychus. In this study, we examined the relationships of nine agriculturally important species in the Tetranychidae from China based on mitochondrial (cytochrome c oxidase subunit 1) and nuclear (internal transcribed spacer 1 and 2 of ribosomal RNA gene) sequences. The results confirm the monophyly of the morphologically defined Tetranychus, Panonychus, Amphitetranychus and Petrobia. However the position of Amphitetranychus viennensis within the Tetranychidae needs to be confirmed. The genetic distances between Tetranychus truncatus, T. turkestani and T. urticae that their taxonomy needs revision. In particular, both cytochrome oxidase 1 and the internal transcribed spacers 1 and 2 of rDNA sequences showed large geographical differences within T. cinnabarinus, suggesting the existence of cryptic species within this species.


Phytotaxa ◽  
2018 ◽  
Vol 336 (3) ◽  
pp. 239 ◽  
Author(s):  
BİROL MUTLU

In this study, Erysimum nemrutdaghense Mutlu (Brassicaceae) is described as a new species from the province of Adıyaman in the South-east Anatolia. In order to determine the phylogenetic relationships of the new species, a portion of the nuclear ribosomal DNA sequences of ITS region was used. In addition to the new species, ITS regions of five Erysimum species were sequenced. Erysimum sintenisianum Bornm., E. lazistanicum (Rupr.) Lipsky, and E. stenophyllum Polatschek were sequenced in this study for the first time. The diagnostic morphological and phylogenetic characteristics are discussed with similar species. SEM images of trichomes on different parts of siliqua, stigma, and seed are given. Chromosome number of the new species is found to be 2n=16.


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