Karyosystematics of the Australasian stipoid grass Austrostipa and related genera: chromosome sizes, ploidy, chromosome base numbers and phylogeny

2015 ◽  
Vol 28 (3) ◽  
pp. 145 ◽  
Author(s):  
Grit Winterfeld ◽  
Julia Schneider ◽  
Hannes Becher ◽  
John Dickie ◽  
Martin Röser

Mitotic metaphase chromosomes were counted in 29 taxa, representing 11 subgenera of Austrostipa, and in 11 species from nine related genera of the grass subfamily Pooideae. Karyotype features were also measured. The cytogenetic data were mapped on molecular phylogenetic trees based on nuclear ITS and plastid 3ʹtrnK DNA sequence data. The trees showed four different main lineages within Austrostipa, but supported only two of the 13 acknowledged subgenera. The phylogenetic positions of the genera Anemanthele, Achnatherum, Nassella and Oloptum indicated paraphyly of the genus Austrostipa. In nuclear-sequence data, Anemanthele was nested within Austrostipa; however, in plastid-sequence data, both were sisters. The newly obtained chromosome counts in Austrostipa showed that most species have 2n = 44, the other 2n = 66. Presuming a chromosome base number of x = 11, the counts corresponded with ploidy levels of 4x and 6x respectively. Karyotype data of Austrostipa and Anemanthele were very similar. Chromosome counting in further genera suggested chromosome base numbers of x = 9, 10, 11, 12 and 13. Chromosome sizes of the phylogenetically derived tribe Stipeae were smaller than those of the earliest diverging Pooideae lineages Nardeae, Meliceae and Phaenospermateae. The mechanisms of chromosome evolution and the origin of the considerable variation in chromosome base numbers in the subfamily Pooideae are discussed in the context of chromosome evolution and biosystematics.


2014 ◽  
Vol 62 (3) ◽  
pp. 235 ◽  
Author(s):  
S. Safaei Chaei Kar ◽  
F. Ghanavati ◽  
M. R. Naghavi ◽  
H. Amirabadi-zade ◽  
R. Rabiee

Onobrychis, comprising more than 130 species, is a genus of the family Fabaceae. At this time, the interspecies relationship of this biologically important genus is still a subject of great discussion and debate. To help resolve this disagreement, we used molecular phylogeny to analyse internal transcribed spacer (ITS) and trnL–trnF sequences of 76 species of Onobrychis. Bayesian interference, maximum parsimony and maximum likelihood analyses of nuclear ITS and plastid trnL–trnF DNA sequence data generated trees with strong posterior probability for two groups: Onobrychis subgen. Sisyrosema (including: Heliobrychis, Hymenobrychis, Afghanicae and Anthyllium sections) along with Laxiflorae section in Group I and Onobrychis subgen. Onobrychis (except Laxiflorae section) in the other (Group II). The Laxiflorae section roots back to the ancestral node for Sisyrosema subgen. O. viciifolia (cultivated species), which is closely associated with O. cyri var. cyri, suggesting that the latter may be a wild progenitor of O. viciifolia. The present study supported the paraphyly of subgenera Onobrychis and Sisyrosema. The study proposed the paraphyletic nature of the sections Onobrychis, Dendrobrychis, Heliobrychis and Hymenobrychis. Together with our molecular phylogenetic analyses we present a review of Onobrychis morphology and discuss and compare our results with those of earlier morphological and molecular phylogenetic analyses.



Phytotaxa ◽  
2017 ◽  
Vol 323 (1) ◽  
pp. 27 ◽  
Author(s):  
VLADIMIR E. FEDOSOV ◽  
ALINA V. FEDOROVA ◽  
ELENA A. IGNATOVA ◽  
MICHAEL S. IGNATOV

The genus Seligeria is revised based on morphological and DNA sequence data of nuclear ITS and chloroplastic trnL-F. Fifteen species from most infrageneric units of the genus are recovered in two well supported phylogenetic clusters that are also distinctive in morphology. The clade with the type species of the genus, S. pusilla, includes also S. donniana, S. brevifolia, S. calcarea, S. patula, S. tristichoides, S. trifaria, and S. oelandica. These species are characterized by short, cupulate or turbinate capsules widened towards the mouth, and the lack of a stem central strand. Another clade includes species with rather long, mainly ovate to cylindrical capsules and more or less developed stem central strand: S. campylopoda, S. recurvata, S. subimmersa, S. diversifolia, and S. polaris. These two clusters do not show sister relationships, but the second one appears more closely related to the Blindia clade. To resolve the apparent paraphyly, the latter phylogenetic group is segregated in a genus Blindiadelphus. In some aspects of morphology and ecology it is intermediate between Seligeria s. str. and Blindia, but differs from both genera in subquadrate upper leaf cells and thin- to moderately thick-walled rectangular exothecial cells. Molecular phylogenetic analyses revealed heterogeneity within the specimens previously referred to Blindiadelphus campylopodus, indicating a presence in Asian Russia of an undescribed species that is described here as Blindiadelphus sibiricus. It differs from B. campylopodus by the larger spores and typically rounded leaf apices. The isotype specimen of S. galinae appeared to be nearly identical to S. donniana in the sequences of ITS and trnL-F, and examination of morphology revealed no substantial differences between these species. Thus, we consider S. galinae as a synonym of S. donniana. The genus Blindiadelphus includes species of Seligeria subg. Blindiadelphus and S. subg. Cyrtoseligeria, which however are found intermingled in the molecular phylogenetic analysis. Thus the genus Blindiadelphus is accepted without any infrageneric taxa. The phylogenetic tree is congruent with the subdivision of the genus Seligeria s.str into subg. Seligeria, subg. Anodon, subg. Megalosporia and one newly established subgenus Robustidontia for S. brevifolia.



Phytotaxa ◽  
2016 ◽  
Vol 263 (2) ◽  
pp. 98 ◽  
Author(s):  
JULIA FERM ◽  
JESPER KÅREHED ◽  
BIRGITTA BREMER ◽  
SYLVAIN G. RAZAFIMANDIMBISON

The Malagasy genus Carphalea (Rubiaceae) consists of six species (C. angulata, C. cloiselii, C. kirondron, C. linearifolia, C. madagascariensis, C. pervilleana) of shrubs or small trees and is recognizable by a distinctly lobed calyx, 2(–4)-locular ovaries, each locule with several ovules on a rod-like stalk arising from the base of the locule, and indehiscent fruits. Carphalea linearifolia, rediscovered in 2010, has not previously been included in any Rubiaceae molecular phylogenetic studies. We re-investigated the monophyly of Carphalea using sequence data from chloroplast (rps16 and trnT-F) and nuclear (ITS and ETS) markers analysed with parsimony and Bayesian methods. Carphalea linearifolia forms a clade with C. cloiselii and the type species C. madagascariensis. This clade is sister to a clade consisting of the rest of the Carphalea species plus the genus Triainolepis. According to these results, the new genus Paracarphalea is here described to accommodate Carphalea angulata, C. kirondron, and C. pervilleana. The conservation status of Carphalea linearifolia is assessed as critically endangered according to IUCN criteria.



Phytotaxa ◽  
2021 ◽  
Vol 480 (1) ◽  
pp. 29-44
Author(s):  
GUO-CHENG ZHANG ◽  
HUA-FENG HONG ◽  
GE-HONG CHEN ◽  
SHU-GANG LU ◽  
YAN-FEN CHANG

The Hymenasplenium obliquissimum group contains the widespread H. obliquissimum and several geographically restricted species, including H. retusulum, H. wuliangshanense, H. latidens, H. changputungense, H. quercicola, H. szechuanense, H. furfuraceum, H. adiantifrons, and H. filipes. However, the taxonomy of this group is still unclear and needs to be revised because some entities were treated infraspecifically or as synonyms and the validation of some species still needs to be assessed. To formulate a natural classification and investigate the relationships in this group, we collected and studied specimens of species related to the H. obliquissimum group and obtained specimens of species described by Ching at their locus classicus in southwestern China. An integrative taxonomic approach was taken to delimit species in the group using cytological, morphological, and DNA sequence data. Specifically, in the phylogenetic analyses, the H. obliquissimum group was recovered as a monophyletic group, comprising five principal chloroplast lineages. Based on our inferences, we provided taxonomic implications of chloroplast lineages discovered in this study and suggested possible reticulate evolution in the H. obliquissimum group which was interpreted by the incongruence of chloroplast and nuclear phylogenies. Further studies to strengthen the taxonomic of taxa especially those with the co-existence of different ploidy levels are still warranted.



2020 ◽  
Author(s):  
Patrick J. Brownsey ◽  
Daniel J. Ohlsen ◽  
Lara D. Shepherd ◽  
Whitney L. M. Bouma ◽  
Erin L. May ◽  
...  

Five indigenous species of Pellaea in Australasia belong to section Platyloma. Their taxonomic history is outlined, morphological, cytological and genetic evidence for their recognition reviewed, and new morphological and chloroplast DNA-sequence data provided. Australian plants of P. falcata (R.Br.) Fée are diploid and have longer, narrower pinnae than do New Zealand plants previously referred to P. falcata, which are tetraploid. Evidence indicates that P. falcata does not occur in New Zealand, and that collections so-named are P. rotundifolia (G.Forst.) Hook. Chloroplast DNA sequences are uninformative in distinguishing Australian P. falcata from New Zealand P. rotundifolia, but show that Australian P. nana is distinct from both. Sequence data also show that Australian and New Zealand populations of P. calidirupium Brownsey & Lovis are closely related, and that Australian P. paradoxa (R.Br.) Hook. is distinct from other Australian species. Although P. falcata is diploid and P. rotundifolia tetraploid, P. calidirupium, P. nana (Hook.) Bostock and P. paradoxa each contain multiple ploidy levels. Diploid populations of Pellaea species are confined to Australia, and only tetraploids are known in New Zealand. Evolution of the group probably involved hybridisation, autoploidy, alloploidy, and possibly apomixis. Further investigation is required to resolve the status of populations from Mount Maroon, Queensland and the Kermadec Islands.



Phytotaxa ◽  
2018 ◽  
Vol 350 (1) ◽  
pp. 42 ◽  
Author(s):  
GALINA V. DEGTJAREVA ◽  
MICHAEL G. PIMENOV ◽  
TAHIR H. SAMIGULLIN

The systematic position of three Apiaceae-Apioideae taxa, Pinacantha porandica, Ladyginia bucharica and Peucedanum mogoltavicum, from Middle Asia and Afghanistan, is clarified based on nrITS DNA sequence data. In the molecular phylogenetic tree, the monotypic Pinacantha is placed in unresolved position within the Ferulinae. Although there is no morphological information on essential characters, we propose a new position of Pinacantha porandica within the genus Ferula. As a result a new combination Ferula porandica is proposed, with a new section Pinacantha to accommodate it. The attribution of Peucedanum mogoltavicum to Ferula has been confirmed, its correct name being Ferula lithophila. The genus Ladyginia should not be included in Ferula, its closest relatives being Mozaffariania and Glaucosciadium from the Glaucosciadium Clade.



2020 ◽  
Vol 190 (3) ◽  
pp. 1002-1019 ◽  
Author(s):  
Donald L J Quicke ◽  
Sergey A Belokobylskij ◽  
Yves Braet ◽  
Cornelis van Achterberg ◽  
Paul D N Hebert ◽  
...  

Abstract A new tribe of braconid wasps provisionally included in the Rhyssalinae, Laibaleini trib. nov., type genus Laibalea gen. nov. (type species Laibalea enigmatica sp. nov.), from Kenya and the Central African Republic, is described. A molecular dataset, with emphasis on basally derived taxa based on four gene fragments (28S D2–D3 expansion region, COI barcode, elongation factor 1-alpha and 16S ribosomal DNA), was analysed both alone and in combination with a morphological dataset. Molecular phylogenetic placement of the new species into an existing subfamily is complicated by the extreme sequence divergence of the three sequences obtained for Laibalea. In both the combined sequence analysis and the combined DNA plus morphological tree, Laibalea is recovered as a sister group to the Rhyssalinae plus all non-cyclostome lineage braconids excluding Mesostoinae, Maxfischeriinae and Aphidiinae. A consensus of morphological characters and molecular analyses suggests inclusion of Laibalea either in the otherwise principally Holarctic subfamily Rhyssalinae or perhap more basally, in the principally Gondwanan Mesostoinae s.l., although we cannot exclude the possibility that it might represent a separate basal lineage. We place Laibalea in its own tribe, provisionally included in Rhyssalinae. The DNA sequence data are presented for several genera for the first time. Avga, the type genus of Avgini, is shown not to belong to Mesostoinae s.l. or Hormiinae, but its exact relationships remain uncertain. The generic compositions of Rhyssalinae and Mesostoinae s.l. are revised. Anachyra, Apoavga, Neptihormius, Neoavga and Opiopterus are shown to belong to Mesostoinae s.s. A key to the tribes of Rhyssalinae is provided.



Phytotaxa ◽  
2017 ◽  
Vol 292 (3) ◽  
pp. 218 ◽  
Author(s):  
JING CAO ◽  
CHENGMING TIAN ◽  
YINGMEI LIANG ◽  
CHONGJUAN YOU

Two new rust species, Chrysomyxa diebuensis and C. zhuoniensis, on Picea asperata are recognized by morphological characters and DNA sequence data. A detailed description, illustrations, and discussion concerning morphologically similar and phylogenetically closely related species are provided for each species. From light and scanning electron microscopy observations C. diebuensis is characterized by the nailhead to peltate aeciospores, with separated stilt-like base. C. zhuoniensis differs from other known Chrysomyxa species in the annulate aeciospores with distinct longitudinal smooth cap at ends of spores, as well as with a broken, fissured edge. Analysis based on internal transcribed spacer region (ITS) partial gene sequences reveals that the two species cluster as a highly supported group in the phylogenetic trees. Correlations between the morphological and phylogenetic features are discussed. Illustrations and a detailed description are also provided for the aecia of C. succinea in China for the first time.



2004 ◽  
Vol 17 (2) ◽  
pp. 145 ◽  
Author(s):  
Randall L. Small ◽  
Richard C. Cronn ◽  
Jonathan F. Wendel

Molecular data have had a profound impact on the field of plant systematics, and the application of DNA-sequence data to phylogenetic problems is now routine. The majority of data used in plant molecular phylogenetic studies derives from chloroplast DNA and nuclear rDNA, while the use of low-copy nuclear genes has not been widely adopted. This is due, at least in part, to the greater difficulty of isolating and characterising low-copy nuclear genes relative to chloroplast and rDNA sequences that are readily amplified with universal primers. The higher level of sequence variation characteristic of low-copy nuclear genes, however, often compensates for the experimental effort required to obtain them. In this review, we briefly discuss the strengths and limitations of chloroplast and rDNA sequences, and then focus our attention on the use of low-copy nuclear sequences. Advantages of low-copy nuclear sequences include a higher rate of evolution than for organellar sequences, the potential to accumulate datasets from multiple unlinked loci, and bi-parental inheritance. Challenges intrinsic to the use of low-copy nuclear sequences include distinguishing orthologous loci from divergent paralogous loci in the same gene family, being mindful of the complications arising from concerted evolution or recombination among paralogous sequences, and the presence of intraspecific, intrapopulational and intraindividual polymorphism. Finally, we provide a detailed protocol for the isolation, characterisation and use of low-copy nuclear sequences for phylogenetic studies.



2005 ◽  
Vol 95 (6) ◽  
pp. 505-516 ◽  
Author(s):  
D. Navia ◽  
G.J. de Moraes ◽  
G. Roderick ◽  
M. Navajas

AbstractOver the past 30 years the coconut mite Aceria guerreronis Keifer has emerged as one of the most important pests of coconut and has recently spread to most coconut production areas worldwide. The mite has not been recorded in the Indo-Pacific region, the area of origin of coconut, suggesting that it has infested coconut only recently. To investigate the geographical origin, ancestral host associations, and colonization history of the mite, DNA sequence data from two mitochondrial and one nuclear region were obtained from samples of 29 populations from the Americas, Africa and the Indo-ocean region. Mitochondrial DNA 16S ribosomal sequences were most diverse in Brazil, which contained six of a total of seven haplotypes. A single haplotype was shared by non-American mites. Patterns of nuclear ribosomal internal transcribed spacer (ITS) variation were similar, again with the highest nucleotide diversity found in Brazil. These results suggest an American origin of the mite and lend evidence to a previous hypothesis that the original host of the mite is a non-coconut palm. In contrast to the diversity in the Americas, all samples from Africa and Asia were identical or very similar, consistent with the hypothesis that the mite invaded these regions recently from a common source. Although the invasion routes of this mite are still only partially reconstructed, the study rules out coconut as the ancestral host of A. guerreronis, thus prompting a reassessment of efforts using quarantine and biological control to check the spread of the pest.



Sign in / Sign up

Export Citation Format

Share Document