利用叶绿体DNA trnL-F序列初步探讨菊科风毛菊属的系统发育

风毛菊属Saussurea DC.是菊科物种分化十分剧烈和分类处理十分困难的一个属。该属的单系起源性质、属下分类系统以及一些独特形态物种的系统位置尚不清楚,有待进一步验证。本文测定了代表该属5个亚属37种植物43个样品和川木香属Dolomiaea DC.的１种样品的叶绿体DNA trnL-F序列,并调取菜蓟族Cardueae Cass.与风毛菊属具有一定亲缘关系的13属的该序列,一起进行了分支分析,重点验证该属的属下形态分类系统以及形态特殊、青藏高原地区特有的雪兔子亚属subgen. Eriocoryne     

A preliminary investigation on the phylogeny of Saussurea (Asteraceae: Cardueae) based on chloroplast DNA trnL-F sequences

Saussurea DC., a highly diversified genus with about 400 species in the Asteraceae, has been an extremely difficult group in both taxonomical and phylogenetic studies. The monophyletic origin, infrageneric classification and systematic positions of some s     

The natural delimitation ofCentaurea (Asteraceae: Cardueae): ITS sequence analysis of theCentaurea jacea group

Taxonomic complexity has hindered partitioning the genusCentaurea into natural subdivisions, even though it has long been recognized as an unwieldy, artificial assemblage. Most of the remaining difficulties center in theCentaurea jacea group, whose taxa share a common advanced type of pollen. Because it comprises half the species of the genusCentaurea, as well as five other disputed genera previously segregated fromCentaurea (Chartolepis, Cheirolepis, Cnicus, Grossheimia andTomanthea), theCentaurea jacea group is a significant taxonomic challenge. Newer molecular approaches are useful for resolving complex relationships because they provide more precise inferences of evolutionary relationships than traditional morphological characters. Sequences of the Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA were analyzed for a comprehensive sample of this group. Results indicated that theCentaurea jacea group is monophyletic and includes the segregated genera, but not two other genera (Oligochaeta andZoegea), whose inclusion in theCentaurea jacea group was doubtful. In addition to pollen morphology, the ITS phylogeny is also supported by karyological evidence and by good correlation with biogeographic distribution of the species. The monophyly of theCentaurea jacea group suggests that a natural delimitation ofCentaurea that minimizes nomenclatural changes is possible, but only if a new type of the genus is designated.     

Comparison of chloroplast and nuclear phylogeny in the autogamous annualMicroseris douglasii (Asteraceae: Lactuceae)

Morphology suggests that the Californian annualMicroseris douglasii is a monophyletic sister group to the other three diploid annuals ofMicroseris. Phylogenetic analysis of 44 inbred strains ofM. douglasii derived from 23 populations with 72 RAPD markers in the nuclear DNA strongly supports this phylogeny. However, 13 chloroplast RFLPs divideM. douglasii into four distinct groups. Two of these each share one or more cpRFLPs withM. bigelovii andM. pygmaea. Several hypotheses can explain the incongruence between nuclear and chloroplast phylogeny: (1) random sorting out of chloroplasts during phylogeny from a polymorphic pool, (2) cytoplasmic introgression from the related annualM. bigelovii intoM. douglasii after hybridization followed by elimination of theM. bigelovii nuclear genome. We suggest cytoplasmic introgression as the most likely origin. Possible remnants of nuclear introgression have been found in two populations ofM. douglasii that are polymorphic for chloroplast types. In these populationsM. bigelovii type chloroplast DNA seems to be accompanied by nuclear genes for flower color and leaf shape.     

Molecular phylogeny ofIva (Asteraceae,Heliantheae) based on chloroplast DNA restriction site variation

Iva s.str. (comprising ten species) was examined by cpDNA restriction site variation to determine phyletic relationships within the group. The results were compared with relationships proposed from other data. A total of 86 restriction site mutations was detected, 47 of which proved phylogenetically informative. A single most parsimonious tree was obtained using both Wagner and Dollo parsimony. The tree revealed three main lineages that are congruent with the three chromosome lineages (base numbers of x = 16, 17, 18). The monophyly of the x = 16 and 18 groups was supported strongly by molecular data, while the monophyly of x = 17 lineage was only supported moderately. Relationships among the three lineages indicate that the sect.Iva is paraphyletic because sect.Linearbractea is nested within it. Both morphological data and the secondary chemical data are in agreement with the proposed cpDNA phylogeny. Because of this agreement, sect.Iva is revised such that,I. axillaris was excluded and positioned within the newly proposed sect.Rhizoma. Patterns and rates of cpDNA evolution were also examined. The results indicated an uneven evolution in the chloroplast genome with different rates of cpDNA evolution in at least a few species ofIva. However, the evolutionary clock hypothesis can not be rejected within most of the lineages inIva.     

Generic delimitation and phylogeny of theCarduncellus-Carthamus complex (Asteraceae) based on ITS sequences

Within the Mediterranean complexCarduncellus-Carthamus, taxonomic classification has proven problematic. Numerous attempts to clarify the relative systematic boundaries have included splittingCarduncellus andCarthamus into several genera, but none of these proposed classifications have been generally accepted. For a comprehensive resolution of the relationships within this group, we used sequences of the Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA. The results indicate that the complex should be classified into four genera:Carduncellus, Carthamus, Femeniasia andPhonus. The relationship between the western group (Carduncellus, Femeniasia andPhonus) and the eastern genusCarthamus are not resolved by analysis of ITS sequences, but the two groups are probably not close relatives. The ITS classifications corresponded with biogeography and less with morphological characters, which have also been the main source of confusion in traditional classifications. Most of the unusual morphological features in theCarduncellus-Carthamus complex appear to be reversals to ancestral character states.     

Phylogenetics and taxonomic delimitation of the genus Guizotia (Asteraceae) based on sequences derived from various chloroplast DNA regions

Parsimony-based phylogenetic analyses of the genus Guizotia were undertaken based on DNA sequence data from the following chloroplast DNA (cpDNA) regions: trnT-trnL, trnL-trnF, trnY-rpoB, trnC-petN, psbM-trnD and rps16-trnQ intergenic spacers, trnL, rps16 and matK-5′trnK introns and matK gene. Out of the 26 primers used in this study, 14 were newly designed. The study was conducted to determine (1) the closest relative of Guizotia abyssinica, (2) the taxonomic status of some Guizotia taxa and (3) the subtribal placement of Guizotia in the tribe Heliantheae. The analyses of the sequence data showed that G. abyssinica, G. scabra ssp. scabra, G. scabra ssp. schimperi and G. villosa are phylogenetically closely related. However, G. scabra ssp. schimperi appeared as the most closely related taxon to G. abyssinica. Based on this phylogenetic analysis, we suggest that the two subspecies of G. scabra are better treated as separate species. The analysis also clearly demonstrated that “Chelelu” and “Ketcha” are distinct Guizotia species. The trnT-trnL and trnL-trnF intergenic spacer-based phylogenetic analysis of various subtribes of the tribe Heliantheae strongly supports the placement of the genus Guizotia within the subtribe Milleriinae.     

Molecular phylogeny ofCheirolophus (Asteraceae:Cardueae-Centaureinae) based on ITS sequences of nuclear ribosomal DNA

The genusCheirolophus has an interesting western Mediterranean and Macaronesian distribution. Here we investigate the delimitation of the genus and its exclusion from the large genusCentaurea, the systematic position of the related genusPaleocyanus, the delimitation of some species and the phylogeny of the group. We have carried out a phylogenetic analysis of the PCR-generated sequences of the internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA. The results suggest that the genus, includingPaleocyanus crassifolius is monophyletic; thus, a new combination of this species underCheirolophus is proposed. The Macaronesian group of species is also monophyletic, indicating a single colonization of the archipelago. The poor resolution of microspecies in the Macaronesian group reinforces the hypothesis of a very recent differentiation of the group.     

Preliminary phylogeny of Valerianaceae (Dipsacales) inferred from nuclear and chloroplast DNA sequence data

Valerianaceae is a relatively small (ca. 350 species), but morphologically diverse angiosperm clade. Sequence data from the entire ndhF gene, the trnL-F intergenic spacer region, the trnL intron, the matK region, the rbcL-atpB intergenic spacer region and internal transcribed spacer (ITS) region of nuclear ribosomal DNA were collected for 21 taxa within Dipsacaceae and Valerianaceae (1 and 20, respectively). These data were included in several phylogenetic analyses with previously published sequences from Dipsacales. Results from these analyses (maximum parsimony, maximum likelihood, and Bayesian analysis) are in strong agreement with many of the conclusions from previous studies, most importantly: (1) Valerianaceae is sister to Dipsacaceae; (2) Triplostegia is more closely related to species of Dipsacaceae than to Valerianaceae; and (3) Valeriana appears not to be monophyletic, with Valeriana celtica falling outside the remainder of the species of Valeriana sampled here (with very strong support). With the exception of V. celtica, these data support two major clades within Valeriana; one that is exclusively New World and another that is distributed in both the Old and New World. Although the species of Valerianaceae and its sister group Dipsacaceae plus Triplostegia, are widely distributed in the Northern Hemisphere, and the data imply that Valerianaceae diversified initially in Asia (the Himalayan Patrinia and Nardostachys falling at the base of the clade), the center of modern species diversity for the group is in the Andes of South America with as many as 175 species restricted to that region. Although the exclusively South American taxa form a clade in the chloroplast and combined ITS and chloroplast analyses, support values tend to be low. Future studies will need to include additional data, in the form of both characters and taxa, before any strong conclusions about the character evolution, diversification, and biogeography of the South American valerians can be made.     

A phylogeny of all species of Arceuthobium (Viscaceae) using nuclear and chloroplast DNA sequences

The genus Arceuthobium (dwarf mistletoes, Viscaceae) comprises 42 species that parasitize hosts in Pinaceae and Cupressaceae in the Old and New Worlds. Maximum parsimony analyses were conducted on two data partitions (separately and combined): nuclear ribosomal internal transcribed spacer (ITS) sequences for all 42 currently recognized species and chloroplast trnT-L-F sequences for 34 New World species. The Old and New World species were phylogenetically distinct using ITS, thus making subgenus Arceuthobium paraphyletic. Arceuthobium pendens and A. guatemalense comprise the basalmost clade of subgenus Vaginata, characterized by the presence of flabellate secondary branching. The trnT-L-F sequences, which vary widely in length depending upon taxon, contain three times less phylogenetic signal than ITS, although homoplasy for this partition is lower. Several of the clades obtained from analysis of nuclear ITS sequences are also recovered using trnT-L-F sequences such as A. guatemalense and A. pendens, the A. rubrum group, the A. vaginatum group, and the A. campylopodum group. The ITS + trnT-L-F tree is well resolved except for four internal nodes. A revised classification of the genus is discussed that recognizes only monophyletic species that are well differentiated by molecular data.     

A new species of Centaurea L. (Cardueae: Asteraceae) from Turkey

A new species of Centaurea L., C. kizildaghensis (Cardueae: Asteraceae), is described and illustrated from south Anatolia. It is restricted to the serpentine rocky slopes of Kızıl Dağ (C3 Konya–Derebucak, Çamlık), and is closely related to C. pseudokotschyi Wagenitz and C. drabifolioides Hub.-Mor., from which it differs in stem, leaf, and phyllary appendage characters. The diagnostic morphological characters are discussed. A new key is produced for Group G species for the flora of Turkey.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 61–66.     

Wax plants disentangled: a phylogeny of Hoya (Marsdenieae, Apocynaceae) inferred from nuclear and chloroplast DNA sequences

Hoya (Marsdenieae, Apocynaceae) includes at least 200 species distributed from India to the Pacific Islands. We here infer major species groups in the genus based on combined sequences from the chloroplast atpB-rbcL spacer, the trnL region, and nuclear ribosomal DNA ITS region for 42 taxa of Hoya and close relatives. To assess levels of ITS polymorphism, ITS sequences for a third of the accessions were obtained by cloning. Most ITS clones grouped by species, indicating that speciation in Hoya usually predates ITS duplication. One ITS sequence of H. carnosa, however, grouped with a sequence of the morphologically similar H. pubicalyx, pointing to recent hybridization or the persistence of paralogous copies through a speciation event. The topology resulting from the combined chloroplast and nuclear data recovers some morphology-based sections, such as Acanthostemma and Eriostemma, as well as a well-supported Australian/New Guinean clade. The combined data also suggest that morphological adaptations for ant-symbiosis evolved at least three times within Hoya.     

Phylogenetic reconstruction of the genus Triptilion (Asteraceae,Nassauvieae) based on nuclear and chloroplast DNA sequences

The genus Triptilion is endemic to central Chile, the Mendoza Province and western Patagonia in Argentina. It is currently composed of seven species: T. achilleae, T. benaventii, T. berteroi, T. capillatum, T. cordifolium, T. gibbosum, and T. spinosum. The main objectives of this paper were to determine the phylogenetic relationships of species of Triptilion. We also traced the evolution of annual and perennial life-forms. Historically a close relationship has been described between genera Triptilion and Nassauvia. Phylogenetic analysis of the genus Triptilion and more closely related genera was undertaken using two nuclear (ITS, ETS) and two chloroplast (trnL-F, rpl32-trnL) markers. The topology of the Bayesian inference tree shows that the genus Triptilion is paraphyletic, because Nassauvia lagascae, the only representative of Nassauvia section Caloptilium grouped with T. achilleae, Clade I. The other species of Triptilion form two clades: Clade II composed of T. cordifolium and T. gibbosum and Clade III that includes T. benaventii, T. berteroi, T. capillatum, and T. spinosum. The genus Triptilion originated and diverged during the Miocene. The results of the life history reconstructions indicate that the common ancestor of Triptilion and Nassauvia was perennial. The annual habit appears to be derived in Triptilion. The life-form of the common ancestor of Triptilion was ambiguous; it may have been annual or perennial.     

A phylogeny of Porella (Porellaceae, Jungermanniopsida) based on nuclear and chloroplast DNA sequences

The cosmopolitan family Porellaceae includes about 60 species in two or three genera: the large genus Porella and the monospecific Ascidiota and Macvicaria (alternatively Porella subg. Macvicaria). Maximum parsimony, maximum likelihood and Bayesian inference of phylogeny of a dataset including three markers (rbcL, trnL-trnF region of cp DNA, nrITS region) of 96 accessions resulted in similar topologies supporting the generic status of Ascidiota. Macvicaria is nested in a subclade of Porella. Relationships among species of Porella are in general well resolved and many terminal nodes achieve good statistical support whereas basal relationships are at best moderately supported. Multiple accessions of single species are usually placed in monophyletic lineages. Accessions of P. platyphylla split into a European and a North American clade with one accession from North America embedded within the European samples. The Macaronesian endemic P. inaequalis is closely related to the Asian species P. grandiloba. Porella obtusata and P. canariensis cannot be separated on the basis of the sequence data presented in this study. The molecular topologies indicate a range extension of the Asian P. gracillima subsp. urogea to Eastern North America and of the Neotropical P. swartziana to South Africa. Current supraspecific classifications of Porella are not reflected in the molecular topologies with a correlation between genetic variation and the geographical distribution of the related accessions rather than a correlation between genetic variation and morphology.     

Evidence from chloroplast DNA restriction site analysis on the relationships of Scalesia (Asteraceae: Heliantheae)

Chloroplast DNA restriction site variation provided data with which to compare the Galápagos Island endemic Scalesia to potential sister groups within subtribe Helianthinae. Pappobolus is suggested by these data to be the most likely sister group to Scalesia. It is an Andean endemic genus that includes the South American species once regarded as a subgenus of Helianthus and later assigned to Helianthopsis. Two other groups considered as potential sister groups based on their geographic distribution in South America were not placed near Scalesia in the most parsimonious tree. Viguiera sect. Diplostichis appears to be relatively basal within subtribe Helianthinae, and the South American species of Viguiera, although previously classified in more than one subgenus, appear to form a single, monophyletic group that is not the sister group to Scalesia. The minimum of ten restriction site differences between Scalesia and Pappobolus of approximately 525 sites surveyed yielded an estimated sequence divergence of 0.19%, and an estimated time of divergence of approximately 1.9–6.2 million years.     

Phylogenetic analysis of Helianthus (Asteraceae) based on chloroplast DNA restriction site data

 Chloroplast DNA (cpDNA) restriction site data were used to analyze phylogenetic relationships within Helianthus. Data from new samples were consistent with previous results and showed the genus to be a well-defined (11 site changes) lineage within subtribe Helianthinae. The affinities of 2 species, Viguiera similis and V. phenax (V. ludens) that have sometimes been included in Helianthus were shown to lie outside the genus. The two species of Phoebanthus, however, formed a phylogenetic ingroup to the perennial Helianthus. Within the genus, cpDNA data indicated that there are four distinct phylogenetic lineages. Two of the lineages each contained a single, annual species (H. agrestis and H. porteri, respectively). The remaining annual species collectively formed a third lineage (sect. Helianthus). The fourth lineage contained all of the perennial species, including those of Phoebanthus. Within the perennial lineage, there was little variation in restriction site characters. The 3 species of series Pumili formed a paraphyletic group at the base of the perennial lineage, and the 3 species of series Ciliares formed a group that was supported by a single restriction site character. Received: 2 September 1996 / Accepted: 25 October 1996     

A first approach to the molecular phylogeny of the genusEchinops (Asteraceae): Sectional delimitation and relationships with the genusAcantholepis

A first attempt to establish the phylogeny of the generaEchinops andAcantholepis has been carried out using the analysis of the internal transcribed spacers (ITS) sequences of the nuclear ribosomal DNA including 30Echinops species and the only species of the monotypicAcantholepis. The results of this analysis are discussed in the light of morphological and cytogenetic characters. The genusAcantholepis is placed in a robust clade withEchinops nanus, and together they appear in a basal position to other members ofEchinops. The ITS phylogeny and several other characters, such as chromosome number and nuclear DNA amount, do not agree with the sections currently recognized withinEchinops. Some groups are defined in the present approach, but further studies are necessary to reach a complete, stable and natural infrageneric classification of this genus.