共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
Jyothi Sethuraman Shelly M. Rudski Kari Wosnitza Mohamed Hafez Brent Guppy Georg Hausner 《Fungal biology》2013,117(11-12):791-806
The mtDNA rnl-U7 region has been examined for the presence of introns in selected species of the genus Ceratocystis. Comparative sequence analysis identified group I and group II introns encoding single and double motif LAGLIDADG open reading frames (ORFs) at the following positions L1671, L1787, and L1923. In addition downstream of the rnl-U7 region group I introns were detected at positions L1971 and L2231, and a group II intron at L2059. A GIY-YIG type ORF was located within one mL1923 LAGLIDADG type ORF and a degenerated GIY-YIG ORF fused to a nad2 gene fragment was found in association with the mL1971 group I intron. The diversity of composite elements that appear to be sporadically distributed among closely related species of Ceratocystis illustrates the potential for homing endonucleases and their associated introns to invade new sites. Phylogenetic analysis showed that single motif LADGLIDADG ORFs related to the mL1923 ORFs have invaded the L1787 group II intron and the L1671 group I intron. Phylogenetic analysis of intron encoded single and double motif LAGLIDADG ORFs also showed that these ORFs transferred four times from group I into group II B1 type introns. 相似文献
3.
María S. Ferrucci 《Brittonia》2006,58(1):83-87
The new speciesUrvillea venezuelensis, from northwestern Venezuela, is described, illustrated, and compared to its putative closest relativeU. dasycarpa. Additionally micromorphological characters of pollen grains are described. The new species belongs toUrvillea sectionStenelytron, which is characterized by compressed fruit locules. 相似文献
4.
5.
Michael Mbenoun Michael J. Wingfield Aimé D. Begoude Boyogueno Brenda D. Wingfield Jolanda Roux 《Mycological Progress》2014,13(2):219-240
The emergence of wattle wilt disease on non-native Acacia mearnsii trees in Africa, caused by the indigenous fungus Ceratocystis albifundus, has highlighted a need to better understand the diversity, ecology and distribution of Ceratocystis species in natural African environments. In this study we applied phylogenetic inference to identify and characterize isolates of Ceratocystis collected in a natural savanna ecosystem in South Africa. Three new species were recognized and are described as C. cryptoformis sp. nov. in the C. moniliformis complex, as well as C. thulamelensis sp. nov. and C. zambeziensis sp. nov., both residing in the C. fimbriata complex. Incorporating the new species into global phylogenies of Ceratocystis provided insights into the patterns of evolution and biogeography of this group of fungi. Notably, the African continent was identified as an important centre of diversification of Ceratocystis spp., from which several lineages of these fungi were shown to have radiated. 相似文献
6.
M. Tarigan J. Roux M. Van WykB. Tjahjono M.J. Wingfield 《South African Journal of Botany》2011,77(2):292-304
Species of Ceratocystis are well-known wound related pathogens of many tree species, including commercially planted Acacia spp. Recently, several Ceratocystis isolates were collected from wilting A. mangium in plantations in Indonesia. The aim of this study was to identify these Ceratocystis isolates and to investigate their ability to cause disease on two plantation-grown Acacia spp. using greenhouse and field inoculation experiments. For identification, morphological characteristics and comparisons of DNA sequence data for the ITS, β-tubulin and TEF 1-α gene regions, was used. Ceratocystis isolates were identified as C. manginecans, a serious pathogen of mango trees in Oman and Pakistan and a previously undescribed species, described here as C. acaciivora sp. nov. Both fungi produced significant lesions in inoculation experiments on A. mangium and A. crassicarpa, however, C. acaciivora was most pathogenic suggesting that this fungus is the primary cause of the death of trees under natural conditions. 相似文献
7.
Ali Sonboli Shahrokh Kazempour Osaloo Joan Vall��s Christoph Oberprieler 《Plant Systematics and Evolution》2011,292(1-2):85-93
In order to evaluate the phylogenetic relationships and taxonomic classification of the Iranian endemic Tanacetum paradoxum Bornm. (Asteraceae, Anthemideae), a molecular analysis based on nrDNA ITS sequences of 16 species of Tanacetum together with representatives of 27 genera of subtribes Artemisiinae and Handeliinae as well as a micromorphological study of achenes and pollen grains was performed. The chromosome number of 2n?=?2x?=?16 and the genome size of T. paradoxum (2C?=?8.81?±?0.19?pg) are reported here for the first time. Due to the well-supported close phylogenetic relationship of T.?paradoxum to the species of the genus Artemisia (Bayesian inference, posterior probability PP?=?1), which is supported by cytological (x?=?8) and micromorphological features concerning the achene shape and pollen type, the combination Artemisia paradoxa (Bornm.) Sonboli is proposed. 相似文献
8.
Grady L. Webster 《Brittonia》1989,41(1):1-9
Dalechampia fernandesii, from Ceará, belongs to sectionTiliifoliae and is related toD. affinis andD. tiliifolia.Dalechampia armbrusteri, of subsectionDalechampia, from Bahia, is close toD. brownsbergensis of Suriname but has well developed resiniferous bractlets.Dalechampia viridissima, from Bahia and Espírito Santo, is an isolated species with the 3-lobed leaves of species in sectionDalechampia subsectionDalechampia but the reduced indumentum and greenish bracts of species in sectionTriphyllae. 相似文献
9.
The desirability is discussed of a subdivision of the genusCeratocystis into a group characterized by the presence of a phialidic conidial state, and a group in which the conidia are usually produced exogenously. Corroborative evidence for this arrangement is found in the carbohydrate constitution of the cells: in all examined species of the former group (Ceratocystis s.str.) rhamnose and cellulose are absent, whereas in the latter both components are present (Ophiostoma H. et P. Sydow). 相似文献
10.
Loran C. Anderson 《Brittonia》1983,35(1):23-27
Chrysothamnus eremobius, endemic to mountains of southern Nevada, is formally described and illustrated. Morphological and anatomical comparisons are made to related taxa. The new species has many features likePetradoria discoidea (=C. gramineus). Although it bears some similarity toC. depressus andC. vaseyi of sectionPulchelli, C. eremobius is better placed in sectionChrysothamnus nearC. viscidiflorus. 相似文献
11.
W. Scott Armbruster 《Brittonia》1989,41(1):44-52
Three new species ofDalechampia are described from the Guayanan region of Venezuela.Dalechampia attenuistylus belongs to sectionRhopalostylis and may be most closely related toD. parvibracteata Lanj.Dalechampia megacarpa belongs to sectionDioscoreifoliae, although it is not especially close to any species in the section.Dalechampia papillistigma is also an isolated member of sectionDioscoreifolieae. 相似文献
12.
As part of our ongoing phylogenetic study of genusHypericum, nuclear ribosomal DNA internal transcribed spacer sequences were analyzed for 36 species ofHypericum as ingroup and two species ofThornea as outgroup. This sampling included most of the previously described species from both Korea and Japan. The ITS phylogeny
suggested that the surveyedHypericum species belong to a monophyletic section,Trigynobrathys, and a polyphyletic section,Hypericum. In addition, two monotypic sections,Sampsonia andRoscyna, were identified. Members of sectionHypericum occur in four different lineages worldwide, which imply at least four independent origins. The Korean and Japanese species
of sectionHypericum form a monophyletic group, except forH. vulcanicum. Instead, that particular species belongs to a distinct monophyletic group withH. scoreri andH. formosa from other geographic areas, and is a sister to sectionTrigynobrathys. The Korean and Japanese species of sectionTrigynobrathys show a monophyletic origin.H. sampsonii is now recognized as a distinct section rather than being a member of sectionsHypericum orDrosocarpium, as had been indicated previously. Our results differ somewhat from those of recent morphological and cytological studies.
The phylogenetic relationships among Korean and Japanese species have now been mostly resolved via ITS phylogeny. 相似文献
13.
John Olsen 《Brittonia》1986,38(4):362-368
A revisionary treatment of the insular CaribbeanVerbesina sectionVerbesina (formerly sectionHamulium) is provided. Four taxa (three species and one variety) are recognized. 相似文献
14.
15.
Described from the Planalto of Brazil are:Calea quadrifolia, C. heteropappa, andC. abbreviata of sectionMeyeria,C. intermedia of sectionLemmatium, andC. lutea of sectionCalea. The relationships of each are discussed and a key to the nearest relatives of each is provided. Additionally, all butC. intermedia are illustrated. 相似文献
16.
Timothy A. Dickinson Svenja Belaoussoff Rhoda M. Love M. Muniyamma 《Folia Geobotanica》1996,31(3):355-371
Differences in the numbers of stamens and styles per flower are conspicuous features of variation in North American hawthorns (Crataegus L.). Variation in stamen number between individuals is discontinuous, with modes of approximately 20 and 10 (or fewer). In North American black-fruited sectionDouglasii Loudon the 10-stamen morphotype is exclusively polyploid, whereas the 20-stamen morphotype comprises both diploids and polyploids. Polyploidy is associated with apospory, self-fertility, and varying degrees of pollen sterility. Variation in stamen number may also be correlated with variation in distribution, phenology, leaf shape, and other features of floral morphology, leading to recognition of taxa at the specific or infraspecific level. Comparable variation in stamen number is virtually unknown in Eurasian hawthorns, as in the majority of flowering plants. In sectionDouglasii stamen number morphotypes have been recognized as either varieties or species; although correlations between stamen number and other features are not as straightforward as was previously surmised, the higher rank appears to be appropriate. These data on breeding system and morphological variation may be explainable in terms of hypotheses linking gametophytic apomixis, polyploidization, and optimal strategies for pollen dispersal. 相似文献
17.
Penstemon ammophilus, an endemic to Canaan Moutain in Washington Co., Utah, is described and illustrated. On the basis of anther characteristics it is placed in sectionGlabri, seriesVirgati, where it nearly links the group to sectionCristati. It is distinct from all the species of both sections with its peculiar papillose-glandular pubescence. 相似文献
18.
Mikio Ono 《Journal of plant research》1977,90(4):313-316
The observed chromosome numbers for four deciduous species of South AmericanNothofagus (Sect.Nothofagus) are 2n=26. This chromosome count is the first report on the South American species of the genus, and is the same number as reported for the New Zealand counterparts of the evergreen sectionCalusparassus. Furthermore, a significant difference between the karyotypes of two subsections within the Sect.Nothofagus has been recognized. 相似文献
19.
A noteworthy wild lupine accession was recently discovered in southwestern Turkey and was proposed as a new separate Old World “smooth-seeded” species close toL. micranthus and namedL. anatolicus. Its species status was controversial with respect to cytological and crossability data. In order to examine the position and the evolutionary relationships of this Anatolian accession relative to the Old World lupines, we investigated new data from seed coat micromorphology, and from internal transcribed spacer (ITS) nucleotide sequences of the nuclear ribosomal DNA repeat. The micromorphological seed coat pattern ofL. anatolicus, as revealed by scanning electron microscopy, is characterized by pluricellular tubercles, which represent the typical and unique pattern of the Old World “rough-seeded” lupines (sect.Scabrispermae). In accordance with the micromorphological results, the genetic distances and phylogenetic relationships among the Old World lupines, estimated from ITS data, unambiguously support the new Anatolian lupine accession as part of theL. pilosus-L. palaestinus lineage within the strongly monophyletic group containing all theScabrispermae. The results provided in this study, together with other lines of data available from the literature, are thus hardly compatible with the hypothesis that this new Anatolian lupine accession could be related to Old World “smooth-seeded” lupines (includingL. micranthus); instead, it appears closely related toL. pilosus. 相似文献
20.
Kerry Barringer 《Brittonia》1985,37(3):286-290
Elleanthus stolonifer andE. tillandsioides are new species in theE. poiformis complex of sectionChloidelyna.Elleanthus lentii is a new species in sectionStachydelyna. Elleanthus stolonifer is widespread in the mountains of Costa Rica and Panama;E. tillandsioides is found only in the lowland forests of southeastern Costa Rica;E. lentii is limited to the Cordillera de Guanacaste of Costa Rica. 相似文献