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1.
A pea rust fungus, Uromyces viciae-fabae, has been classified into two varieties, var. viciae-fabae and var. orobi, based on differences in urediniospore wall thickness and putative host specificity in Japan. In principal component analyses, morphological features of urediniospores and teliospores of 94 rust specimens from Vicia, Lathyrus, and Pisum did not show definite host-specific morphological groups. In molecular analyses, 23 Uromyces specimens from Vicia, Lathyrus, and Pisum formed a single genetic clade based on D1/D2 and ITS regions. Four isolates of U. viciae-fabae from V. cracca and V. unijuga could infect and sporulate on P. sativum. These results suggest that U. viciae-fabae populations on different host plants are not biologically differentiated into groups that can be recognized as varieties.Contribution no. 184, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan  相似文献   

2.
The sap-sucking mirid, Falconia intermedia (Distant) (Hemiptera: Miridae), released as a biological control agent of Lantana camara L. (Verbenaceae) in South Africa in 1999, has established at only one site. We investigated the role of induced plant defences as a possible explanation for this lack of establishment. F. intermedia inoculated plants from the five test varieties significantly increased the toughness of their new leaves compared to control plants. Additionally, plants from three L. camara varieties significantly increased leaf trichome density on new leaves after prolonged feeding by F. intermedia, significantly reducing F. intermedia oviposition, survival and feeding damage. The defensive responses were systemic and rapidly induced about eight weeks after insect feeding. We suggest that these leaf quality responses played a role in the non-establishment of F. intermedia in South Africa.  相似文献   

3.
The significance of the taxonomic distinction of two species of Blackbutt was studied by analysing patterns of genetic (microsatellite markers; n = 13) and phenetic (capsule morphology) differentiation. Analysis of genetic structure using a Bayesian modelling approach on range-wide samples of both taxa (n = 457) showed the major division was within the more widely distributed species, Eucalyptus pilularis, and not aligned with taxonomy. Comparisons of intra- and inter-taxon genetic differentiation in paired-samples of taxa from each of four locations spanning the distribution of the more restricted E. pyrocarpa, showed that around twice as much variation was found among locations within taxa, than between taxa. Despite the lack of differentiation at effectively neutral microsatellite markers, significant phenetic differences (including capsule size) were evident between taxa at most sites. A landscape mosaic of taxa, coincident with changes in elevation, vegetation and soil types, suggested some phenetic differences were probably adaptive and spatial differentiation was stabilised by environmental factors. An absence of morphological intermediates and a lack of correlation in the rankings of locus inter-taxon differentiation (PhiBT) across locations, was consistent with parapatric origins for E. pyrocarpa. We conclude the taxa are at the lower end of the speciation spectrum and might best be viewed as ecotypes, divergent in evolutionary potential, but with genomes broadly permeable to inter-taxa gene flow. Gene exchange between plantings of E. pilularis and nearby E. pyrocarpa forest is likely as the two taxa appear to have few barriers to reproduction.  相似文献   

4.
The genetic diversity and evolutionary divergence in Liquidambar species and Liquidambar orientalis varieties were compared with respect to the matK gene. A total of 66 genotypes from 18 different populations were sampled in southwestern Turkey. The matK region, which is about 1,512 bp in length, was sequenced and studied. L. orientalis, L. styraciflua, and L. formosana had similar magnitude of nucleotide diversity, while L. styraciflua and L. acalycina possessed higher evolutionary divergence. The highest evolutionary divergence was found between L. styraciflua and eastern Asian Liquidambar species (0.0102). However, the evolutionary divergence between L. orientalis and other species was of a similar magnitude. The maximum-parsimony phylogenetic tree showed that L. styraciflua and L. orientalis formed a closer clade while East Asian species were in a separate clade. This suggests that the North Atlantic Land Bridge through southern Greenland may have facilitated continuous distribution of Liquidambar species from southeastern Europe to eastern North America in early Tertiary period. The maximum-parsimony tree with only 18 Oriental sweetgum populations indicated that there were two main clusters: one with mainly L. orientalis var. integriloba and the other with var. orientalis and undetermined populations. High nucleotide diversity (0.0028) and divergence (0.00072) were found in L. orientalis var. integriloba populations and Muğla-1 geographical region. This region could be considered as the major refugium and genetic diversity center for the species. The low genetic diversity and divergence at intraspecies level suggest that L. orientalis populations in Turkey share an ancestral polymorphism from which two varieties may have evolved.  相似文献   

5.
Four species of the genus Berberis L. have been reported from different regions, including Khorassan provinces. In this article, a revision of this genus in Khorassan provinces is presented. For better validation of the results, morphological, palynological, chromosomal and molecular studies were conducted on specimens collected from Khorassan provinces and preserved in FUMH and TARI herbaria. Morphological study resulted in recognition of three species of Berberis, from which two species are new records for Khorassan. Four unknown new taxa with new morphological characters were also identified, but left for further analysis because of the high percentage of polyploidy and hybridization in this genus. In order to analyze morphological data, 35 OTUs were provided and scored using the distance method and PCoA. The shape and size of pollen grains were nearly equal in the examined taxa, and there were no obvious differences between them. Chromosomal examination indicated tetraploidy (2n = 4x = 56) in all of the studied taxa. Molecular studies were accomplished by RAPD and sequencing of the ITS region to construct a framework of relationships between the taxa. Molecular studies emphasized the difference in the four unknown taxa from others. The total evidence indicates that Berberis L. shows a high percentage of polyploidy and hybridization.  相似文献   

6.
Lantana camara L. (Verbenaceae) is a weed of major importance in South Africa. It invades indigenous forests and veld, valuable commercial and agricultural forests, plantations and orchards, as well as river-catchment areas. Several natural enemies, including insect and pathogen species, have been released in South Africa, some of which established successfully. These do not exert sufficient control and additional natural enemies are required. Leptostales ignifera Warren (Lepidoptera: Geometridae), one of several new species being investigated as potential biocontrol agents, was collected in the subtropical parts of Florida, USA and Mexico. Host specificity trials indicated L. camara to be the preferred host plant of this quick-developing, voracious leaf-feeder, with some of the African indigenous Lippia species qualifying as very marginal hosts. The possible preference that L. ignifera might have for different South African naturalized L. camara varieties was studied during quarantine laboratory preference trials. Variety 029WP was the most suitable host for L. ignifera, although the other four tested varieties were able to support viable populations of the insect. Not taking other abiotic and biotic factors such as climate and predation into consideration, once released, L. ignifera should be able to establish on all five of the tested varieties in the field and contribute to the biological control of the complex of L. camara as a whole. Based on the above studies, permission has been granted for the release of L. ignifera in South Africa.  相似文献   

7.
The aim of this work was to determine the cytogenetic characteristics of Brazilian Lippia alba (Mill) N. E. Brown and Lantana camara Plum. that could be useful for future characterization of these genera. Our analyses revealed that Li. alba has 2n=30 chromosomes consisting of ten metacentric and five submetacentric pairs, while La. camara has 44 metacentric chromosomes. The large blocks of heterochromatin seen in both species suggest an apomorphic condition. Six 45S rDNA sites were detected in both species by fluorescence in situ hybridization (FISH). Two and four 5S rDNA sites were observed in Li. alba and La. camara, respectively. Meiotic analysis revealed a normal chromosomal behaviour. The number of chromosomes and the presence of 45S rDNA and 5S rDNA sites do not exclude a possible polyploid origin. The cytogenetic differences between La. camara and Li. alba may be useful markers for differentiating these species.  相似文献   

8.
Petra Hoffmann 《Brittonia》2008,60(2):136-166
Heterosavia (Phyllanthaceae) is segregated from Savia (tribe Bridelieae), recognized at generic rank, and placed in tribe Phyllantheae. Floral, fruit, leaf anatomical, leaf venation, and pollen characters of the neotropical taxa previously united as Savia including Gonatogyne are discussed and illustrated. Keys to the three genera and to the species of Heterosavia are presented. Four species (all new combinations), Heterosavia bahamensis, H. erythroxyloides, H. laurifolia, and H. maculata, are recognized. The new combinations Heterosavia laurifolia var. intermedia and H. maculata var. clementis are proposed. The names Heterosavia, H. erythroxyloides, H. laurifolia, Savia clementis, S. clusiifolia, S. clusiifolia var. fallax, and S. longipes are lectotypified. Distribution maps and conservation assessments (IUCN ratings) of Heterosavia species and varieties are provided.  相似文献   

9.
Rheophilous Osmunda lancea often hybridizes with a dryland ally, Osmunda japonica, to produce O. × intermedia, forming zonation in riverbanks and the adjacent dryland along flooding frequency clines. This study examined the genetic structure of populations consisting of O. × intermedia and the two parental species by analyzing ten nuclear DNA markers [six cleaved amplified polymorphic sequence (CAPS) markers and three simple sequence repeat (SSR) markers developed from an expressed sequence tag (EST) library, and the sequence of the glyceraldehyde-3-phosphate dehydrogenase gene GapCp] and chloroplast DNA sequences. The results suggest that the nuclear genes of O. japonica and O. lancea are genetically differentiated despite shared polymorphism in their chloroplast DNA sequences. This discrepancy may be attributable to natural selection and recent introgression, although it is not evident if introgression occurs between O. japonica and O. lancea in the examined populations. Our findings of putative F2 hybrids in O. × intermedia support its partial reproducibility, and also suggest that formation of later-generation hybrids generates morphological variation in O. × intermedia. O. lancea plants collected from geographically distant localities were genetically very similar, and it is suggested that O. lancea originated monotopically.  相似文献   

10.
The genus Betula comprises various species in boreal and temperate climate zones of the Northern Hemisphere. The taxonomy of Betula is controversial and complicated by parallel evolution of morphological traits, polyploidization events, and extensive hybridization and introgression among species. Multilocus molecular data from AFLPs were used to provide phylogenetic information. A large number of polymorphic markers (321 variable bands) were produced in 107 Betula accessions from 23 species and 11 hybrids. The AFLP results were largely congruent with the results from previously examined nuclear DNA markers. Four distinct subgenera were identified within the genus Betula. These subgenera were partly in disagreement with the traditional (but disputed) division of the genus. In addition, the results indicated several groups of conspecific taxa. The majority of the species fell within subgenus Betula and shared a high degree of similarity with B. pendula. All hybrids were associated with this group, and the AFLP data contained signals on putative parents for some of the interspecific hybrids. Subgenus Chamaebetula and part of the Neurobetula species should be merged with Betula. The subgenera Betulenta, Betulaster, and the remaining part of Neurobetula are distinct and well supported. Although our results indicate that four major taxonomic groups can be recognized within the genus Betula, the relationship between them remains unclear. This may be due to the occurrence of hybridization and introgression, which would have a homogenizing effect on the relationships between species. Naturally occurring Betula species of hybrid origin may explain the low bootstrap values within the Betula clade. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

11.
Eight taxa of the genus Bellevalia (Hyacinthaceae) occurring in Greece, all with basic chromosome number x = 4, were cytologically studied using classical and molecular-cytogenetic techniques [fluorochrome banding with chromomycin A3, fluorescence in situ hybridization (FISH) using probes of 18S–5.8S–26S and 5S ribosomal RNA genes]. Two of the examined taxa are endemic, i.e., B. brevipedicellata and B. sitiaca, both restricted to the Island of Kriti. B. hyacinthoides and B. edirnensis are Balkan endemics, and the four remaining taxa, i.e., B. dubia subsp. boissieri, B. trifoliata, B. romana, and B. ciliata, are more widely distributed Mediterranean elements. Genome size, estimated by flow cytometry, ranged from 18.59 to 53.38 pg. The results of fluorochrome banding and FISH are reported for the first time for the genus Bellevalia. Despite the morphological similarity of the chromosome complement, which is in accordance with the general “basic” Bellevalia karyotype formula, the karyotypes of the studied species are clearly distinguished by the number and position of GC-rich bands and ribosomal DNA (rDNA) loci, revealing clear interspecific differentiation among the taxa. Additionally, examination of the polyploid species B. sitiaca and B. edirnensis and populations of B. hyacinthoides and B. ciliata with different ploidy levels permits discussion about the origin of polyploids and the taxonomic relationships among the taxa.  相似文献   

12.
The present study was done to determine the modulation effect(s) of polymorphisms of XRCC1, GSTM1, and GSTT1 on concentration of serum testosterone in females exposed to natural sour gas. Also we examine whether chronic exposure to natural gas containing sulfur compounds act as natural selection force on XRCC1 polymorphisms. The present study was performed on 68 healthy unrelated female students living in polluted areas of MIS. Also for investigating the effect of natural selection on XRCC1 polymorphism, a study was performed on two groups of healthy individuals of MIS citizens. The first and second groups including 94 (age range 30–85 years) and 187 individuals (age range 5–20 years), respectively. First and second groups were born and were not born in contaminated areas of the MIS, respectively. There was no significant difference between genotypes of XRCC1 for concentration of serum testosterone. Although GSTT1-null genotype had higher level of serum testosterone in comparison with the present genotype (t = 2.392, df = 66, P = 0.023), a borderline difference between genotypes of GSTM1 for serum testosterone was observed (t = 1.928, df = 66, P = 0.058). Analysis of variance revealed significant difference between combination genotypes of GSTM1 and GSTT1 for serum testosterone (F = 4.167; df = 3, 64; P = 0.009). The Duncan post hoc test indicated that the combination genotype of “present GSTM1/null GSTT1” had significant higher level of testosterone. There is no evidence that XRCC1 polymorphisms have advantage/disadvantage when population exposed to natural sour gas. The polymorphisms of GSTM1 and GSTT1 modulate serum testosterone concentration in young females exposed to natural sour gas.  相似文献   

13.
Natural hybridization is common in the genus Lespedeza. No hybrids between Lespedeza leptostachya Englem. and Lespedeza capitata Michx. are formally recognized in any of the current floras, however observations in the field suggest that hybridization might occur in many of their shared habitats. Putative hybrids were compared to L. leptostachya and L. capitata using morphological measurements and screened for the presence of species-specific trnL-F gene region (cpDNA) and the ITS gene region (nrDNA). A discriminate analysis of 10 morphological measurements identified the hybrids as intermediate to both parents with two PCA axes explaining 99% of the variation between taxa. The presence of hybrids was confirmed by genetic markers with individuals morphologically identified as hybrids having cpDNA trnL-F genotypes identical to L. leptostachya and the ITS (nrDNA) phenotypes in most cases contain the ITS genotype of both parents, however, some putative hybrid individuals contained the ITS genotype of only one parents. Those individuals with L. leptostachya ITS and trnL-F could be a case of misclassification, but the presence of both L. capitata ITS genotypes and L. leptostachya trnL-F genotypes suggest segregation has occurred, which may result from either selfing or backcrossing.  相似文献   

14.
To allow to discriminate rapidly the strains of Porphyra tenera var. tamatsuensis, cultivars of which grow more vigorously than strains of P. tenera var. tenera, strains of both varieties were examined by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis using mitochondrial DNA related to the ATP synthase F0 subunit 6 (ATP6) gene. The lengths of all sequences in this region of three strains of each variety were 670 bp and had just a single nucleotide substitution. Digestion with the restriction enzyme of TaaI yielded three visible bands which appeared in the three strains of P. tenera var. tamatsuensis, whereas two bands appeared in the three strains of P. tenera var. tenera. We therefore conclude that PCR-RFLP analysis is a valuable tool for discrimination of P. tenera var. tamatsuensis among the stock of P. tenera strains used for mariculture.  相似文献   

15.
Relationships among three Japanese Laetiporus taxa (“L. sulphureus var. sulphureus” auct. jap., L. sulphureus var. miniatus, and L. versisporus) were assessed with phylogenetic analysis and incompatibility tests. Gene phylogenies inferred from the internal transcribed spacer region of nuclear ribosomal DNA, elongation factor 1α, and β-tubulin gene regions suggested that Japanese Laetiporus was divided into four groups: the yellow pore form of L. sulphureus var. miniatus, the white pore form of L. sulphureus var. miniatus, and two “L. sulphureus var. sulphureus”/ L. versisporus groups. A morphologically distinct species, Laetiporus versisporus, sharing a clade with “L. sulphureus var. sulphureus” auct. jap., was proved to be an anamorphic form of “L. sulphureus var. sulphureus” auct. jap. The “sulphureus/versisporus” isolates showed two divergent sequence types in each region. Some isolates had intraindividual polymorphism assigned to both sequence types. This finding suggests that speciation via hybridization is ongoing in the “sulphureus/versisporus” group. Single spore isolates from the “sulphureus/versisporus” group, white pore group, and yellow pore group were incompatible with each other. Our results provided strong support for the new recognition of three Laetiporus taxa in Japan.  相似文献   

16.
The Italian hare, Lepus corsicanus, was first described in Corsica more than 100 years ago, but the knowledge on the status of the species in this island remains scarce. Moreover, frequent introductions of thousands of individuals from other hare species, namely Lepus europaeus and Lepus granatensis, into Corsica are known to have occurred and an updated assessment of the prevalence of L. corsicanus in Corsica is therefore of utmost importance. Here, to estimate the relative prevalence of the hare species present in Corsica, we conducted a molecular analysis on 67 samples collected by hunters between 2002 and 2007 in 36 Corsican communes. Sequencing of portions of the nuclear gene transferrin and of the control region of the mitochondrial DNA allowed classifying most of the collected samples as belonging to L. corsicanus (70.1%). Of the sampled Corsican communes, 86.1% contained this species, while only in 11.1%, L. europaeus was present. Three of the analyzed specimens showed an inconsistent molecular assignment between markers suggesting a hybrid origin: L. corsicanus × L. europaeus, L. corsicanus × L. granatensis, and L. europaeus × L. granatensis. The first two cases of hybridization had never been described in nature, even in studies focusing on hares from Italy where L. corsicanus and L. europaeus are often sympatric. These results stress the real risk of corrosion of the native gene pool of L. corsicanus via hybridization with introduced species. We highlight the need of urgently rethinking the management plan of hare populations in Corsica.  相似文献   

17.
Three Australian native animal species yielded 60 samples composed of three indigenous ticks. Hosts included twelve koalas, two echidnas and one wombat from Victoria, and ticks were of the species Ixodes tasmani (n = 42), Bothriocroton concolor (n = 8) and B. auruginans (n = 10), respectively. PCR screening and sequencing detected a species of Coxiella, sharing closest sequence identity to C. burnetii (>98%), in all B. auruginans, as well as a species of Rickettsia, matching closest to R. massiliae, in 70% of the same samples. A genotype sharing closest similarity to Rickettsia bellii (>99%) was identified in three female B. concolor collected from one of the echidnas. Three samples of I. tasmani, taken from three koalas, yielded different genotypes of Rickettsiella. These results represent the first detection of the three genera in each tick species and identify a high level of previously undetected bacterial diversity in Australian ticks.  相似文献   

18.
The cross compatible wild relatives of crops have furnished valuable genes for crop improvement. Understanding the genetics of these wild species may enhance their further use in breeding. In this study, sequence variation of the nuclear Lhs1 gene was used to investigate the population genetic structure and gene flow of Oryza rufipogon and O. nivara, two wild species most closely related to O. sativa. The two species diverge markedly in life history and mating system, with O. rufipogon being perennial and outcrossing and O. nivara being annual and predominantly inbreeding. Based on sequence data from 105 plants representing 11 wild populations covering the entire geographic range of these wild species, we detected significantly higher nucleotide variation in O. rufipogon than in O. nivara at both the population and species levels. At the population level the diversity in O. rufipogon (Hd = 0.712; θ sil = 0.0017) is 2–3 folds higher than that in O. nivara (Hd = 0.306; θ sil = 0.0005). AMOVA partitioning indicated that genetic differentiation among O. nivara populations (78.2%) was much higher than that among O. rufipogon populations (52.3%). The different level of genetic diversity and contrasting population genetic structure between O. rufipogon and O. nivara might be explained by their distinct life histories and mating systems. Our simulation using IM models demonstrated significant gene flow from O. nivara to O. rufipogon, indicating a directional introgression from the annual and selfing species into the perennial and outcrossing species. The ongoing introgression has played an important role in shaping current patterns of genetic diversity of these two wild species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

19.
The Falkland’s mullet, Eleginops maclovinus, is the only modern representative of the Sub-Antarctic family Eleginopidae, suborder Notothenioidei. Based on specimens from the Falkland Islands/Islas Malvinas, the Magellan Straits, and the southern coast of Chile, we have established the specific karyotype by conventional cytogenetic methods and have mapped the chromosomal loci of the ribosomal genes by fluorescence in situ hybridization (FISH). With respect to the basal notothenioid family Bovichtidae and to the hypothetical basal condition of the suborder (diploid number = 48, fundamental number = 48), E. maclovinus displays a slightly derived karyotype (diploid number = 48, fundamental number = 54). In contrast to the bovichtids, the 45S and 5S ribosomal DNAs are co-localized to a single chromosome pair. Condensation of the ribosomal genes to a single locus is likely to represent an intermediate stage in the evolution of notothenioid karyology. Features unique to E. maclovinus (e.g., morphology of its large, rDNA-bearing chromosome pair) probably result from divergence during the long evolutionary isolation of the family.  相似文献   

20.
Five strains (LN12, LN14T, LN15T, LN16 and LN17T) representing three novel methylotrophic yeast species were isolated from the external surface of plant leaves by three-consecutive enrichments. On the basis of morphological, biochemical, physiological and chemotaxonomic characteristics, the sequence analysis of the D1/D2 domain of the large subunit (LSU) rRNA gene and the phylogenetic analysis, the five strains were assigned to be one novel Ogataea species and two novel Candida species. Three strains (LN12, LN14T and LN16) represent a single novel species of the genus Ogataea, for which the name Ogataea phyllophila sp. nov. is proposed. The type strain is LN14T (= BCC 42666T = NBRC 107780T = CBS 12095T). Strain LN15T was assigned to be Candida chumphonensis sp. nov. (type strain LN15T = BCC 42667T = NBRC 107781T = CBS 12096T). Strain LN17T represented another novel species of Candida that was named Candida mattranensis sp. nov. (type strain LN17T = BCC 42668T = NBRC 107782T = CBS 12097T).  相似文献   

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