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1.
Y. Ono 《Mycoscience》2002,43(1):0037-0045
Kuehneola japonica has a microcyclic life cycle with a regular alternation of generations. Single basidiospore inoculations onto Rosa wichuraiana resulted in teliospore production, indicating its homothallic nature. Dikaryotization in a vegetative mycelium in the host
seemed to occur through nuclear division that was not followed by septum formation. Karyogamy and meiosis took place through
teliospore and metabasidium development; this fungus was considered to reproduce genetically homogeneous progenies. Puccinia lantanae and P. patriniae were also microcyclic in their life cycle; however, these fungi differed from K. japonica in the mode of nuclear behavior. In the former two fungi, both vegetative and reproductive cells were uninucleate. No karyogamy
was observed, and nuclear division in the metabasidium development was thought to be mitotic. In P. lantanae, a basidiospore was formed on a sterigma, whereas a whiplike hypha emerged from each metabasidium cell in P. patriniae. Inoculations of Justicia procumbens with a single basidiospore of P. lantanae resulted in teliospore production. The fungus seemed to remain uninucleate, either haploid or diploid, throughout the life
cycle. Thus, reproduction was considered to be apomictic.
Received: August 16, 2001 / Accepted: October 1, 2001 相似文献
2.
Reinhard Berndt 《Mycological Progress》2008,7(1):7-19
The rust fungi (Uredinales, basidiomycota) occuring on ferns (Pteridophyta) in South Africa are described, illustrated and
keyed out. All species belong to the pucciniastraceous genera Milesina (M. blechni), Uredinopsis (U. pteridis) or to the related uredinial anamorph genus Milesia (M. nervisequa, M. cf. magellanica, M. silvae-knysnae). Milesia silvae-knysnae on Polystichum pungens is new to science; it probably belongs to the teleomorph genus Milesina. Milesina blechni is reported from South Africa for the first time on the new hosts Blechnum punctulatum and Rumohra adiantoides; it has hitherto been known only from the Northern Hemisphere on Blechnum spicant. Rust specimens collected on Asplenium aethiopicum and A. rutifolium were tentatively assigned to Milesia magellanica which has been known so far only from southern Chile. Hyalopsora neocheilanthis, Milesina neoexigua and M. neovogesiaca are proposed as new names for Hyalopsora cheilanthis, Milesia exigua and M. vogesiaca. It is discussed that the pucciniastraceous fern rusts could have reached South Africa either by migration (M. blechni) or by long-distance air dispersal. In the absence of their gametophyte hosts, species of Abies (Pinaceae), the rusts have to propagate in South Africa by urediniospores infecting fern to fern.
Taxonomical novelties
Milesia silvae-knysnae R. Berndt
Milesina neoexigua R. Berndt
Milesina neovogesiaca R. Berndt
Hyalopsora neocheilanthis R. Berndt 相似文献
3.
M. Catherine Aime 《Mycoscience》2006,47(3):112-122
Rust fungi (Basidiomycota, Uredinales) consist of more than 7000 species of obligate plant pathogens that possess some of
the most complex life cycles in the Eumycota. Traditionally, a limited number of synapomorphic characters and incomplete life-cycle
and host-specificity data have hampered phylogenetic inference within the Uredinales. The application of modern molecular
characters to rust systematics has been limited, and current contradictions, especially in the deeper nodes, have not yet
been resolved. In this study, two nuclear rDNA genes (18S and 28S) were examined across the breadth of the Uredinales to resolve
some systematic conflicts and provide a framework for further studies of the group. Three suborders of rusts are recovered.
Of the 13 rust families most widely accepted, 8 are supported in full or in part (Coleosporiaceae, Melampsoraceae, Mikronegeriaceae,
Phakopsoraceae p.p., Phragmidiaceae, Pileolariaceae, Pucciniaceae, Raveneliaceae), 3 are redundant (Cronartiaceae, Pucciniastraceae,
Pucciniosiraceae), and the status of 2 (Chaconiaceae, Uropyxidaceae) could not be resolved. The Mikronegeriaceae and Caeoma torreyae are the most basal rusts sampled. It is concluded that morphology alone is a poor predictor of rust relationships at most
levels. Host selection, on the other hand, has played a significant role in rust evolution.
Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information
and does not imply recommendation or endorsement by the US Department of Agriculture. 相似文献
4.
Crassulacean acid metabolism (CAM) is one of the photosynthetic pathways regarded as adaptations to water stress in land plants.
Little is known about correlations among the level of CAM activity, environment of habitat, life form, and phylogenetic relationship
of a plant group from an evolutionary perspective. We examined these relationships in 18 species of Cymbidium (Orchidaceae) because the genus shows distinctive diversification of habitats and life forms. The photosynthetic type was
classed into three categories, strong CAM, weak CAM, and C3 on the basis of CAM activity. CAM expression in Cymbidium was confined to the epiphytic and lithophytic species. Especially, all of these species from tropical to subtropical rainforest
exhibited CAM activity. On the other hand, the terrestrial species always exhibited C3 metabolism irrespective of their varied habitats. Regarding the evolution of photosynthetic characters, weak CAM was the
ancestral state in Cymbidium and strong CAM and C3 metabolism occurred subsequently. The evolution of strong CAM likely enabled Cymbidium to extend to exposed sites in tropical lowland where marked water stress exists. Further, different levels of CAM activity
characterized each species and such potential plasticity of CAM may realize the radiation of Cymbidium into sites with different environmental conditions. 相似文献
5.
Intraspecific physiological variation: implications for understanding functional diversity in ectomycorrhizal fungi 总被引:6,自引:0,他引:6
J. W. G. Cairney 《Mycorrhiza》1999,9(3):125-135
Several thousand fungal species worlwide are thought to form ectomycorrhizas (ECM) with tree hosts and there is currently
much interest in determining the functional significance of such diversity in natural and managed ecosystems. While only a
few taxa have been investigated in detail, it is clear that ECM fungi display extensive intraspecific variation in a range
of physiological and other life-history parameters. Thus, comparative investigations of single (or even a few) isolates of
different species are unlikely to provide reliable information on functional capabilities. Extensive screening of taxonomically
well-defined isolates is required. This must take into account spatial and temporal variation in gene expression in mycelia
growing in axenic culture or in association with a host plant.
Accepted: 29 June 1999 相似文献
6.
Levels of genetic diversity at different stages of the domestication cycle of interior spruce in British Columbia 总被引:3,自引:0,他引:3
M. U. Stoehr Y. A. El-Kassaby 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):83-90
Concerns over the reductionist nature of the domestication of forest-tree species focus on the possibility of potential genetic
erosion during this process. To address these concerns, genetic diversity assessments in a breeding zone the Province of British
Columbia “interior” spruce (Picea glauca×engelmanni) program was conducted using allozyme markers. Genetic-variation comparisons were made between natural and production (seed
orchard) populations as well as seed and seedling crops produced from the same breeding zone’s seed orchard. The natural population
sample consisted of a total of 360 trees representing three stands within each of three watersheds present in the Shuswap-Adams
low-elevation zone of interior British Columbia. Small amounts of genetic differentiation were observed among the nine natural
populations (4%) and this was attributable to extensive gene flow Consequently, the sum of these nine populations was considered as a baseline for the genetic variation present in the breeding
zone. The comparisons between the seed orchard and the breeding zone produced a similar percentage of polymorphic loci while the expected hetrozygosity (0.207 vs 0.210) and the average number of alleles per locus (2.7 vs 2.4) were slightly lower in the seed orchard. A total
of seven natural populations’ rare alleles were not present in the orchard population, while one allele was unique to the orchard. The %P increased to 70.6% in the seedlot, but dropped to the natural populations level (64.7%) in the plantation. The observed increase
in %P was a result of pollen contamination in the orchard. It is suspected that the reduction in the plantation was caused by an
unintentional selection in the nursery. Simulated roguing in the orchard did not drastically reduce even if up to 50% of the orchard’s clones were rogued. However, roguing was associated with a reduction in the average number
of alleles per locus (i.e., sampling effect).
Received: 2 January 1996 / Accepted: 24 May 1996 相似文献
7.
Three species of rust fungi were reported based on the specimens collected in the islands of the Yaeyama group and Okinawa,
Japan.Puccinia tarennicola onTarenna gracilipes andUredo daphniphylli onDaphniphyllum teijsmannii were described as new species.Villebrunea frutescens was added to the host plants ofUredo pipturi.
Contribution No. 115, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba. 相似文献
8.
This study correlates a distinctive pattern of external gas exchange, referred to as the discontinuous gas exchange cycle
(DGC), observed in the laboratory, with habitat associations of five species of telecoprid dung beetles. The beetles were
chosen from a variety of habitats that would be expected to present different amounts of water stress. All five species exhibited
DGC. Sisyphus fasciculatus has been recorded only in woodland areas, and does not have strict spiracular control during its DGC. Anachalcos convexus and Scarabaeus rusticus are associated with open mesic habitats. Both species exhibit a distinct DGC, previously found in some other insect species,
but intermediate within this study group. Sc. flavicornis and Circellium bacchus are typically found in arid regions, and have the most unusual form of DGC, with spiracular fluttering during the burst phase.
These results support the hypothesis that spiracular fluttering reduces respiratory water loss. From this study we conclude
that the DGC is an ancestral adaptation, most probably as a result of anoxic environments in underground burrows, but that
spiracular control is enhanced to reduce respiratory water loss in beetle species that live in arid habitats.
Received 4 August 1999 / Accepted: 7 October 1999 相似文献
9.
10.
T. Krugman A. Korol E. Nevo J. W. Snape O. Levy B. Rubin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):46-51
Chlorotoluron is a selective phenylurea herbicide widely used for broad-leaved and annual grass weed control in cereals. Variation in the response to chlorotoluron (CT) was found in both hexaploid bread wheat (Triticum aestivum L.) and wild tetraploid wheat (Triticum dicoccoides KöRN.). Here, we describe the comparative mapping of the CT resistance gene (Su1) on chromosome 6B in bread and wild wheat using RFLP markers. In bread wheat, mapping was based on 58 F4 single-seed descent (SSD) plants of the cross between a genotype sensitive to chlorotoluron, ‘Chinese Spring’ (CS), and a resistant derivative, the single chromosome substitution line, CS (‘Cappele-Desprez’ 6B) [CS (CAP6B). In T dicoccoides, mapping was based on 37 F2 plants obtained from the cross between the CT-susceptible accession B-7 and the resistant accession B-35. Nine RFLP probes spanning the centromere were chosen for mapping. In bread wheat Su1 was found to be linked to α-Amy-1 (9.84 cM) and Xpsr371 (5.2 cM), both on the long arm of 6B, and Nor2 (2.74 cM) on the short arm. In wild wheat the most probable linkage map was Nor2-Xpsr312-Su1-Pgk2, and the genetic distances between the genes were 24.8cM, 5.3cM, and 6.8cM, respectively. These results along with other published map data indicate that the linear order of the genes is similar to that found in T. aestivum. The results of this study also show that the Su1 gene for differential response to chlorotoluron has evolved prior to the domestication of cultivated wheat and not in response to the development and use of chemicals. 相似文献
11.
Enrique Meléndez-Hevia Thomas G. Waddell Marta Cascante 《Journal of molecular evolution》1996,43(3):293-303
The evolutionary origin of the Krebs citric acid cycle has been for a long time a model case in the understanding of the origin and evolution of metabolic pathways: How can the emergence of such a complex pathway be explained? A number of speculative studies have been carried out that have reached the conclusion that the Krebs cycle evolved from pathways for amino acid biosynthesis, but many important questions remain open: Why and how did the full pathway emerge from there? Are other alternative routes for the same purpose possible? Are they better or worse? Have they had any opportunity to be developed in cellular metabolism evolution? We have analyzed the Krebs cycle as a problem of chemical design to oxidize acetate yielding reduction equivalents to the respiratory chain to make ATP. Our analysis demonstrates that although there are several different chemical solutions to this problem, the design of this metabolic pathway as it occurs in living cells is the best chemical solution: It has the least possible number of steps and it also has the greatest ATP yielding. Study of the evolutionary possibilities of each one-taking the available material to build new pathways-demonstrates that the emergence of the Krebs cycle has been a typical case of opportunism in molecular evolution. Our analysis proves, therefore, that the role of opportunism in evolution has converted a problem of several possible chemical solutions into asingle-solution problem, with the actual Krebs cycle demonstrated to be the best possible chemical design. Our results also allow us to derive the rules under which metabolic pathways emerged during the origin of life. 相似文献
12.
The genomic organization and evolution of the natural killer immunoglobulin-like receptor (KIR) gene cluster 总被引:18,自引:7,他引:11
Natural killer (NK) immunoglobulin-like receptors (KIRs) are a family of polymorphic receptors which interact with specific
motifs on HLA class I molecules and modulate NK cytolytic activity. In this study, we analyzed a recently sequenced subgenomic
region on chromosome 19q13.4 containing eight members of the KIR receptor repertoire. Six members are clustered within a 100-kb continuous sequence. These genes include a previously unpublished
member of the KIR gene family 2DS6, as well as 2DL1, 2DL4, 3DL1, 2DS4, 3DL2, from centromere to telomere. Two additional KIR genes, KIRCI and 2DL3, which may be located centromeric of this cluster were also analyzed. We show that the KIR genes have undergone repeated gene duplications. Diversification between the genes has occurred postduplication primarily
as a result of retroelement indels and gene truncation. Using pre- and postduplication Alu sequences identified within these
genes as evolutionary molecular clocks, the evolution and duplication of this gene cluster is estimated to have occurred 30–45 million
years ago, during primate evolution. A proposed model of the duplication history of the KIR gene family leading to their present organization is presented.
Received: 25 November 1999 / Revised: 10 January 2000 相似文献
13.
Matsuoka Y Mitchell SE Kresovich S Goodman M Doebley J 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(2-3):436-450
To evaluate the performance of microsatellites or simple sequence repeats (SSRs) for evolutionary studies in Zea, 46 microsatellite loci originally derived from maize were applied to diverse arrays of populations that represent all the
diploid species of Zea and 101 maize inbreds. Although null phenotypes and amplification of more than two alleles per plant were observed at modest
rates, no practical obstacle was encountered for applying maize microsatellites to other Zea species. Sequencing of microsatellite alleles revealed complex patterns of mutation including frequent indels in the regions
flanking microsatellite repeats. In one case, all variation at a microsatellite locus came from indels in the flanking region
rather than in the repeat motif. Maize microsatellites show great variability within populations and provide a reliable means
to measure intraspecific variation. Phylogeographic relationships of Zea populations were successfully reconstructed with good resolution using a genetic distance based on the infinite allele model,
indicating that microsatellite loci are useful in evolutionary studies in Zea. Microsatellite loci show a principal division between tropical and temperate inbred lines, and group inbreds within these
two broad germplasm groups in a manner that is largely consistent with their known pedigrees.
Received: 10 February 2001 / Accepted: 21 May 2001 相似文献
14.
15.
Olivier Verneau François Catzeflis Anthony V. Furano 《Journal of molecular evolution》1997,45(4):424-436
We determined ∼215 bp of DNA sequence from the 3′-untranslated region (UTR) of 240 cloned L1 (LINE-1) elements isolated from
22 species of Rattus sensu lato and Rattus sensu stricto murine rodents. The sequences were sorted into different L1 subfamilies, and oligonucleotides cognate to them
were hybridized to genomic DNA of various taxa. From the distribution of the L1 subfamilies in the various species, we inferred
the partial phylogeny of Rattus sensu lato. The four Maxomys species comprise a well-defined clade separate from a monophyletic cluster that contains the two Leopoldamys and four Niviventer species. The Niviventer/Leopoldamys clade, in turn, shares a node with the clade that contains Berylmys, Sundamys, Bandicota, and Rattus sensu stricto. The evolutionary relationships that we deduced agree with and significantly extend the phylogeny of Rattus sensu lato established by other molecular criteria. Furthermore, the L1 amplification events scored here produced a unique
phylogenetic tree, that is, in no case did a character (a given L1 amplification event) appear on more than one branch. The
lack of homoplasy found in this study supports the robustness of L1 amplification events as phylogenetic markers for the study
of mammalian evolution.
Received: 8 November 1996 / Accepted: 11 April 1997 相似文献
16.
This work presents research on the diversity of the southern African rust mycobiota (Uredinales). It describes new species, lists new reports and adds new information on several rust fungi. Puccinia cornurediata, Puccinia dioscoreae-mundtii, Puccinia horti-kirstenboschi, Puccinia othonnoides, Puccinia rapipes, Puccinia subindumentana, Uredo otholobii and Uromyces lotononidicola are described as new; Puccinia verwoerdiana is assigned to Puccinia lycii as a synonym, and Uredo lotononi to U. lotononidicola. Comprehensive accounts and keys are presented for Puccinia species on Lycium (Solanaceae), Helichrysum and Othonna (Asteraceae). Puccinia butleri and Uromyces bidenticola are new reports for South Africa, and Puccinia spinulosa is new for Namibia. So far, the latter species has only been known from Madagascar, and P. butleri from the Indian subcontinent. Taxonomical novelties are P. cornurediata R. Berndt; P. dioscoreae-mundtii R. Berndt, A.R. Wood & E. Uhlmann; P. horti-kirstenboschi R. Berndt & E. Uhlmann; P. othonnoides R. Berndt, A.R. Wood & E. Uhlmann; P. rapipes R. Berndt & E. Uhlmann; P. subindumentana R. Berndt; U. otholobii R. Berndt, A.R. Wood & E. Uhlmann and U. lotononidicola R. Berndt 相似文献
17.
The fully enclosed Taiaro lagoon is hypersaline (42.5 psu) and non-tidal; constant salinity and water level result from strong
evaporation balanced by low percolation through the lagoon floor. Seawater can flow over the atoll rim during exceptionally
high seas and may then replenish lagoonal communities with propagules of oceanic origin. The distinctive water chemistry of
the lagoon suggests a possible way of identifying these immigrants. We established this potential by analysing stable isotopes
of carbon and oxygen in the recent growth layers of otoliths of two adult reef fishes, Chaetodon ulietensis and Acanthurus triostegus, collected from both sides of the atoll rim. Fish from the two locations were discriminated by their isotopic signatures,
suggesting that analysis of the microchemical signatures deposited during the larval development could be used in future work
to determine which individuals and species complete their life-cycles in this unusual lagoon.
Accepted: 28 August 1997 相似文献
18.
T. Tsuruishi 《Limnology》2003,4(1):0011-0018
The life cycle of a giant carnivorous caddisfly, Himalopsyche japonica (Morton), was studied in two mountain streams in Nagano Prefecture, Central Japan. Field surveys and rearing experiments
in the laboratory were conducted from October 1997 to September 2001. The life cycle of H. japonica was estimated to be a complex univoltine cycle that partly includes bivoltine populations. The adults had a long flight period,
from April to September, with three distinct peaks of emergence. First to third instar larvae were collected from June to
February, and the last (fifth) instar larvae and pupae appeared throughout the year. In autumn, the larvae belonging to all
instars were found, and younger ones overwintered in the fourth instar stage and others in the fifth instar stage. On the
other hand, fifth instar larvae and pupae ceased developing in autumn even though the water temperature was higher than the
developmental zero temperature. The overwintered pupae emerged as adults in April, and the overwintered fifth instar larvae
pupated in May and emerged in June. The larvae which overwintered in the fourth instar stage probably emerged after June.
Received: March 19, 2002 / Accepted: January 10, 2003
Present address: United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan Tel. +81-265-77-1401;
Fax +81-265-74-7496 e-mail: himalo@f8.dion.ne.jp
Acknowledgments The author thanks Prof. T. Yoshida, Prof. H. Nakamura, and Associate professor K. Soma, Shinshu University; Mr. T. Nozaki,
Kanagawa Environmental Research Center; and Mr. N. Kubota, Environmental Assessment Center in Matsumoto laboratory for their
advice and help in accomplishing this research. The author is also grateful to Prof. K. Tanida, Osaka Prefecture University;
Dr. T. Ito, Hokkaido Fish Hatchery; Mr. K. Okazaki, Kutchan City Museum; and Mrs. Y. Isobe, Nara Women's University, for suggesting
references. Miss. T. Ishiyama, Mr. H. Kojima, Mr. M. Yagyu, and the students of the Forest Animals Laboratory in Shinshu University
kindly provided field samples.
Correspondence to:T. Tsuruishi 相似文献
19.
R. Galzin S. Planes M. Adjeroud C. Chauvet P. J. Doherty J. Poupin 《Coral reefs (Online)》1998,17(1):15-21
The 9 km2 uplifted lagoon of Taiaro Atoll (15°45′S, 144°38′W) is hypersaline due to its isolation from the ocean, yet it contains a
high diversity of fish. The question unifying our expedition was to discover whether these assemblages could be self-sustaining
despite very limited contact with the ocean. Although we were constrained by time, collections of fish larvae showed that
some species can complete their life-cycle within the lagoon, while others differed genetically between the lagoon and the
ocean, consistent with restricted gene flow. The lagoon contained few oceanic species of zooplankton, confirming its general
isolation, but nevertheless some fish species may depend upon infrequent colonisation from the ocean (when large waves drive
water over the normally dry reef crest). Isotopic signatures in fish otoliths suggest the basis for a more definitive and
inclusive test of the sources of the lagoonal assemblage.
Accepted: 28 August 1997 相似文献
20.
The ectomycorrhizas of Shorea leprosula Miq. are described and their putative fungal associates discussed. Of the 24 ectomycorrhizal types reported from seedlings,
wildlings and 20-year-old trees of Shorea leprosula, 20 were associated with the Basidiomycotina, two with the Ascomycotina and two with either members of the Ascomycotina or
the Russulaceae. The dominant group of fungi associated with Shorea leprosula ectomycorrhizas were members of the Russulaceae. This was confirmed by collections of fungal fruiting bodies made under adult
Shorea leprosula trees in various parts of Peninsular Malaysia over a period of 3 years. Of the 28 species of putative ectomycorrhizal fungi
collected, 15 were members of the Russulaceae.
Accepted: 26 March 1997 相似文献