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141.
Morales-Rodríguez I Yañez-Morales M Silva-Rojas HV García-de-Los-Santos G Guzmán-de-Peña DA 《Mycopathologia》2007,163(1):31-39
Fusarium
proliferatum, F. subglutinans, and F. verticillioides are known causes of ear and kernel rot in maize worldwide. In Mexico, only F. verticillioides and F. subglutinans, have been reported previously as causal agents of this disease. However, Fusarium isolates with different morphological characteristics to the species that are known to cause this disease were obtained in
the Highland-Valley region of this country from symptomatic and symptomless ears of native and commercial maize genotypes.
Moreover, while the morphological studies were not sufficient to identify the correct taxonomic position at the species level,
analyses based in the Internal Transcribed Spacer region and the Nuclear Large Subunit Ribosomal partial sequences allowed
for the identification of F. subglutinans, F. solani, and F. verticillioides, as well as four species (F. chlamydosporum, F. napiforme, F. poae, and F. pseudonygamai) that had not previously been reported to be associated with ear rot. In addition, F. napiforme and F. solani were absent from symptomless kernels. Phylogenetic analysis showed genetic changes in F. napiforme, and F. pseudonygamai isolates because they were not true clones, and probably constitute separate sibling species. The results of this study suggest
that the biodiversity of Fusarium species involved in ear rot in Mexico is greater than that reported previously in other places in the world. This new knowledge
will permit a better understanding of the relationship between all the species involved in ear rot disease and their relationship
with maize. 相似文献
142.
王兴红 《天然产物研究与开发》2007,19(1):11-15
利用龙血树产脂部位获得的真菌菌株和细菌菌株共同转化龙血树白木质,形成了木质成分中原来没有的黄酮类化合物,表明龙血树体内存在着一类能被转化成黄酮类化合物的前体物质,龙血树这种独特的抗性机制,可能与血竭形成有关。 相似文献
143.
In this study we have analysed the genetic variation and phylogeography in a global sample of the cellar fungus Coniophora puteana, which is an important destroyer of wooden materials indoor. Multilocus genealogies of three DNA regions (beta tubulin, nrDNA ITS and translation elongation factor 1alpha) revealed the occurrence of three cryptic species (PS1-3) in the morphotaxon C. puteana. One of the lineages (PS3) is apparently restricted to North America while the other two (PS1-2) have wider distributions on multiple continents. Interspecific hybridization has happened between two of the lineages (PS1 and PS3) in North America. In three dikaryotic isolates, two highly divergent beta tubulin alleles coexisted, one derived from PS1 and one from PS3. Furthermore, one isolate included a recombinant ITS sequence, where ITS1 resembled the ITS1 version of PS3 while ITS2 was identical to a frequent PS1 ITS2 version. This pattern must be due to hybridization succeeded by intralocus recombination in ITS. The results further indicated that introgression has happened between subgroups appearing in PS1. We hypothesize that the observed reticulate evolution is due to previous allopatric separation followed by more recent reoccurrence in sympatry, where barriers to gene flow have not yet evolved. A complex phylogeographical structure is observed in the morphotaxon C. puteana caused by (i) cryptic speciation; (ii) the interplay between natural migration and distribution patterns and probably more recent human mediated dispersal events; and (iii) hybridization and introgression. 相似文献
144.
Norman L. Carreck Tariq M. Butt Suzanne J. Clark Ludmilla Ibrahim Elizabeth A. Isger Judith K. Pell Ingrid H. Williams 《Biocontrol Science and Technology》2007,17(2):179-191
Pollen beetles (Meligethes aeneus) and cabbage seed weevils (Ceutorhynchus assimilis) are major pests of oilseed rape (Brassica napus) throughout Europe. In field cage experiments in both winter and spring rape, honey bees (Apis mellifera) effectively transported the entomopathogenic fungus Metarhizium anisopliae to the flowers, causing infection and mortality of both adult and larval pollen beetles, as well as of adult seed weevils. External conidiation was observed on many of the dead pest insects. Although some external conidiation also occurred on dead honey bees, reduction in honey bee colony size during the experiments appeared unrelated to the fungus. The potential of this technique for integration into pest management strategies for the crop, particularly in association with a trap crop, is discussed. 相似文献
145.
Anderson S. Dias Jackson V. Araújo Artur K. Campos Fabio R. Braga Thiago A. Fonseca 《World journal of microbiology & biotechnology》2007,23(9):1245-1252
The viability of a formulation of Duddingtonia flagrans was assessed in the control of parasite gastrointestinal nematodes of cattle. Two groups (A and B) of eight crossbred Holstein × Zebu
cattle, approximately one year old, were placed in Brachiaria decumbens pasture. Each animal in group B (treated) received orally 20 g sodium alginate pellets containing mycelial mass of the D. flagrans fungus, while the animals in the group A (control) received pellets without fungus for seven months, starting in March 2005.
The egg per gram of feces counting the gastrointestinal nematodes showed a difference (P < 0.05) in the treated group in June, July and August, with reductions of 58% (June), 47% (July) and 51% (August) compared
to the control group. The infective larvae recovered in the pastures collected up to 20 cm from distance of the fecal dung
in group B differed (P < 0.01) from the larvae recovered in group A. At the end of the experimental period, the animals in group B presented a greater
weight gain (P < 0.01) compared to the untreated group (A). The treatment of cattle with pellets containing the D. flagrans nematophagous fungus, at the dose and duration used was effective in controlling the infective larvae of gastrointestinal
nematodes of cattle. 相似文献
146.
Bryan J. Culbertson Jaymie Krone Erastus Gatebe Norbert C. Furumo Steven L. Daniel 《World journal of microbiology & biotechnology》2007,23(10):1357-1362
The impact of various supplemental carbon sources (oxalate, glyoxylate, glycolate, pyruvate, formate, malate, acetate, and
succinate) on growth and oxalate formation (i.e., oxalogenesis) by Sclerotinia sclerotiorum was studied. With isolates D-E7, 105, W-B10, and Arg-L of S. sclerotiorum, growth in an undefined broth medium (0.1% soytone; pH 5) with 25 mM glucose and 25 mM supplemental carbon source was increased
by the addition of malate and succinate. Oxalate accumulation occurred in the presence of glucose and a supplemental carbon
source, with malate, acetate, and succinate supporting the most oxalate synthesis. With S. sclerotiorum Arg-L, oxalate-to-biomass ratios, an indicator of oxalogenic potential, were dissimilar when the organism was grown in the
presence of different carbon sources. The highest oxalate-to-biomass ratios were observed with pyruvate, formate, malate,
acetate, and succinate. Time-course studies with acetate-supplemented cultures revealed that acetate and glucose consumption
by S. sclerotiorum D-E7 coincided with oxalogenesis and culture acidification. By day 5 of incubation, oxalogenesis was halted when cultures
reached a pH of 3 and were devoid of acetate. In succinate-supplemented cultures, oxalogenesis essentially paralleled glucose
and succinate utilization over the 9-day incubation period; during this time period, culture pH declined but never fell below
4. Overall, these results indicate that carbon sources can regulate the accumulation of oxalate, a key pathogenicity determinant
for S. sclerotiorum. 相似文献
147.
148.
The white‐nose syndrome (WNS), caused by the fungal pathogen Pseudogymnoascus destructans, is threatening the cave‐dwelling bat fauna of North America by killing individuals by the thousands in hibernacula each winter since its appearance in New York State less than ten years ago. Epidemiological models predict that WNS will reach the western coast of the USA by 2035, potentially eliminating most populations of susceptible bat species in its path (Frick et al. 2015; O'Regan et al. 2015). These models were built and validated using distributional data from the early years of the epidemic, which spread throughout eastern North America following a route driven by cave density and winter severity (Maher et al. 2012). In this issue of Molecular Ecology, Wilder et al. (2015) refine these findings by showing that connectivity among host populations, as assessed by population genetic markers, is crucial in determining the spread of the pathogen. Because host connectivity is much reduced in the hitherto disease free western half of North America, Wilder et al. make the reassuring prediction that the disease will spread more slowly west of the Great Plains. 相似文献
149.
Matthew H. Becker Jenifer B. Walke Shawna Cikanek Anna E. Savage Nichole Mattheus Celina N. Santiago Kevin P. C. Minbiole Reid N. Harris Lisa K. Belden Brian Gratwicke 《Proceedings. Biological sciences / The Royal Society》2015,282(1805)
Symbiotic microbes can dramatically impact host health and fitness, and recent research in a diversity of systems suggests that different symbiont community structures may result in distinct outcomes for the host. In amphibians, some symbiotic skin bacteria produce metabolites that inhibit the growth of Batrachochytrium dendrobatidis (Bd), a cutaneous fungal pathogen that has caused many amphibian population declines and extinctions. Treatment with beneficial bacteria (probiotics) prevents Bd infection in some amphibian species and creates optimism for conservation of species that are highly susceptible to chytridiomycosis, the disease caused by Bd. In a laboratory experiment, we used Bd-inhibitory bacteria from Bd-tolerant Panamanian amphibians in a probiotic development trial with Panamanian golden frogs, Atelopus zeteki, a species currently surviving only in captive assurance colonies. Approximately 30% of infected golden frogs survived Bd exposure by either clearing infection or maintaining low Bd loads, but this was not associated with probiotic treatment. Survival was instead related to initial composition of the skin bacterial community and metabolites present on the skin. These results suggest a strong link between the structure of these symbiotic microbial communities and amphibian host health in the face of Bd exposure and also suggest a new approach for developing amphibian probiotics. 相似文献
150.