Enhanced Resistance to Sclerotium rolfsii in Populations of Alfalfa Selected for Quantitative Resistance to Sclerotinia trifoliorum     

Pratt RG  Rowe DE 《Phytopathology》2002,92(2):204-209

ABSTRACT Sclerotinia trifoliorum and Sclerotium rolfsii are pathogens for which similar mechanisms of parasitism have been proposed. This suggested that resistance to these pathogens may be related in a common host plant. This study was undertaken to determine whether selection for quantitative resistance to Sclerotinia trifoliorum in alfalfa also increases resistance to Sclerotium rolfsii as expressed in excised leaf tissues and whole plants. Resistance in excised leaf tissues was evaluated according to the rate of necrosis induced by Sclerotium rolfsii following inoculation with mycelium. Resistance to Sclerotium rolfsii in whole plants was evaluated according to their survival following crown inoculations. Three alfalfa populations previously selected from cv. Delta for quantitative resistance to Sclerotinia trifoliorum exhibited enhanced resistance to Sclerotium rolfsii, in comparison with Delta or with susceptible populations, in excised leaf tissues. When whole plants of Delta and two of these populations, Sclerotinia trifoliorum resistant (STR) and Mississippi Sclerotinia resistant (MSR), were inoculated with Sclerotium rolfsii at 3 to 8 weeks of age, significant (P = 0.01) differences in survival were attributed to plant age at inoculation and alfalfa populations. Survival of both MSR and STR was significantly (P = 0.05) greater than for Delta; the best differential results were obtained by inoculating plants 5 to 7 weeks old. To evaluate relationships of resistance to Sclerotinia trifoliorum and Sclerotium rolfsii over a broader genetic background, additional populations were selected for resistance to Sclerotinia trifoliorum from four other alfalfa cultivars by leaf-inoculation techniques, and this resistance was confirmed by whole-plant inoculations. In excised leaf tissues, all four of these populations also expressed enhanced resistance to Sclerotium rolfsii in comparison with either parent cultivars or populations of comparable size selected at random. These results establish that selection for quantitative resistance to Sclerotinia trifoliorum in alfalfa also confers enhanced resistance to Sclerotium rolfsii as expressed in excised leaf tissues and whole plants. Results suggest, therefore, that genes for quantitative resistance to Sclerotinia trifoliorum and Sclerotium rolfsii in alfalfa are likely to be synonymous, overlapping, or closely linked.  相似文献   

Effects of various adjuvants on efficacy of a vaccine against Streptococcus bovis and Lactobacillus spp in cattle     

Shu Q  Hillard MA  Bindon BM  Duan E  Xu Y  Bird SH  Rowe JB  Oddy VH  Gill HS 《American journal of veterinary research》2000,61(7):839-843

OBJECTIVE: To determine efficacy of vaccines incorporating QuilA, alum, dextran combined with mineral oil, or Freund adjuvant for immunization of feedlot cattle against Streptococcus bovis and Lactobacillus spp. ANIMALS: 24 steers housed under feedlot conditions. PROCEDURE: Steers were randomly assigned to 4 experimental groups and a control group. Animals in experimental groups were inoculated on days 0 and 26 with vaccines containing Freund adjuvant (FCA), QuilA, dextran combined with mineral oil (Dex), or alum as adjuvant. Serum anti-S bovis and anti-Lactobacillus IgG concentrations were measured, along with fecal pH, ruminal fluid pH, and number of S bovis and Lactobacillus spp in ruminal fluid. RESULTS: Throughout the study, serum anti-S bovis and anti-Lactobacillus IgG concentrations for animals in the Dex, QuilA, and alum groups were similar to or significantly higher than concentrations for animals in the FCA group. Serum anti-S bovis and anti-Lactobacillus IgG concentrations were significantly increased on days 26 through 75 in all 4 experimental groups, and there was a linear relationship between anti-S bovis and anti-Lactobacillus IgG concentrations. For animals in the QuilA and Dex groups, mean pH of feces throughout the period of experiment were significantly higher and numbers of S bovis and Lactobacillus spp in ruminal fluid on day 47 were significantly lower than values for control cattle. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that immunization of feedlot steers against S bovis and Lactobacillus spp with vaccines incorporating Freund adjuvant, QuilA, dextran, or alum as an adjuvant effectively induced high, long-lasting serum anti-S bovis and anti-Lactobacillus IgG concentrations. Of the adjuvants tested, dextran may be the most effective.  相似文献   

Comparative Expression Analysis of Gametogenesis‐Associated Genes in Foetal and Adult Bubaline (Bubalus bubalis) Ovaries and Testes          下载免费PDF全文

SM Shah  N Saini  S Ashraf  M Zandi  MK Singh  RS Manik  SK Singla  P Palta  MS Chauhan 《Reproduction in domestic animals》2015,50(3):365-377

This study was conducted to identify and analyse the expression of gametogenesis‐associated genes and proteins in foetal and adult buffalo gonads of both the sexes. Relative quantification of the genes was determined by qPCR and Western blotting. Immunohistochemistry was also performed for various gametogenesis‐associated proteins in foetal and adult gonads of both the sexes. We observed significantly (p < 0.05) increased expression of primordial germ cell‐specific, meiotic as well as genes associated with oocyte maturation and development in foetal ovaries as compared to the adult ones. However, significantly (p < 0.05) increased expression of proteins associated with oocyte maturation like GDF9 and ZP4 was found in adult ovaries, indicating temporal regulation of mRNA translation during oogenesis. Meiotic genes showed significantly (p < 0.05) increased expression in adult testes as compared to foetal testes and ovaries, indicating onset of meiosis at a later stage in spermatogenesis. In general, the expression of primordial germ cell‐associated as well as meiotic genes was higher in adult testes, indicating the increased biological activity in the organ. Immunohistochemistry revealed localized expression of gametogenesis‐associated proteins in ovarian follicles and seminiferous tubules of testes, while the surrounding somatic tissues were devoid of these proteins. The study gives an understanding of the sequential and temporal events of gene expression as well as mRNA translation during male and female gametogenesis. It could also be concluded that follicles and seminiferous tubules are the functional units of the female and male gonads, respectively, and their function could be enhanced by appropriate chemical and genetic intervention of the somatic tissue immediately surrounding them. This assumes importance in the context that buffalo attains sexual maturity at an older age of 2–3 years and have smaller ovaries with lesser number of primordial follicles in comparison with cattle, which is suggested to be the main reason of their poor breeding performance.  相似文献   

Response of the bovine corpus luteum to increased secretion of luteinizing hormone induced by exogenous gonadotropin releasing hormone     

T L Martin  L V Swanson  L H Appell  K E Rowe  F Stormshak 《Domestic animal endocrinology》1990,7(1):27-34

Two experiments were conducted to investigate the response of the bovine corpus luteum to surges of luteinizing hormone (LH) induced by natural gonadotropin-releasing hormone (GnRH) administered twice during the same estrous cycle. In experiment 1, eight mature beef cows, each cow serving as her own control, were injected intravenously (iv) with saline on days 2 and 8 of the cycle (day of estrus = day 0 of the cycle), then with 100 micrograms GnRH on days 2 and 8 of the subsequent cycle. Jugular blood samples were taken immediately prior to an injection and at 15, 30, 45, 60, 120 and 240 min postinjection, to quantitate changes in serum luteinizing hormone. Blood was also collected on alternate days after an injection until day 16 of the cycle, to characterize changes in serum progesterone concentrations. Although exogenous GnRH caused release of LH on days 2 and 8 of the cycle, the quantity of LH released was greater on day 8 (P less than .025). Serum levels of progesterone after treatment with GnRH on day 8 of the cycle did not differ significantly from those observed during the control cycles of the heifers. Because exposure of the bovine corpus luteum to excess LH, induced by GnRH early during the estrous cycle, causes attenuated progesterone secretion during the same cycle, these data suggest that a second surge of endogenous LH may ameliorate the suppressive effect of the initial release of LH on luteal function. Duration of the estrous cycle was not altered by treatment (control, 20.4 +/- .5 vs. treated, 20.4 +/- .4 days).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Spatial patterns of soil nutrients,plant diversity,and aboveground biomass in the Inner Mongolia grassland: before and after a biodiversity removal experiment     

Fei Yuan  Jianguo Wu  Ang Li  Helen Rowe  Yongfei Bai  Jianhui Huang  Xingguo Han 《Landscape Ecology》2015,30(9):1737-1750

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The inheritance of winter hardiness in Pisum II. Description and release of advance generation breeding lines     

D. Markarian  R. R. Harwood  Ph. R. Rowe 《Euphytica》1968,17(1):110-113

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Crossability relationships of andean potato varieties of three ploidy levels     

M. T. Jackson  P. R. Rowe  J. G. Hawkes 《Euphytica》1978,27(2):541-551

Summary The formation of triploids in 4x×2x crosses was studied in primitive potato varieties from the Andes of Peru and Bolivia. Triploid frequencies were as high as 80–100% in some crosses, although the actual number of seeds was low. The triploid block varied according to the tetraploid parent, and was never entirely absent. The likelihood of triploid formation was studied in 4x×2x crosses where pollen from both tetraploids and diploids of known genotype was used. Even though the diploids were chosen for their non-production of 2n gametes, as detected in pollen grain size, 66% of the hybrids were tetraploid. The amount and probability of gene-flow between the tetraploid and diploid gene-pools, either directly through 2n gametes or through triploid bridges was examined. Most of the 20 cultivars of S. x chaucha produced seed in crosses with tetraploids and diploids, although the fertility of the latter crosses was four times higher. The female fertility of some of the triploids thus allows them to exchange genes with the tetraploids and diploids, although gene-flow occurs more rapidly through direct transfer from diploids to tetraploids via 2n gametes.  相似文献   

The nature of Solanum × chaucha Juz. et Buk., a triploid cultivated potato of the South American Andes     

M. T. Jackson  J. G. Hawkes  P. R. Rowe 《Euphytica》1977,26(3):775-783

Summary The variation in Solanum × chaucha Juz. et Buk. (2n=3x=36) was studied using 114 accessions from the Potato Collection maintained by the International Potato Center. These accession represented less than 5% of the collection originally screened for ploidy. Twenty morphological characters of the tubers, inflorescences and leaves were scored. The accessions were grouped into 20 morphotypes on the basis of the tuber characters. Two-qualitative characters, red-anther tip and sky-blue flowers were diagnostic of 4 morphotypes, but the variation of the quantitative characters overlapped among morphotypes, and were of limited value. Electrophoretic separation of tuber proteins in 7.5% polyacrylamide gels generally confirmed the morphotype groupings. It is concluded that each of the morphotypes represents a single genotype, and these are named according to the International Code of Nomenclature for Cultivated Plants. The variation within S. × chaucha apparently has been restricted by its hybrid origin.  相似文献   

The prefrontal cortex: response selection or maintenance within working memory?   总被引：1，自引：0，他引：1  

Rowe JB  Toni I  Josephs O  Frackowiak RS  Passingham RE 《Science (New York, N.Y.)》2000,288(5471):1656-1660

It is controversial whether the dorsolateral prefrontal cortex is involved in the maintenance of items in working memory or in the selection of responses. We used event-related functional magnetic resonance imaging to study the performance of a spatial working memory task by humans. We distinguished the maintenance of spatial items from the selection of an item from memory to guide a response. Selection, but not maintenance, was associated with activation of prefrontal area 46 of the dorsal lateral prefrontal cortex. In contrast, maintenance was associated with activation of prefrontal area 8 and the intraparietal cortex. The results support a role for the dorsal prefrontal cortex in the selection of representations. This accounts for the fact that this area is activated both when subjects select between items on working memory tasks and when they freely select between movements on tasks of willed action.  相似文献   

A Chemoautotrophically Based Cave Ecosystem   总被引：1，自引：0，他引：1  

SM Sarbu  TC Kane  BK Kinkle 《Science (New York, N.Y.)》1996,272(5270):1953-1955

Microbial mats discovered in a ground-water ecosystem in southern Romania contain chemoautotrophic bacteria that fix inorganic carbon, using hydrogen sulfide as an energy source. Analysis of stable carbon and nitrogen isotopes showed that this chemoautotrophic production is the food base for 48 species of cave-adapted terrestrial and aquatic invertebrates, 33 of which are endemic to this ecosystem. This is the only cave ecosystem known to be supported by in situ autotrophic production, and it contains the only terrestrial community known to be chemoautotrophically based.  相似文献