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S. Kresovich J. G. K. Williams J. R. McFerson E. J. Routman B. A. Schaal 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1992,85(2-3):190-196
Summary Effective conservation and the use of plant genetic resources are essential for future agricultural progress. Critical to this conservation effort is the development of genetic markers which not only distinguish individuals and accessions but also reflect the inherent variation and genetic relationships among collection holdings. We have examined the applicability of the random amplified polymorphic DNA (RAPD) assay for quick, cost-effective, and reliable use in addressing these needs in relation to collection organization and management. Twenty-five decamer oligonucleotide primers were screened individually with a test array composed of individuals representing a range of genetic relationships in Brassica oleracea L. (vegetable and forage cole crops). Over 140 reproducible, polymorphic fragments were generated for study. Each individual of the test array exhibited a unique molecular genotype and composites specific for accessions and botanical varieties could be established. An analysis of similarity based on amplified DNA fragments reflected the known genetic relationships among the selected entries. These results demonstrated that RAPD markers can be of great value in gene bank management for purposes of identification, measurement of variation, and establishment of genetic similarity at the intraspecific level. 相似文献
2.
Fuchs Marc Klas Ferdinand E. McFerson James R. Gonsalves Dennis 《Transgenic research》1998,7(6):449-462
Transgenic melon and squash containing the coat protein (CP) gene of the aphid transmissible strain WL of cucumber mosaic cucumovirus (CMV) were grown under field conditions to determine if they would assist the spread of the aphid non-transmissible strain C of CMV, possibly through heterologous encapsidation and recombination. Transgenic melon were susceptible to CMV strain C whereas transgenic squash were resistant although the latter occasionally developed chlorotic blotches on lower leaves. Transgenic squash line ZW-20, one of the parents of commercialized cultivar Freedom II, which expresses the CP genes of the aphid transmissible strains FL of zucchini yellow mosaic (ZYMV) and watermelon mosaic virus 2 (WMV 2) potyviruses was also tested. Line ZW-20 is resistant to ZYMV and WMV 2 but is susceptible to CMV. Field experiments conducted over two consecutive years showed that aphid-vectored spread of CMV strain C did not occur from any of the CMV strain C-challenge inoculated transgenic plants to any of the uninoculated CMV-susceptible non- transgenic plants. Although CMV was detected in 3% (22/764) of the uninoculated plants, several assays including ELISA, RT- PCR-RFLP, identification of CP amino acid at position 168, and aphid transmission tests demonstrated that these CMV isolates were distinct from strain C. Instead, they were non-targeted CMV isolates that came from outside the field plots. This is the first report on field experiments designed to determine the potential of transgenic plants expressing CP genes for triggering changes in virus-vector specificity. Our results indicate that transgenic plants expressing CP genes of aphid transmissible strains of CMV, ZYMV, and WMV 2 are unlikely to mediate the spread of aphid non-transmissible strains of CMV. This finding is of practical relevance because transgenic crops expressing the three CP genes are targeted for commercial release, and because CMV is economically important, has a wide host range, and is widespread worldwide. 相似文献
3.
W. B. Phippen S. Kresovich F. G. Candelas J. R. McFerson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(2):227-234
To better characterize and conserve crop genetic resources, the assessment of genetic identity, relatedness, and structure
among entries and collections becomes a priority. In the present study, a random amplified polymorphic DNA (RAPD) assay was
applied as a quick, cost-effective, and preliminary screen to quantify and partition the molecular variation among accessions.
Fourteen phenotypically uniform accessions of Brassica oleracea var. capitata L. (cabbage) similarly designated as `Golden Acre' were tested with nine decamer oligonucleotide primers. These amplifications
generated 110 fragments, of which 80 were polymorphic ranging in size from 370 to 1720 bp. The 80 polymorphic fragments were
sufficient to distinguish between all 14 accessions. Data based on the partitioning of variation among accessions indicated
that `Golden Acre' entries could be reduced to as few as four groups, with the potential loss of variation being only 4.6%
of the absolute current genetic variation in those holdings as estimated from RAPD analysis. This proposed grouping would
concurrently save approximately 70% [$750–1000 (US) per accession] for each cycle of regeneration (approximately 20–25 years
at most) which alternatively could then be used for other priorities in B. oleracea conservation and use. This case represents but one example where targeted use of a molecular-marker assay linked with rigorous
statistical analysis will be useful for plant genebank management, particularly for questions at the intraspecific level.
Molecular markers will provide genebank curators with additional sources of information to better plan and organize collection
holdings and use finite financial support in a more effective manner.
Received: 10 June 1996 / Accepted: 23 August 1996 相似文献
4.
Summary The nitrogenous compounds in the xylem (bleeding) sap of lines of field-grownPhaseolus vulgaris L., known to vary in N2 fixation and yield, were measured during growth with and without N fertilizer. Forty nine-67% of the total sap N was in the form of nitrate in fertilized plants, with low amounts of the ureides, allantoin and allantoic acid (4–12%). Ureides contributed between 17 and 38% to the total sap N of non-fertilized plants, with nitrate generally comprising less than 40%. Among the nine lines grown without fertilizer there were significant differences in the % of the sap N as ureides and also in the total mol N ml–1 sap.The ASN/GLN ratio (mol/mol) was greater in sap collected from the two parental lines given fertilizer compared with non-fertilized plants. However the actual ratio varied between the parental lines. Together the two amides generally comprised between 43–62% of the amino-N in sap samples from the two parental lines with or without N fertilizer.For each N treatment (fertilized or non-fertilized) there were no obvious differences in sap composition between the high N2 fixing lines and the low N2 fixing lines. However there was generally a positive relationship between the rate of N translocation (total N concn. ml–1 sap x rate of exudation) and the ranking of the lines on the basis of higher N2 fixation rates (acetylene reduction), which was to a large extent independent of the source of N available to the plant. 相似文献
5.
S. Kresovich A. K. Szewc-McFadden S. M. Bliek J. R. McFerson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,91(2):206-211
A size-fractionated library of Brassica napus L. (rapeseed), composed of 15000 clones, was screened for the presence of GA-, CA-, and GATA-simple-sequence repeats (SSRs). GA-SSRs were four- and five-fold more abundant than CA- and GATA-SSRs, respectively, and present at a frequency of approximately one SSR for every 100 kb of DNA. Following the sequencing of 124 positive clones, primer pairs were designed and evaluated for seven selected SSRs. Products were amplified in an array of individuals of B. napus, B. oleracea and B. rapa, demonstrating that the seven SSRs were conserved among species. Two SSRs were polymorphic. Among 11 accessions, the dinucleotide (GA)-repeat, B.n.9A, yielded 12 fragments, while the tetranucleotide-repeat (GATA), B.n.6A2, revealed two fragments. Automated, fluorescence-based detection of polyacrylamide gels has been employed to simultaneously increase throughput, reduce unit cost, improve analytical resolution, and expedite data acquisition of SSR analysis. Though initial financial investment and technical capabilities may prevent some from directly employing our documented approach, SSR analysis warrants further investigation as a tool in genetic studies for enhancing both the conservation and utilization of genetic resources. 相似文献
6.
Fuchs Marc McFerson James R. Tricoli David M. McMaster J. Russell Deng Rosaline Z. Boeshore Maury L. Reynolds John F. Russell Paul F. Quemada Hector D. Gonsalves Dennis 《Molecular breeding : new strategies in plant improvement》1997,3(4):279-290
Cantaloupe line CZW-30 containing coat protein gene constructs of cucumber mosaic cucumovirus (CMV), zucchini yellow mosaic potyvirus (ZYMV), and watermelon mosaic virus 2 potyvirus (WMV-2) was investigated in the field over two consecutive years for resistance to infections by CMV, ZYMV, and/or WMV-2. Resistance was evaluated under high disease pressure achieved by mechanical inoculations and/or natural challenge inoculations by indigenous aphid vectors. Across five different trials, homozygous plants were highly resistant in that they never developed systemic symptoms as did the nontransformed plants but showed few symptomatic leaves confined close to the vine tips. Hemizygous plants exhibited a significant delay (2–3 weeks) in the onset of disease compared to control plants but had systemic symptoms 9–10 weeks after transplanting to the field. Importantly, ELISA data revealed that transgenic plants reduced the incidence of mixed infections. Only 8% of the homozygous and 33% of the hemizygous plants were infected by two or three viruses while 99% of the nontransformed plants were mixed infected. This performance is of epidemiological significance. In addition, control plants were severely stunted (44% reduction in shoot length) and had poor fruit yield (62% loss) compared to transgenic plants, and most of their fruits (60%) were unmarketable. Remarkably, hemizygous plants yielded 7.4 times more marketable fruits than control plants, thus suggesting a potential commercial performance. This is the first report on extensive field trials designed to assess the resistance to mixed infection by CMV, ZYMV, and WMV-2, and to evaluate the yield of commercial quality cantaloupes that are genetically engineered. 相似文献
7.
Identification of polymorphic,conserved simple sequence repeats (SSRs) in cultivated Brassica species 总被引:20,自引:0,他引:20
A. K. Szewc-McFadden S. Kresovich S. M. Bliek S. E. Mitchell J. R. McFerson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(4):534-538
The application of simple sequence repeat (SSR) genotyping for the characterization of genetic variation in crop plants has been hindered by ready access to useful primer pairs and potentially limited conservation of the repeat sequences among related species. In this phase of work, we report on the identification and characterization of SSRs that are conserved in Brassica napus L. (rapeseed) and its putative progenitors, B. oleracea L. (cabbage, and related vegetable types) and B. rapa (vegetable and oil types). Approximately 140 clones from a size-fractionated genomic library of B. napus were sequenced, and primer pairs were designed for 21 dinucleotide SSRs. Seventeen primer pairs amplified products in the three species and, among these, 13 detected variation between and within species. Unlike findings on SSR information content in human, no relationship could be established between the number of tandem repeats within the target sequence and heterozygosity. All primer pairs have been designed to work under identical amplification conditions; therefore, single-reaction, multiplex polymerase chain reaction (PCR) with these SSRs is possible. Once moderate numbers of primer pairs are accessible to the user community, SSR genotyping may provide a useful method for the characterization, conservation, and utilization of agricultural crop diversity. 相似文献
8.
S. C. Hokanson A. K. Szewc-McFadden W. F. Lamboy J. R. McFerson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(5-6):671-683
A collection of 66 Malus×domestica Borkh. accessions from the USDA-ARS Plant Genetic Resources Unit’s core collection was screened with a set of eight SSR (simple
sequence repeat) primers developed at the PGRU in order to determine genetic identities, estimate genetic diversity, and to
identify genetic relationships among these accessions. All eight primer pairs generated multiple fragments when used in amplification
reactions with DNA from these accessions. High levels of variation were detected with a mean of 12.1 alleles per locus and
a mean heterozygosity across all eight loci of 0.693. The eight primer pairs utilized in this study unambiguously differentiated
all but seven pairs of accessions in this collection of 66 M.×domestica Borkh. genotypes. The probability of matching any two genotypes at all eight loci in this study was approximately 1 in 1
billion. The markers detected two misnamed accessions in the collection. Genetic-identity data produced a genetic-relatedness
phenogram which was concordant with geographic origins and/or known pedigree information. These SSR markers show great promise
as tools for managing Malus ex situ germplasm collections as well as for collection and preservation strategies concerning wild Malus populations in situ.
Received: 28 March 1998 / Accepted: 29 April 1998 相似文献
9.
乙酰乳酸合成酶基因在芸苔属栽培种内的遗传变异 总被引:4,自引:0,他引:4
利用乙酰乳酸合成酶(ALS)基因开发抗除草剂的转基因植物引起了植物分子生物学家的广泛兴趣。了解农业上重要物种中ALS基因的结构、组织、功能及其遗传变异是十分必要的。在芸苔属植物中,ALS基因是以多基因家族的形式存在。本研究采用PCR技术试验:1)揭示ALS基因在芸苔属3个栽培种间的遗传变异;2)确定在种、亚种和品种3个水平上ALS基因变异的分布;3)评价利用由ALS基因产生的遗传标记区别B.nap 相似文献
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