共查询到20条相似文献,搜索用时 15 毫秒
1.
X. Reboud I. Till-Bottraud 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,82(6):690-696
Summary The cost of resistance has been measured by a competition experiment over a range of densities, in the absence of herbicide treatment, on two nearly isogenic lines of Foxtail millet, differing in a chloroplastic resistance to herbicide. Three characters have been measured: shoot height, shoot weight, and seed production. Sensitive individuals were better competitors despite a larger decrease in production under within-biotype competition. The cost of resistance was density dependent and increased with density. The cost was higher when measured on seed production and reached 65% at the higher density for resistant individuals. This is compatible with the low frequency or the absence of that gene in natural populations. This work illustrates that the cost is easiest to observe when high levels of constraints are used. 相似文献
2.
E. Purba C. Preston S. B. Powles 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,87(5):598-602
The mode of inheritance of resistance to bipyridyl herbicides in bipyridyl-resistant biotypes of Arctotheca calendula and of Hordeum leporinum was investigated. F1 plants from reciprocal crosses between diquat-resistant and -susceptible plants of A. calendula showed an intermediate response to diquat application that was nuclearly inherited. Treatment of F2 plants with 100 g ai ha-1 of diquat or 800 g ai ha-1 of paraquat killed all homozygous-susceptible plants, caused severe injury to heterozygous plants but only slight or no injury to homozygous-resistant plants. Back crosses of F1 to susceptible plants exhibited intermediate and susceptible phenotypes. The observed segregation ratios in F2 and test-cross populations fitted predicted segregation ratios, 1:2:1 (R:I:S) and 1:1 (I:S) respectively, showing that bipyridyl resistance is conferred by a single incompletely-dominant gene. Biotypes of paraquat-resistant and -susceptible H. leporinum were crossed reciprocally. F1 plants from reciprocal crosses showed an intermediate response to paraquat application. The F2 progeny showed segregation ratios that fitted the predicted segregation ratio of 1:2:1 (R:I:S) forinheritance of resistance being governed by a single partially-dominant gene. 相似文献
3.
Field assessments of gene flow from transgenic to cultivated rice (Oryza sativa L.) using a herbicide resistance gene as tracer marker 总被引:6,自引:0,他引:6
J. Messeguer C. Fogher E. Guiderdoni V. Marfà M. M. Català G. Baldi E. Melé 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(8):1151-1159
Development of plant genetic engineering has led to the deployment of transgenic crops and, simultaneously, to the need for
a thorough assessment of the risks associated with their environmental release. This study investigated the occurrence of
gene flow from transgenic rice to non-transgenic rice plants under agronomic conditions using a herbicide resistance gene
as a tracer marker. Two field experiments were established in the paddy fields of two main Mediterranean rice-growing areas
of Spain and Italy. In both locations analyses of phenotypic, molecular and segregation data showed that pollination of recipient
plants with pollen of the transgenic source occurred at a significant frequency. A gene flow slightly lower than 0.1% was
detected in a normal side-by-side plot design. Similar results were found in a circular plot when the plants were placed at
1-m distance from the transgenic central nucleus. A strong asymmetric distribution of the gene flow was detected among this
circle and highest values (0.53%) were recorded following the direction of the dominant wind. A significant lowest value (0.01%)
was found in the other circle (5 m from the transgenic plants) as was expected according to the characteristics of rice pollen.
Such circular-field trial designs could also prove to be very useful in studying the gene flow to other commercial cultivars
of rice with the aim of establishing strategies to prevent pollen dispersal from commercial transgenic fields to the neighbouring
conventional fields.
Received: 23 February 2001 / Accepted: 31 March 2001 相似文献
4.
5.
D. T. Singh K. Nirmala D. R. Modi S. Katiyar H. N. Singh 《Molecular & general genetics : MGG》1987,208(3):436-438
Summary An aerobic diazotrophic Gloeocapsa strain contained genes conferring resistance to the growth toxic effects of rice field herbicides Machete and Basalin. The results of genetic crosses and of DNA-mediated genetic transformation experiments both suggested the absence of a heterospecific barrier for the transfer of herbicide resistance genes from a Gloeocapsa strain to Nostoc muscorum and their stable expression and maintenance in the latter. These findings will have considerable implications in cyanobacterial biofertilizer technology. 相似文献
6.
E. Frascaroli D. D. Songstad 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(2-3):342-346
Pollen genotype selection for genes expressed in both the haploid and diploid phases of the plant life cycle can lead to correlated
responses detectable in the sporophyte. A pollen selection was conducted in two genetic backgrounds of maize (Zea mays L.) for chlorsulfuron resistance, conferred by the XA17 allele. Plants of two backcross (BC) lines segregating 1 (heterozygote, resistant) : 1 (homozygote, susceptible) for chlorsulfuron
resistance were used as pollen donor. Selection treatment was applied during microspore development, and tassels were cut
about 10 days before anthesis and placed into a liquid medium with or without 40 mg l–1 of chlorsulfuron. Pollen was used to fertilize an unrelated susceptible genotype (tester). The resulting testcrosses (TC)
were evaluated in the greenhouse by spraying seedlings with chlorsulfuron at 23 g ha–1. Non-selected TC progenies derived from heterozygous BC plants showed a proportion of resistant and susceptible plants close
to the expected 1:1 ratio, while non-selected TC progenies derived from homozygous BC plants showed susceptible plants only.
Selected TC progenies derived from heterozygous BC plants showed a frequency of resistant plants ranging from 89% to 100%.
BC plants homozygous for the susceptible allele, subjected to selection treatment, gave poor seed set, and no resistant plants
were found in their TC progenies. Resistant TC plants obtained through pollen genotype selection were selfed, and the proportion
of resistant plants was close to 3:1 in all selfed families, in accordance with the hypothesis that all of them inherited
the XA17 allele through selection. In this study, pollen genotype selection was extremely effective, and its effect persisted in the
second sporophytic generation.
Received: 19 November 1999 / Accepted: 30 April 2000 相似文献
7.
Guoying Xiao Longping Yuan Samuel S. M. Sun 《Molecular breeding : new strategies in plant improvement》2007,20(3):287-292
Hybrid rice plays an important role in China's aim to improve rice production as it accounts for some 50% of rice planting
area but produces about 60% of the total rice grain. However, the existing three-line system used in hybrid rice production
has its limitations. The two-line system, which makes use of photoperiod-sensitive genic male-sterile (PGMS) and thermo-sensitive
genic male-sterile (TGMS) lines to generate the male-sterile parental line, was developed to overcome some of these limitations.
The sterility of the male-sterile line of two-line hybrid rice, however, fluctuates when the temperature-sensitive phase of
fertility encounters abnormal low temperatures during hybrid seed production, which induces selfing and decreases the purity
of hybrid. We describe here the strategy of utilizing a herbicide resistance gene in two-line hybrid rice to eliminate this
fluctuation in the sterility of the P/TGMS lines during hybrid seed production and reports the development of the herbicide
resistance restorer line Bar68-1 and its herbicide-resistant early season hybrid rice Xiang125s/Bar68-1. When the restorer
line and its derived hybrid are herbicide resistant, the selfed seeds can be removed easily from the hybrid by herbicide spraying.
A herbicide resistance gene bar was transferred into a restorer line by particle bombardment. The resulting transgenic restorer line Bar68-1 and its hybrid
Xiang125 s/Bar68-1 inherited stable herbicide resistance. The purity of Xiang125s/Bar68-1 was increased by spraying the seed
bed with herbicide, which resulted in a significant increase in yield, grain quality, and disease resistance in comparison
to the controls in a regional trial. 相似文献
8.
Bolette P. Pedersen Paul Neve Christian Andreasen Stephen B. Powles 《Basic and Applied Ecology》2007,8(3):258-268
Repeated use of glyphosate has resulted in evolution of glyphosate-resistant Lolium rigidum populations in Australia. The relative growth, competitiveness and reproductive output of glyphosate resistant (R) and susceptible (S) L. rigidum phenotypes from a single population were compared in competition with wheat. Vegetative growth of R and S individuals was studied in response surface experiments in the glasshouse and seed production was measured using an additive neighbourhood design experiment conducted in pots outside during the normal growing season of L. rigidum in Australia. There were no significant differences in vegetative growth or competitiveness of the R and the S phenotypes. The mean weight of seeds produced by R plants was significantly greater than that produced by S individuals. In the absence of wheat and at low wheat densities, S plants produced more seeds than R plants. However, at higher crop densities, differences in seed production were not significant. This is the first study to compare components of fitness at key life history stages for glyphosate R and S phenotypes isolated from a single weed population. The results presented indicate important differences in resource allocation during the reproductive stage for R and S phenotypes. Subtle differences in life history strategies may be manipulated by agronomic management to exploit the potential ecological fitness costs of the R phenotype. Further studies are required to provide a greater understanding of the occurrence and extent of fitness costs associated with glyphosate resistance. This knowledge can then be incorporated into models that simulate resistance evolution to design management strategies to prevent and/or contain the spread of glyphosate resistance. 相似文献
9.
Lei Zhang Qing Lu Honggao Chen Gang Pan Shushu Xiao Yuntao Dai Qiang Li Jiwen Zhang Xiaozhi Wu Jiangsheng Wu Jumin Tu Kede Liu 《Molecular breeding : new strategies in plant improvement》2007,19(1):59-68
Bentazon and sulfonylureas have been used for selective control of broadleaf weeds and sedges in rice fields for more than
20 years. A bentazon and sulfonylurea susceptible mutant, bel, was previously identified for the purpose of allowing these herbicides to be used for removing false hybrids from hybrid
rice. While this mutation has been used successfully in rice breeding, the genetic nature of bel is not known. Using 1,776 susceptible plants from a population of 10,000 F2 individuals, we constructed a fine map for the Bel locus and delimited it to a 36-kb DNA fragment between two restriction fragment length polymorphism markers, L5 and P17.
Bioinformatic analysis indicated that there are five genes within this interval, an ethylene-responsive OsER33 gene and four tandem repeats of cytochrome P450 genes designated as CYP81A5, CYP81A6, CYP81A7, and CYP81A8. Comparative sequencing could not find any differences in the coding regions of the OsER33, CYP81A5, CYP81A7, and CYP81A8 genes between the mutant bel and its wild-type progenitor W6154S, but did identify a single base guanine deletion at position +1,332 bp downstream from
the translation start codon of CYP81A6. This deletion introduces a premature stop codon and leads to the loss of the heme-binding motif, which is essential for
cytochrome P450 function because it contains an absolutely conserved cysteine that serves as the fifth ligand to the heme
iron. CYP81A6 presumably functions as a hydroxylase for the detoxification of bentazon and sulfonylurea herbicides in rice. A gene-specific
cleaved amplified polymorphic sequence marker and tightly linked flanking markers were developed that will be very useful
for selection of the bel allele when transferred to photoperiod-/thermo-sensitive genic male sterility and CMS lines in hybrid rice breeding programs. 相似文献
10.
We evaluated in the present study the effect of deltamethrin resistance on the fitness cost of the filed populations of Anopheles labranchiae. A susceptible population was used as reference to do different comparisons. We selected the most resistant larvae population collected from northern Tunisia. Eggs were used for study of life history traits including developmental time, larvae mortality, fertility, hatchability and adult sex-ratio. Our results showed that deltamethrin resistance affected negatively (p < 0.05) the developmental time with the median range of 70 h, mortality with the rate of 7 folds in resistant population and hatchability which are lower than in susceptible population. Whereas, no significant differences were detected in adult sex-ratio and fertility of the two studied populations. Our results could help to determine the evolution of population dynamics of the resistant studied population in the areas where insecticide resistance is reported and resistance management is needed. 相似文献
11.
The cost of adaptations may depend on environmental conditions. We consider how the fitness cost of resistance to the herbicide triazine in Amaranthus hybridus interacts with folivory from the beetle Disonycha glabrata. Triazine-resistant (TR) genotypes suffer a fitness cost because of a pleiotropic reduction in the light reaction of photosynthesis, which in turn often leads to a reduction in photosynthetic rate. We found that the fitness cost of triazine resistance was 360% greater in the presence than absence of D. glabrata. This resulted from multiple phenotypic trade-offs, with TR plants suffering greater herbivory and displaying a diminished tolerance of damage. Our work highlights the importance of incorporating appropriate ecological variation into the assessment of fitness trade-offs. The results of this study also illustrate the potential for herbivores to impose selection on photosynthetic variation, and for variation in resource acquisition to obscure fitness costs. 相似文献
12.
Rubén álvarez José M. álvarez Jaime M. Humara ángeles Revilla Ricardo J. Ordás 《Biotechnology letters》2009,31(9):1477-1483
The bar gene was introduced into the cork oak genome. Cork oak embryogenic masses were transformed using the Agrobacterium strain AGL1 which carried the plasmid pBINUbiBar. This vector harbours the genes, nptII and bar, the latter under control of the maize ubiquitin promoter. The transgenic embryogenic lines were cryopreserved. Varying activities
of phosphinothricin acetyl transferase were detected among the lines, which carried 1–4 copies of the insert. Molecular and
biochemical assays confirmed the stability and expression of the transgenes 3 months after thawing the cultures. These results
demonstrate genetic engineering of herbicide tolerance in Quercus spp.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Rubén álvarez, Ricardo J. Ordás are contributed equally. 相似文献
13.
Jeong E Houn T Kuk Y Kim ES Chandru HK Baik M Back K Guh JO Han O 《Bioorganic chemistry》2003,31(5):389-397
In an effort to asses the effect of Val311Met point mutation of Bacillus subtilis protoporphyrinogen oxidase on the resistance to diphenyl ether herbicides, a Val311Met point mutant of B. subtilis protoporphyrinogen oxidase was prepared, heterologously expressed in Escherichia coli, and the purified recombinant Val311Met mutant protoporphyrinogen oxidase was kinetically characterized. The mutant protoporphyrinogen oxidase showed very similar kinetic patterns to wild type protoporphyrinogen oxidase, with slightly decreased activity dependent on pH and the concentrations of NaCl, Tween 20, and imidazole. When oxyfluorfen was used as a competitive inhibitor, the Val311Met mutant protoporphyrinogen oxidase showed an increased inhibition constant about 1.5 times that of wild type protoporphyrinogen oxidase. The marginal increase of the inhibition constant indicates that the Val311Met point mutation in B. subtilis protoporphyrinogen oxidase may not be an important determinant in the mechanism that protects protoporphyrinogen oxidase against diphenyl ether herbicides. 相似文献
14.
The dominance of the herbicide resistance cost in several Arabidopsis thaliana mutant lines 总被引:6,自引:0,他引:6
Resistance evolution depends upon the balance between advantage and disadvantage (cost) conferred in treated and untreated areas. By analyzing morphological characters and simple fitness components, the cost associated with each of eight herbicide resistance alleles (acetolactate synthase, cellulose synthase, and auxin-induced target genes) was studied in the model plant Arabidopsis thaliana. The use of allele-specific PCR to discriminate between heterozygous and homozygous plants was used to provide insights into the dominance of the resistance cost, a parameter rarely described. Morphological characters appear more sensitive than fitness (seed production) because 6 vs. 4 differences between resistant and sensitive homozygous plants were detected, respectively. Dominance levels for the fitness cost ranged from recessivity (csr1-1, ixr1-2, and axr1-3) to dominance (axr2-1) to underdominance (aux1-7). Furthermore, the dominance level of the herbicide resistance trait did not predict the dominance level of the cost of resistance. The relationship of our results to theoretical predictions of dominance and the consequences of fitness cost and its dominance in resistance management are discussed. 相似文献
15.
The advantage of the resistance conferred by a mutation can sometimes be offset by a high fitness-cost penalty. This balance will affect possible fate of the resistance allele. Few studies have explored the impact of the genetic background on the expression of the resistance fitness cost and none has attempted to measure the variation in fitness-cost dominance. However, both the fitness penalty and its dominance may modify evolutionary trajectory and outcome. Here the impact of Arabidopsis thaliana intraspecific genetic diversity on fitness cost and its associated dominance was investigated by analysing 12 quantitative traits in crosses between a mutant conferring resistance to the herbicide 2,4-D and nine different natural genetic backgrounds. Fitness cost values were found to be more affected by intraspecific genetic diversity than fitness cost dominance, even though this effect depends on the quantitative trait measured. This observation has implications for the choice of the best strategy for preventing herbicide resistance development. In addition, our results pinpoint a potential compensatory improvement of the resistance fitness cost and its associated dominance by the genetic diversity locally present within a species. 相似文献
16.
The spread of bacterial antibiotic resistance mutations is thought to be constrained by their pleiotropic fitness costs. Here we investigate the fitness costs of resistance in the context of the evolution of multiple drug resistance (MDR), by measuring the cost of acquiring streptomycin resistance mutations (StrepR) in independent strains of the bacterium Pseudomonas aeruginosa carrying different rifampicin resistance (RifR) mutations. In the absence of antibiotics, StrepR mutations are associated with similar fitness costs in different RifR genetic backgrounds. The cost of StrepR mutations is greater in a rifampicin‐sensitive (RifS) background, directly demonstrating antagonistic epistasis between resistance mutations. In the presence of rifampicin, StrepR mutations have contrasting effects in different RifR backgrounds: StrepR mutations have no detectable costs in some RifR backgrounds and massive fitness costs in others. Our results clearly demonstrate the importance of epistasis and genotype‐by‐environment interactions for the evolution of MDR. 相似文献
17.
The molecular basis of resistance to the herbicide norflurazon 总被引:14,自引:0,他引:14
We have cloned and sequenced a gene, pds, from the cyanobacterium Synechococcus PCC7942 that is responsible for resistance to the bleaching herbicide norflurazon. A point mutation in that gene, leading to an amino acid substitution from valine to glycine in its polypeptide product, was found to confer this resistance. Previous studies with herbicide-resistant mutants have indicated that this gene encodes phytoene desaturase (PDS), a key enzyme in the biosynthesis of carotenoids. A short amino acid sequence that is homologous to conserved motifs in the binding sites for NAD(H) and NADP(H) was identified in PDS, suggesting the involvement of these dinucleotides as cofactors in phytoene desaturation. 相似文献
18.
Increased stable inheritance of herbicide resistance in transgenic lettuce carrying a petE promoter-bar gene compared with a CaMV 35S-bar gene 总被引:5,自引:0,他引:5
M. S. McCabe F. Schepers A. van der Arend U. Mohapatra A. M. M. de Laat J. B. Power M. R. Davey 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(3-4):587-592
Inheritance of resistance to herbicide (300 mg/l glufosinate ammonium) up to the third (T3) seed generation was compared
in two populations of transgenic lettuce (Lactuca sativa L. cv ’Evola’) harbouring a T-DNA containing the bar gene, linked to either the Cauliflower Mosaic Virus (CaMV) 35S promoter, or a –784-bp plastocyanin promoter from pea (petE). Only 2.5% (4/163) of CaMV 35S-bar plants, selected by their kanamycin resistance(T0 generation), transmitted herbicide resistance at high frequency to their
T3 seed generation compared with 97% (29/30) for kanamycin resistant petE-bar plants. In the case of 35S-bar transformants, only 16% (341/2,150) of the first seed generation (T1) plants, 22% (426/1,935) T2 plants and 11% (1,235/10,949)
T3 plants were herbicide-resistant. In contrast, 63% (190/300) T1 plants, 83% (2,370/2,845) T2 plants and 99% (122/123) T3
petE-bar transformed plants were resistant to glufosinate ammonium. The T-DNAs carrying the petE-bar and CaMV 35S-bar genes also contained a CaMV 35S-neomycin phosphotransferase (nptII) gene. ELISA showed that NPTII protein was absent in 29% (45/156) of the herbicide-resistant T2 plants from 8/19 herbicide-resistant
petE-bar lines. This indicated specific inactivation of the CaMV 35S promoter on the same T-DNA locus as an active petE promoter. The choice of promoter and T-DNA construct are crucial for long-term expression of transgenes in lettuce.
Received: 13 November 1998 / Accepted: 20 February 1999 相似文献
19.