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1.
The anthracnose resistance locus Co-4 of common bean is located on chromosome 3 and contains putative disease resistance-related genes 总被引:1,自引:0,他引:1
Melotto M Coelho MF Pedrosa-Harand A Kelly JD Camargo LE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(4):690-699
2.
R. A. Young M. Melotto R. O. Nodari J. D. Kelly 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(1):87-94
Two independently assorting dominant genes conditioning resistance to bean anthracnose were identified in an F2 population derived from the highly resistant bean differential cultivar, ‘G 2333’. One gene was allelic to the Co-4 gene in the differential cultivar ‘TO’ and was named Co-4
2
, whereas the second gene was assigned the temporary name Co-7 until a complete characterization with other known resistance genes can be conducted. Two RAPD markers linked to the Co-4
2
allele were identified. One RAPD, OAS13950, co-segregated with no recombinants in two segregating populations of 143 F2 individuals, whereas the second RAPD, OAL9740, mapped at 3.9 cM from the Co-4
2
allele. Two 24-mer SCAR primers (SAS13), developed from the OAS13950 RAPD marker, were dominant and polymorphic, similar to the original RAPD, and supported the tight linkage between the marker(s)
and the Co-4
2
allele. The markers were present in germplasm with known resistance alleles at the Co-4 locus. The presence of the markers in two other differential cultivars not previously characterized and in four navy bean
cultivars suggests the existence of a gene family for anthracnose resistance at or near the Co-4 locus. Since the Co-7 gene was present only in germplasm which also possessed the Co-4
2
and Co-5 genes, the SAS13 markers were used in combination with standard inoculation techniques to identify F3 lines in which the Co-7 gene was homozygous and the Co-4
2
allele was absent. A similar strategy of marker-assisted dissection is proposed to identify resistant lines in which the
Co-5 gene is absent and the Co-7 gene is present by selecting against the OAB3450 marker, which has been shown previously to be linked to the Co-5 gene. These genes cannot be distinguished using traditional screening methods since all current races of the pathogen virulent
to the Co-5 gene are avirulent to the Co-4
2
and Co-7 genes. We describe the use of molecular markers tightly linked to resistance genes to facilitate the identification of an
uncharacterized resistance gene for which no discriminating race of the pathogen is known.
Received: 22 March 1997 / Accepted: 15 July 1997 相似文献
3.
Rodríguez-Suárez C Ferreira JJ Campa A Pañeda A Giraldez R 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(6):807-814
Resistance to races 19, 31, 38, 65, 73, 102, and 449, of the pathogenic fungus Colletotrichum lindemuthianum (anthracnose) was evaluated in F3 families derived from the cross between the anthracnose differential bean cultivars Mexico 222 (resistant to races 19, 31,
and 38) and Widusa (resistant to races 38, 65, 73, 102, and 449). Molecular marker analyses were carried out in the corresponding
F2 individuals in order to identify the genes for anthracnose resistance present in these two differential cultivars. The results
of the combined segregation indicate that the resistance to anthracnose races 19, 31, and 38, present in Mexico 222, is conferred
by single dominant race-specific genes organized in a cluster located in B4 linkage group, corresponding to the previously
described Co-3/Co-9 locus. The resistance to anthracnose races 65, 73, 102, and 449, present in Widusa, is conferred by a dominant gene (or genes)
representing a different haplotype of the same Co-3/Co-9 cluster. A single dominant gene located in a position independent from cluster Co-3/Co-9 (probably at the Co-1 locus) confers specific resistance to race 38 in Widusa. Recombinants for closely linked resistance specificities belonging
to the Co-3/Co-9 cluster have been detected. The possibility of pyramiding race-specific resistance genes by means of intra-cluster recombination,
and its potential use in plant breeding, is indicated.
C. Rodríguez-Suárez and J.J. Ferreira equally share for authorship. 相似文献
4.
Rodríguez-Suárez C Méndez-Vigo B Pañeda A Ferreira JJ Giraldez R 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(4):713-722
A genetic map of common bean was constructed using 197 markers including 152 RAPDs, 32 RFLPs, 12 SCARs, and 1 morphological
marker. The map was established by using a F2 population of 85 individuals from the cross between a line derived from the Spanish landrace Andecha (Andean origin) and
the Mesoamerican genotype A252. The resulting map covers about 1,401.9 cM, with an average marker distance of 7.1 cM and includes
molecular markers linked to disease resistance genes for anthracnose, bean common mosaic virus, bean golden yellow mosaic
virus, common bacterial blight, and rust. Resistance to races 6, 31, 38, 39, 65, and 357 of the pathogenic fungus Colletotrichum lindemuthianum (anthracnose) was evaluated in F3 families derived from the corresponding F2 individuals. The intermediate resistance to race 65 proceeding from Andecha can be explained by a single dominant gene located
on linkage group B1, corresponding to the Co-1 gene. The recombination between the resistance specificities proceeding from A252 agrees with the assumption that total resistance
to races 6, 31, 38, 39, 65, and 357, is organized in two clusters. One cluster, located on B4 linkage group, includes individual
genes for specific resistance to races 6, 38, 39, and 357. The second cluster is located on linkage group B11 and includes
individual genes for specific resistance to races 6, 31, 38, 39, and 65. These two clusters correspond to genes Co-3/Co-9 and Co-2, respectively. It is concluded that most anthracnose resistance Co- genes, previously described as single major genes conferring resistance to several races, could be organized as clusters
of different genes conferring race-specific resistance.
C. Rodríguez-Suárez and B. Méndez-Vigo equally share for authorship. 相似文献
5.
Ana Campa Ramón Giraldez Juan José Ferreira 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(1):1-11
Resistance to nine races of the pathogenic fungus Colletotrichum lindemuthianum, causal agent of anthracnose, was evaluated in F3 families derived from the cross between the anthracnose differential bean cultivars TU (resistant to races, 3, 6, 7, 31,
38, 39, 102, and 449) and MDRK (resistant to races, 449, and 1545). Molecular marker analyses were carried out in the F2 individuals in order to map and characterize the anthracnose resistance genes or gene clusters present in these two differential
cultivars. The results of the combined segregation indicate that at least three independent loci conferring resistance to
anthracnose are present in TU. One of them, corresponding to the previously described anthracnose resistance locus Co-5, is located in linkage group B7, and is formed by a cluster of different genes conferring specific resistance to races,
3, 6, 7, 31, 38, 39, 102, and 449. Evidence of intra-cluster recombination between these specific resistance genes was found.
The second locus present in TU confers specific resistance to races 31 and 102, and the third locus confers specific resistance
to race 102, the location of these two loci remains unknown. The resistance to race 1545 present in MDRK is due to two independent
dominant genes. The results of the combined segregation of two F4 families showing monogenic segregation for resistance to race 1545 indicates that one of these two genes is linked to marker
OF10530, located in linkage group B1, and corresponds to the previously described anthracnose resistance locus Co-1. The second gene conferring resistance to race 1545 in MDRK is linked to marker Pv-ctt001, located in linkage group B4,
and corresponds to the Co-3/Co-9 cluster. The resistance to race 449 present in MDRK is conferred by a single gene, located in linkage group B4, probably
included in the same Co-3/Co-9 cluster.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
6.
Carmen M. Avila Salvador Nadal M. Teresa Moreno Ana M. Torres 《Molecular breeding : new strategies in plant improvement》2006,17(3):185-190
We have developed the first molecular marker suitable for the selection of determinate growth habit in faba bean using the
candidate gene approach. We obtained the sequences of TFL1/CEN like genes from public databases and designed primers on conserved domains. We used three cultivars with determinate growth
habit and four accessions (two cultivars and two lines) with indeterminate growth habit. All these genotypes are used in our
faba bean breeding program. A single monomorphic PCR fragment was obtained. A set of restriction enzymes was assayed. The
enzyme Hind1II produced a clear polymorphism between determinate and indeterminate genotypes. This new cleaved amplified polymorphism
(CAP) marker was tested using an F2 population contrasting for growth habit derived from the cross ‘Verde Bonita’ × 2N52. This marker showed 100% efficiency
in discriminating both types of genotypes. Moreover, the codominancy of this marker allows the detection of heterozygous individuals
facilitating the breeding process when pyramiding different genes. The perfect cosegregation of the marker with the trait
indicates that an orthologue of TFL1/CEN controls the growth habit in faba bean. This marker has been tested in all the genotypes used in our faba bean breeding program
as donors of the determinate growth habit. Therefore, it is expected to work well in all the crosses performed with these
parental lines as happens in the F2 tested. The CAPS marker developed in this work will be useful for Marker Assisted Selection programs. In addition, this marker
is useful for quality control to determinate the percentage of outsider seeds in commercial seed lots. Moreover, it is a valuable
tool to breeders when submitting new faba bean varieties for registration since the method allows guaranteeing that outsider
plants remains under the requested limit for registration. 相似文献
7.
E. Venter A.-M. Botha 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(6):965-970
Through random amplified polymorphic DNA (RAPD) analysis we identified a putative marker linked to the Dn5 resistance gene. This marker was converted to a more reliable sequence-characterised-amplified regions (SCAR) marker. The
initial SCAR marker amplified the correct amplification product but failed to discern between the susceptible and resistant
individuals. Hence, it was utilised to sequence the internal fragment. All nested primers designed from the internal sequences
were also unable to produce any polymorphism between the susceptible and resistant cultivars. Restriction digests were then
performed on these fragments, and the restriction enzyme EcoRI was able to discern between the susceptible and resistant F2 individuals of the Dn5 population. This granted one marker amplified with the internal SCAR primer set OPF141083 the ability to differentiate between parental individuals carrying the Dn5 genes. This marker was tested in a segregating F2 population carrying the Dn5 resistance gene and proved able to differentiate between the segregating individuals. This marker may prove useful in marker
assisted selection (MAS), although performing restriction digests may hamper the throughput of a high number of samples.
Received: 4 August 1999 / Accepted: 27 August 1999 相似文献
8.
Miura Y Ding C Ozaki R Hirata M Fujimori M Takahashi W Cai H Mizuno K 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(5):811-818
Ryegrass blast, also called gray leaf spot, is caused by the fungus Pyricularia sp. It is one of the most serious diseases of Italian ryegrass (Lolium multiflorum Lam.) in Japan. We analyzed segregation of resistance in an F1 population from a cross between a resistant and a susceptible cultivar. The disease severity distribution in the F1 population suggested that resistance was controlled by a major gene (LmPi1). Analysis of amplified fragment length polymorphisms with bulked segregant analysis identified several markers tightly linked
to LmPi1. To identify other markers linked to LmPi1, we used expressed sequence tag-cleaved amplified polymorphic sequence (EST-CAPS) markers mapped in a reference population
of Italian ryegrass. Of the 30 EST-CAPS markers screened, one marker, p56, flanking the LmPi1 locus was found. The restriction pattern of p56 amplification showed a unique fragment corresponding to the resistant allele
at the LmPi1 locus. A linkage map constructed from the reference population showed that the LmPi1 locus was located in linkage group 5 of Italian ryegrass. Genotype results obtained from resistant and susceptible cultivars
indicate that the p56 marker is useful for introduction of the LmPi1 gene into susceptible germplasm in order to develop ryegrass cultivars with enhanced resistance to ryegrass blast. 相似文献
9.
M. Mohan P. V. Sathyanarayanan A. Kumar M. N. Srivastava S. Nair 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(5-6):777-782
A PCR-based marker (E20570) linked to the gene Gm4t, which confers resistance to a dipteran pest gall midge (Orseolia oryzae), has been mapped using the restriction fragment length polymorphism (RFLP) technique in rice. Gm4t is a dominant resistance gene. We initially failed to detect useful polymorphism for this marker in a F3 mapping population derived from a cross between two indica parents, ‘Abhaya’בShyamala’, with as many as 35 restriction enzymes. ‘Abhaya’ carries the resistance gene Gm4t and ‘Shyamala’ is susceptible to gall midge. Subsequently, E20570 was mapped using another mapping population represented by a F2 progeny from a cross between ‘Nipponbare’, a japonica variety, and ‘Kasalath’, an indica variety, in which the gene Gm4t was not known to be present. Gm4t mapped onto chromosome 8 between markers R1813 and S1633B. Our method, thus, presents an alternative way of mapping genes
which otherwise would be difficult to map because of a lack of polymorphism between closely related parents differing in desired
agronomic traits.
Received: 1 April 1997 / Accepted: 13 May 1997 相似文献
10.
Andrew J. Burt H. Manilal William Gregory Perry Raja Khanal K. Peter Pauls James D. Kelly Alireza Navabi 《PloS one》2015,10(10)
Anthracnose, caused by Colletotrichum lindemuthianum, is an important fungal disease of common bean (Phaseolus vulgaris). Alleles at the Co–4 locus confer resistance to a number of races of C. lindemuthianum. A population of 94 F4:5 recombinant inbred lines of a cross between resistant black bean genotype B09197 and susceptible navy bean cultivar Nautica was used to identify markers associated with resistance in bean chromosome 8 (Pv08) where Co–4 is localized. Three SCAR markers with known linkage to Co–4 and a panel of single nucleotide markers were used for genotyping. A refined physical region on Pv08 with significant association with anthracnose resistance identified by markers was used in BLAST searches with the genomic sequence of common bean accession G19833. Thirty two unique annotated candidate genes were identified that spanned a physical region of 936.46 kb. A majority of the annotated genes identified had functional similarity to leucine rich repeats/receptor like kinase domains. Three annotated genes had similarity to 1, 3-β-glucanase domains. There were sequence similarities between some of the annotated genes found in the study and the genes associated with phosphoinositide-specific phosphilipases C associated with Co-x and the COK–4 loci found in previous studies. It is possible that the Co–4 locus is structured as a group of genes with functional domains dominated by protein tyrosine kinase along with leucine rich repeats/nucleotide binding site, phosphilipases C as well as β-glucanases. 相似文献
11.
V. Geffroy F. Creusot J. Falquet M. Sévignac A.-F. Adam-Blondon H. Bannerot P. Gepts M. Dron 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(3-4):494-502
Molecular markers offer new opportunities for breeding for disease resistance. Resistance gene pyramiding in a single cultivar,
as a strategy for durable resistance, can be facilitated by marker-assisted selection (MAS). A RAPD marker, ROH20450, linked to the Mesoamerican Co-2 anthracnose resistance gene, was previously transformed into a SCAR marker, SCH20. In the present paper we have further characterized
the relevance of the SCH20 SCAR marker in different genetic backgrounds. Since this SCAR marker was found to be useful mainly
in the Andean gene pool, we identified a new PCR-based marker (SCAreoli) for indirect scoring of the presence of the Co-2 gene. The SCAreoli SCAR marker is polymorphic in the Mesoamerican as well as in the Andean gene pool and should be useful
in MAS. We also report that PvH20, the cloned sequence corresponding to the 450-bp RAPD marker ROH20450, contains six imperfect leucine-rich repeats, and reveals a family of related sequences in the vicinity of the Co-2 locus. These results are discussed in the context of the recent cloning of some plant resistance genes.
Received: 26 June 1997 / Accepted: 13 October 1997 相似文献
12.
Geffroy V Sévignac M Billant P Dron M Langin T 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(3):407-415
Anthracnose, caused by the hemibiotrophic fungal pathogen Colletotrichum lindemuthianum is a devastating disease of common bean. Resistant cultivars are economical means for defense against this pathogen. In the
present study, we mapped resistance specificities against 7 C. lindemuthianum strains of various geographical origins revealing differential reactions on BAT93 and JaloEEP558, two parents of a recombinant
inbred lines (RILs) population, of Meso-american and Andean origin, respectively. Six strains revealed the segregation of
two independent resistance genes. A specific numerical code calculating the LOD score in the case of two independent segregating
genes (i.e. genes with duplicate effects) in a RILs population was developed in order to provide a recombination value (r) between each of the two resistance genes and the tested marker. We mapped two closely linked Andean resistance genes (Co-x, Co-w) at the end of linkage group (LG) B1 and mapped one Meso-american resistance genes (Co-u) at the end of LG B2. We also confirmed the complexity of the previously identified B4 resistance gene cluster, because four
of the seven tested strains revealed a resistance specificity near Co-y from JaloEEP558 and two strains identified a resistance specificity near Co-9 from BAT93. Resistance genes found within the same cluster confer resistance to different strains of a single pathogen such
as the two anthracnose specificities Co-x and Co-w clustered at the end of LG B1. Clustering of resistance specificities to multiple pathogens such as fungi (Co-u) and viruses (I) was also observed at the end of LG B2. 相似文献
13.
Jena KK Jeung JU Lee JH Choi HC Brar DS 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(2):288-297
Brown planthopper (BPH) is a destructive insect pest of rice in Asia. Identification and the incorporation of new BPH resistance
genes into modern rice cultivars are important breeding strategies to control the damage caused by new biotypes of BPH. In
this study, a major resistance gene, Bph18(t), has been identified in an introgression line (IR65482-7-216-1-2) that has inherited the gene from the wild species Oryza australiensis. Genetic analysis revealed the dominant nature of the Bph18(t) gene and identified it as non-allelic to another gene, Bph10 that was earlier introgressed from O. australiensis. After linkage analysis using MapMaker followed by single-locus ANOVA on quantitatively expressed resistance levels of the
progenies from an F2 mapping population identified with marker allele types, the Bph18(t) gene was initially located on the subterminal region of the long arm of chromosome 12 flanked by the SSR marker RM463
and the STS marker S15552. The corresponding physical region was identified in the Nipponbare genome pseudomolecule 3 through
electronic chromosome landing (e-landing), in which 15 BAC clones covered 1.612 Mb. Eleven DNA markers tagging the BAC clones were used to construct a high-resolution
genetic map of the target region. The Bph18(t) locus was further localized within a 0.843-Mb physical interval that includes three BAC clones between the markers R10289S
and RM6869 by means of single-locus ANOVA of resistance levels of mapping population and marker-gene association analysis
on 86 susceptible F2 progenies based on six time-point phenotyping. Using gene annotation information of TIGR, a putative resistance gene was
identified in the BAC clone OSJNBa0028L05 and the sequence information was used to generate STS marker 7312.T4A. The marker
allele of 1,078 bp completely co-segregated with the BPH resistance phenotype. STS marker 7312.T4A was validated using BC2F2 progenies derived from two temperate japonica backgrounds. Some 97 resistant BC2F2 individuals out of 433 screened completely co-segregated with the resistance-specific marker allele (1,078 bp) in either
homozygous or heterozygous state. This further confirmed a major gene-controlled resistance to the BPH biotype of Korea. Identification
of Bph18(t) enlarges the BPH resistance gene pool to help develop improved rice cultivars, and the PCR marker (7312.T4A) for the Bph18(t) gene should be readily applicable for marker-assisted selection (MAS).
K. K. Jena and J. U. Jeung contributed equally to this study. 相似文献
14.
M. A. Pallotta R. D. Graham P. Langridge D. H. B. Sparrow S. J. Barker 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(7):1100-1108
In many cropping regions of the world, yield is limited by the availability of micronutrients, and micronutrient-efficient
cultivars provide a yield advantage. Traditional methods of testing cultivars for micronutrient efficiency are time-consuming
and laborious. Molecular markers linked to loci controlling micronutrient efficiency will allow more rapid and efficient selection
and introgression of these traits than is currently possible. Using a pot-based bioassay and bulked segregant analysis of
an F2 population, we have identified several RFLPs (grouped distally on chromosome 4HS) linked to a locus for manganese efficiency
in barley. This manganese efficiency locus has been designated Mel1. Pot bioassay analysis of intercrosses suggests that three useful sources of manganese efficiency are likely to be allelic
at the Mel1 locus. Field evaluation of marker selected F4 progeny supports the major role of Mel1 in the genetic control of manganese efficiency. Adoption of marker assisted selection for this trait in the Southern Australian
barley breeding program has occurred. This has been facilitated by the demonstration that the Mel1 allele of Amagi Nijo can be distinguished from 95 other locally useful varieties and breeder’s lines on the basis of RFLPs
identified by just two molecular markers.
Received: 20 October 1999 / Accepted: 18 February 2000 相似文献
15.
A. Graner E. Bauer 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,86(6):689-693
RFLP (restriction fragment length polymorphism) mapping of a recessive gene (ym4) conferring resistance to barley yellow mosaic and barley mild mosaic virus was performed using progeny of 86 F1 anther-derived doubled haploid lines. Two closely linked RFLP markers that flank the gene at a distance of 1.2 centiMorgans were identified. Using one of these markers (MWG10) we obtained a clear differentiation between resistant and susceptible German cultivars. An analysis of a series of unrelated barley lines with probe MWG10 did not reveal additional RFLP fragments. The use of this probe for both marker-assisted selection and the generation of a high-density map around the resistance locus is discussed. 相似文献
16.
Bruchid resistance, controlled by a single dominant gene (Br) in a wild mungbean accession (TC1966), has been incorporated into cultivated mungbean (Vigna radiata). The resistance gene simultaneously confers inhibitory activity against the bean bug, Riptortus clavatus Thunberg (Hemiptera: Alydidae). The resultant isogenic line (BC20 generation) was characterized by the presence of a group of novel cyclopeptide alkaloids, called vignatic acids. A linkage
map was constructed for Br and the vignatic acid gene (Va) using restriction fragment length polymorphism (RFLP) markers and a segregating BC20F2 population. By screening resistant and susceptible parental lines with 479 primers, eight randomly amplified polymorphic
DNA (RAPD) markers linked to Br were identified and cloned for use as RFLP probes. All eight RAPD-based markers, one mungbean, and four common bean genomic
clones were effectively integrated around Br within a 3.7-cM interval. Br was mapped to a 0.7-cM segment between a cluster consisting of six markers and a common bean RFLP marker, Bng110. The six
markers are closest to the bruchid resistance gene, approximately 0.2 cM away. The vignatic acid gene, Va, cosegregated with bruchid resistance. However, one individual was identified in the BC20F2 population that retained vignatic acids in spite of its bruchid susceptibility. Consequently, Va was mapped to a single locus at the same position as the cluster of markers and 0.2 cM away from Br. These results suggest that the vignatic acids are not the principal factors responsible for bruchid resistance in V. radiata but will facilitate the use of map-based cloning strategies to isolate the Br gene.
Received: 20 November 1997 / Accepted: 6 January 1998 相似文献
17.
18.
Identification of flanking SSR markers for a major rice gall midge resistance gene <Emphasis Type="Italic">Gm1</Emphasis> and their validation 总被引:1,自引:0,他引:1
Biradar SK Sundaram RM Thirumurugan T Bentur JS Amudhan S Shenoy VV Mishra B Bennett J Sarma NP 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(7):1468-1473
Host-plant resistance is the preferred strategy for management of Asian rice gall midge (Orseolia oryzae), a serious pest in many rice-growing countries. The deployment of molecular markers linked to gall midge resistance genes in breeding programmes can accelerate the development of resistant cultivars. In the present study, we have tagged and mapped a dominant gall midge resistance gene, Gm1, from the Oryza sativa cv. W1263 on chromosome 9, using SSR markers. A progeny-tested F2 mapping population derived from the cross W1263/TN1 was used for analysis. To map the gene locus, initially a subset of the F2 mapping population consisting of 20 homozygous resistant and susceptible lines each was screened with 63 parental polymorphic SSR markers. The SSR markers RM316, RM444 and RM219, located on chromosome 9, are linked to Gm1 at genetic distances of 8.0, 4.9 and 5.9 cM, respectively, and flank the gene locus. Further, gene/marker order was also determined. The utility of the co-segregating SSR markers was tested in a backcross population derived from the cross Swarna/W1263//Swarna, and allelic profiles of these markers were analysed in a set of donor rice genotypes possessing Gm1 and in a few gall midge-susceptible, elite rice varieties. 相似文献
19.
Wang C Ulloa M Roberts PA 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(4):770-777
Host-plant resistance is the most economic and effective strategy for root-knot nematode (RKN) Meloidogyne incognita control in cotton (Gossypium hirsutum L.). Molecular markers linked to resistance are important for incorporating resistance genes into elite cultivars. To screen
for microsatellite markers (SSR) closely linked to RKN resistance in G. hirsutum cv. Acala NemX, F1, F2, BC1F1, and F2:7 recombinant inbred lines (RILs) from intraspecific crosses and an F2 from an interspecific cross with G. barbadense cv. Pima S-7 were used. Screening of 284 SSR markers, which cover all the known identified chromosomes and most linkage groups
of cotton, was performed by bulked segregant analysis, revealing informative SSRs. The informative SSRs were then mapped on
the above populations. One co-dominant SSR marker CIR316 was identified tightly linked to a major resistance gene (designated
as rkn1), producing amplified DNA fragments of approximately 221 bp (CIR316a) and 210 bp (CIR316c) in Acala NemX and susceptible
Acala SJ-2, respectively. The linkage between CIR316a marker and resistance gene rkn1 in Acala NemX had an estimated distance of 2.1–3.3 cM depending on the population used. Additional markers, including BNL1231
with loose linkage to rkn1 (map distance 25.1–27.4 cM), BNL1066, and CIR003 allowed the rkn1 gene to be mapped to cotton linkage group A03. This is the first report in cotton with a closely linked major gene locus
determining nematode resistance, and informative SSRs may be used for marker-assisted selection. 相似文献
20.
Colletotrichum lindemuthianum, the causal agent of anthracnose in the common bean (Phaseolus vulgaris), presents a wide genetic and pathogenic variability that gives rise to complications in the development of resistant bean
cultivars. The aim of this study was to identify the variability within race 65 of C. lindemuthianum, the race most commonly encountered in Brazil, through randomly amplified polymorphic DNA (RAPD) and anastomosis analyses.
Thirteen isolates of race 65, collected in different years and from various host cultivars located in diverse areas of the
state of Minas Gerais, Brazil, were investigated. Twenty-four RAPD primers were employed and 83 polymorphic bands amplified.
Genetic similarities were estimated from the Sorensen-Dice coefficient and ranged from 0.54 to 0.82. The dendrogram obtained
by cluster analysis classified the isolates into 11 separate groups. For the purposes of the analysis of anastomosis, isolates
were considered to be compatible when the fusion of hyphae from different isolates could be observed. The proportion of compatible
reactions for each isolate was estimated and similarity estimates, based on the Russel & Rao coefficient, ranged from 0.28
to 0.85. Isolates were classified into 11 anastomosis groups, 10 of which were formed by only one isolate. Although isolates
LV61, LV73 and LV58 were classified in the same anastomosis group, they were genetically distinct according to RAPD analysis.
Results from both RAPD and anastomosis analyses revealed great variability within C. lindemuthianum race 65. 相似文献