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1.
Mapping of SMV resistance gene Rsc-7 by SSR markers in soybean 总被引:8,自引:0,他引:8
Soybean mosaic virus (SMV) is one of the most prevalent pathogens that limit soybean production. In this study, segregation
ratios of resistant plants to susceptible plants in P1, P2, F1, F2 populations of Kefeng No. 1 (P1)×Nannong 1138-2 (P2) and derived RIL populations, were used to study the inheritance of resistance to the SMV strain SC-7. Populations Kefeng
No. 1 and F1 were found to be completely resistant to this SMV strain while Nannong 1138-2 was susceptible to it. The F2 and RIL populations segregated to fit a ratio of 3:1 and 1:1for resistant plants to susceptible ones, respectively. These
results indicated that a single dominant gene, designated as Rsc-7, controlled resistance to the SMV strain SC-7 in Kefeng No.1. SSR markers were used to analyze the RIL population and MAPMAKER/EXP
3.0b was employed to establish linkage between markers and this resistance gene. Combining the data of SSRs and resistance
identification, a soybean genetic map was constructed. This map, covering 2625.9 cM of the genome, converged into 24 linkage
groups, consisted of 221 SSR markers and the resistance gene Rsc-7. The Rsc-7 gene was mapped to the molecular linkage group G8-D1b+W. SSR markers Satt266, Satt634, Satt558, Satt157, and Satt698 were
found linked to Rsc-7 with distances of 43.7, 18.1, 26.6, 36.4 and 37.9 cM, respectively. 相似文献
2.
T. M. Golas H. van de Geest J. Gros A. Sikkema N. D’Agostino J. P. Nap C. Mariani J. J. H. M. Allefs I. Rieu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2013,126(1):59-68
Phytophthora infestans, the causal agent of late blight, remains the main threat to potato production worldwide. Screening of 19 accessions of Solanum dulcamara with P. infestans isolate Ipo82001 in detached leaf assays revealed strong resistance in an individual belonging to accession A54750069-1. This plant was crossed with a susceptible genotype, and an F1 population consisting of 63 individuals was obtained. This population segregated for resistance in 1:1 ratio, both in detached leaf assays and in an open-field experiment. Presence of the formerly mapped Rpi-dlc1 gene as the cause of the observed segregating resistance could be excluded. Subsequently, AFLP analyses using 128 primer combinations enabled identification of five markers linked to a novel resistance gene named Rpi-dlc2. AFLP markers did not show sequence similarity to the tomato and potato genomes, hampering comparative genetic positioning of the gene. For this reason we used next-generation mapping (NGM), an approach that exploits direct sequencing of DNA (in our case: cDNA) pools from bulked segregants to calculate the genetic distance between SNPs and the locus of interest. Plotting of these genetic distances on the tomato and potato genetic map and subsequent PCR-based marker analysis positioned the gene on chromosome 10, in a region overlapping with the Rpi-ber/ber1 and -ber2 loci from S. berthaultii. Pyramiding of Rpi-dlc2 and Rpi-dlc1 significantly increased resistance to P. infestans, compared with individuals containing only one of the genes, showing the usefulness of this strategy to enhance resistance against Phytophthora. 相似文献
3.
S. K. Naess J. M. Bradeen S. M. Wielgus G. T. Haberlach J. M. McGrath J. P. Helgeson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(5-6):697-704
Somatic hybrids between potato and Solanum bulbocastanum, a wild diploid (2n=2x=24) Mexican species, are highly resistant to late blight, caused by Phytophthora infestans. Both randomly amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) markers that are closely
linked to the resistance have been noted by analysis of three different backcross-2 populations derived from two different
somatic hybrids. With reference to previously published potato and tomato maps, resistance appears to be on the long arm of
chromosome 8 and is flanked by RFLP markers CP53 and CT64. In a population of BC2 plants derived from a cross between the BC1 line J10lK6 [(S. tuberosum PI 203900+S. bulbocastanum PI 243510) ×Katahdin)]×Atlantic, late blight resistance cosegregated with RFLP marker CT88 and RAPD marker OPG02–625.
Received: 26 November 1999 / Accepted: 22 December 1999 相似文献
4.
Marinely Bustamante Gomez Liléia Gon?alves Diotaiuti David E. Gorla 《PLoS neglected tropical diseases》2016,10(3)
BackgroundA number of studies published during the last 15 years showed the occurrence of insecticide resistance in Triatoma infestans populations. The different toxicological profiles and mechanisms of resistance to insecticides is due to a genetic base and environmental factors, being the insecticide selective pressure the best studied among the last factors. The studies on insecticide resistance on T. infestans did not consider the effect of environmental factors that may influence the distribution of resistance to pyrethroid insecticides. To fill this knowledge gap, the present study aims at studying the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables.Conclusions/SignificanceThe occurrence of these two groups concentrated over a particular region that coincides with the area where populations of the intermediate cytogenetic group were found might reflect the spatial heterogeneity of the genetic variability of T. infestans, that seems to be the cause of the insecticide resistance in the area, even on sylvatic populations of T. infestans, never before exposed to pyrethroid insecticides, representing natural and wild toxicological phenotypes. The strong linear relationship found between LD50 and RR50 suggest RR50 might not be the best indicator of insecticide resistance in triatomines. 相似文献
5.
Laetitia Mahé Marie-Christine Combes Vitor M. P. Várzea Claire Guilhaumon Philippe Lashermes 《Molecular breeding : new strategies in plant improvement》2008,21(1):105-113
Coffee leaf rust due to Hemileia vastatrix is one of the most serious diseases in Arabica coffee (Coffea arabica). A resistance gene (SH3) has been transferred from C. liberica into C. arabica. The present work aimed at developing sequence-characterized genetic markers for leaf rust resistance. Linkage between markers
and leaf rust resistance was tested by analysing two segregating populations, one F2 population of 101 individuals and one backcross (BC2) population of 43 individuals, derived from a cross between a susceptible and a SH3-introgressed resistant genotype. A total
of ten sequence-characterized genetic markers closely associated with the SH3 leaf rust resistance gene were generated. These included simple sequence repeats (SSR) markers, sequence-characterised amplified
regions (SCAR) markers resulting from the conversion of amplified fragment length polymorphism (AFLP) markers previously identified
and SCAR markers derived from end-sequences of bacterial artificial chromosome (BAC) clones. Those BAC clones were identified
by screening of C. arabica genomic BAC library using a cloned AFLP-marker as probe. The markers we developed are easy and inexpensive to run, requiring
one PCR step followed by gel separation. While three markers were linked in repulsion with the SH3 gene, seven markers were clustered in coupling around the SH3 gene. Notably, two markers appeared to co-segregate perfectly with the SH3 gene in the two plant populations analyzed. These markers are suitable for marker-assisted selection for leaf rust resistance
and to facilitate pyramiding of the SH3 gene with other leaf rust resistance genes. 相似文献
6.
A new SNP haplotype associated with blue disease resistance gene in cotton (Gossypium hirsutum L.) 总被引:1,自引:0,他引:1
David D. Fang Jinhua Xiao Paulo C. Canci Roy G. Cantrell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,120(5):943-953
Resistance to cotton blue disease (CBD) was evaluated in 364 F2.3 families of three populations derived from resistant variety ‘Delta Opal’. The CBD resistance in ‘Delta Opal’ was controlled
by one single dominant gene designated Cbd. Two simple sequence repeat (SSR) markers were identified as linked to Cbd by bulked segregant analysis. Cbd resides at the telomere region of chromosome 10. SSR marker DC20027 was 0.75 cM away from Cbd. DC20027 marker fragments amplified from 3 diploid species and 13 cotton varieties whose CBD resistance was known were cloned
and sequenced. One single nucleotide polymorphism (SNP) was identified at the 136th position by sequence alignment analysis.
Screening SNP markers previously mapped on chromosome 10 identified an additional 3 SNP markers that were associated with
Cbd. A strong association between a haplotype based on four SNP markers and Cbd was developed. This demonstrates one of the first examples in cotton where SNP markers were used to effectively tag a trait
enabling marker-assisted selection for high levels of CBD resistance in breeding programs. 相似文献
7.
Mirjam M. J. Jacobs Ben Vosman Vivianne G. A. A. Vleeshouwers Richard G. F. Visser Betty Henken Ronald G. van den Berg 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,120(4):785-796
Mapping resistance genes is usually accomplished by phenotyping a segregating population for the resistance trait and genotyping
it using a large number of markers. Most resistance genes are of the NBS-LRR type, of which an increasing number is sequenced.
These genes and their analogs (RGAs) are often organized in clusters. Clusters tend to be rather homogenous, viz. containing
genes that show high sequence similarity with each other. From many of these clusters the map position is known. In this study
we present and test a novel method to quickly identify to which cluster a new resistance gene belongs and to produce markers
that can be used for introgression breeding. We used NBS profiling to identify markers in bulked DNA samples prepared from
resistant and susceptible genotypes of small segregating populations. Markers co-segregating with resistance can be tested
on individual plants and directly used for breeding. To identify the resistance gene cluster a gene belongs to, the fragments
were sequenced and the sequences analyzed using bioinformatics tools. Putative map positions arising from this analysis were
validated using markers mapped in the segregating population. The versatility of the approach is demonstrated with a number
of populations derived from wild Solanum species segregating for P. infestans resistance. Newly identified P. infestans resistance genes originating from S. verrucosum, S. schenckii, and S. capsicibaccatum could be mapped to potato chromosomes 6, 4, and 11, respectively. 相似文献
8.
Rauscher GM Smart CD Simko I Bonierbale M Mayton H Greenland A Fry WE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(4):674-687
Phytophthora infestans, the causal agent of late blight, threatens potato production worldwide. An important tool in the management of the disease
is the use of resistant varieties. Eleven major resistance genes have been identified and introgressed from Solanum demissum. However, new sources of resistance are continually sought. Here, we report the characterization and refined genetic localization
of a resistance gene previously identified as Rber in a backcross progeny of Solanum tuberosum and Solanum berthaultii. In order to further characterize Rber, we developed a set of P. infestans isolates capable of identifying each of the 11 R-genes known to confer resistance to late blight in potato. Our results indicate
that Rber is a new resistance gene, different from those recognized in S. demissum, and therefore, it has been named R
Pi-ber
according to the current system of nomenclature. In order to add new molecular markers around R
Pi-ber
, we used a PCR-based mapping technique, named MASP-map, which located R
Pi-ber
in a 3.9 cM interval between markers CT240 and TG63 on potato chromosome X. The location of R
Pi-ber
coincides with an area involved in resistance to different pathogens of potato and tomato. 相似文献
9.
Y. H. Lu J. M. Melero-Vara J. A. García-Tejada P. Blanchard 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(3-4):625-632
A consensus molecular linkage map of 61.9 cM containing the Or5 gene, which confers resistance to race E of broomrape orobanche cumana, five SCAR markers (three dominant, two codominant) and one RAPD marker were identified based on segregation data scored
from two F2 populations of susceptible×resistant sunflower line crosses. Bulked segregant analysis was carried out to generate the five
SCAR markers, while the single RAPD marker in the group was identified from 61 segregating RAPD markers that were directly
screened on one of the two F2 populations. The five SCAR markers, RTS05, RTS28, RTS40, RTS29 and RTS41, were significantly (LOD≥4.0) linked to the Or5 gene and mapped separately at 5.6, 13.6, 14.1, 21.4 and 39.4 cM from the Or5 locus on one side, while the RAPD marker, UBC120_660, was found at 22.5 cM (LOD=1.4) on the opposite side. These markers
should facilitate the efficient transfer of the resistance gene among sunflower breeding lines. As the first report on molecular
markers linked to a broomrape resistance gene, the present work provides a starting point to study other genes and to examine
the hypothesis of the clustering of broomrape resistance genes in sunflower.
Received: 16 September 1998 / Accepted: 22 June 1999 相似文献
10.
Jirapong Jairin Kittiphong Phengrat Sanguan Teangdeerith Apichart Vanavichit Theerayut Toojinda 《Molecular breeding : new strategies in plant improvement》2007,19(1):35-44
The brown planthopper (BPH) is one of the most destructive insect pests of rice in Thailand. We performed a cluster analysis
that revealed the existence of four groups corresponding to the variation of virulence against BPH resistance genes in 45
BPH populations collected in Thailand. Rice cultivars Rathu Heenati and PTB33, which carry Bph3, showed a broad-spectrum resistance against all BPH populations used in this study. The resistant gene Bph3 has been extensively studied and used in rice breeding programs against BPH; however, the chromosomal location of Bph3 in the rice genome has not yet been determined. In this study, a simple sequence repeat (SSR) analysis was performed to identify
and localize the Bph3 gene derived from cvs. Rathu Heenati and PTB33. For mapping of the Bph3 locus, we developed two backcross populations, BC1F2 and BC3F2, from crosses of PTB33 × RD6 and Rathu Heenati × KDML105, respectively, and evaluated these for BPH resistance. Thirty-six
polymorphic SSR markers on chromosomes 4, 6 and 10 were used to survey 15 resistant (R) and 15 susceptible (S) individuals
from the backcross populations. One SSR marker, RM190, on chromosome 6 was associated with resistance and susceptibility in
both backcross populations. Additional SSR markers surrounding the RM190 locus were also examined to define the location of
Bph3. Based on the linkage analysis of 208 BC1F2 and 333 BC3F2 individuals, we were able to map the Bph3 locus between two flanking SSR markers, RM589 and RM588, on the short arm of chromosome 6 within 0.9 and 1.4 cM, respectively.
This study confirms both the location of Bph3 and the allelic relationship between Bph3 and bph4 on chromosome 6 that have been previously reported. The tightly linked SSR markers will facilitate marker-assisted gene pyramiding
and provide the basis for map-based cloning of the resistant gene. 相似文献
11.
Q. Li X. M. Chen M. N. Wang J. X. Jing 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(1):189-197
Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most destructive diseases of wheat worldwide. Growing resistant cultivars is the most effective approach to
control the disease, but only a few genes confer effective all-stage resistance against the current populations of the pathogen
worldwide. It is urgent to identify new genes for diversifying sources of resistance genes and for pyramiding genes for different
types of resistance in order to achieve high levels of durable resistance for sustainable control of stripe rust. The common
spring wheat genotype ‘PI 181434’, originally from Afghanistan, was resistant in all greenhouse and field tests in our previous
studies. To identify the resistance gene(s) PI 181434 was crossed with susceptible genotype ‘Avocet Susceptible’. Adult plants
of 103 F2 progeny were tested in the field under the natural infection of P. striiformis f. sp. tritici. Seedlings of the parents, F2 and F3 were tested with races PST-100 and PST-127 of the pathogen under controlled greenhouse conditions. The genetic study showed
that PI 181434 has a single dominant gene conferring all-stage resistance. Resistance gene analog polymorphism (RGAP) and
simple sequence repeat (SSR) techniques were used to identify molecular markers linked to the gene. A linkage map of 8 RGAP
and 2 SSR markers was constructed for the gene using data from the 103 F2 plants and their derived F3 lines tested in the greenhouse. Amplification of the complete set of nulli-tetrasomic lines and selected ditelosomic lines
of Chinese Spring with an RGAP marker and the two SSR markers mapped the gene on the long arm of chromosome 3D. Because it
is the first gene for stripe rust resistance mapped on chromosome 3DL and different from all previously named Yr genes, the gene in PI 181434 was designated Yr45. Polymorphism rates of the two closest flanking markers, Xwgp115 and Xwgp118, in 45 wheat genotypes were 73.3 and 82.2%, respectively. Single nucleotide polymorphisms (SNPs) were identified in the eight
wheat genotypes sharing both flanking markers. The RGAP markers and potential SNP markers should be useful in incorporating
the gene into wheat cultivars and in pyramiding it with other genes for durable resistance. 相似文献
12.
A potato hypersensitive resistance gene against potato virus X maps to a resistance gene cluster on chromosome 5 总被引:2,自引:0,他引:2
W. De Jong A. Forsyth D. Leister C. Gebhardt D.C. Baulcombe 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(1-2):246-252
The dominant Nb gene of potato confers strain-specific hypersensitive resistance against potato virus X (PVX). A population segregating for
Nb was screened for resistance by inoculating with PVX strain CP2, which is sensitive to Nb. Through a combination of bulked segregant analysis and selective restriction fragment amplification, several amplified fragment
length polymorphism (AFLP) markers linked to Nb were identified. These were cloned and converted into dominant cleaved amplified polymorphic sequence (CAPS) markers. The
segregation of these markers in a Lycopersicon esculentum×L. pennellii mapping population suggested that Nb is located on chromosome 5. This was confirmed by examining resistant and susceptible potato individuals with several tomato
and potato chromosome-5-specific markers. Nb maps to a region of chromosome 5 where several other resistance genes– including R1, a resistance gene against Phytophthora infestans, Gpa, a locus that confers resistance against Globodera pallida, and Rx2, a gene that confers extreme resistance against PVX–have previously been identified.
Received: 2 January 1997/Accepted: 7 February 1997 相似文献
13.
Molecular tagging of stripe rust resistance gene YrZH84 in Chinese wheat line Zhou 8425B 总被引:5,自引:0,他引:5
Li ZF Zheng TC He ZH Li GQ Xu SC Li XP Yang GY Singh RP Xia XC 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(6):1098-1103
Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most damaging diseases in common wheat (Triticum aestivum L.). With the objective of identifying and tagging new genes for resistance to stripe rust, F1, F2 and F3 populations from the cross Zhou 8425B/Chinese Spring were inoculated with Chinese PST isolate CYR32 in the greenhouse. A
total of 790 SSR primers were used to test the parents and resistant and susceptible bulks. The resulting seven polymorphic
markers on chromosome 7BL were used for genotyping F2 and F3 populations. Results indicated that Zhou 8425B carries a single dominant resistance gene, temporarily designated YrZH84, closely linked to SSR markers Xcfa2040-7B and Xbarc32-7B with genetic distances of 1.4 and 4.8 cM, respectively. In a seedling test with 25 PST isolates, the reaction patterns of
YrZH84 were different from those of lines carrying Yr2 and Yr6. It was concluded that YrZH84 is probably a new stripe rust resistance gene. 相似文献
14.
J. Pauquet A. Bouquet P. This A.-F. Adam-Blondon 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(8):1201-1210
The monogenic dominant genetic determinism of total resistance to powdery mildew, introduced from Muscadinia
rotundifolia into Vitis
vinifera, was further assessed in BC4 and BC5 full-sib families. A BC5 population of 157 individuals was used to select AFLP markers linked to the resistance gene, Run1. Thirteen AFLP markers were selected and a local map was constructed around the Run1 gene. Ten markers among the 13 were found to co-segregate with the resistance gene. The usefulness of these 13 AFLP markers
for the selection of Run1-carrying genotypes was further assessed through their analysis in a set of 22 Run1-carrying resistant genotypes and 16 susceptible genotypes. Three markers out of the 13 analysed were found to be absent
in all susceptible genotypes and present in all resistant individuals, and may thus represent good tools for the marker-assisted
selection of grapevine varieties resistant to powdery mildew. A recombination event among the markers that were originally
found to co-segregate was observed in one of the resistant individuals, showing that recombination is possible in this region
and may therefore be observed in larger populations.
Received: 18 October 2000 / Accepted: 4 April 2001 相似文献
15.
Molecular mapping of stripe rust resistance gene YrCH42 in Chinese wheat cultivar Chuanmai 42 and its allelism with Yr24 and Yr26 总被引:15,自引:0,他引:15
Li GQ Li ZF Yang WY Zhang Y He ZH Xu SC Singh RP Qu YY Xia XC 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(8):1434-1440
Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most devastating diseases in common wheat (Triticum aestivum L.) worldwide. The objectives of this study were to map a stripe rust resistance gene in Chinese wheat cultivar Chuanmai 42 using molecular markers and to investigate its allelism with Yr24 and Yr26. A total of 787 F2 plants and 186 F3 lines derived from a cross between resistant cultivar Chuanmai 42 and susceptible line Taichung 29 were used for resistance gene tagging. Also 197 F2 plants from the cross Chuanmai 42×Yr24/3*Avocet S and 726 F2 plants from Chuanmai 42×Yr26/3*Avocet S were employed for allelic test of the resistance genes. In all, 819 pairs of wheat SSR primers were used to test the two parents, as well as resistant and susceptible bulks. Subsequently, nine polymorphic markers were employed for genotyping the F2 and F3 populations. Results indicated that the stripe rust resistance in Chuanmai 42 was conferred by a single dominant gene, temporarily designated YrCH42, located close to the centromere of chromosome 1B and flanked by nine SSR markers Xwmc626, Xgwm273, Xgwm11, Xgwm18, Xbarc137, Xbarc187, Xgwm498, Xbarc240 and Xwmc216. The resistance gene was closely linked to Xgwm498 and Xbarc187 with genetic distances of 1.6 and 2.3 cM, respectively. The seedling tests with 26 PST isolates and allelic tests indicated that YrCH42, Yr24 and Yr26 are likely to be the same gene.G.Q. Li and Z.F. Li contributed equally to the work. 相似文献
16.
McCartney CA Brûlé-Babel AL Lamari L Somers DJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(7):1181-1186
Septoria tritici blotch, caused by Mycosphaerella graminicola, is a serious foliar disease of wheat worldwide. Qualitative, race-specific resistance sources have been identified and utilized for resistant cultivar development. However, septoria tritici blotch resistant varieties have succumbed to changes in virulence of M. graminicola on at least three continents. The use of resistance gene pyramids may slow or prevent the breakdown of resistance. A clear understanding of the genetics of resistance and the identification of linked PCR-based markers will facilitate the recovery of wheat lines carrying multiple septoria tritici blotch resistance genes. The resistance gene in ST6 to isolate MG2 of M. graminicola was mapped with microsatellite markers in two populations, ST6/Erik and ST6/Katepwa. Bulk segregant analysis identified a marker on chromosome 4AL putatively linked to the resistance gene. A large linkage group was identified in each population using additional microsatellite markers mapping to chromosome 4AL. The resistance gene in ST6 mapped to the distal end of chromosome 4AL in each mapping population and was designated Stb7. Three of the microsatellite loci, Xwmc313, Xwmc219 and Xgwm160, mapped within 3.5 cM of Stb7; however, none flanked Stb7. Xwmc313 was the closest and mapped 0.3 and 0.5 cM from Stb7 in the crosses ST6/Katepwa and ST6/Erik, respectively. WMC313 will be very useful for marker-assisted selection of Stb7 in Canadian breeding programs because the ST6 allele of Xwmc313 was not identified in any of the Canadian common wheat cultivars tested.Communicated by P. Langridge 相似文献
17.
A. El-Kharbotly C. Palomino-Sánchez F. Salamini E. Jacobsen C. Gebhardt 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(7):880-884
In potato, 11 resistance alleles (R1–R11) are known which confer race-specific resistance to the fungus Phytophthora infestans. R1 has been mapped previously to potato chromosome V and R3 to chromosome XI. Here we report on the localization of the R6 and R7 alleles on the genetic map of potato. Differential resistant strains of tetraploid Solanum tuberosum, clones MaR6 and MaR7, were used as parental plants for the parthenogenetic induction and selection of diploid genotypes containing the R6 or the R7 resistance allele to P. infestans. One resistant dihaploid from MaR7 could be used directly as a parent to produce diploid F1 progeny suitable for phenotypic and RFLP analysis. MaR6 did not produce useful dihaploids directly. After crossing MaR6 with a tetraploid susceptible genotype, resistant F1 clones were selected. The resistant genotypes were then used as parents for the induction of dihaploids. Six dihaploids bearing R6 were identified that could be crossed with a diploid susceptible genotype. Two diploid F1 populations, segregating for R6 and R7, respectively, were analysed with RFLP markers known to be linked with previously identified R genes. Markers linked with R3 were found also to be linked with R6 and R7. The resistance alleles R6 and R7 mapped to a similar distal position on chromosome XI as the R3 allele. 相似文献
18.
Yang DE Jin DM Wang B Zhang DS Nguyen HT Zhang CL Chen SJ 《Molecular genetics and genomics : MGG》2005,274(3):229-234
The maize inbred lines 1145 (resistant) and Y331 (susceptible), and the F1, F2 and BC1F1 populations derived from them were inoculated with the pathogen Pythium inflatum Matthews, which causes stalk rot in Zea mays. Field data revealed that the ratio of resistant to susceptible plants was 3:1 in the F2 population, and 1:1 in the BC1F1population, indicating that the resistance to P. inflatum Matthews was controlled by a single dominant gene in the 1145×Y331 cross. The gene that confers resistance to P. inflatum Matthews was designated Rpi1 for resistance to P. inflatum) according to the standard nomenclature for plant disease resistance genes. Fifty SSR markers from 10 chromosomes were first
screened in the F2 population to find markers linked to the Rpi1 gene. The results indicated that umc1702 and mmc0371 were both linked to Rpi1, placing the resistance gene on chromosome 4. RAPD (randomly amplified polymorphic DNA) markers were then tested in the F2population using bulked segregant analysis (BSA). Four RAPD products were found to show linkage to the Rpi1 gene. Then 27 SSR markers and 8 RFLP markers in the region encompassing Rpi1 were used for fine-scale mapping of the resistance gene. Two SSR markers and four RFLP markers were linked to the Rpi1 gene. Finally, the Rpi1 gene was mapped between the SSR markers bnlg1937 and agrr286 on chromosome 4, 1.6 cM away from the former and 4.1 cM distant
from the latter. This is the first time that a dominant gene for resistance to maize stalk rot caused by P. inflatum Matthews has been mapped with molecular marker techniques. 相似文献
19.
Identification of a YAC clone carrying the Xa-1 allele, a bacterial blight resistance gene in rice 总被引:5,自引:0,他引:5
S. Yoshimura Y. Umehara N. Kurata Y. Nagamura T. Sasaki Y. Minobe N. Iwata 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(1-2):117-122
Map-based cloning methods have been applied for isolation of Xa-1, one of the bacterial blight resistance genes in rice.Xa-1 was previously mapped on chromosome 4 using molecular markers. For positional cloning of Xa-1, a high-resolution genetic map was made for theXa-1 region using an F2 population of 402 plants and additional molecular markers. Three restriction fragment length polymorphism (RFLP) markers, XNpb235, XNpb264 and C600 were found to be linked tightly to Xa-1, with no recombinants, and U08
750
was mapped 1.5 cM from Xa-1. The screening of a yeast artificial chromosome (YAC) library using theseXa-1-linked RFLP markers resulted in the identification of ten contiguous YAC clones. Among these, one YAC clone, designated Y5212, with an insert of 340 kb, hybridized with all three tightly linked markers. This YAC was confirmed to possess the Xa-1 allele by mapping the Xa-1 gene between both end clones of this YAC (Y5212R and Y5212L). 相似文献
20.
Sandbrink Johannes M. Colon Leontine T. Wolters Petra J.C.C. Stiekema Willem J. 《Molecular breeding : new strategies in plant improvement》2000,6(2):215-225
Six F1 populations produced from crosses between two Solanum microdontum genotypes and three S. tuberosum genotypes have been assessed for resistance to Phytophthora infestans (late blight; LB) in the field and proved to segregate for P. infestans resistance. The six populations were subjected to genetic mapping using AFLP markers in combination with a core map consisting of RFLPs and a few PCR-based markers. The two S. microdontum parents MCD167 and MCD178 harbour different alleles contributing to resistance. In the MCD167 set of populations a major QTL contributing to resistance was located on chromosome 4. This locus was not detected in the MCD178 set of populations. In the latter set of populations, a major QTL for resistance was detected on chromosome 10. This locus for resistance was not detected in the MCD167 set of populations. A third QTL contributing strongly to resistance was detected on chromosome 5. However, this locus was not consistently detected in all populations. For the loci on chromosome 5 and 10, segregation for resistance alleles from the susceptible parents was also observed. The results provide a starting point for future combinations of genes, to predict the value of each combination and finally to obtain potato germplasm carrying high levels of durable resistance to LB. 相似文献