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1.
Ballvora A Flath K Lübeck J Strahwald J Tacke E Hofferbert HR Gebhardt C 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(8):1281-1292
The obligate biotrophic, soil-borne fungus Synchytrium endobioticum causes wart disease of potato (Solanum tuberosum), which is a serious problem for crop production in countries with moderate climates. S. endobioticum induces hypertrophic cell divisions in plant host tissues leading to the formation of tumor-like structures. Potato wart
is a quarantine disease and chemical control is not possible. From 38 S. endobioticum pathotypes occurring in Europe, pathotypes 1, 2, 6 and 18 are the most relevant. Genetic resistance to wart is available
but only few current potato varieties are resistant to all four pathotypes. The phenotypic evaluation of wart resistance is
laborious, time-consuming and sometimes ambiguous, which makes breeding for resistance difficult. Molecular markers diagnostic
for genes for resistance to S. endobioticum pathotypes 1, 2, 6 and 18 would greatly facilitate the selection of new, resistant cultivars. Two tetraploid half-sib families
(266 individuals) segregating for resistance to S. endobioticum pathotypes 1, 2, 6 and 18 were produced by crossing a resistant genotype with two different susceptible ones. The families
were scored for five different wart resistance phenotypes. The distribution of mean resistance scores was quantitative in
both families. Resistance to pathotypes 2, 6 and 18 was correlated and independent from resistance to pathotype 1. DNA pools
were constructed from the most resistant and most susceptible individuals and screened with genome wide simple sequence repeat
(SSR), inverted simple sequence region (ISSR) and randomly amplified polymorphic DNA (RAPD) markers. Bulked segregant analysis
identified three SSR markers that were linked to wart resistance loci (Sen). Sen1-XI on chromosome XI conferred partial resistance to pathotype 1, Sen18-IX on chromosome IX to pathotype 18 and Sen2/6/18-I on chromosome I to pathotypes 2,6 and 18. Additional genotyping with 191 single nucleotide polymorphism (SNP) markers confirmed
the localization of the Sen loci. Thirty-three SNP markers linked to the Sen loci permitted the dissection of Sen alleles that increased or decreased resistance to wart. The alleles were inherited from both the resistant and susceptible
parents. 相似文献
2.
Brugmans B Hutten RG Rookmaker AN Visser RG van Eck HJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(2):269-277
A marker-saturated linkage map of potato was used to genetically map a locus involved in the resistance against wart disease
Synchytrium endobioticum race 1. The locus mapped on the long arm of chromosome 4 and is named Sen1-4 in contrast to a Sen1 locus on chromosome 11. The AFLP markers from the Sen1-4 interval enabled the isolation of BAC clones from an 11 genome equivalent BAC library. This was achieved via fingerprinting
of BAC pools with the AFLP primer pairs that resemble the genetic marker loci. With non-selective AFLP primers, fingerprints
of individual BAC clones were generated to analyse the overlap between BAC clones using FPC. This resulted in a complete contig
and a minimal tiling path of 14 BAC clones enclosing the Sen1-4 locus. The BAC contig has a genetic length of ~6 cM and a physical length of ~1 Mb. Our results demonstrate that map-based
cloning of Sen1-4 can be pursued on the basis of a strategy of marker saturation alone. Genetic resolution achieved by screening large numbers
of offspring for recombination events may not be required. Together with the construction of the BAC contig, a physical map
with the position of the markers is accomplished in one step. This provides proof of concept for the utility of the marker
saturation that is offered by the ultra dense AFLP map of potato for gene cloning. 相似文献
3.
Jude Ejikeme Obidiegwu Kerstin Flath Christiane Gebhardt 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2014,127(4):763-780
Key message
Identification of resistance genes to potato wart disease caused by Synchytrium endobioticum is the key for developing diagnostic markers for breeding resistant cultivars. We present an overview on the current knowledge of this host-pathogen system and molecular advances while highlighting future research focus.Abstract
Potato wart is a quarantined disease of cultivated potato (Solanum tuberosum L.) caused by the obligate biotrophic, soil-borne fungus Synchytrium endobioticum (Schilb.) Perc. Since its discovery by Schilberszky in 1896, the management of wart disease was enabled by research efforts focusing on understanding and classifying the causative agent, its mode of infection, pathogenesis, geographical distribution, detection and chemical control, on developing screening methods for host resistance and on genetic analyses, which led to the development of resistant cultivars. These early successes are currently challenged by new S. endobioticum pathotypes evolving and the increased risk of dissemination by potato tuber trade. New research efforts are therefore required to ensure continuation of effective and sustainable management of the potato wart disease. Advances in molecular biology and genomic tools offer potential for innovations. This review presents an overview on what we know about this complex host-pathogen interaction, highlights recent molecular work and embarks on an outlook towards future research directions. 相似文献4.
Gebhardt C Bellin D Henselewski H Lehmann W Schwarzfischer J Valkonen JP 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(8):1458-1464
Closely linked PCR-based markers facilitate the tracing and combining of resistance factors that have been introgressed previously into cultivated potato from different sources. Crosses were performed to combine the Ry
adg
gene for extreme resistance to Potato virus Y (PVY) with the Gro1 gene for resistance to the root cyst nematode Globodera rostochiensis and the Rx1 gene for extreme resistance to Potato virus X (PVX), or with resistance to potato wart (Synchytrium endobioticum). Marker-assisted selection (MAS) using four PCR-based diagnostic assays was applied to 110 F1 hybrids resulting from four 2× by 4× cross-combinations. Thirty tetraploid plants having the appropriate marker combinations were selected and tested for presence of the corresponding resistance traits. All plants tested showed the expected resistant phenotype. Unexpectedly, the plants segregated for additional resistance to pathotypes 1, 2 and 6 of S. endobioticum, which was subsequently shown to be inherited from the PVY resistant parents of the crosses. The selected plants can be used as sources of multiple resistance traits in pedigree breeding and are available from a potato germplasm bank. 相似文献
5.
Jennifer Groth Yesu Song Adolf Kellermann Andrea Schwarzfischer 《Journal of applied genetics》2013,54(2):169-178
Potato wart is caused by the obligate biotrophic fungus Synchytrium endobioticum, which is subject to quarantine regulations due to the production of long persisting spores in the soil and the lack of effective fungicides. The objective of this study was to identify quantitative trait loci (QTL) for resistance against potato wart races (R) 1, 2, 6 and 18 in a tetraploid potato population developed by crossing cv. Saturna (resistant to R1) with cv. Panda (resistant to R1, R2, R6, R18). A total of 92 progenies were used for phenotyping and genotyping. Resistance tests were performed for races 1 and 18 in 2 years and for races 2 and 6 in 1 year on 10 to 20 eyepieces per genotype. Based on amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers, linkage maps were established for the female and male parent, respectively. Single marker analysis followed by a multiple regression analysis revealed initial marker–trait associations. The interval mapping routine of TetraploidMap was applied for QTL analysis. A major QTL for resistance against race 1 explaining between 46 % and 56 % of the phenotypic variation was identified near Sen1, a known resistance locus for potato wart race 1 on chromosome XI. Other resistance QTL were detected on chromosomes I (to R2), II (to R6, 18), VI (to R1, 2, 6, 18), VII (to R2, 6, 18), VIII (to R1, 2, 6, 18), X (to R2, 6, 18), XI (to R2, 6, 18) and on an unknown linkage group (to R18) explaining minor to moderate effects of the phenotypic variation. Resistance QTL against different potato wart races often overlapped, particularly concerning races 2, 6 and 18. Overall, this study gives a valuable insight into the complex inheritance of resistance against potato wart. 相似文献
6.
Annette Bartkiewicz Friederike Chilla Diro Terefe-Ayana Jens Lübeck Josef Strahwald Eckhard Tacke Hans-Reinhard Hofferbert Kerstin Flath Marcus Linde Thomas Debener 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2018,131(12):2555-2566
Key message
We achieved improved mapping resolution of the major wart resistance locus Xla-TNL containing also Sen1 in a dihaploid population using SNP data and developed additional markers with diagnostic value in tetraploid varieties.Abstract
We analyzed a segregating monoparental dihaploid potato population comprising 215 genotypes derived from a tetraploid variety that is highly resistant to Synchytrium endobioticum pathotypes 18 and 6. The clear bimodal segregation for both pathotypes indicated that a major dominant resistance factor in a simplex allele configuration was present in the tetraploid donor genotype. Compared to that in previous analyses of the same tetraploid donor in conventional crosses with susceptible tetraploid genotypes, a segregation pattern with a reduced genetic complexity of resistance in dihaploids was observed here. Using the 12.8 k SolCAP SNP array, we mapped a resistance locus to the Xla-TNL region containing also Sen1 on potato chromosome 11. The improved mapping resolution provided by the monoparental dihaploids allowed for the localization of the genes responsible for the resistance to both pathotypes in an interval spanning less than 800 kbp on the reference genome. Furthermore, we identified eight molecular markers segregating without recombination to pathotype 18 and pathotype 6 resistance. Also, two developed markers display improved diagnostic properties in an independent panel of tetraploid varieties. Overall, our data provide the highest resolution mapping of wart resistance genes at the Xla-TNL locus thus far.7.
D. Leister A. Berger H. Thelen W. Lehmann F. Salamini C. Gebhardt 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(5-6):954-960
A yeast artificial chromosome (YAC) library was constructed from high-molecular-weight DNA of potato (Solanum tuberosum). Potato DNA fragments obtained after complete digestion with four different rare-cutter restriction enzymes were cloned
using the pYAC-RC vector. The library consists of 21 408 YAC clones with an average insertion size of 140 kb. The frequency
of YAC clones having insertions of chloroplast or mitochondrial DNA was estimated to be 0.5% and 0.3%, respectively. The YAC
library was screened by PCR with 11 DNA markers detecting single genes or small gene families in the potato genome. YACs for
8 of the 11 markers were detected in the library. Using 2 markers that are linked to the resistance genes R1 and Gro1 of potato, we isolated two individual YAC clones. One of these YAC clones was found to harbour one member of a small family
of candidate genes for the nematode resistance gene Gro1.
Received : 5 May 1997 / Accepted : 20 May 1997 相似文献
8.
Somatic hybrids between Solanum bulbocastanum and potato: a new source of resistance to late blight 总被引:4,自引:0,他引:4
J. P. Helgeson J. D. Pohlman S. Austin G. T. Haberlach S. M. Wielgus D. Ronis L. Zambolim P. Tooley J. M. McGrath R. V. James W. R. Stevenson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):738-742
Solanum bulbocastanum, a wild, diploid (2n=2x=24) Mexican species, is highly resistant to Phytophthora infestans, the fungus that causes late blight of potato. However this 1 EBN species is virtually impossible to cross directly with
potato. PEG-mediated fusion of leaf cells of S. bulbocastanum PI 245310 and the tetraploid potato line S. tuberosum PI 203900 (2n=4x=48) yielded hexaploid (2n= 6x=72) somatic hybrids that retained the high resistance of the S. bulbocastanum parent. RFLP and RAPD analyses confirmed the hybridity of the materials. Four of the somatic hybrids were crossed with potato
cultivars Katahdin or Atlantic. The BC1 progeny segregated for resistance to the US8 genotype (A-2 mating type) of P. Infestans. Resistant BC1 lines crossed with susceptible cultivars again yielded populations that segregated for resistance to the fungus. In a 1996
field-plot in Wisconsin, to which no fungicide was applied, two of the BC1 lines, from two different somatic hybrids, yielded 1.36 and 1.32 kg/plant under a severe late-blight epidemic. In contrast,
under these same conditions the cultivar Russet Burbank yielded only 0.86 kg/plant. These results indicate that effective
resistance to the late-blight fungus in a sexually incompatible Solanum species can be transferred into potato breeding lines by somatic hybridization and that this resistance can then be further
transmitted into potato breeding lines by sexual crossing.
Received: 27 October 1997 / Accepted: 11 November 1997 相似文献
9.
Predicted kinase-3a motif of a resistance gene analogue as a unique marker for virus resistance 总被引:2,自引:1,他引:1
V. A. Sorri K. N. Watanabe J. P. T. Valkonen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(1-2):164-170
A DNA fragment (ADG2, 310 bp) 77% homologous to the gene N (resistance to tobacco mosaic virus in Nicotiana glutinosa) and 53% homologous to RPP5 (resistance to Peronospora parasitica in Arabidopsis thaliana) was amplified by PCR from the diploid potato genotype 2x(v-2)7 that carries the gene Ry
adg
located on chromosome XI and conferring extreme resistance to potato virus Y(PVY). Sequence comparison revealed that ADG2
spans a region corresponding to the predicted kinase-2 and kinase-3a motifs in N and RPP5. One of the 12 nucleotide differences detected between ADG2 and a homologous fragment from a PVY-susceptible potato genotype
was located within the predicted kinase-3a motif. This single nucleotide substitution of G→C, resulting in an amino-acid substitution
Ser→Thr, abolished the BbvI recognition site of ADG2, which was shown to distinguish all tested potato genotypes carrying Ry
adg
from those lacking this gene, irrespective of the genetic background and ploidy level. This PCR-based resistance marker,
developed using a resistance gene analogue as a target, is the first example of a PCR-based marker that is generally applicable
for selection of an economically important trait in potato.
Received: 28 November 1998 / Accepted: 28 December 1998 相似文献
10.
A single disease resistance gene candidate,MbR4, was isolated from the wild-type apple speciesMalus baccta. This gene was predicted to encode motifs characteristic of the Toll Interleukin 1 Receptor (TIR) — Nucleotide Binding Site
(NBS) of theR gene. Starting with an isolated cDNA clone, genomic clones were obtained via inverse polymerase chain reaction (IPCR). TheMbR4 gene has a single open reading frame (ORF) of 2178 nucleotides, a 41-b untranslated 5’ region, a 21-b untranslated 3’ region,
and a predicted protein of 726 amino acids (82 kDa). Its deduced amino acid sequence resembles the N protein of tobacco and
the NL25 protein of potato. Ectopic expression ofMbR4 induced enhanced resistance in transgenicArabidopsis plants against the virulent pathogen,Pseudomonas syringae pv.tomato DC3000. Microarray analysis confirmed the induction of defense-related gene expression in pathogen-free 35S::MbR4 heterologousArabidopsis plants, thereby indicating that theMbR4 gene likely activates a pathogen-independent resistance pathway, rather than a gene-for-gene pathway. Our results suggest
thatMbR4 plays a role in theR gene, and may be a source of resistance for cultivated apple species. 相似文献
11.
Abdullahi I Koerbler M Stachewicz H Winter S 《Applied microbiology and biotechnology》2005,68(3):368-375
Resting spores extracted from wart (Synchytrium endobioticum)-infected potato tubers were used for DNA extraction and amplification of 18S rDNA. Analysis of the cloned, sequenced fragment revealed high similarity to members of the Chytridiomycota. Using this information, specific oligonucleotide probes were designed and arrayed onto glass slides for detection of the pathogen. Viral sequence information available in the databank was retrieved, or new viral sequences were generated, and used to design probes for specific detection of important quarantine viruses of potato. To determine the sensitivity and specificity of the oligonucleotide probes, total RNA from infected plants was reverse transcribed, labelled with Cyanine 5, and hybridised with the microarray. A significant number of the oligonucleotide probes exhibited high specificity to S. endobioticum, Andean potato latent virus, Andean potato mottle virus, Potato black ringspot virus, and Potato spindle tuber viroid. Hybridisation signals of sub-arrays within slides were reproducible (r=0.79) with a high correlation coefficient of hybridisation repetitions (0.73). Our results demonstrate the potential of microarray-based hybridisation for identification of multiple pathogen targets, which will find application in quarantine laboratories, where parallel testing for diverse pathogens is essential. 相似文献
12.
Lipid classes and fatty acid distribution were analysed in the resting sporangium of Synchytrium endobioticum, the causal agent of the potato wart disease. The sporangium contents were shown to have lipid droplets, the major fatty acids there being C16.0, C18.1, and C19.0. The sporangium wall on the other hand was composed of C18.0, C18.1, C18.2, C20.0, and C20.4 fatty acids. A significantly large portion of the sporangium wall lipids contained wax esters with branched chains. 相似文献
13.
Targeted resistance gene mapping in soybean using modified AFLPs 总被引:7,自引:0,他引:7
A. J. Hayes M.A. Saghai Maroof 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(8):1279-1283
The soybean [Glycine max (Merr.) L.] linkage group F contains a vital region of clustered genes for resistance to numerous pathogens including the
soybean mosaic virus resistance gene, Rsv1. In order to develop new genetic markers that map to this gene cluster, we employed a targeted approach that utilizes the
speed and high-throughput of AFLP, but modified it to incorporate sequence information from the highly conserved nucleotide
binding site (NBS) region of cloned disease resistance genes. By using a labeled degenerate primer corresponding to the p-loop
portion of the NBS region of resistance genes, such as N, L6, and Rps2, we were able to quickly amplify numerous polymorphic bands between parents of a population segregating for resistance to
Rsv1. Of these polymorphic bands, bulk segregant analysis revealed four markers that were closely linked to Rsv1. These markers were cloned and used as probes for RFLP analysis. The four clones mapped to within a 6-cM region surrounding
Rsv1, the closest being 0.4 cM away from the gene. Sequence analysis showed that all four clones contain the p-loop sequence
corresponding to the degenerate primer and that one of the four clones contains an open reading frame sequence which when
translated is related to the NBS region of other cloned disease resistance genes. The rapid identification of four markers
closely linked to Rsv1 in soybean demonstrates the utility of this method for generating markers tightly linked to important plant disease resistance
genes.
Received: 25 September 1999 / Accepted: 3 November 1999 相似文献
14.
J. H. Hämäläinen V. A. Sorri K. N. Watanabe C. Gebhardt J. P. T. Valkonen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(8):1036-1043
The gene Ry
adg
that confers resistance to potato Y potyvirus (PVY) in the cultivated potato [Solanum tuberosum subsp. andigena, line 2x(v-2)7] is located on chromosome XI in a segment that contains three other known resistance genes in other syntenic solanaceous
species. One of them is the gene N that controls resistance to tobacco mosaic tobamovirus in tobacco and has previously been isolated and sequenced. Three sequence-related,
resistance gene-like (RGL) DNA fragments (354–369 bp) highly homologous to the gene N were PCR-amplified from the potato line 2x(v-2)7. Two RGL fragments (79 and 81% homologous to the N gene) co-segregated with Ry
adg
among the 77 F1 progeny tested. These RGLs may originate from a resistance gene family on chromosome XI. The potato line
2x(v-2)7 also expressed resistance to potato A potyvirus (PVA), which was controlled by another locus on chromosome XI mapped
ca. 6.8 cM distal to Ry
adg
.
Received: 18 December 1997 / Accepted: 30 December 1997 相似文献
15.
K. J. Williams A. Lichon P. Gianquitto J. M. Kretschmer A. Karakousis S. Manning P. Langridge H. Wallwork 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(1-2):323-327
Spot form of net blotch (SFNB) (Pyrenophora teres f maculata) is an economically damaging foliar disease of barley in many of the world’s cereal growing areas. The development of SFNB-resistant
cultivars may be accelerated through the use of molecular markers. A screen for SFNB resistance in 96 lines identified four
new sources of resistance, including a feed variety, ‘Galleon’, for which a fully mapped doubled haploid population was available.
Segregation data indicated SFNB resistance was conferred by a single gene in the ‘Galleon’בHaruna Nijo’ cross, positioned
on the long arm of chromosome 7H. This gene is designated Rpt4 and is flanked by the RFLP loci Xpsr117(D) and Xcdo673 at distances of 6.9 cM and 25.9 cM, respectively. The marker Xpsr117(D) was validated using another population segregating for Rpt4, correctly predicting SFNB resistance with more than 90% accuracy.
Received: 24 September 1998 / Accepted: 19 December 1998 相似文献
16.
L. Gentzbittel S. Mouzeyar S. Badaoui E. Mestries F. Vear D. Tourvieille De Labrouhe P. Nicolas 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(3-4):519-525
A candidate-gene approach to analyse the resistance of plants to phytopathogenic fungi is presented. The resistance of sunflower
(Helianthus annuus L.) to downy mildew (Plasmopara halstedii) shows a gene-for-gene interaction (monogenic resistance), whereas resistance to white rot (Sclerotinia sclerotiorum) is quantitative, with different levels of resistance for different plant parts. By homology cloning, probes were obtained
homologous to some plant resistance genes (nucleotide binding site-like, NBS, genes and serine-threonine protein kinase-like,
PK, genes). These clones were used as probes for linkage mapping of the corresponding genes. It was demonstrated that at least
three NBS-like loci are located on linkage-group 1, in the region where downy mildew resistance loci have been described.
Quantitative trait loci for S. sclerotiorum resistance to penetration or extension of the mycelium in different tissues were studied in three crosses. Major QTLs for
resistance were found on linkage group 1, with up to 50% of the phenotypic variability explained by peaks at the map position
of the PK locus, 25 cM from the downy mildew loci.
Received: 24 September 1997 / Accepted: 21 October 1997 相似文献
17.
18.
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
19.
The hypersensitive response is associated with host and nonhost resistance to Phytophthora infestans
The interaction between Phytophthora infestans (Mont.) de Bary and Solanum was examined cytologically using a diverse set of wild Solanum species and potato (S. tuberosum L.) cultivars with various levels of resistance to late blight. In wild Solanum species, in potato cultivars carrying known resistance (R) genes and in nonhosts the major defense reaction appeared to be the hypersensitive response (HR). In fully resistant Solanum species and nonhosts, the HR was fast and occurred within 22 h. This resulted in the death of one to three cells. In partially
resistant clones, the HR was induced between 16 and 46 h, and resulted in HR lesions consisting of five or more dead cells,
from which hyphae were occasionally able to escape to establish a biotrophic interaction. These results demonstrate the quantitative
nature of the resistance to P. infestans. The effectiveness of the HR in restricting growth of the pathogen differed considerably between clones and correlated with
resistance levels. Other responses associated with the defense reaction were deposition of callose and extracellular globules
containing phenolic compounds. These globules were deposited near cells showing the HR, and may function in cell wall strengthening.
Received: 22 April 1999 / Accepted: 4 November 1999 相似文献
20.
Resistance gene analogues from rice: cloning, sequencing and mapping 总被引:18,自引:0,他引:18
R. Mago S. Nair M. Mohan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(1-2):50-57
Degenerate oligonucleotide primers were designed on the basis of nucleotide-binding-site (NBS) motifs conserved between resistance
genes of Arabidopsis, flax and tobacco and subsequently used as PCR primers to amplify resistance gene analogues (RGA) in rice. Primers amplified
a major band of approximately 500 bp. Restriction analysis of the amplified product revealed that the band was made up of
several different fragments. Many of these fragments were cloned. Sixty different cloned fragments were analysed and assigned
to 14 categories based on Southern blot analysis. Fourteen clones, each representing one of the 14 categories of RGAs were
mapped onto the rice genetic map using a Nipponbare ( japonica)בKasalath’ (indica) mapping population consisting of 186 F2 lines. Of the 14 clones representing each class 12 could be mapped onto five different chromosomes of rice with a major cluster
of 8 RGAs on chromosome 11. Our results indicate that it is possible to use sequence homology from conserved motifs of known
resistance genes to amplify candidate resistance genes from diverse plant taxa.
Received: 23 September 1998 / Accepted: 28 November 1998 相似文献