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1.
Comparative genetic maps of foxtail millet (Setaria italica) and rice (Oryza sativa) 总被引:4,自引:0,他引:4
K. M. Devos Z. M. Wang J. Beales T. Sasaki M. D. Gale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(1):63-68
A foxtail millet-rice comparative genetic map was constructed using mapped rice RFLP markers and wheat genomic and cDNA clones
with known map position in rice. About 74% and 37% of the cDNA and genomic clones, respectively, were transferable to foxtail
millet, confirming that conservation at the DNA level is greatest in genic regions. A high degree of conserved colinearity
was observed between the two genomes. Five entire foxtail millet chromosomes appear to be colinear with five entire rice chromosomes.
The remaining four foxtail millet linkage groups each show colinearity with segments of two rice chromosomes. The rearrangements
of rice chromosomes 3 and 10 to form foxtail millet chromosome IX, and 7 and 9 to form chromosome II are very similar to those
required to form maize chromosomes 1 and 7 and sorghum linkage groups C and B, indicating Setaria’s clear taxonomic position within the subfamily of the Panicoideae.
Received: 18 December 1996 / Accepted: 4 August 1997 相似文献
2.
Integrated map of AFLP, SSLP and RFLP markers using a recombinant inbred population of rice (Oryza sativa L.) 总被引:7,自引:0,他引:7
Y. G. Cho S. R. McCouch M. Kuiper M.-R. Kang J. Pot J. T. M. Groenen M. Y. Eun 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(3):370-380
A molecular map of rice consisting of 231 amplified fragment length polymorphisms (AFLPs), 212 restriction fragment length
polymorphisms (RFLPs), 86 simple-sequence length polymorphisms (SSLPs), five isozyme loci, and two morphological mutant loci
[phenol staining of grain (Ph), semi-dwarf habit (sd-1)] has been constructed using an F11 recombinant inbred (RI) population. The mapping population consisted of 164 RI lines and was developed via single-seed descent
from an intercross between the genetically divergent parents Milyang 23 (M) (tongil type) and Gihobyeo (G) ( japonica type). A subset of previously mapped RFLP and SSLP markers were used to construct the map framework. The AFLP markers were
derived from ten EcoRI(+2) and MseI(+3) primer combinations. All marker types were well distributed throughout the 12 chromosomes. The integrated map covered
1814 cM, with an average interval size of 3.4 cM. The MG map is a cornerstone of the Korean Rice Genome Research Program (KRGRP)
and is being continuously refined through the addition of partially sequenced cDNA markers derived from an immature-seed cDNA
library developed in Korea, and microsatellite markers developed at Cornell. The population is also being used for quantitative
trait locus (QTL) analysis and as the basis for marker-assisted variety development.
Received: 24 June 1997 / Accepted: 25 November 1997 相似文献
3.
S. Fukuoka H. Namai K. Okuno 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(3):446-449
Complementary recessive genes hwd1 and hwd2 controlling hybrid breakdown (weakness of F2 and later generations) were mapped in rice using RFLP markers. These genes produce a plant that is shorter and has fewer
tillers than normal plants when the two loci have only one or no dominant allele at both loci. A cultivar with two dominant
alleles at the hwd1 locus and a cultivar with two dominant alleles at the hwd2 locus were crossed with a double recessive tester line. Linkage analysis was carried out for each gene independently in two
F2 populations derived from these crosses. hwd1 was mapped on the distal region of rice genetic linkage map for chromosome 10, flanked by RFLP markers C701 and R2309 at
a distance of 0.9 centiMorgans (cM) and 0.6 cM, respectively. hwd2 was mapped in the central region of rice genetic linkage map for chromosome 7, tightly linked with 4 RFLP markers without
detectable recombination. The usefulness of RFLP mapping and map information for the genes controlling reproductive barriers
are discussed in the context of breeding using diverse rice germplasm, especially gene introduction by marker-aided selection. 相似文献
4.
A genome-wide analysis of wide compatibility in rice and the precise location of the S5 locus in the molecular map 总被引:24,自引:0,他引:24
K. D. Liu J. Wang H. B. Li C. G. Xu A. M. Liu X. H. Li Q. Zhang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(5-6):809-814
The discovery of wide-compatibility varieties (WCVs) that are able to produce normal fertility hybrids when crossed both
to indica and japonica rice has enabled the fertility barrier between indica and japonica subspecies to be broken and provided
the possibility of developing inter-subspecific hybrids in rice breeding programs. However, a considerable variation in the
fertility level of hybrids from the same WCV crossed to different varieties has often been observed. One hypothesis for this
variable fertility is that additional genes are involved in hybrid fertility besides the wide-compatibility gene (WCG). To
assess such a possibility, we performed a genome-wide analysis by assaying a large population from a three-way cross ‘02428’/‘Nanjing
11’//‘Balilla’ using a total of 171 RFLP probes detecting 191 polymorphic loci distributed throughout the entire rice linkage
map. Our analysis recovered 3 loci conferring significant effects on hybrid fertility. The major locus on chromosome 6 coincided
in chromosomal location with the previously identified S
5
locus, and the 2 minor loci that mapped to chromosomes 2 and 12, respectively, were apparently distinct from all previously
reported hybrid sterility genes. Interaction between the indica and japonica alleles at each of the loci caused a reduction
in hybrid fertility. The joint effect of the 2 minor loci could lead to partial sterility even in the presence of the WCG.
The location of the S
5
locus on the molecular marker linkage map was determined to be approximately 1.0 cM from the RFLP locus R2349. This tight
linkage will be useful for marker-aided transfer of the WCG in hybrid rice breeding and for map-based cloning.
Received: 5 February 1997 / Accepted: 4 April 1997 相似文献
5.
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
6.
Resistance to submergence stress is an important breeding objective in areas where rice cultivars are subjected to complete
inundation for a week or more. The present study was conducted to develop a high-resolution map of the region surrounding
the submergence tolerance gene Sub1 in rice, which derives from the Indian cultivar FR13A. Submergence screening of 8-day-old plants of F3 families kept for 14 days submerged in 60 cm of water allowed an accurate classification of Sub1 phenotypes. Bulked segregant analysis was used to identify AFLP markers linked to Sub1. A population of 2950 F2 plants segregating for Sub1 was screened with two RFLP markers flanking the Sub1 locus, 2.4 and 4.9 cM away. Submergence tolerance was measured in the recombinant plants, and AFLP markers closely linked
to Sub1 were mapped. Two AFLP markers cosegregated with Sub1 in this large population, and other markers were localized within 0.2 cM of Sub1. The high-resolution map should serve as the basis for map-based cloning of this important locus, as it will permit the identification
of BAC clones spanning the region.
Received: 15 December 1999 / Accepted: 18 February 2000 相似文献
7.
《Molecular & general genetics : MGG》1997,253(5):615-623
With the aim of elucidating the complex genetic system controlling flower morphogenesis in cereals, we have characterized
two rice and two sorghum MADS box genes isolated from cDNA libraries made from developing inflorescences. The rice clones
OsMADS24 and OsMADS45, which share high homology with the Arabidopsis AGL2 and AGL4 MADS box genes, are expressed in the floral meristem, in all the primordia, and in mature floral organs. High expression
levels have also been found in developing kernels. The sorghum clone SbMADS1 is also homologous to AGL2 and AGL4: expression analysis and mapping data suggest that it is the ortholog of OsMADS24. The pattern of expression of SbMADS2, the other sorghum MADS box gene, suggests that it may play a role as a meristem identity gene, as does AP1 in Arabidopsis, to which it shows considerable homology. The four genes have been mapped on a rice RFLP genetic map: the results are discussed
in terms of synteny among cereals.
Received: 25 April 1996 / Accepted: 29 August 1996 相似文献
8.
By using differential display PCR (DD-PCR) technique, two salt-inducible and one salt-repressed cDNA fragments were isolated
from rice. The three cDNA fragments were characterized respectively as partial sequence of rice S-adenosylmethionine decarboxylase
(SAMDC) gene, a new member of translation elongation factor 1A gene (namedREF1 A), and a novel gene whose function is unknown (namedSRG1). The full-length cDNA of SAMDC gene (namedSAMDC1) was further isolated by RT-PCR approach and the deduced polypeptide was found to be homologous to SAMDC proteins of other
plants, yeast and buman. Northern hybridization revealed that expression of SAMDCl and REFlA was induced, while SRGl was dramatically repressed, by salinity stress. Southern blot analysis demonstrated that SAMDCl and
SRGl were present as a single copy gene in rice genome, whereas riceREF1 A gene was organized as a gene family. TheREF1 A,SAMDC1, andSRG1 genes were located on chromosome 3,4, and 6 respectively by RFLP mapping approach using ZYQ8/JX17 DH population and RFLP
linkage maps.
Project supported by the National “863” High-Technology Program. 相似文献
9.
B. F. Matthews M. H. MacDonald J. S. Gebhardt T. E. Devine 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(7):1047-1052
The restriction fragment length polymorphism (RFLP) clone pBLT65 is a 450-nt soybean cDNA encoding a portion of the bifunctional
enzyme aspartokinase-homoserine dehydrogenase (AK-HSDH). pBLT65 maps within 3.5 cM of the i locus, conferring a pigmented seed coat, on linkage group A; hence, it is closely linked to the Rhg
4
locus conferring resistance to race 3 of the soybean cyst nematode. From this useful RFLP we developed a PCR reaction yielding
polymorphic bands for use in marker-assisted breeding programs to select progeny containing the Rhg
4
allele. The polymorphic bands were sequenced to determine the cause of the polymorphisms. Using primers 548 and 563, PCR
amplification of DNA from the soybean cultivar Peking (Rhg
4
) yielded three DNA fragments, 1a (1160 bp), 1b (1146 bp) and 3 (996 bp). Amplification of DNA from the cultivar Kent (rhg
4) yielded DNA fragments 2 (1020 bp), 3 (996 bp) and 4 (960 bp). Fragments 1a, 1b, 2 and 4 were also polymorphic between the
soybean lines PI 290136 and BARC-2(Rj
4
). A segregating population of 80 F2 and F3 plants derived from the cross PI 290136×BARC-2 (Rj
4
) was used to confirm the map position of the PCR polymorphisms near the i locus, and hence the Rhg
4
locus on linkage group A. The nucleotide sequences of fragments 1b, 3 and 4 were determined. Large and small deletions in
the intronic region were responsible for the size differences of the different fragments, whereas the exon was well conserved.
Received: 8 January 1998 / Accepted: 15 July 1998 相似文献
10.
Direct amplification of minisatellite-region DNA with VNTR core sequences in the genus Oryza 总被引:3,自引:0,他引:3
Z. Zhou P. J. Bebeli D. J. Somers J. P. Gustafson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(5-6):942-949
A polymerase chain reaction (PCR) application, involving the directed amplification of minisatellite-region DNA (DAMD) with
several minisatellite core sequences as primers, was used to detect genetic variation in 17 species of the genus Oryza and several rice cultivars (O. sativa L.). The electrophoretic analysis of DAMD-PCR products showed high levels of variation between different species and little
variation between different cultivars of O. sativa. Polymorphisms were also found between accessions within a species, and between individual plants within an accession of
several wild species. The DAMD-PCR yielded genome-specific banding patterns for the species studied. Several DAMD-PCR-generated
DNA fragments were cloned and characterized. One clone was capable of detecting multiple fragments and revealed individual-specific
hybridization banding patterns using genomic DNA from wild species as well as rice cultivars. A second clone detected only
a single polymorphic locus, while a third clone expressed a strong genome specificity by Southern analysis. The results demonstrated
that DAMD-PCR is potentially useful for species and genome identification in Oryza. The DAMD-PCR technique also allows for the isolation of informative molecular probes to be utilized in DNA fingerprinting
and genome identification in rice.
Received: 1 October 1996 / Accepted: 25 April 1997 相似文献
11.
Construction of a BAC contig containing the xa5 locus in rice 总被引:9,自引:0,他引:9
D. Yang A. Sanchez G. S. Khush Y. Zhu N. Huang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(7):1120-1124
The recessive gene xa5 confers resistance to bacterial blight in rice. To generate a physical map of the xa5 locus, three RFLP markers RG556, RG207 and RZ390, closely linked to xa5, were used to screen a rice bacterial artificial chromosome (BAC) library. The identified overlapping BAC clones formed two
small contigs which were extended to both sides by chromosome walking. The final physical map consisted of 14 BAC clones and
covered 550 kb. Genetic analysis with an F2 population showed that two RFLP markers 28N22R and 40F20R, derived from the BAC clones in the contig, flanked the xa5 locus. To further delimit the location of the xa5 locus, RFLP markers RG556 and RG207 were converted to sequence tagged sites and used to perform genetic analysis. The results
indicated that the xa5 locus was most likely located between RG207 and RG556. Among the BAC clones in the contig, one clone, 44B4, hybridized to
both RG207 and RG556. This suggests that BAC clone 44B4 carried the xa5 locus.
Received: 12 January 1998 / Accepted: 27 May 1998 相似文献
12.
Construction of an RFLP linkage map for cultivated sunflower 总被引:5,自引:0,他引:5
C. C. Jan B. A. Vick J. F. Miller A. L. Kahler E. T. Butler III. 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(1):15-22
An RFLP linkage map was constructed for cultivated sunflower Helianthus annuus L., based on 271 loci detected by 232 cDNA probes. Ninety-three F2 plants of a cross between inbred lines RHA 271 and HA 234 were used as the mapping population. These genetic markers plus
a fertility restoration gene, Rf
1, defined 20 linkage groups, covering 1164 cM of the sunflower genome. Of the 71 loci 202 had codominant genotypic segregation,
with the rest showing dominant segregation. Thirty-two of the 232 probes gave multiple locus segregation. There were 39 clusters
of tightly linked markers with 0 cM distance among loci. This map has an average marker-to-marker distance of 4.6 cM, with
11 markerless regions exceeding 20 cM.
Received: 17 June 1997 / Accepted: 19 June 1997 相似文献
13.
T. Komatsuda S. Kawasaki I. Nakamura F. Takaiwa F. Taguchi-Shiobara S. Oka 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(4):637-642
Recombinant backcross lines of barley were produced from a cross between Kanto Nakate Gold (KNG; two-rowed) and Azumamugi
(AZ; six-rowed) after backcrosses of F1 plants with AZ as the recurrent parent. Each of these lines had an introgressed segment from chromosome 2 of KNG. Two recombinant
backcross lines, L1 and M3-13, were used for an initial screening of polymorphism. After screening a total of 888 oligonucleotides
as arbitrary primers, we identified eight random amplified polymorphic DNAs (RAPDs) between backcross lines and AZ. Among
the RAPD fragments, CMNA-38700 was linked to the v locus with a recombination frequency of zero, while OPJ-09850 and OPP-02700 were linked to the v locus at a map distance of 1.4 cM. Thus, the three RAPD markers were clustered around the v locus since the lengths of introgressed chromosomal segments in the L1 and M3-13 lines were no less than 38 cM. The other
five RAPD fragments that we identified were not linked to the v locus.
Received: 14 January 1997 / Accepted: 14 February 1997 相似文献
14.
S. C. Pessino J. P. A. Ortiz O. Leblanc C. B. do Valle C. Evans M. D. Hayward 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):439-444
A bulked segregant analysis using RFLPs and RAPDs was carried out to identify molecular markers co-segregating with apomixis
in a Brachiaria F1 population. The test population used was a cross between sexual B. ruziziensis R44 and the aposporous apomictic Brachiaria brizantha cv Marandu. The Brachiaria genome was systematically scanned using 61 cDNA and genomic maize clones detecting 65 loci located at 40 cM, on average,
one from each other in the maize genome. The finding of a clone that presented a polymorphic band co-segregating with apomixis
(umc147) led to the identification of another marker within the same area (umc72). The clones belong to a duplicated linkage
group that maps to the distal part of maize chromosome-1 long arm and chromosome-5 short arm. RAPD analysis using 184 primers
from Operon sets yielded one more marker (OPC4) significantly linked to the trait mapping the same locus. OPC4 had been previously
reported as a potential marker for apospory in Pennisetum. A map of the region was constructed using additional clones that belong to the same maize linkage group. Since that was
the only genomic region that presented an apomixis-linked polymorphism our observations support the existence of a single
locus directing apospory in Brachiaria.
Received: 9 September 1996 / Accepted: 20 September 1996 相似文献
15.
A restriction map of the entire Schizosaccharomyces pombe genome was constructed using two restriction enzymes (BamHI and PstI) that recognize 6 bp. The restriction map contains 420 minimally overlapping clones (miniset) and has 22 gaps. We located
126 genes, marker fragments of DNA (NotI and SfiI linking clones), and 36 transposable elements by hybridization to unique restriction fragments.
Received: 21 November 1996; in revised form: 3 March 1997 / Accepted: 27 March 1997 相似文献
16.
Construction and characterization of a bacterial artificial chromosome library of apple 总被引:8,自引:0,他引:8
B. A. Vinatzer H.-B. Zhang S. Sansavini 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(7):1183-1190
A bacterial artificial chromosome (BAC) library has been constructed from apple (Malus×domestica Borkh.) using the variety “Florina”, which is resistant to scab (Venturia inaequalis) by virtue of the Vf gene. Since apple leaves are rich in polyphenols, high-molecular-weight DNA was extracted from leaf nuclei with a protocol
adapted to apple. The nuclei were then embedded in agarose microbeads and partially digested by varying ratios of EcoRI to EcoRI methylase. The resulting DNA fragments were size-selected by pulsed-field gel electrophoresis, ligated to the BAC cloning
vector pECBAC1 and transformed into Escherichia coli cells by electroporation. A total of 36 864 recombinant clones (BACs) were obtained. The library has an average insert size
of 120 kb and represents approximately 5×apple haploid-genome equivalents. It was screened with six cDNA probes using the
chemiluminescent DIG system. An average of 4.4 clones was detected for each locus. The apple BAC library will be used to isolate
the Vf scab resistance gene through map-based cloning. In this connection the library was screened with a marker closely linked
to the Vf gene and six positive clones have been isolated. This library should thus be well suited for map-based gene cloning, in particular
for the isolation of the Vf gene and for the construction of a physical map of the apple genome.
Received: 19 February 1998 / Accepted: 30 April 1998 相似文献
17.
W. Y. Cheung L. Friesen G. F. W. Rakow G. Séguin-Swartz B. S. Landry 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(6-7):841-851
A genetic linkage map of Brassica juncea was constructed based on restriction fragment length polymorphism (RFLP) detected by anonymous cDNA markers from B. napus, using a segregating F1-derived doubled haploid (DH) progeny from a cross between a canola-quality mustard line (J90-4317) and a high-oil-content
mustard line (J90-2733). The RFLP probes consisted of 229 cDNA probes from B. napus and a B. napus tandem repeat sequence, RDA2. The map consisted of 343 marker loci arranged in 18 major linkage groups plus five small segments
with two to five marker loci, covering a total map distance of 2073 cM. Twenty-four percent of the markers were dominant in
nature. Sixty-two percent of the marker loci were duplicated, and the majority were involved in inter-linkage group duplications,
illustrating that complex duplications and subsequent rearrangements occurred after allopolyploidy. Deviation from the Mendelian
segregation ratio for a DH population was observed for 27% of the markers. Two-thirds of these markers with a skewed segregation
were clustered in 6 linkage groups and two unassigned segments. The overall average marker interval of the B. juncea map reported here was 6.6 cM, which would provide a marker density satisfactory for efficient use of the map in breeding
applications, such as tagging of important agronomic traits and marker-assisted selection.
Received: 14 May 1996 / Accepted: 11 October 1996 相似文献
18.
D. Zhang M. Ayele H. Tefera H. T. Nguyen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(6-7):957-964
Tef [Eragrostis
tef (Zucc)Trotter] is one of the most important cereal crops in Ethiopia. It is an allotetraploid species with a genome size
of 720 Mbp. In this paper we report results of genetic linkage-map construction for E. tef using tef and heterologous cDNA probes for the first time. One hundred and sixteen F8 recombinant inbred lines (RILs) from the cross E. tef cv Kaye Murri×Eragrostis pilosa (accession30–5) were used for mapping. Parental lines were digested with nine restriction enzymes and screened using 159 tef
cDNA and 162 heterologous probes including the grass genome anchor probes. The polymorphism level between parental lines was
66.9%. One hundred and thirty nine polymorphic probes were hybridized against 116 RILs. Both the tef and the heterologous
probes hybridized well against tef genomic DNA. The linkage map defined 1,489 cM of the tef genome comprising 149 marker loci
distributed among 20 linkage groups. The average interval between markers was 9.99 cM. A fraction (14.8%) of the markers deviated
significantly from the expected segregation. Such a genetic linkage map is useful for tagging economically useful genes in
tef because a wide range of agronomically important traits is segregating within this population. This would enable the use
of a marker assisted breeding strategy which, in turn, will enhance breeding efficiency. Alignment of the tef RFLP map with
the rice RFLP map indicates that a number of syntenic chromosomal fragments exist between tef and rice in which the gene order
was for the most part collinear. The comparative mapping information should enable tef scientists to take advantage of whatever
genetic progress is made on the cereal model species rice.
Received: 9 June 2000 / Accepted: 31 August 2000 相似文献
19.
A. Lezhava D. Kameoka H. Sugino K. Goshi H. Shinkawa O. Nimi S. Horinouchi T. Beppu H. Kinashi 《Molecular & general genetics : MGG》1997,253(4):478-483
We have recently constructed a physical map of the Streptomyces griseus 2247 genome using the restriction enzymes AseI and DraI, which revealed that this strain carries a 7.8 Mb linear chromosome. Based on this map, precise macrorestriction fragment
and cosmid maps were constructed for both ends of the chromosome, which localized the afsA gene 150 Kb from the left end. Two afsA
− mutants were found to have suffered chromosomal deletions that removed the afsA locus. The sizes of the deletions were 20 and 130 Kb at the right end and 180 and 350 kb at the left end, respectively. Hybridization
experiments using cosmids carrying a deletion endpoint indicated that the ends of the chromosome in the mutants were fused
to form a circular chromosome.
Received: 29 July 1996 / Accepted: 27 August 1996 相似文献
20.
Luo-Ye Li Ling Wang Jin-Xue Jing Zhen-Qi Li Fei Lin Li-Fei Huang Qing-Hua Pan 《Molecular breeding : new strategies in plant improvement》2007,20(2):179-188
The Pik
m
gene in rice confers a high and stable resistance to many isolates of Magnaporthe oryzae collected from southern China. This gene locus was roughly mapped to the long arm of rice chromosome 11 with restriction
fragment length polymorphic (RFLP) markers in the previous study. To effectively utilize the resistance, a linkage analysis
was performed in a mapping population consisting of 659 highly susceptible plants collected from four F2 populations using the publicly available simple sequence repeat (SSR) markers. The result showed that the locus was linked
to the six SSR markers and defined by RM254 and RM144 with ≈13.4 and ≈1.2 cM, respectively. To fine map this locus, additional
10 PCR-based markers were developed in a region flanked by RM254 and RM144 through bioinformatics analysis (BIA) using the
reference sequence of cv. Nipponbare. The linkage analysis with these 10 markers showed that the locus was further delimited
to a 0.3-cM region flanked by K34 and K10, in which three markers, K27, K28, and K33, completely co-segregated with the locus.
To physically map the locus, the Pik
m
-linked markers were anchored to bacterial artificial chromosome clones of the reference cv. Nipponbare by BIA. A physical
map spanning ≈278 kb in length was constructed by alignment of sequences of the clones anchored by BIA, in which only six
candidate genes having the R gene conserved structure, protein kinase, were further identified in an 84-kb segment. 相似文献