Mapping of a Major Stripe Rust Resistance Gene in Chinese Native Wheat Variety Chike Using Microsatellite Markers

Journal of Genetics and Genomics (Formerly Acta Genetica Sinica) December 2007, 34(12): 1123-1130

Research Article

Mapping of a Major Stripe Rust Resistance Gene in Chinese Native Wheat Variety Chike Using Microsatellite Markers Fanghui Liu 1, 3, Yongchun Niu 1, 2, ①, Hui Deng 1, Genjia Tan 3 1. Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; 2. Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100094, China; 3. Plant Protection Academy, Agricultural University of Anhui, Hefei 230036, China

Abstract: Chike (accession number Su1900), a Chinese native wheat (Triticum aestivum L.) variety, is resistant to the currently prevailing physiological races of Puccinia striiformis Westend. f. sp. tritici in China. Genetic analysis indicated that resistance to the physiological race CY32 of the pathogen in the variety was controlled by one dominant gene. In this study, BSA (bulked segregant analysis) methods and SSRs (simple sequence repeats) marker polymorphic analysis are used to map the gene. The resistant and susceptible DNA bulks were prepared from the segregating F2 population of the cross between Taichung 29, a susceptible variety as maternal parent, and Chike as paternal parent. Over 400 SSR primers were screened, and five SSR markers Xwmc44, Xgwm259, Xwmc367, Xcfa2292, and Xbarc80 on the chromosome arm 1BL were found to be polymorphic between the resistant and the susceptible DNA bulks as well as their parents. Genetic linkage was tested on segregating F2 population with 200 plants, including 140 resistant and 60 susceptible plants. All the five SSR markers were linked to the stripe rust resistance gene in Chike. The genetic distances for the markers Xwmc44, Xgwm259, Xwmc367, Xcfa2292, and Xbarc80 to the target gene were 8.3 cM, 9.1 cM, 17.2 cM, 20.6 cM, and 31.6 cM, respectively. Analysis using 21 nulli-tetrasomic Chinese Spring lines further confirmed that all the five markers were located on chromosome 1B. On the basis of the above results, it is reasonable to assume that the major stripe rust resistance gene YrChk in Chike was located on the chromosome arm 1BL, and its comparison with the other stripe rust resistance genes located on 1B suggested that YrChk may be a novel gene that provides the resistance against stripe rust in Chike. Exploration and utilization of resources of disease resistance genes in native wheat varieties will be helpful both to diversify the resistance genes and to amend the situation of resistance gene simplification in the commercial wheat cultivars in China. Keywords: wheat; native variety; Puccinia striiformis; resistance gene; microsatellite marker; gene mapping

Stripe rust (yellow rust), caused by Puccinia striiformis Westend. f. sp. tritici, is one of the most important diseases of wheat (Triticum aestivum L.) worldwide. In China, stripe rust prevailed for several times in large wheat-growing areas and this caused serious yield losses. The use of resistant cultivars is the most economical, effective, and environmentfriendly method to reduce damage and loss cau-

sed by stripe rust. However, resistance of most commercial wheat cultivars will “breakdown” after continual growing for several years because of the appearance and development of novel races of the stripe rust pathogen. In the past decades, most of the resistant resources used for the breeding of wheat were brought from abroad. Simplification of resistance genes in the commercial wheat cultivars has

Received: 2007−04−17; Accepted: 2007−05−31 This work was supported by the National Natural Science Foundation of China (No. 30571157) and the National Basic Research Program (973 Program) (No. 2006CB100203). ① Corresponding author. E-mail: [email protected]; Tel: +86-10-6891 8647 www.jgenetgenomics.org

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become the latent basis for stripe rust epidemic in several areas. Therefore, it is vital to breed and use novel wheat cultivars with effective and diverse resistance genes that provide protection against stripe rust. Native wheat varieties are abundant in China, but they were often ignored in wheat breeding because of

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Vol. 34 No. 12 2007

for agronomic traits and resistance to stripe rust through selection. Taichung 29, as maternal parent, was crossed with Chike, as paternal parent, to obtain F1 seeds. F1 plants were self-pollinated to obtain F2 seeds, and backcrossed with the female parent Taichung 29 to obtain BC1 seeds. F2 plants were self-pollinated to obtain F3 seeds.

their poor agronomic traits. Native wheat varieties are

The wheat varieties Clement and Lovrin10, the

the outcome of both natural and artificial selection

carrier of stripe rust resistance gene Yr9, were col-

through long evolutionary processes, and they have

lected and preserved by the Institute of Plant Protec-

high adaptability even in unfavorable environment.

tion, CAAS, China. The varieties Vilmorin 23, Hybrid

There may be valuable gene resources that provide

46, Lemhi, Lalbahadur, the carriers of stripe rust re-

resistance against stripe rust in these varieties. The

sistance genes Yr3a, Yr3b, Yr21, Yr29, respectively,

study, exploration, and utilization of resistance gene

and disomic and the nulli-tetrasomic Chinese Spring

resources in native wheat varieties are significant to

lines were provided by Dr. X. M. Chen of Washington

change the simplification of stripe rust resistance

State University.

genes in the commercial wheat cultivars in China

[1]

.

Chike (accession number Su1900), a Chinese native wheat variety, is resistant to several physiological races of P. striiformis f. sp. tritici, which are currently prevalent in China. On the basis of genetic analysis, a major stripe rust resistance gene in Chike was mapped using microsatellite (simple sequence repeat, SSR) polymorphic analysis in this study. The results will

1.1.2

Strain of P. striiformis f. sp. tritici

Tested single-spore strain of physiologic race CY32 of Chinese wheat stripe rust was preserved at the Institute of Plant Protection, CAAS, China. Fresh uredospores of CY32 were prepared by propagating it on seedlings of susceptible variety Mingxian 169 in advance of use.

facilitate the effective, reasonable utilization of the

1.2

resistant germplasm resource, and it will also provide

Seeds of tested wheat materials were sown in pots of 10 cm in diameter with 15 plants per pot and then cultivated in greenhouse. When the first leaves were fully spread out, the seedlings were inoculated with fresh spores of CY32 using the brush method. Inoculated plants were placed in dew chambers at 10℃ for 24 h and then incubated at 18/12℃ (day/night) with a photoperiod of 12–14 h of light per day in an air-conditioned greenhouse. Infection types (ITs) were recorded 15 days after inoculation when the susceptibility of the check, Taichung 29, was fully expressed. Infection types were scored on a common 0–4 scale. Infection types in the range of 0–2 were considered to be resistant, and the infection types in the range of 3–4 were considered to be susceptible.

the scientific basis for the exploration of novel resistance genes in native wheat varieties and the selection of resistance genes in wheat breeding.

1

Materials and Methods

1.1

Materials

1.1.1

Plant materials

Seeds of the Chinese native wheat variety Chike and the susceptible variety Taichung 29 were collected and preserved by the Institute of Plant Protection, Chinese Academy of Agricultural Sciences (CAAS), China. Before analysis, the plants of Chike were self-pollinated for three generations and purified

Assessment of resistance

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Fanghui Liu et al.: Mapping of a Major Stripe Rust Resistance Gene in Chinese Native Wheat Variety Chike…

1.3

Extraction of genomic DNA and preparation of resistant and susceptible DNA bulks

After the assessment of disease resistance, the newly spread second and the third leaves were used to extract genomic DNA. Each plant of F2 population was collected and extracted separately. Genomic DNA was extracted using CTAB protocol as described by Rogers and Bendich [2]. Extracted DNA was quantified on agarose gels. Equal amounts of DNA were taken both from 10 resistant F2 plants and 10 susceptible F2 plants to make resistant and susceptible DNA pools, respectively.

1.5

SSR marker polymorphic analysis

SSR marker polymorphic analysis between resistant and susceptible DNA pools was carried out with the resistant variety Chike and the susceptible variety Taichung 29 as checks. SSR primers for the markers located on specific wheat chromosomes were screened. The sequences of the tested SSR primers were obtained from Röder et al.[3] and Somers et al.[4] and synthesized by Shanghai Sangon Biological Engineering Technology and Services Company Ltd, China. PCR reaction was performed in a PTC-200 Peltier thermal cycler (MJ Research, Inc.) in 25 μL reaction volume containing 2.5 μL of 10× PCR buffer (100 mmol/L Tris-HCl, pH 8.8, 500 mmol/L KCl, 0.8% Nonidet P-40), 1.8 μL of MgCl2 (25 mmol/L), 0.2 μL of dNTPs (2.5 mmol/L), 3 μL of SSR primers (mix of 2 primers, 2 μmol/L for each), 50 ng of template DNA, and 1.0 U of Taq DNA polymerase. The temperature profile of PCR is as follow: initial dena-

Genetic linkage analysis and mapping

The polymorphic microsatellite markers were tested to find their genetic linkage with the target gene using the segregating F2 population. The software Mapmaker 3.0b was used to analyze the data, to calculate the genetic distances, and to make the genetic map. The SSR markers linked to the resistance gene in Chike were examined with the nulli-tetrasomic Chinese Spring lines.

2 2.1

1.4

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Results Assessment and inheritance of resistance Resistance of wheat seedlings against stripe rust

was assessed by artificial inoculation with race CY32 of P. striiformis f. sp. tritici. All the F1 plants and Chike were resistant, and Taichung 29 was highly susceptible. The resistance of F2 and BC1 plants was segregated. Among the 204 plants of F2 population, there were 144 resistant and 60 susceptible plants, which is consistent with the theoretical segregation ratio of 3R: 1S (χ23:1=2.12, P>0.10). There were 14 resistant and 16 susceptible plants among 30 BC1 plants, which is consistent with the theoretical segregation ratio of 1R: 1S (χ21:1=0.13, P>0.70) (Table 1). This suggested that the resistance of Chike to race CY32 was conferred by a single dominant gene. The resistance of F3 progenies derived from some resistant F2 plants were segregated. The ratio of the resistant F2 plants with the segregating progenies to the resistant F2 plants with nonsegregating progenies was 2: 1. All the F3 progenies derived from susceptible F2 plants were uniformly susceptible. The results of resistance

turation at 94℃ for 5 min, followed by 30 cycles of

assessment of F3 plants further confirmed that the

94℃ for 1 min, 50–60℃ (depending on each pair of

resistance to CY32 race was controlled by a single

primers) for 50 s and 72℃ for 1 min, and then a final

dominant gene, which was tentatively designated as

extension at 72℃ for 10 min. PCR products were

YrChk in this study.

analyzed by 6% denaturing polyacrylamide gel electrophoresis at 65 W for approximately 1.5 h and then displayed by silver staining method [5]. www.jgenetgenomics.org

The results of resistance assessment also indicated that all the varieties, Clement (Yr9), Lovrin 10 (Yr9), Vilmorin 23 (Yr3a), Hybrid 46 (Yr3b), Lemhi

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Table 1

Vol. 34 No. 12 2007

Reaction of the progenies of Taichung 29 × Chike to race CY32 of Puccinia striiformis f. sp. tritici Parents and crosses

Generation

Taichung 29 (maternal parent) Chike (paternal parent) Taichung 29/Chike Taichung 29/Chike Taichung 29//Taichung 29/Chike

P1 P2 F1 F2 BC1

Number of plants Resistant 0 15 30 144 14

(Yr21), and Lalbahadur (Yr29) with known stripe rust resistance genes are susceptible to race CY32. 2.2

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SSR marker analysis

Over 400 pairs of SSR primers were used to identify the polymorphism between the resistant and the susceptible DNA bulks. SSR markers Xwmc44, Xgwm259, Xwmc367, Xcfa2292, and Xbarc80 at the end of chromosome 1BL showed clear polymorphisms between the resistant and the susceptible DNA bulks as well as between their parents. The five SSR markers were examined on the segregating F2 population. Most of the resistant F2 plants presented the same DNA fragments as Chike or the resistant DNA bulk did, and most of the susceptible F2 plants did not present these DNA fragments or

Susceptible 15 0 0 60 16

Ratio of separation

Chi square test

Observed

Theoretical

χ2

P value

2.4: 1 0.88: 1

3: 1 1: 1

2.12 0.13

> 0.10 > 0.70

presented the same DNA fragments as Taichung 29 or the susceptible DNA bulk did (Figs. 1–5). This suggested that the five SSR markers were linked to the major stripe rust resistance gene in Chike. Among these markers, Xwmc44 was the closest to the resistant gene. Among 140 resistant plants, 136 plants presented the same DNA fragments as Chike or the resistant DNA bulk did, the other 4 plants presented the same DNA fragments as Taichung 29 or the susceptible DNA bulk did. Out of 60 susceptible plants, 45 plants presented the same DNA fragments as Taichung 29 or the susceptible DNA bulk did, the other 15 plants presented the same DNA fragments as Chike or the resistant DNA bulk did. The exchange rate was 9.5%.

Fig. 1 Genetic linkage analysis of SSR maker Xwmc44 to the target gene M: 100 bp DNA ladder; 1: Chike; 2: Taichung 29; 3: resistant DNA pool; 4: susceptible DNA pool; R: resistant F2 plants; S: susceptible F2 plants.

Fig. 2 Genetic linkage analysis of SSR maker Xgwm259 to the target gene M: 100 bp DNA ladder; 1: Chike; 2: resistant DNA pool; 3: Taichung 29; 4: susceptible DNA pool; R: resistant F2 plants; S: susceptible F2 plants. www.jgenetgenomics.org

Fanghui Liu et al.: Mapping of a Major Stripe Rust Resistance Gene in Chinese Native Wheat Variety Chike…

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Fig. 3 Genetic linkage analysis of SSR maker Xwmc367 to the target gene M: 100 bp DNA ladder; 1: Chike; 2: resistant DNA pool; 3: Taichung 29; 4: susceptible DNA pool; R: resistant F2 plants; S: susceptible F2 plants.

Fig. 4 Genetic linkage analysis of SSR maker Xcfa2292 to the target gene M: 100 bp DNA ladder; 1: Chike; 2: Taichung 29; 3: resistant DNA pool; 4: susceptible DNA pool; R: resistant F2 plants; S: susceptible F2 plants.

Fig. 5 Genetic linkage analysis of SSR maker Xbarc80 to the target gene M: 100 bp DNA ladder; 1: Chike; 2: Taichung 29; 3: resistant DNA pool; 4: susceptible DNA pool; R: resistant F2 plants; S: susceptible F2 plants. Table 2

Distribution of band patterns of the five SSR markers in segregating F2 population

SSR markers

Number of plants with different band patterns

Ratio of separation

Chi square test χ2

P value

1: 2: 1

0.08

>0.99

1: 1.8: 1

1: 2: 1

1.64

>0.50

53

1: 2.2: 1

1: 2: 1

0.51

>0.70

155

45

3.4: 1

3: 1

0.67

>0.70

148

52

2.8: 1

3: 1

0.11

>0.90

A

H

B

Observed

Xwmc44

49

102

49

1: 2.1: 1

Xcfa2292

51

92

57

Xbarc80

46

101

Xgwm259 Xwmc367

Theoretical

A: the same banding patterns as resistant parent. B: the same banding pattern as susceptible parent. H: mixed banding patterns.

Statistics of the band patterns of SSR markers in F2 individuals showed that the polymorphic markers Xwmc44, Xcfa2292, and Xbarc80 linked to YrChk gene belonged to the codominant markers for their segregation fits the theoretical ratio of 1: 2: 1 in www.jgenetgenomics.org

F2 population. Whereas the polymorphic markers Xgwm259 and Xwmc367 linked to YrChk gene belonged to the dominant markers for their segregation fits the theoretical ratio of 3: 1 in F2 population (Table 2).

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Vol. 34 No. 12 2007

Mapping of YrChk gene

The data obtained from the genetic linkage analysis of the five SSR markers and the resistant gene YrChk were calculated and mapped by the software Mapmaker 3.0b. YrChk was flanked by the five markers. Xwmc44, the closest to gene YrChk, was on the side close to the centromere, with a genetic distance of 8.3 cM to gene YrChk. The other four markers Xgwm259, Xwmc367, Xcfa2292, and Xbarc80 were on the side apart from the centromere, their genetic distances to gene YrChk were 9.1 cM, 17.2 cM, 20.6 cM, and 31.6 cM, respectively. The genetic linkage map was drawn with the software Genemap (Fig. 6). Twenty-one nulli-tetrasomic Chinese Spring lines were examined using the five SSR markers. The results indicated that the markers Xwmc44, Xgwm259, Xcfa2292, and Xbarc80 appeared only on chromosome 1B in wheat genome, these markers did not appear on any other chromosomes. The marker Xwmc367

Fig. 6 The genetic linkage map of SSR markers and wheat stripe rust resistance gene YrChk

appeared both on chromosome 7D and chromosome 1B, but the polymorphic DNA fragments in the two parents appeared only on chromosome 1B (Fig. 7). This further confirmed that the stripe rust resistance gene YrChk in Chike was located on chromosome 1B.

Fig. 7 SSR marker examination of the nulli-tetrasomic Chinese Spring lines a, b, c, d, and e indicate the marker Xwmc44, Xcfa2292, Xwmc367, Xbarc80, and Xgwm259, respectively. Chk: Chike; T29: Taichung 29; CS: Chinese Spring; 1A−7A, 1B−7B, 1D−7D: nulli-tetrasomic Chinese Spring lines. www.jgenetgenomics.org

Fanghui Liu et al.: Mapping of a Major Stripe Rust Resistance Gene in Chinese Native Wheat Variety Chike Using Microsatellite Markers 1129

3

Discussion

Chike is a native winter wheat variety present in Jingmen, Hubei Province, China. It is resistant to several currently prevailing stripe rust races, such as CY32, CY31, and CY29. Genetic analysis indicated that the resistance in Chike against race CY32 was conferred by a single dominant gene. In this article, using SSR marker analysis, it is found that the resistance gene in Chike is located on the chromosome arm 1BL, and it is tentatively designated as YrChk. Simplification of resistance genes in the commercial wheat cultivars in several areas has become significant for a long time in China. Understanding of resistance gene in Chike is helpful to enrich the resources of disease resistance gene for wheat breeding program, thereby providing the basis for the sustainable control of wheat stripe rust. Previously, it was found that the stripe rust resistance genes, Yr9 and Yr29, were located on the chromosome arm 1BL [6−8], and Yr3 and Yr21 were located on chromosome 1B

[9−12]

. However, there are no arti-

cles about the fine chromosome location for these genes. Gene Yr9 was originated from rye (Secale cereale L.) [6, 7]. The wheat translocation lines carrying this gene were introduced in China in 1965. All the domestic wheat cultivars with Yr9 were used commercially after 1970. Gene Yr29 is an adult plant resistance gene [8], whereas YrChk is a seedling resistance gene. The seedlings of Clement and Lovrin 10 with Yr9 and Lalbahadur with Yr29 were all susceptible to race CY32. It is concluded that the stripe rust resistance gene YrChk is not the same as Yr9 and Yr29. The stripe rust resistance gene Yr3 has three allelic genes, Yr3a, Yr3b, and Yr3c. According to this study and literature, their carriers, Cappelle-Desprez, Hybrid 46, and Vilmorin 23 were all susceptible to race CY32 [13]. Lemhi, the carrier of Yr21, is also susceptible to race CY32. On the basis of resistance against stripe rust, it is reasonable to assume that YrChk should be a different gene from Yr3 and Yr21. To www.jgenetgenomics.org

clarify the allelism of YrChk and Yr3 or Yr21, further allelic analysis is required. The novel physiological races such as CY31 and CY32 are widely virulent in China in recent years. Race CY32, virulent to genes, Yr1, Yr2, Yr3, Yr4, Yr6, Yr7, Yr9, Yr27, YrA, YrAlba, YrCle, YrCV, YrGaby, YrRes, YrSD, YrSpP, and YrSu [14], caused the loss of resistance of several wheat cultivars against stripe rust, which brought a significant epidemic stripe rust in 2002 and frequent epidemic stripe rust in recent years in China. Stripe rust is a major threat in the production of wheat. However, the Chinese native wheat variety Chike is resistant to several physiological races, for example CY32, of P. striiformis f. sp. tritici, which is currently prevalent in China, and it is an effective resistance resource in wheat breeding. This study indicated that the stripe rust resistance gene YrChk in Chike might be a novel gene, which is significant to exploit and utilize the resistance gene resources in Chinese native varieties and in wheat breeding for its rust resistance. Acknowledgments: We are grateful to Dr. X. M. Chen of Washington State University for providing seeds of the nulli-tetrasomic Chinese Spring lines and several other wheat cultivars. References 1

Wu LR, Niu YC. Strategies of sustainable control of wheat

2

with an English abstract). Rogers SO, Bendich AJ. Extraction of DNA from milligram amounts of fresh, herbarium and mummified plant tissues.

stripe rust in China. Sci Agri Sin, 2000, 33: 46−54 (in Chinese

Plant Mol Biol, 1985, 5: 69−76. 3

Röder MS, Korzun V, Wendehake K, Plaschke J, Tixier MH, Leroy P, Ganal MW. A microsatellite map of wheat. Genetics, 1998, 149: 2007−2023.

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Somers DJ, Isaac P, Edwards K. A high-density microsatellite consensus map for bread wheat (Triticum aestivum L.). Theor

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Bassam BJ, Gaetano-Anollés G, Gresshoff PM. Fast and sensitive silver staining of DNA in polyacrylamide gels. Anal

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Zeller FJ. 1B/1R Wheat-rye chromosome substitutions and translocations. In: Proceedings of the 4th International Wheat Genetics Symposium. Columbia, Missouri, USA, 1973, 209−221.

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McIntosh RA, Hart GE, Devos KM, Gale MD, Rogers WJ. Catalogue of gene symbols for wheat. In: Proceedings of the 9th International Wheat Genetics Symposium. Saskatoon, Canada, 1998, 139−142.

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William M, Singh RP, Huerta-Espino J, Ortiz-Islas S, Hoisington D. Molecular marker mapping of leaf rust resistance gene Lr46 and its association with stripe rust resistance gene Yr29 in wheat. Phytopathology, 2003, 93: 153−159.

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Chen XM, Jones SS, Line RF. Chromosomal location of genes for resistance to Puccinia striiformis in seven wheat cultivars with resistance genes at the Yr3 and Yr4 loci. Phytopathology, 1996, 86: 1228−1233.

10 Chen XM, Line RF, Jones SS. Chromosomal location of genes for resistance to Puccinia striiformis in wheat cultivars

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Druchamp, Stephens, and Yamhill. Phytopathology, 1994, 84: 1116. 11 Chen XM, Jones SS, Line RF. Chromosomal location of genes for stripe rust resistance in spring wheat cultivars Compair, Fielder, Lee, and Lemhi and interactions of aneuploid wheats with races of Puccinia striiformis. Phytopathology, 1995, 85(3): 375−381. 12 Lupton FGH, Macer RCF. Inheritance of resistance to yellow rust (Puccinia glumarum Erikss. and Henn.) in seven varieties of wheat. Trans Brit Mycol Soc, 1962, 45: 21−45. 13 Wan AM, Wu LR, Jin SL, Yao G, Wang BT. Discovery and studies on CY32, a new race of Puccinia striiformis f. sp. tritici in China. J Plant Prot, 2003, 30: 347−352 (in Chinese with an English abstract). 14 Niu YC, Wu LR, Qiao Q, Wan AM. Virulence analysis of main races and pathotypes of wheat yellow rust from China. In: Proceedings of the First Asian Conference on Plant Pathology. Beijing, China, 2000, 251.

小麦农家品种赤壳中一个主效抗条锈病基因的微卫星标记和 定位 刘方慧1, 3，牛永春1, 2，邓 晖1，檀根甲3 1. 中国农业科学院农业资源与农业区划研究所，北京 100081； 2. 中国农业科学院植物保护研究所，北京 100094； 3. 安徽农业大学植物保护学院，合肥 230036 摘 要：小麦农家品种赤壳(苏 1900)对当前我国小麦条锈菌(Puccinia striiformis Westend. f. sp. tritici)多个流行小种均有较好 抗性。遗传分析表明，该品种对条中 32 号小种的抗性是由一对显性基因控制。本文采用分离群体分析法(bulked segregant analysis，BSA)和微卫星多态性分析方法，对该基因进行了分子标记和定位研究。用 Taichung 29×赤壳的 F2 代分离群体建 立抗、感 DNA 池，共筛选了 400 多对 SSR 引物，发现 5 个标记 Xwmc44、 Xgwm259、Xwmc367、Xcfa2292、Xbarc80 在 抗、感 DNA 池间与在抗、感亲本间同样具有多态性，它们均位于 1BL 染色体臂上。经用具有 140 株抗病株、60 株感病株 共 200 株植株的 F2 代分离群体进行的遗传连锁性检测，上述 5 个标记均与目的基因相连锁，遗传距离分别为 8.3 cM、9.1 cM、 17.2 cM、20.6 cM 和 31.6 cM。用全套 21 个中国春缺-四体材料进行的检测进一步证实了这 5 个 SSR 标记均位于小麦 1B 染 色体上。综合上述结果，将赤壳中的主效抗条锈病基因 YrChk 定位在 1BL 染色体臂上。与以前已定位于 1B 染色体上的抗 条锈病基因的比较研究表明，YrChk 基因可能是一个新的抗条锈病基因。小麦农家品种中抗病基因资源的发掘和利用将有 助于提高我国小麦生产品种中的抗病基因丰富度，有助于改善长期以来小麦生产品种中抗病基因单一化的局面。 关键词：小麦；农家品种；条锈病；抗病基因；微卫星标记；基因定位 作者简介：刘方慧(1980−)，女，硕士研究生，研究方向：植物抗病分子遗传。 www.jgenetgenomics.org