【作者】 李强；

【导师】 井金学； 陈贤明；

【作者基本信息】 西北农林科技大学 ， 植物病理学， 2010， 博士

【摘要】 小麦条锈病是由条锈菌(Puccinia striiformis f.sp.tritici)引起的世界性小麦病害之一。在美国,该病害在西部地区危害最严重,近年来在中南部地区的危害亦呈上升趋势。我国小麦条锈病主要发生在西北、西南、华北和黄淮海等地的冬麦区和春麦区。1950、1964、1990和2002年4次全国范围内大流行分别给我国小麦生产造成60、32、18和13亿公斤的产量损失。培育和种植抗病品种是防治该病最经济、有效和对环境安全的措施,但是目前仅有极少数全生育期抗条锈病基因对美国和中国的小麦条锈菌流行小种表现抗病性。因此,发掘新的、高品位的抗条锈病基因,利用其与其它有效抗条锈病基因聚合培育高水平的、持久抗病性品种,对于增加小麦抗条锈病基因丰富度,减轻病原菌选择压力,实现小麦条锈病的可持续控制具有重要意义。小麦品种PI 181434,来源于Afghanistan,从2004至2009年在美国华盛顿州东部和西部小麦条锈病田间自然诱发病圃中均表现高度抗病;Libellula和N.Strampelli均来源于Italy,在我国甘肃陇南小麦条锈病常发易变区大面积种植30余年抗病性至今依然很稳定;小麦-华山新麦草易位系H9020-1-6-8-3对我国目前小麦条锈菌流行小种均表现抗病。为了发掘和利用这几个重要小麦品种(系)的抗条锈病基因,本研究对其分别进行了遗传分析和分子标记。主要取得了以下结果:1.小麦品种PI 181434苗期对美国小麦条锈菌重要生理小种PST-17、PST-37、PST -43、PST-45、PST-78、PST-100和PST-127均表现高度抗病。AVS/PI 181434 F2和F3代遗传分析结果表明,PI 181434对PST-100和PST-127的抗病性由1对相同的显性基因控制。利用103个F2代单株构建作图群体,共筛选到8个与抗病基因连锁的多态性RGAP标记Xwgp111、Xwgp112、Xwgp113、Xwgp114、Xwgp115、Xwgp116、Xwgp117、Xwgp118和2个SSR标记Xwmc656、Xbarc6,遗传距离从4.8到32.1cM。应用21个中国春缺四体、2个3D端体和RGAP标记Xwgp114以及2个SSR标记Xwmc656、Xbarc6将PI 181434的全生育期抗条锈病基因定位于小麦3DL染色体。由于这是第一个定位于小麦3DL的抗条锈病基因,因此,已被命名为Yr45。Yr45侧翼的2个RGAP标记Xwgp115和Xwgp118在美国45个小麦基因型中的多态性分别为73.3%和82.2%。并且在8个含有Xwgp115和Xwgp118标记的小麦基因型中均鉴定出了SNPs。这些RGAP标记和SNPs标记将有助于将Yr45导入小麦品种或与其它抗病基因聚合培育持久抗病性品种。2.持久抗病性小麦品种Libellula苗期除对弱毒菌系CYR29-mut3表现抗病,对Su11-4表现中抗-中感外,对其余当前流行小种CYR29、CYR30、CYR31、CYR32、CYR33和Su11-11均表现感病。铭贤169/Libellula杂交F1、F2及BC1代遗传分析结果表明,Libellula苗期对CYR29-mut3的抗病性由1对隐性基因控制。基因显隐性及等位性分析表明,Libellula控制对CYR29-mut3抗病性的基因不同于已知抗病基因Yr3。N. Strampelli苗期对我国小麦条锈菌流行小种CYR29、CYR29-mut3、CYR30、CYR31、CYR33、Su11-4和Su11-11等表现抗病,对CYR32表现中抗-中感。N.Strampelli/铭贤169和N.Strampelli/中国春杂交F1、F2、F3及BC1代遗传分析结果表明,N.Strampelli对CYR29和CYR31的抗病性由2对隐性基因累加作用控制,对CYR29-mut3和CYR33的抗病性分别由1对不同的隐性基因控制,暂命名为YrN.S-1和YrN.S-2。利用中国春单体分析和SSR分子标记,将控制对CYR29-mut3抗病性的基因YrN.S-1和控制对CYR33抗病性的基因YrN.S-2分别定位于小麦5BL和1BL染色体。应用3个与抗病基因连锁的SSR标记Xgwm499、Xwmc415和Xwmc537构建了YrN.S-1的遗传连锁图,遗传距离分别为7.6、5.4和10.7cM;4个SSR标记Xcfa2147、Xgwm124、Xwmc719和Xwmc44构建了YrN.S-2的遗传连锁图,遗传距离分别为11.3、4.6、3.2和5.7 cM。对已知定位于小麦5BL和1BL染色体的抗条锈病基因抗病性检测及分子标记检测结果表明,YrN.S-1和YrN.S-2很可能是2个不同于这些已知基因的新基因,建议在小麦抗条锈病育种加以合理利用。3. H9020-1-6-8-3苗期对我国小麦条锈菌重要生理小种CYR25、CYR29、CYR29 -mut3、CYR30、CYR31、CYR32、CYR33、Su11-4、Su11-11均表现抗病。抗病基因供体亲本华山新麦草和受体亲本7182抗病性分析表明,H9020-1-6-8-3的抗条锈病基因来自华山新麦草。铭贤169/H9020-1-6-8-3杂交F2和F3代遗传分析结果表明,H9020-1-6-8-3对CYR33的抗病性由1对显性基因控制,暂命名为YrH9020。利用其中164个F2代抗感单株构建作图群体,从300对SSR引物中共筛选到3个与YrH9020连锁的SSR分子标记Xgwm 261、Xwmc503和Xgwm102,遗传距离分别为8.9、7.0和11.2cM,并将其定位于小麦2DS染色体。目前已知定位于2DS染色体的抗病基因仅有Yr16,抗病性及基因来源分析表明,YrH9020是1个不同于Yr16的新基因。目前,华山新麦草的抗条锈病基因还没有在小麦抗条锈病育种中得到广泛应用,本研究对于其抗条锈病遗传规律的明确以及分子标记的获得,必将有助于其在小麦抗条锈病育种的应用和进行分子标记辅助选择育种。更多还原

【Abstract】 Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a major disease of wheat (Triticum aestivum L.) worldwide. In the US, the disease is most destructive in the western states and has become increasingly important in the south-central states in the past decade. In China, stripe rust is also the most important disease on winter and spring wheat in northwestern, southwestern, huabei and huanghuaihai regions. Estimated losses of 6.0, 3.2, 1.8 and 1.3 million metric tons of wheat occurred in 1950, 1964, 1990 and 2002 nationwide stripe rust epidemics, respectively. Growing resistant cultivars is the most effective approach to control the disease, but only few genes are available conferring effective all-stage resistance against the current populations of the pathogen worldwide. It is urgent to identify new genes for diversifying resistance genes and pyramiding genes for different types of resistance in order to achieve high-level and durable resistance for sustainable control of stripe rust.The common spring wheat genotype PI 181434, originally from Afghanistan, was resistant in germplasm screening nurseries planted in eastern and western Washington from 2004 to 2009. Wheat varieties Libellula and N. Strampelli, which were introduced to China from Italy in 1974, have been widely grown for more than 30 years in the Longnan region of Gansu Province, where stripe rust epidemics are frequent and severe. Although many virulence changes have occurred in the region over the past 35 years, the varieties are still resistant. The wheat-P. huashanica translocation line H9020-1-6-8-3 is also resistant to most of Chinese predominant PST races. The objectives of this study were to identify and map the gene(s) for all-stage resistance in these cultivars (lines) using genetic analysis and molecular markers. The main results gained are as follows:1. PI 181434 was resistant to all tested races of U.S. P. striiformis f. sp. tritici, PST-17, PST-37, PST-43, PST-45, PST-78, PST-100 and PST-127. The genetic study of F2 and F3 derived from AVS/ PI 181434 showed that PI 181434 has a single dominant gene conferring all-stage resistance to PST-100 and PST-127. A linkage map of 8 RGAP markers, Xwgp111, Xwgp112, Xwgp113, Xwgp114, Xwgp115, Xwgp116, Xwgp117, Xwgp118 and 2 SSR markers, Xwmc656 and Xbarc6, was constructed for the gene using the 103 F2 plants. The genetic distance rang from 4.8 to 32.1cM. 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 chromosome 3DL. Because it is the first gene for stripe rust resistance mapped on 3DL, and different from all previously named Yr genes, the gene in PI 181434 was designated as 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 pyramiding with other genes for durable resistance.2. In the seedling tests, Libellula was susceptible to most of prevalent races except resistant to CYR29-mut3 and moderately resistant to moderately susceptible to Su11-4. The resistance to CYR29-mut3 was controlled by one recessive gene. Gene property and allelic analysis showed that the gene is different from known resistance gene Yr3.N. Strampelli was resistant to CYR29, CYR29-mut3, CYR30, CYR31, CYR33, Su11-4, Su11-11, and moderately resistant to moderately susceptible to CYR32. The inheritance results of F1, F2, F3 and BC1 seedling progenies derived from the cross N. Strampelli /Mingxian 169 and N. Strampelli/ Chinese Spring indicated that there are two recessive genes conferring resistance to CYR29 and CYR31, and one confers resistance to CYR29-mut3 and another confers resistance to CYR33, temporarily designated as YrN.S-1 and YrN.S-2. Amplification of Chinese Spring monosomic analysis and SSR markers, the gene YrN.S-1 was located on chromosome 1BL and the gene YrN.S-2 was located on chromosome 5BL. Linkage maps were constructed with three SSR markers, Xgwm499, Xwmc415 and Xwmc537, for the gene YrN.S-1 with genetic distance ranging from 5.4 to 10.7cM and four SSR markers, Xcfa2147, Xgwm124, Xwmc719 and Xwmc44, for the gene YrN.S-2 with genetic distance ranging from 3.2 to 10.3cM. Resistance analysis and molecular tests between the previously named Yr genes located on chromosome 5BL, 1BL and YrN.S-1, YrN.S-2 suggested that both YrN.S-1 and YrN.S-2 are different from these known genes and likely two new stripe rust resistance genes. The markers could be useful in pyramiding these resistance genes with others to develop wheat cultivars with high-level and durable resistance to stripe rust.3. Seedlings tests under controlled greenhouse conditions showed that H9020-1-6-8-3 was resistant to Chinese stripe rust races, CYR25、CYR29、CYR29-mut3、CYR30、CYR31、CYR32、CYR33、Su11-4、Su11-11. Resistance analysis of the parents Psathyrostachys huashanica and common wheat 7182 suggested that the stripe rust resistance gene of H9020-1-6-8-3 was originating from Psathyrostachys huashanica. Genetic studies of F2 and F3 progenies derived from Mingxian169/H9020-1-6-8-3 indicated that a single dominant gene conferring resistance to CYR33, temporarily designated as YrH9020. The mapping population was constructed by 164 F2 individual plants. The linkage map was constructed with three SSR markers, Xgwm261、Xwmc503 and Xgwm102, for the gene YrH9020 with genetic distance rang from 7.0 to 11.2 cM. And the gene was located on chromosome 2DS by three SSR loci. To date, Yr16 was located on chromosome 2DS, which derived from common wheat (Triticum aestivum L.) and is an adult plant resistance gene, so YrH9020 is different from Yr16. The genes from Psathyrostachys huashanica haven’t been used widely in wheat resistant breeding. The demonstration of YrH9020 as a new gene and the availability of the flanking SSR markers identified in this study should accelerate its application in breeding programs.更多还原