Virulence and Diversity of Blumeria graminis f. sp. tritici Populations in China

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is an important disease in China. To characterize the virulence and diversity of the pathogen, 1 082 isolates were obtained from 8 major wheat-growing regions during the spring growing season in 2011. The virulence test was performed by inoculation on detached leaves of 22 differential lines with known Pm genes. Frequencies of virulence on these genotypes ranged from 0 to 97.4%. None of the 1 082 isolates was compatible to Pm21 and less than 20.0%were virulent to the genotype carrying Pm13. In contrast, the virulence frequencies of each population was more than 50.0%to differentials carrying Pm1a, Pm3b, Pm3c, Pm3f, Pm5a, Pm6 and Pm8. In total, 1 028 pathotypes were detected, of which 984 were unique. Phenotypic diversity indices revealed a high level of diversity within populations. Genetic distance between different populations correlated signiifcantly with geographical distance （R2=0.494, P 0.001）. In addition, isolates from Xinjiang appear to form a separate group. Signiifcant positive or negative associations between alleles at pairs of virulence loci were detected in 57 allele pairs to Pm genes. Virulence and diversity of the 8 populations suggested that varieties with effective resistance gene combinations should be developed at a regional level.     

小麦秆锈菌特异性SSR分子标记的开发

 【目的】研发简单、快速、准确的分子检测技术用于小麦秆锈菌的准确诊断和秆锈病的早期预警。【方法】采用FIASCO法构建秆锈菌基因组微卫星富集文库,分离微卫星DNA序列,设计合成小麦秆锈菌的特异性引物。【结果】根据小麦秆锈菌基因组微卫星富集文库,设计1对小麦秆锈菌特异性微卫星引物Pgtfssr1(f/r),可在来自中国不同麦区的20份小麦秆锈菌分离物基因组DNA中扩增出395 bp的特异性片段,而在小麦条锈菌、小麦叶锈菌和其它麦类病原真菌中未扩增出该特异性片段。病菌侵入寄主30 h后便可检测到特异性DNA片段的存在,灵敏度达到1 ng•μL-1模板DNA浓度水平。【结论】成功研发出小麦秆锈菌的特异性SSR分子标记,为小麦秆锈病早期诊断在生产上的应用奠定了基础。     

Development of SSR Markers for a Phytopathogenic Fungus,Blumeria graminis f.sp.tritici,Using a FIASCO Protocol

Simple sequence repeats （SSR） have been widely used as molecular markers due to their abundance and high polymorphism, However, up to now, the SSR markers had not been developed in the obligate biotrophic phytopathogenic fungus, Blumeria graminis f.sp. tritici. From （AC）10 and （AG）10 enriched genomic libraries for Bgt, 25 primer pairs were designed using the FIASCO （fast isolation by AFLP of sequences containing repeats） protocol. Five primer pairs exhibited polymorphism with allelic diversity from two to seven alleles and produced 29 alleles in a survey of 90 isolates collected from six provinces （cities） in China, while the others displayed monomorphic. Levels of observed heterozygosity ranged from 0.000-0.044 （mean 0.025） and expected heterozygosity ranged from 0.297-0.816 （mean 0.538）. These molecular markers provide a novel source to genetic diversity assays and to genetic and physical mapping ofBgt. SSR markers of Bgt need to be further explored.     

Molecular Mapping of a Stripe Rust Resistance Gene YrH9020a Transferred from Psathyrostachys huashanica Keng on Wheat Chromosome 6D

Stripe rust （yellow rust）, caused by Puccinia striiformis f. sp. tritici （Pst）, is one of the most devastating diseases of wheat throughout the world. H9020-1-6-8-3 is a translocation line originally developed from interspeciifc hybridization between wheat line 7182 and Psathyrostachys huashanica Keng and is resistant to most Pst races in China. To identify the resistance gene（s） in the translocation line, H9020-1-6-8-3 was crossed with susceptible cultivar Mingxian 169, and seedlings of the parents, F1, F2, F3, and BC1 generations were tested with prevalent Chinese Pst race CYR32 under controlled greenhouse conditions. The results indicated that there is a single dominant gene, temporarily designated as YrH9020a, conferring resistance to CYR32. The resistance gene was mapped by the F2 population from Mingxian 169/H9020-1-6-8-3. It was linked to six microsatellite markers, including Xbarc196, Xbarc202, Xbarc96, Xgpw4372, Xbarc21, and Xgdm141, lfanked by Xbarc96 and Xbarc202 with at 4.5 and 8.3 cM, respectively. Based on the chromosomal locations of these markers and the test of Chinese Spring （CS） nullitetrasomic and ditelosomic lines, the gene was assigned to chromosome 6D. According to the origin and the chromosomal location, YrH9020a might be a new resistance gene to stripe rust. The lfanking markers linked to YrH9020a could be useful for marker-assisted selection in breeding programs.     

Population Genetic Analysis of Blumeria graminis f. sp. tritici in Qinghai Province,China

To gain more precise information about molecular genetic variation for wild populations of Blumeria graminis f. sp. tritici from Qinghai Province, China, 38 single-colony isolates were purified from samples collected from Haidong District, Xining City and Hainan Tibetan Autonomous Prefecture in 2010. The virulence of 21 isolates among them was tested at seedling stage on 34 wheat cultivars（lines） carrying known powdery mildew（Pm） resistant genes. The results showed that V1 a, V3 a, V3 c, V3 e, V5 a, V6, V7, V8 and V19 had high virulence frequencies（〉75%）, indicating a wide distribution; and V1 c, V5 b, V12, V13, V16, V21, VXBD, V2＋6, V2＋Mld and V4＋8, with less distribution, appeared to be lower in frequencies（0-20%）. The Nei＇s gene diversity（H）, Shannon＇s information index（I） and the percentage of polymorphic loci（P） were 0.23, 0.35 and 67.65%, respectively, which revealed a virulent diversity. The results from single nucleotide polymorphisms（SNPs） of 38 isolates showed that three housekeeping genes were found to contain a total of 9 SNP sites. 10 haplotypes（H1-H10） were inferred from the concatenated sequences, with 1 haplotype（H1） comprising of over 55% of Qinghai population. Phylogenic analysis did not show obvious geographical subdivision between the isolates. A multilocus haplotype network presented a radial structure, with H1 in the central as an inferred ancestor. Using analysis of molecular variance（AMOVA）, we found 1.63% of the total variation was among populations and 98.37% within populations, with a low fixations index（FST=0.01634, P〈0.05）. This revealed a relatively high genetic diversity but a low genetic divergence in Qinghai population. Moreover, the molecular data on gene flow（Nm=6.32） confirmed the migration of pathogen populations among areas in Qinghai Province.     

加拿大小麦生产和锈病防治

小麦是加拿大种植面积最大的作物,大部分种植于加拿大西部曼尼托巴省、萨斯喀彻温省、阿尔伯塔省的草原省份。在加拿大小麦种植面积大约有1 000万hm2,包括700万hm2的六倍体春小麦,200万hm2的硬粒小麦和100万hm2的冬小麦。六倍体小麦又根据不同的质量标准和多样化的食品分类、市场需要等划分成很多类。其中最主要的一类叫加西硬红类(CWRS),是加拿大最主要用于做面包的春小麦品种系列。历史上危害小麦的病害主要是由秆锈菌(Puccinia graminisf.sp.tritici)引起的小麦秆锈病。在加拿大抗秆锈病的第一个重要品种是Thatcher,从20世纪30年代到70年代早期广泛种植。然而Thatcher对由叶锈菌(P.triticina)引起的叶锈病十分感病。多年来,随着含其他抗锈基因(主要是Sr2,Sr6,Sr7a,Sr9b,Lr13,Lr14a,Lr16,Lr34)品种的育成和推广,秆锈病得到了很好的控制,但叶锈病却由于P.triticina种群变化,导致例如Lr13和Lr16抗性基因的抗性丧失,仍然造成很大的损失。小麦条锈病主要由柄锈菌(P.striiformisf.sp.tritici)引起的,长期以来,条锈病是阿尔伯塔南部灌溉区小麦生产上的主要病害,但是自2000年以来,小麦条锈病已经在加拿大中部草原区和安大略南部发现,并造成严重危害。加拿大小麦品种中,只有少数含有中抗水平的Yr18抗条锈基因,而大多数小麦品种对条锈病的抗性基础及抗病遗传尚不清楚。展望未来,锈病仍然是加拿大小麦的主要病害,如条锈病或者是具有高致病力的秆锈病小种,Ug-99可能会是加拿大小麦及谷物生产的新威胁,目前解决这些问题的最好策略是致力于长期的抗锈病遗传育种研究,包括聚合有效耐用的基因,对基因进行有效的部署和聚合抗性基因使遗传资源最大化等手段。将科研重点放在自然遗传抗病方面旨在使加拿大农民能够按对自然环境有利的方式来生产化学残余量最少的小麦,从而在国内和国际市场竞争中占据优势。     

北方麦区120个小麦品种抗秆锈病基因的推导

利用含已知Sr5～38、SrGT和SrWld基因的42个单基因系和19个不同毒性的秆锈菌系,对北方麦区的120个生产品种和后备品系进行了抗秆锈病的基因推导．研究结果表明：黄淮冬麦区和北方冬麦区抗病品种（系）含有的抗秆锈病基因相似,绝大多数品种（系）主要含有Sr5、Sr31,少量品种含有Sr11、21、29等抗病基因;东北春麦区的小麦抗病品种（系）主要含有Sr5、6、8a、9b、9e、11、21、27、30、31、34、36等多基因组合。     

我国北方四省52个重要小麦品种抗秆锈病基因推导分析

为了探明我国北方四省小麦品种的抗秆锈病基因情况及可能发现对秆锈病新小种Ug99(TTKSK)抗病的基因型(品种),选择52个重要的小麦生产、后备品种进行测定.依据待测小麦品种及42个抗秆锈病单基因品系与中国和美国15个秆锈菌致病型的互作信息,结合系谱分析和基因遗传连锁关系推导待测52个品种的抗病基因.结果表明:从其中4...     

中国小麦秆锈菌鉴别寄主品种Rulofen抗秆锈病基因的单体分析

普通小麦品种Rulofen是我国小麦杆锈菌的鉴別寄主。用中国春单体系列和对Rulofen无毒性的小麦秆锈菌的三个生理小种21C3、34、34C2对Rulofen进行了抗秆锈病基因的单体分析,并将Rulofen所含的抗秆锈病基因与国际上已命名的Sr基因进行了异同比较。结果表明;Rulofen在2D染色体上含有兼抗三个供试生理小种的抗病基因Sr6.其抗性效应为;-;1~ 或1X~=-x~- ,因环境条件的影响,Sr6的抗性反应型不稳定;在5D染色体上含有兼抗21C3、34和34C2三个生理小种的抗病基因Sr30,其抗性效应为2=、抗秆锈病基因Sr6和Sr30对我国的小麦秆锈菌小种34类群都具有进一步的区分作用。     

小麦条锈病和白粉病成株抗性研究进展与展望

 利用成株抗性是小麦抗病育种的重要方向,本文综述了小麦条锈病和白粉病成株抗性鉴定方法、基因定位和克隆及其在育种中的应用。将报道的72个条锈病成株抗性数量性状遗传位点（quantitative trait loci,QTL）和82个白粉病成株抗性QTL整合到一张连锁图谱上,控制2种病害的基因簇（≥5个QTL）有8个,其中位于7DS的Yr18/Lr34/Pm38和1BS的Yr29/Lr46/Pm39对条锈病、叶锈病和白粉病均表现成株抗性,位于4DL的Yr46/Lr67位点可能也对白粉病表现成株抗性,Yr18/Lr34/Pm38和Yr36已被克隆,Yr29/Lr46/Pm39的克隆已取得良好进展,为培育兼抗和成株抗性相结合的品种提供了可用基因。总结了成株抗性在中国小麦育种中的应用现状,并用实例证实了培育成株抗性品种的可行性,建议对兼抗条锈病和白粉病成株抗性的咸农4号和小偃6号等进行遗传分析,育种工作者和品种审定部门需要转变观念,将成株抗性利用作为国内条锈病和白粉病抗性育种的重要内容。     

小麦秆锈菌新小种Ug99及其抗病育种研究进展(英文)

为帮助我国小麦研究人员全面了解秆锈菌新小种-Ug99 及其对我国小麦生产的潜在威胁,呼吁加强 Ug99 及其变异小种传播与扩散的监控,加强抗病种质创新和持久性耐病新品种选育,提前预防 Ug99 的危害。对 Ug99 小种变异、致病力、分布扩散以及小麦及其亲缘种属抗病基因发掘、连锁分子标记筛选,抗性育种策略与进展,中国 Ug99 研究现状进行了总结,由此不难看出,Ug99 是容易发生小种变异、毒力极强、扩展速度较快的秆锈菌新小种,极有可能对世界小麦生产带来的全球性危害。应该加强小麦及其亲缘种属新抗病基因的发掘与利用和持久性耐病新品种的培育,控制和预防 Ug99 及其变异小种的危害。     

中国41个小麦生产品种抗秆锈基因推导及其抗性稳定性初步分析

用中国小麦秆锈菌小种Ｚ１Ｃ３,３４,３４Ｃ２及３５Ｃ５中９个不同菌系推导了来自秆锈菌不同传播区间里有代表性的４１个小麦生产品种的抗秆锈基因,综合分析了中国小麦秆锈菌优势小种稳定的原因．基因推导表明：来自秆锈菌次要越冬及冬后北传桥梁区内的品种除鄂恩１号外,其余均未含有效抗性基因;来自秆锈菌越夏偶发区内的品种含有Ｓｒ５,２２,２５等基因;来自秆锈菌越夏易发区（主要东北春麦区）内的品种主要含有Ｓｒ１３,１４,２２,３２,３５,３６,３７,Ｇｔ等单个或结合基因．结果也表明：中国小麦品种对秆锈菌,尤其是对优势小种ＺＩＣ３的抗性水平明显地由南向北呈梯度增强局势．     

Evaluation of a set of introgressive spring bread wheat lines developed for resistance to stem rust race Ug99 + Sr24 (TTKST) at the Southeast Agricultural Research Institute

Under conditions of a natural stem rust epiphytotic caused by Puccinia graminis f. sp. tritici race Ug99 + Sr24 (TTKST), a set of introgressive spring bread wheat lines developed at the Southeast Agricultural Research Institute was evaluated at KARI’s international stem rust screening nursery (Kenya). New sources of resistance to the pathogen and effective resistance genes have been revealed.     

小麦白粉病抗性基因在河北省的有效性研究

本研究利用91个河北省的小麦白粉菌菌株对13个已知抗白粉基因的品系接种,测定各基因的毒力频率。结果表明,Pm2,Pm4a和Pm4b的毒力频率低于18%,是高抗基因;Pm1,Pm3c,Pm5和Pm8的毒力频率高于78%,不宜单独应用;Pm3a,Pm3b,Pm6和MA介于以上两种类型之间,有一定的利用价值。基因间的互作是复杂的,并不只是简单的累加。Pm3a,Pm3b,Pm3c和Pm6对不同地区的白粉菌群体的毒力频率不同,在利用抗性基因及其布局时应考虑各地区小麦白粉菌毒性的特殊性。     

中国冬小麦区域试验品种抗病性评价

【目的】明确中国小麦主要后备品种和高代品系对条锈病、叶锈病、秆锈病、白粉病、赤霉病、纹枯病、黄矮病的抗性程度和水平,为培育抗病新品种、品种审定与推广、抗病品种合理布局、降低品种抗性“丧失”风险提供依据。【方法】以中国小麦条锈菌流行小种条中32（CYR32）、条中33号（CYR33）等、叶锈菌PHT、THT等、秆锈菌21C3、34C2等、对15个已知抗白粉病基因具有毒性的白粉菌混合菌系、赤霉病菌、纹枯病菌强毒力菌株和BYDV-GAV株系对1999-2014年度国家小麦区域试验品种（系）1 815份次试验材料进行成株期人工接种抗性鉴定,重要材料连续进行两年试验,以确保结果的重复和可靠。【结果】在所鉴定的品系中,具有3种抗病性以上的品种（系）共250个,通过农业部国家农作物品种审定委员会审定的品种共310个;中抗和高抗条锈病品种占参试品种的（39.8±21.7）%、中感和高感品种占（39.7±27.9）%;赤霉病、纹枯病、秆锈病和白粉病抗病品种所占比例分别为（31.5±27.5）%、（31.1±35.6）%、（48.2±25.6）%和（25.0±14.6）%、感病品种分别占（68.5±27.5）%、（62.2±38.6）%、（31.3±20.7）%和（70.7±14.6）%;抗叶锈病品种比例仅为（9.9±3.8）%,感病品种高达（70.4±15.1）%;除河农831表现中抗外,所有品种对黄矮病均表现感病,未出现高抗品种。【结论】抗源缺乏的病害未鉴定出抗性强的品种,抗条锈病和白粉病品种主要出现在甘肃、四川等地,抗叶锈小麦品种（系）较少。     

Stomatal Penetration of Wheat Seedlings by Stem and Leaf Rust: Effect of Light and Carbon Dioxide

Removal of atmospheric carbon dioxide enhanced penetration of seedling wheat by stem rust Puccinia graminis in light and dark but did not materially affect penetration by leaf rust P. recondita. A concentration of 5 percent CO(2) nearly suppressed penetration by P. graminis but not by P. recondita. Thus light may promote penetration by P. graminis through photosynthetic reduction of CO(2) within the leaf and P. recondita may penetrate independently of light because it is relatively insensitive to the effects of CO(2).     

小麦条锈菌条中29号生理小种SCAR检测标记的建立

用210条随机引物对中国小麦条锈菌(Pucciniastriiformisf.sp.tritici)5个主要生理小种进行了RAPD分析,寻找到了2个条中29号特异性的RAPD标记。根据其中一个特异片段的测序结果,设计了特异PCR引物,成功获得了条中29号小种专化的SCAR标记。     

小麦条锈菌和叶锈菌的复合PCR检测

利用真菌β-微管蛋白基因的保守序列和小麦条锈菌(Puccinia striiformi f.sp.tritici)、叶锈菌(Puccinia tri-ticina)的SCAR标记引物,对锈菌孢子与感病小麦叶片总DNA进行复合PCR检测,扩增获得了小麦条锈菌171bp和叶锈菌226 bp的特异性DNA片段,其检测灵敏度可达到50 μg·L~(-1)模板DNA浓度水平.在此基础上,可进一步制备小麦锈菌不同种的分子诊断、检测试剂盒.     

中国小麦条锈菌4个流行小种的RAPD标记

以210条随机引物,对目前中国小麦条锈菌(Pucciniastriiformisf.sp.Tritici)的主要优势菌系进行了RAPD片段的规模筛选,寻找到了条中31号、条中29号、条中23号、水源类型4个流行生理小种的特异性RAPD标记。此结果表明,通过寻找小麦条锈菌生理小种的特异性RAPD片段,能够建立起中国小麦条锈菌生理小种的分子检测体系。