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.     

A FIASCO-Based Approach for Detection and Diagnosis of Puccinia graminis f. sp. tritici in China

Stem or black rust of wheat, caused by the fungus Puccinia graminis Pers. f. sp. tritici Eriks.＆E. Henn. （Pgt）, has historically caused severe losses to wheat （Triticum aestivum L.） production worldwide. In the Fujian and Guangdong provinces of China, six moderate-to-severe epidemics of wheat stem rust have occurred, which caused destructive losses of wheat between 1949 and 1966, although these were brought under control by integrated management. A rapid and reliable detection of the pathogen will contribute to the accurate forecast and seasonal control of this disease. The objective of this study was to develop a diagnostic molecular marker generated from simple sequence repeats （SSR） for the early rapid identiifcation of P. graminis. The genomic DNA of P. graminis, Puccinia striiformis, Puccinia triticina and seven other species was ampliifed by a pair of SSR primers generated by the FIASCO （fast isolation by AFLP sequences containing repeats） enrichment protocol. The primer set Pgtw （f）/Pgtw （r） generated a polymorphic pattern displaying a 330-bp DNA fragment speciifc for P. graminis whereas no DNA fragment was obtained from other non-target wheat fungal pathogens. The detection limit of the primer was 1 ng DNA in a 25-mL PCR reaction. The SSR markers of P. graminis can also be used to detect the presence of latent hyphae in Pgt-infected wheat leaves as early as 30 h post-inoculation. A rapid approach to distinguish P. graminis from similar pathogenic fungi would be anticipated in further study.     

甘肃中西部春小麦白粉菌群体毒性分析

利用小麦苗期离体培养 ,对甘肃中西部地区的小麦白粉病菌进行生理小种鉴定及群体毒性频率分析 ,结果 :( 1 )纯化菌株 36份 ,鉴定出生理小种 2 0个。其中优势小种是 0 1 5 ,分布频率为 1 6.7% ,0 77号为次优势小种。( 2 )群体毒性频率分析中毒性基因 VEra,V8,V1 ,V3c,V3f频率达 70 %以上 ,而 V2 ,MID,V2 0 ,V2 1 ,V4b,V4频率在 1 6.7%以下 ,46%的白粉菌毒性基因频率高于 40 % ,说明目前甘肃省白粉菌毒性基因频率高 ,含有Pm2 MID,Pm2 0 ,Pm2 1 ,Pm1 b,Pm1 等抗病基因的品种在育种中有一定的利用价值     

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.     

BTH对小麦产生白粉病抗性的诱导作用

用化学诱抗剂BTH(benzothiadiazole)分别处理幼苗期和成株期小麦后,再接种小麦白粉病菌,以研究BTH诱发小麦对白粉病产生系统性抗性的能力。结果表明,用BTH处理幼苗期小麦后,小麦白粉病的病情指数较对照显著降低,BTH诱发小麦幼苗对白粉病产生抗性的最佳浓度为0.20~0.25mmol/L,最佳时间间隔应大于6d。对于成株期小麦,在分蘖中期和后期以0.20mmol/LBTH喷雾,对小麦白粉病的防效为60.82%,较对照增产16.00%。说明BTH可以诱导小麦对白粉病产生系统获得抗性,并可用于田间白粉病防治。     

小麦白粉菌在小麦属以外的寄主范围

温室接种试验证明,小麦白粉病能成功地侵染小麦属以外的6属18种禾草,其中6属17种为国内首次报道的该菌寄主。野外调查中发现,纤毛鹅观草(Roegneria ciliaris(Trin.)Nevski)雀麦(Bromus japonicusThunb.)、早熟禾一种(Poa sp.)和披碱草属一种(Elymus sp.)上的白粉菌发生严重,但室内试验证实前两种禾草上的白粉菌与小麦白粉病无关,后两种禾草上的白粉菌需进一步研究。用小麦白粉菌河南菌系和陕西菌系分别接种同一物种的禾草,所得结果不尽一致。关于野生禾草在小麦白粉病流行中的作用,尚需进一步研究。     

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。     

用活动苗圃法测定小麦白粉菌群体的变异

1991年在重庆市6个县、区,用活动苗圃法测定田间小麦白粉菌群体的变异。结果表明,含有Pm2,4b、MlkPm4b、MliPm6抗性基因组合的小麦品种Sappo、Turbo、Bert和含Ba单基因的品系81—7241都高抗白粉病。而含Pm4a、Pm4b、Pm6、Mlk抗性基因的Khapli/Cc8、Armada、Timgalen、Herold品种以及含Pm2x、KG基因的白免3号、肯贵阿和含有Pm2,6基因组合的CI12632品种,虽然在大部分地区中也高度抗病,但在个别地点或县却表现感病。对这类抗源品种,应特别留意其病菌毒性变异。活动苗圃能及时侦察到病原群体中某些稀有的、具潜在危险的毒性小种,可作为一种补充监测方法。     

漯河小麦白粉病菌生理小种组成及动态研究

对2007—2010年小麦白粉病菌的生理小种类型、小种动态变化进行研究。结果表明:白粉病菌小种种群结构复杂,共鉴定出36个生理小种,优势小种分别为31号、111号、311号生理小种,出现频率分别为27.27%、27.27%、26.19%,其次为11号、115号和401号小种。同时小麦白粉病菌具有低毒力小种锐减、中毒力和高毒力小种增加的变化趋势。     

小麦对白粉菌过敏性反应与H_2O_2及3种氧化酶活性变化的关系(英文)

[目的]研究小麦对白粉菌过敏性反应与H2O2及3种氧化酶活性变化的关系,为探讨小麦对白粉菌抗性生理机制奠定基础。[方法]以白粉菌菌株17(Bgt17)和菌株6(Bgt6)及小麦品种扬158为试验材料,测定H2O2处理的小麦叶片过敏性细胞数量及POD、PPO、SOD酶活性。POD活性测定参照Hammershmidt方法并加以改进,用0.05mmol/LpH值为5.5的磷酸缓冲液进行提取,以愈创木酚作为底物测定,以1minA470变化0.01为1个酶活力单位;PPO活性测定参照ConstableandRyan方法进行,用0.05mmol/LpH值为5.5的磷酸缓冲液提取,以儿茶酚为底物测定,以1minA525变化0.01为PPO活力单位;SOD活性的测定参照Levine等方法进行,用提取液(50mmol/LMet,0.1mol/LpH值为7.8的磷酸缓冲液,1mmol/L二硫苏糖醇(DDT))提取。测定SOD对氮蓝四唑(NBT)光还原的抑制率,以抑制NBT光还原50%为1个酶活力单位。[结果]乳突在亲和性与非亲和性组合叶表细胞形成的差异不大,非亲和性反应叶表细胞过敏性反应发生早且明显比亲和性反应多;接种Bgt17后不同时间及非亲和性组合中含H2O2的过敏性反应细胞频率明显高于亲和性组合;用5、10、20mmol/L抗坏血酸处理后,小麦叶片中过敏性细胞数量显著减少,15.0与30.0mmol/LH2O2处理后诱导亲和性反应小麦叶片中过敏性细胞数量显著增加;接种白粉菌后,小麦叶片中POD、PPO、SOD活性均呈先上升后下降趋势,且非亲和性组合比亲和性组合3种酶的活性高。[结论]HO、PPO、SOD活性与小麦对白粉菌抗性存在一定相关性。     

小麦对白粉菌过敏性反应与H2O2及3种氧化酶活性变化的关系

[目的]研究小麦对白粉菌过敏性反应与H2O2及3种氧化酶活性变化的关系,为探讨小麦对白粉菌抗性生理机制奠定基础。[方法]以白粉菌菌株17（Bt17）和菌株6（Bt6）及小麦品种扬158为试验材料,测定H2O2处理的小麦叶片过敏性细胞数量及POD、PPO、SOD酶活性。[结果]乳突在亲和性与非亲和性组合叶表细胞形成的差异不大,非亲和性反应叶表细胞过敏性反应发生早且明显比亲和性反应多;接种Bgt17后不同时间及非亲和性组合中含H2O2的过敏性反应细胞频率明显高于亲和性组合;用5、10、20mmol/L抗坏血酸处理后,小麦叶片中过敏性细胞数量显著减少,15.0与30.0mmol/LH2O2处理后诱导亲和性反应小麦叶片中过敏性细胞数量显著增加;接种白粉菌后,小麦叶麦中POD、PPO、SOD活性均呈先上升后下降趋势,且非亲合组合比亲合组合3种酶的活性高。[结论]H2O2、PPO、SOD活性与小麦对白粉菌抗性存在一定相关性。     

天水地区小麦白粉病菌致病类群初步测定

1987～1989年,对甘肃天水地区的小麦白粉病菌致病类群,用鉴别寄主品种进行了室内测定和田间自然感染监测。结果表明,有11个致病类群,三年结果基本一致,没有明显变化。优势类群(015,011)的频率在48.1％～67.9％,它们是弱致病类群,但对生产上的品种,大部分能侵染。供试的菌样对鉴别寄主品种的毒性频率为:阿夫,100％;Ulka×Cc8(Pm2),22.4％;Era,55％,高加索(Pm8),100％;CI12633(Pm2+Pm6),14.3％;Maris Huntsman (Pm2+Pm6),14.3％;肯贵阿,2.5％;白免3号(Pm2x),12.3％;新疆小白冬麦,0.0％。另外,对洛夫林10的毒性频率100％,对Khapli(Pm4等)免疫。     

我省小麦白粉菌小种及抗性遗传的初步研究分析

把贵白4、16、64号与我省一些白粉病菌系进行比较鉴定，初步发现目前我省生产上小麦白粉病菌优势小种为类似贵白16号的冀白2号，但还没有致病力更强的64号小种。另外，用冀白2号、贵白16号和贵白64号小种分别对2个小麦抗源与我省部分感病品种杂交的F1、F2幼苗离体叶段接种，通过抗性遗传分析，发现抗源2号对冀白2号和贵白64号小种的抗性分别由l对显抗白粉病基因控制。     

小麦白粉病抗源筛选及抗源分布规律研究

小麦白粉病是由小麦白粉病菌（Erysiphe graminis D C.f.sp.tritici Marshsl）引起的真菌性病害,是重要的小麦病害之一。通过对359份小麦材料进行白粉病鉴定,筛选出抗白粉病或对白粉病免疫的人工合成小麦材料6份、小麦稀有种21份,推广品种1份。     

小麦秆锈病细胞间隙液的提取及注射技术研究

通过真空渗入离心法提取小麦秆锈病病组织的细胞间隙液,并采用注入法将细胞间隙液注入到健康的小麦细胞,研究了小麦秆锈病细胞间隙液对小麦叶片细胞HR的诱导作用,明确了细胞间隙液的提取和注射技术在小麦秆锈病细胞间隙液研究中利用的可行性。     

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。     

小麦白粉菌对小麦属物种的寄生致病性研究

田间和温室试验的结果表明，供试的小麦属１５个物种中，除波斯小麦对小麦白粉菌表现免疫外，其它１４个物种均对该菌表现感染。其中栽培一粒小麦，瓦维洛夫小麦，莫加小麦，斯插尔脱小麦和印度圆粒小麦感染该菌在国内属首次报道。本研究从一个侧面进一步支持了小麦属的现代分类理论。     

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。