Yr5-virulent races of Puccinia striiformis f.sp.tritici possess relative parasitic fitness higher than current main predominant races and potential risk

Wheat stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst),is one of the most destructive fungal diseases of wheat,and seriously threatens safe production of the crop worldwide.In China,new races historically appeared and rapidly developed to be predominant races and have resulted in ineffectiveness and replacement of wheat resistance cultivars as well as massive reduction in yield.In the present study,the relative parasitic fitness of the two newlyemerged Yr5-virulent races(TSA-6 and TSA-9)were compared with those of four currently predominant Chinese races(CYR31,CYR32,CYR33,and CYR34)based on evaluation on 10 Chinese wheat cultivars.As a result,there were significant differences in the relative parasitic fitness parameters among overall tested races based on multiple comparison(LSD)analysis(P<0.05).The principal component analysis(PCA)of overall parasitic fitness parameters indicated that the sporulation ability,infection and spore survivability,expansion capacity,and potential pathogenicity were the most important parasitic fitness attributes of the tested races.Based on the establishment of extracted three principal components and a comprehensive factor score mathematical models,evaluations of the parasitic fitness attributes of tested races showed that the level of relative parasitic fitness of the tested six races was:CYR32(1.15)>TSA-9(0.95)>TSA-6(0.92)>CYR34(0.29)>CYR31(–1.54)>CYR33(–1.77).The results indicated that two Yr5-virulent races TSA-9 and TSA-6 possessed relative parasitic fitness higher than races CYR34,CYR31,and CYR33,but lower than race CYR32,and have potential risks in developing to be predominant races.Therefore,continual monitoring of both Yr5-virulent races,and their variants is needed.The use of wheat cultivars(lines)with Yr5 resistance gene singly in wheat breeding is essential for being avoided,and is suggested to combine with other effective stripe rust resistance genes.

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.

Identification of eight Berberis species from the Yunnan-Guizhou plateau as aecial hosts for Puccinia striiformis f.sp.tritici,the wheat stripe rust pathogen

Puccinia striiformis Westend.f.sp.tritici Erikss.(Pst)infects wheat and causes stripe rust.The rust is heteroecious with wheat as the primary uredinial and telial host and barberry(Berberis spp.)as the alternate pycnial and aecial host.More than 40 Berberis species have been identified as alternate hosts for Pst,and most of these are Chinese Berberis species.However,little is known about Berberis species or their geographic distributions in the Yunnan-Guizhou plateau in southwestern China.The Yunnan-Guizhou plateau is considered to be an important and relatively independent region for the evolution of the wheat stripe rust pathogen in China because the entire disease cycle can be completed within the region.In this study,we conducted a survey of barberry plants in the Yunnan-Guizhou plateau and identified the eight Pst-susceptible Berberis species under controlled conditions,including B.julianae,B.tsienii,B.veitchii,B.wilsonae,B.wilsonae var.guhtzunica,B.franchetiana,B.lepidifolia and B.pruinosa.These species are reported here for the first time to serve as alternate hosts for the wheat stripe rust pathogen under controlled conditions.

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.

Characterization of wheat monogenic lines with known Sr genes and wheat cultivars for resistance to three new races of Puccinia graminis f. sp. tritici in China

Wheat stem rust, caused by Puccinia graminis f. sp. tritici(Pgt), is a potentially devastating fungal disease of wheat worldwide. The present study was to evaluate the resistance of 42 wheat monogenic lines with known stem rust resistance(Sr) genes and 69 wheat cultivars to three new Pgt races(34C0MRGQM, 34C3MKGQM, and 34C6MTGSM)identified from aeciospores at the seedling and adult-plant stages. The phenotyping results revealed that monogenic lines harboring resistance genes Sr9e, Sr17, Sr21, Sr22, Sr26, Sr30, Sr31, Sr33, Sr35, Sr36, Sr37, Sr38, Sr47, SrTmp,and SrTt3 were effectively resistant to all three Pgt races at the seedling and adult-plant stages. In contrast, monogenic lines containing Sr5, Sr6, Sr7b, Sr9a, Sr9d, Sr9f, Sr9g, Sr9b, Sr16, Sr24, Sr28, and Sr39 were highly susceptible to these races at both seedling and adult-plant stages. The other lines with Sr8a, Sr10, Sr11, Sr13, Sr14, Sr15, Sr18, Sr20,Sr19, Sr23, Sr25, Sr27, Sr29, Sr32, and Sr34, displayed variable levels of resistance to one or two of the tested races.Seedling infection types(ITs) and adult-plant infection responses(IRs) indicated that 41(59.4%) of the wheat cultivars showed high resistance to all the three races. Molecular marker analysis showed that four wheat culitvars likely carried Sr2, 20 wheat culitvars likely carried Sr31, 9 wheat culitvars likely carried Sr38, and none of the cultivars carried Sr24,Sr25, and Sr26. Our results provide a scientific basis for rational utilization of the tested Sr genes and wheat cultivars against these novel Pgt races.

A small knottin-like peptide negatively regulates in wheat to stripe rust resistance during early infection of wheat

Although Blufensins(Bln)have important functions in the response of plants to biotic stress the precise functioning of Bln in wheat remains largely unknown.Here we isolated a Bln gene(TaBln4)from Suwon 11 infected by Puccinia striiformis f.sp.tritici(Pst).Expression of TaBln4 increased in host plants at the early stage of infection with a virulent Pst race(CYR31)but was unchanged in response to infection by an avirulent race(CYR23).Transcription levels of TaBln4 were also regulated by hormone and abiotic stresses.Expression of TaBln4 in tobacco leaves suppressed Bax-induced programmed cell death.Knockdown of TaBln4 by virus-induced gene silencing inhibited colonization of race CYR31 by increasing the accumulation of H2O2 and formation of hypersensitive responses(HR).Transient overexpression of TaBln4 by a transient overexpression system(BSMV-VOX)increased the susceptibility of wheat to CYR31.Results from bimolecular fluorescence complementation and pull-down assays demonstrated that TaBLN4 interacted with calmodulin.Taken together,our results suggest that TaBln4 negatively regulates resistance in wheat to Pst in a reactive oxygen species(ROS)-and HR-dependent manner.

分子标记选择小麦抗白粉病基因Pm4b、Pm13和Pm21聚合体

培育多个抗病基因聚合的小麦品种是提高其抗病广谱性和持久性的有效途径之一。利用小麦抗白粉病基因Pm4、Pm13、Pm2 1的特异PCR标记 ,对含有Pm4b、Pm13、Pm2 1的小麦品系复合杂交F2 代 4 0个植株进行检测 ,从中选择到Pm4b +Pm13+Pm2 13个基因聚合的抗病植株 11个 ,检测、选择到Pm4b +Pm13、Pm4b +Pm2 1、Pm13+Pm2 12个基因聚合的抗病植株 19个 ,为持久、广谱抗病小麦育种奠定了基础。研究还表明 ,3个独立的显性抗病基因在F2 代分离群体中的分离比例基本符合孟德尔独立分配定律 ,在小麦背景下的遗传稳定性 ,与该基因供体和普通小麦的亲缘关系密切相关 ,亲缘关系越远 ,丢失的概率越大。因此 。

2017年我国小麦条锈病流行特点及重发原因分析

2017年小麦条锈病在我国黄淮海麦区大范围流行,表现出汉水流域及黄淮南部见病时间早、扩散速度快、黄淮海麦区流行范围广等特点。本文在系统总结2017年全国小麦条锈病流行特点的基础上,分析认为极端暖冬气候、春季多雨适温气候条件和主产麦区缺乏抗性品种等因素是导致2017年我国小麦条锈病大流行的主要原因。

RAPD技术和聚类分析在小麦条锈病菌生理小种研究中的应用

试用４５个随机引物对我国小麦条锈病菌的６个生理小种（ＣＹＲ１７，ＳＵ１１，ＣＹＲ２３，ＣＹＲ２８，ＣＹＲ２９和ＣＹＲ３０）进行了ＲＡＰＤ分析，其中１０个适宜引物具有鉴别作用，共扩增出８９条ＲＡＰＤ图带，多态性为７３％。自ＣＹＲ２３、ＣＹＲ２８和ＣＹＲ２９三个生理小种中扩增出了特征性ＲＡＰＤ图带。根据ＲＡＰＤ分析结果，将这一结果与６个小种对不同小麦品种苗期和成株期致病性的聚类分析作了比较。可将供试小种分为两组，第一组包括ＣＹＲ１７、ＳＵ１１和ＣＹＲ２３，其中前两者的相似性最大；ＣＹＲ２８和ＣＹＲ２９也较相近，属于第二组；新小种ＣＹＲ３０与其它小种的相关性尚待进一步研究。

2007年我国部分麦区小麦白粉菌对三唑酮的抗药性监测

采用拌种离体叶段法测定了我国9个省(市)的112个小麦白粉菌株对三唑酮的抗性。结果表明,供试菌株的平均EC50为57.25mg/L,平均抗性水平为27.39倍,其中86.61%供试菌株已经产生抗性,抗药性比敏感菌株高出10～40倍的菌株占47.32%,四川、山东、甘肃和贵州等地菌株的抗性高于其他地区。此结果可为三唑类杀菌剂在我国的推广应用和制定合理的抗药性治理措施提供依据。

不同小麦抗条锈基因及小麦品种在四川的有效性

将以Avocet为背景的27份抗小麦条锈病近等基因系、131个抗性基因型较明确的小麦抗源品种和59份四川小麦生产品种和抗源以及和感病对照铭贤169分行种在位于四川省雅安市草坝(N:29°57′09.6,″E:103°07′11.9,″海拔525.1 m)、梓潼县豢龙(N:31°44′07.0,″E:105°10′48.5,″海拔484.1 m)和剑阁县武连(N:31°52′21.5,″E:105°16′23.5,″海拔:481 m)的病圃中,含Yr5、Yr10、Yr15、Yr26的近等基因系、审定品种川麦43、川麦46、川麦47、川农18、川农23、绵麦39、绵麦41、绵麦42、杏麦2号、和内麦8号、区试材料C1、C5、30375和SW 18155、抗源M ega(含Yr3,4)和Hybrid 46(含Yr3 b,Yr4 b,H46)、93-1-22v-2、CP93-10-1-1-1、SMT-35、SMT-47、贵农22、贵农22-1和贵州蓝麦+MO连续两年在各病圃中表现抗病。216份品种或材料两年在雅安、剑阁和梓潼的鉴定结果中,有27个品种或材料同年在梓潼或剑阁表现感病而在雅安表现抗病,5个品种同年在梓潼或剑阁表现抗病而在雅安表现感病,紧邻阿坝州和陇南越夏菌源的剑阁、梓潼的条锈病菌毒性强于紧邻甘孜州越夏菌源的雅安。

80份国外春小麦种质资源抗条锈性评价

【目的】小麦条锈病是由小麦条锈菌(Puccinia striiformis f.sp.tritici,Pst)引起的世界范围内小麦重要病害之一,培育和种植抗病品种是控制该病害的最有效策略。评价80份国外春小麦种质资源对中国当前小麦条锈菌流行小种的抗条锈性,为中国小麦抗条锈病育种提供依据和抗源。【方法】应用中国流行小麦条锈菌生理小种CYR29、CYR31、CYR32、CYR33以及致病类型PST-HY8和PST-V26对80份国外小麦种质资源进行苗期温室抗病性鉴定,以铭贤169和Av S为感病对照品种;并于2013年和2014年分别在陕西省杨凌和甘肃省天水进行田间成株期抗病性鉴定。根据苗期和田间成株期的抗病性鉴定结果对其进行抗病类型分类和评价。【结果】80份小麦种质资源的抗病类型可分为3类。第1类为全生育期抗病类型,有8份。其中PI660067、PI660119和PI660122在苗期和田间成株期均表现较高水平的抗病性。其余5个品系PI660056、PI607839、PI591045、TA5602和PI660064在苗期则对个别小种表现感病,并且在不同年份和不同测试地点成株期也表现感病。第2类为成株抗病类型,有28份。其苗期对所有测试小种均表现感病,有23份在田间成株期均表现抗病。但PI660075、PI660083、PI660085、PI660097和PI660107在不同年份和不同测试地点成株期表现感病。第3类为兼具成株期和对部分中国小种失去抗性的全生育期抗病类型,有44份,其苗期至少对一个测试小种表现抗病。有37份在田间成株期均表现抗病。但PI660065、PI660076、PI660079、PI660080、PI660095、PI660096和PI610750在不同年份和不同测试地点成株期表现感病。【结论】80份国外小麦种质资源中大部分对中国小麦条锈菌流行小种表现优良的抗病性。这些种质资源可作为抗源在今后抗病育种中加以利用,将丰富中国小麦抗条锈病基因的多样性。可能由于不同年份田间流行小种不同,造成一些成株抗病品系在不同年份和不同测试地点表现感病,由此推测成株抗病性可能也具有小种专化性。

若干小麦抗白粉病品系的有效抗病基因的测定

采用具有不同毒性基因的白粉菌菌株进行苗期接种,通过与已知抗病基因材料抗谱的相似性比较,对17个抗白粉病育种品系的有效抗病基因进行了分析,其中3个阿拉拉特小麦(T.araraticum)杂种后代品系、4个V.P.M系统的杂种后代品系及另外1个杂交组合的后代品系含主效抗病基因Pm2;4个具有V.P.M或C39血缘的品系及另外1个品系含主效抗病基因Pm4b;1个品系含Pm2+6;2个普通小麦-黑麦6D/6R代换系的抗谱相似,且不同于所有已知抗病基因材料;此外,含Pm21的普通小麦-簇毛麦6AL/6VS易位系对所有供试菌株免疫。

源于硬粒小麦-节节麦人工合成种的小麦新品种川麦38抗条锈性及遗传分析

利用硬粒小麦-节节麦人工合成种与四川小麦杂交、回交,育成高抗条锈小麦新品种川麦38(99-607)。为明确川麦38抗条锈性状的遗传规律,将川麦38与绵阳26、绵阳335、SY95-71、川育12等5个高感条锈小麦品种杂交,获得杂种F1、F2群体;利用条中32对抗×感杂种F1、F2群体接种鉴定抗性分析表明,川麦38对条锈病新小种的抗性受一对显性基因控制。将川麦38与含Yr13的德国小麦8661及源于硬粒小麦-节节麦人工合成种的3个抗病新品种(川麦42、川3736、复小穗小麦)杂交,分析川麦38与4个抗病品种的抗性基因等位性,结果发现抗×抗F2群体中均分离出一定比例的感病单株,表明川麦38与德国小麦(Yr13)、川麦42、川3736、复小穗小麦等的抗锈基因不等位,为不同的抗性基因。

小麦多品种混播控制条锈病的效果和机理研究

【目的】研究多品种混播对条锈病的控制效果及其机理,为利用品种混播这种生态控制条锈病的方法应用提供理论依据。【方法】在田间分别设计6个品种单播及其9个组合的混播小区,比较研究条锈病的发生情况和产量差异;并采用TP-M13-SSR技术分析自然发病条件下条锈菌群体的遗传多样性。【结果】多品种混播小区苗期发病中心较少,且发病中心的扩展速度明显受到抑制,在春季流行阶段病情指数显著降低;品种混播以抗-感组合较好,2007年其相对防效平均为73.27%,相对增产率平均为13.26%;混播中组分数目对病害和产量的影响无明显差异;混播小区条锈菌的遗传多样性高于单播小区。【结论】多品种混播对小麦小麦条锈病有较好的控制效果,并可明显降低产量损失;品种多样化有利于条锈菌群体结构的稳定;品种混播可作为生态防病措施之一。

小麦条锈菌条中32号生理小种SCAR检测标记的建立

【目的】建立具有应用价值的小麦条锈菌条中32生理小种的SCAR检测标记。【方法】用100条随机引物对我国目前主要流行的12个小麦条锈菌生理小种进行RAPD筛选,寻找特异性片断,并对其进行克隆、测序,将该特异性片段转化成条中32号小种的SCAR专化型标记。设计并合成SCAR特异性引物,对不同来源的条中32号进行SCAR检测。【结果】引物S1271从条中32号生理小种中扩增出长度为320 bp的特异片段,该片段可作为条中32号的SCAR标记。从不同来源的条中32号生理小种中扩增出了筛选到的SCAR标记。【结论】成功建立了条中32专化SCAR标记。

细胞骨架解聚药物对小麦与叶锈菌互作诱发的细胞过敏性反应的影响

小麦 (Triticum aestivum)品种洛夫林 10和叶锈菌小种 36 6组成不亲和组合 ,小麦叶片发生过敏性坏死反应 (HR)是小麦抵抗叶锈菌侵染的重要因素。在接种前给小麦叶片分别预注射微管解聚药物磺草硝 (oryzalin)和微丝解聚药物细胞松弛素 D(cytochalasin D,CD) ,结果表明 2种药物注射使得寄主因叶锈菌侵染诱导的细胞过敏性坏死数目明显减少 ,并且注射药物的浓度越大 ,寄主细胞发生 HR的数量越少。说明肌动蛋白和微管蛋白的聚合状态是诱发小麦叶片发生 HR防卫反应所必需的 ,细胞骨架在小麦抵抗叶锈菌侵染过程中可能起着重要作用。

湖北麦区小麦白粉病菌毒性结构分析

对湖北省不同年度(2001、2003年和2007年)、同一年度(2007年)不同生态区间的小麦白粉病菌毒性基因频率进行了比较。结果表明,毒性基因V2、V4 b、V13、V20、V21、V2+MLD、V2+6、V4+8和V4 b+Mli在测定的3个年度中毒性频率均低于25%,而V1、V3 b、V3 c、V3 d、V3 e、V5、V8、V17和V193个年度的毒性频率均高于50%;白粉病菌毒性结构年度之间和生态区之间均基本相似,但个别毒性基因年度及生态区间存在一定的差异;V2、V3 a、V3 b、V3 c、V3 e、V5、V6、V7、V8和V20在十堰以及武昌2个生态区毒性频率年度间均有明显的上升趋势,而V4 b、V5(MLi)、V13、V21、V5+6则表现为下降的趋势;2007年仅在十堰生态区检测到V2+Mld和V2+6菌株。

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0.20～0.25 mmol/L,最佳时间间隔应大于6 d.对于成株期小麦,在分蘖中期和后期以0.20 mmol/L BTH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.

小麦白粉病菌对喹氧灵和苯菌酮的敏感基线及药剂的生物活性

采用离体叶段法,分别测定了从河北、河南、湖北、陕西和四川5省分离的53个小麦白粉病菌单孢菌株对苯菌酮和喹氧灵的敏感性,并分析了白粉病菌对三唑酮和苯菌酮以及喹氧灵之间的交互抗性。结果表明:小麦白粉病菌群体对苯菌酮和喹氧灵的平均EC50值分别为(0.001 9±0.000 6)和(0.013 1±0.002 0)mg/L,苯菌酮比喹氧灵具有更高的抑菌活性;小麦白粉病菌对三唑酮和苯菌酮与喹氧灵之间均不存在交互抗性(R2值分别为0.102 6和0.491 9);室内盆栽试验结果显示:接种前1 d和接种后1 d施药,苯菌酮和喹氧灵对小麦白粉病的保护与治疗作用防效分别为92.21%、84.25%和82.43%、70.25%,表明这2种药剂不仅具有优异的保护作用,同时还具有较好的治疗作用。