小麦条锈菌转主寄主小檗(Berberis germanensis)的人工接种鉴定

正条形柄锈菌小麦专化型(Puccinia striiformis f.sp.tritici),简称小麦条锈菌,是引起小麦条锈病(wheat stripe rust or yellow rust)的病原菌。近年通过人工室内接种证实小檗(Berberis spp.)是小麦条锈菌的转主寄主~([1]),由此揭示了小麦条锈菌是具有性、锈、夏、冬和担孢子5种孢子类型的全孢     

东北中部地区大叶小蘖与小麦秆锈病发生关系的研究

为了探讨大叶小蘖对小麦稈锈病流行无关的原因,以大叶小蘖上的锈孢子接种小麦上,和 P.Elymina P.Pygmaea 的冬孢子接种大叶小蘖上,结果肯定大叶小蘖在自然条件下对当地小麦稈锈病流行无关。大叶小蘖是这两种杂草锈菌的锈孢子阶段寄主。大叶小蘖展叶时期的气候条件不利于小麦稈锈菌冬孢子发芽,这是它在自然条件下不起转主寄主作用的关键因素。在小蘖展叶盛期(最易感染时期)的5月中旬,平均气温适合小麦稈锈菌冬孢子发芽,但缺少必要的湿度条件。而在连雨潮湿天气,湿度条件虽然具备了,但温度又降得很低,这就使小麦稈锈菌冬孢子很难发芽,使小蘖错过了最易感染的机会,5月下旬以后,气温日渐增高,又超过了小麦稈锈菌参孢子发芽的最高温度,虽有充足的水分,冬孢子也很少发芽。此时小蘖陆续长出新梢,发出嫩叶,也不再被侵染了。三年来,在小蘖邻近麦地调查,和进行稈锈菌生理小种分析结果,小麦稈锈菌不通过大叶小蘖产生多种生理小种。冬孢子发芽试验证明,在斗沟子各处散乱的麦稈上的小麦稈锈菌冬孢子,到5月中旬已正常成熟,发芽率很高。只要有充足的水分,在9°—21℃温度范围内,小麦稈锈菌冬孢子发芽很好,且长小孢子;而在9℃以下或22℃以上,冬孢子很少发芽。     

不同海拔对天水市小麦条锈菌夏孢子萌发的影响

为明确不同海拔对天水市小麦条锈菌Puccinia striiformis f. sp. tritici夏孢子萌发的影响,于显微镜下观察天水市低、中、高海拔地区小麦条锈菌夏孢子在不同温度下的萌发及融合情况,并对与夏孢子萌发相关的温敏基因的表达水平进行测定。结果显示,低海拔和中海拔地区的小麦条锈菌夏孢子的最适萌发温度为9℃,萌发率分别为64.72%和54.21%,高海拔地区的小麦条锈菌夏孢子的适宜萌发温度在12～16℃之间,平均萌发率为59.09%;高海拔和低海拔地区小麦条锈菌夏孢子都存在芽管融合和孢子融合现象,其中高海拔地区小麦条锈菌夏孢子的异核率为6.13%,超过了其无性阶段变异的阈值1%。与夏孢子萌发相关的10个温敏基因在不同海拔地区小麦条锈菌夏孢子中的表达趋势不同,其中,与能量代谢相关的葡萄糖转运蛋白基因和低亲和力磷酸转运蛋白基因在高海拔地区小麦条锈菌夏孢子中的表达量高于低海拔地区小麦条锈菌夏孢子,与毒性变异相关的易化因子超家族（major facilitator superfamily,MFS）转运蛋白基因在高海拔和低海拔地区小麦条锈菌夏孢子中的表达模式均呈上升趋势。表明由于海拔...     

甘肃陇南感病小檗在小麦条锈病发生中起提供(初始)菌源作用的直接证据

陇南是中国小麦条锈菌易变区、小麦条锈病的常发流行区和防治的关键地区.明确陇南小麦条锈菌转主寄主小檗在小麦条锈病发生中的作用,对阐释该地区小麦条锈菌新小种产生的来源和指导小麦条锈病的综合防控具有重要意义.本研究从陇南春季自然受锈菌侵染的堆花小檗及其邻近的小麦上分离获得小麦条锈菌菌系,19个来自发病小檗的单夏孢子堆菌系在中...     

不同培养载体对小麦条锈菌夏孢子人工萌发的影响

为探索适合小麦条锈菌寄主体外萌发的载体,并建立基于不同研究目的的小麦条锈菌夏孢子人工萌发技术,采用超声波水雾培养法,以小麦条锈菌生理小种CYR32为供试材料,探讨了不同培养载体对小麦条锈菌夏孢子萌发特性的影响.在最适温度和湿度条件下,以4种不同材料为培养载体,小麦条锈菌夏孢子的萌发率、芽管生长率和外观显示情况有显著差异.在尼龙纱网上的夏孢子萌发速度和芽管伸长速度最快,12 h内萌发率最高可达93.40％,芽管最长可达446.71 μm;亲水滤膜上夏孢子的萌发率和芽管长仅次于纱网;亲水塑料膜和PVDF膜上夏孢子的萌发率均高于普通亲水载玻片,而芽管长度低于普通亲水载玻片.采用侧光照明时,在亲水滤膜和PVDF膜上极易清晰观测到夏孢子及其芽管内的黄色颗粒物.在亲水塑料膜上,还可观察到夏孢子萌发12 h后,芽管尾部膨大形成类似附着胞的结构.结果显示,超声波水雾可使条锈菌夏孢子处于水分饱和的环境,而纱网纤维组成的小格具有很好的保水结露功能,能使夏孢子萌发快,萌发效率高,芽管生长快;另一方面,使用其他培养载体还可满足观测条锈菌夏孢子内黄色颗粒物向芽管内转移和芽管尾部形成类似附着胞结构的目的.     

小麦锈菌夏孢子经盐酸处理后的形态观察

为了快速区分小麦条锈菌、叶锈菌和秆锈菌,用不同浓度的盐酸处理3种小麦锈菌的新鲜夏孢子和在4 ℃冰箱内保存4个月以上的锈菌夏孢子,在显微镜下观察夏孢子形态以及原生质体变化。结果表明, 24.5%、28.5%、32.5%、36.5%4种浓度的盐酸处理条锈菌夏孢子后其原生质体均浓缩成多个分散的小团。而同样方法处理叶锈菌和秆锈菌新鲜菌种时其原生质体浓缩成一个大团或多个小团,浓缩成一个大团的比例随盐酸浓度的增大而提高;用不同浓度盐酸处理保存4个月以上的2种小麦锈菌时,95%以上的夏孢子原生质体浓缩成多个分散的小团,少数（不超过5%）的夏孢子原生质体浓缩成一个大团。研究还发现叶锈菌和秆锈菌夏孢子活力、盐酸浓度等对夏孢子原生质体浓缩状况有很大影响,且与病菌生理小种有一定的关系。因此,锈菌夏孢子经36.5%浓盐酸处理后的原生质体浓缩状况只能作为小麦锈病田间快速诊断检测的辅助手段,不能作为锈病种类鉴别的唯一标准,必须结合病害症状特征、孢子形态以及分子生物学方法等进行综合判别。     

新疆玉米病害新纪录-玉米普通锈病症状及病原形态特征

报道了2007年发生在新疆奇台县玉米上一种新病害玉米普通锈病症状及病原特征。对该病的症状及病原形态作出了详尽地描述,并与玉米上已知的其他两种锈菌的形态进行了缜密的比较研究与评述。根据病原的形态特征,确定了奇台县玉米的叶锈病病原应为高粱柄锈菌（Puccinia sorghi Schw.）。研究者发现该病原冬孢子柄的长度及其与冬孢子体长的比是判别与其相似的玉米多堆柄锈菌（P. polysora Underw.）的关键而稳定的特征。即冬孢子柄长度大于冬孢子体长1倍以上者鉴定为高粱柄锈菌,相反冬孢子柄长度小于冬孢子体长1倍以上者鉴定为多堆柄锈菌。     

甘谷县春季空气中小麦条锈菌孢子动态的监测及其与气象因素的相关性分析

为了解甘谷县春季空气中小麦条锈菌Puccinia striiformis f.sp.tritici夏孢子的动态变化、孢子密度与病情的关系以及气象因素对孢子密度和病情的影响,利用孢子捕捉器和定量PCR法对2013—2015年春季甘谷县南山和北山地区空气中小麦条锈菌夏孢子密度的动态变化进行监测,同时调查病情和记录相同时间段的气象因素,并利用Pearson和Spearman等级相关进行相关分析。结果显示,甘谷县南山和北山地区春季夏孢子动态变化趋势相似,均在5—6月出现孢子密度的峰值。南山和北山地区空气中的孢子密度与各地区田间病情指数显著相关,且相关系数分别达到0.851和0.931。除2013年外,空气中孢子密度与温度、光照呈正相关,而与相对湿度、降水量呈负相关;南山地区田间病情指数与光照、温度和降水天数显著相关,北山地区田间病情指数则仅与平均相对湿度显著相关。根据空气中小麦条锈菌夏孢子的监测并结合当地的气象因素有助于制定合理的病害防治策略,实现对小麦条锈病的定点和定期防治。     

紫外线照射对小麦条锈菌生物学效应的研究

以紫外线(UV)不同剂量照射小麦条锈菌夏孢子,结果表明,其严重削弱夏孢子的存活,剂量效应曲线无明显肩区和尾指数区,小表条锈菌夏孢子对低剂量照射较为敏感;经紫外线照射的夏孢子接种小麦感病品种,其致病性发生改变,潜伏期延长,反应型降低,严重度减少;亦降低了小麦条锈菌的繁殖能力,单叶孢子堆数量减少,孢子堆长度变短,产孢量降低,产孢期缩短。这些生物学效应随照射剂量增加而加强。     

紫外线照射对小麦条锈菌生物学效应的研究

 以紫外线(UV)不同剂量照射小麦条锈菌夏孢子,结果表明,其严重削弱夏孢子的存活,剂量效应曲线无明显肩区和尾指数区,小表条锈菌夏孢子对低剂量照射较为敏感;经紫外线照射的夏孢子接种小麦感病品种,其致病性发生改变,潜伏期延长,反应型降低,严重度减少;亦降低了小麦条锈菌的繁殖能力,单叶孢子堆数量减少,孢子堆长度变短,产孢量降低,产孢期缩短。这些生物学效应随照射剂量增加而加强。     

红花锈病菌的生物学特性及侵染研究

 本病为害特征为叶片干枯,植株早衰,含油量下降,地下茎感染,使许多病株在营养期萎蔫死亡。初侵染源——冬孢子粘附于种子表面和冠毛上;散落田间时也能侵染。冬孢子人工接种下侵染真叶,但田间自然条件下不起作用。新鲜冬孢子有少量萌发,隔年冬孢子萌发率明显提高。冬孢子萌发温度极限为10至33℃,适温18至28℃,最适温度为25℃。冬孢子水滴上萌发率低,红花幼苗榨出液具激发作用;而夏孢孢子水滴上萌发远高于榨出液。冬孢子干藏可存活两年.夏孢子残存期可延续166天以上。共鉴定87份红花种质抗病性,差异很显著,但无一表现免疫。     

我国小麦条锈菌体细胞遗传重组的分子证据

 小麦条锈病是影响我国小麦生产的重要病害之一,条锈菌毒性变异是引致小麦品种抗病性丧失的主要原因。本文应用SSR分子标记技术,研究了陇南越夏区小麦条锈菌群体遗传结构,以期寻找条锈菌群体遗传重组的分子证据。研究结果表明,陇南地区小麦条锈菌群体遗传多样性比较丰富而遗传分化较小,遗传变异主要存在于群体内部,而在群体之间,遗传多样性有显著的差异。在11对SSR引物中,有4对能够检测到陇南地区小麦条锈菌群体存在遗传重组,而且重组体出现的频率不同,CPS15揭示的条锈菌重组体出现的频率为20.0%,CPS34揭示的条锈菌重组体出现的频率为18.5%,RJ20揭示的条锈菌重组体出现的频率为12.8%,RJ18揭示的条锈菌重组体出现的频率为15.0%,陇南地区小麦条锈菌群体重组体出现频率平均为16.6%。本文揭示的遗传重组现象表明陇南地区条锈菌体细胞结合十分普遍,由此推测我国小麦条锈菌在自然条件下通过遗传重组而导致毒性变异的可能性。     

2010年西藏小麦条锈菌生理小种群体结构与分析

西藏地区是中国相对独立的小麦种植区,小麦条锈病是西藏冬小麦上最重要的病害.长期以来,对西藏小麦条锈菌生理小种群体结构缺乏全面系统的了解.为了弄清西藏小麦条锈菌生理小种群体结构,本研究从西藏地区小麦条锈病发生的关键地区采集并鉴定了小麦条锈菌标样261份.西藏地区小麦条锈菌群体结构复杂,小种类型数多,主要优势小种以CYR32和CYR33为主,水源11类群为优势类群,Hybrid46类群结构简单,未发现CYR32以外的类型;CYR32之前的小种数较多、其中CYR17、CYR20、CYR31出现频率较高;西藏小麦条锈菌群体结构与内地有着较大的相似性,同时也有其自身的独特性,表现西藏小麦条锈菌优势小种组成与四川、云南两省相似,与青海省差异较大.推测西藏地区小麦条锈菌与四川和云南省存在较密切的菌源交流,与青海省交流较少.     

Removal of urediniospores of brown (Puccinia recondita f.sp. tritici) and yellow (P. striiformis) rusts of wheat from infected leaves submitted to a mechanical stress

The passive spore removal from colonies due to mechanical stress was compared in the brown (Puccinia recondita f.sp. tritici) and yellow (P. striiformis) rusts of wheat. Mechanical stress was applied using either a miniaturized wind tunnel or a centrifuge. In wind-tunnel experiments, a wind of minimum velocity of 1.3 and 1.8 m s^-1 for P. recondita f.sp. tritici and P. striiformis, respectively, applied for at least 10 seconds, was necessary to remove spores. The interaction between wind velocity and cumulated duration was significant for both rusts. At low wind velocity, a longer duration was required to remove the spores than at high wind velocity, and vice versa. In centrifugation experiments, the maximum spore removal occurred for angular velocities of 10³ and 2 10³ rotations min^-1, for P. recondita f.sp. tritici and P. striiformis, respectively, applied for 5 min. Calculation of the aerodynamic and centrifugal forces showed that the forces necessary to remove spores are greater for P. striiformis than for P. recondita f.sp. tritici. This difference can be related to the size of the dispersal unit, which is larger in P. striiformis than in P. recondita f.sp. tritici due to spore clustering. These observations are consistent with the differences in the mean spore dispersal distance, which is usually smaller in P. striiformis than in P. recondita f.sp. tritici.     

Genetic analysis and molecular mapping of wheat genes conferring resistance to the wheat stripe rust and barley stripe rust pathogens

ABSTRACT Stripe rust is one of the most important diseases of wheat and barley worldwide. On wheat it is caused by Puccinia striiformis f. sp. tritici and on barley by P. striiformis f. sp. hordei Most wheat genotypes are resistant to P. striiformis f. sp. hordei and most barley genotypes are resistant to P. striiformis f. sp. tritici. To determine the genetics of resistance in wheat to P. striiformis f. sp. hordei, crosses were made between wheat genotypes Lemhi (resistant to P. striiformis f. sp. hordei) and PI 478214 (susceptible to P. striiformis f. sp. hordei). The greenhouse seedling test of 150 F(2) progeny from the Lemhi x PI 478214 cross, inoculated with race PSH-14 of P. striiformis f. sp. hordei, indicated that Lemhi has a dominant resistance gene. The single dominant gene was confirmed by testing seedlings of the F(1), BC(1) to the two parents, and 150 F(3) lines from the F(2) plants with the same race. The tests of the F(1), BC(1), and F(3) progeny with race PSH-48 of P. striiformis f. sp. hordei and PST-21 of P. striiformis f. sp. tritici also showed a dominant gene for resistance to these races. Cosegregation analyses of the F(3) data from the tests with the two races of P. striiformis f. sp. hordei and one race of P. striiformis f. sp. tritici suggested that the same gene conferred the resistance to both races of P. striiformis f. sp. hordei, and this gene was different but closely linked to Yr21, a previously reported gene in Lemhi conferring resistance to race PST-21 of P. striiformis f. sp. tritici. A linkage group consisting of 11 resistance gene analog polymorphism (RGAP) markers was established for the genes. The gene was confirmed to be on chromosome 1B by amplification of a set of nullitetrasomic Chinese Spring lines with an RGAP marker linked in repulsion with the resistance allele. The genetic information obtained from this study is useful in understanding interactions between inappropriate hosts and pathogens. The gene identified in Lemhi for resistance to P. striiformis f. sp. hordei should provide resistance to barley stripe rust when introgressed into barley cultivars.     

5种药剂对小麦光腥黑穗病菌的毒力和孢子萌发形态结构的影响

采用琼脂平板孢子萌芽法测定了卫福 200、多菌灵、烯唑醇、戊唑醇和三唑酮5种药剂对小麦光腥黑穗病菌的抑制作用和毒力,同时检测了药剂对病菌冬孢子萌发形态结构的影响。结果表明,5种药剂在一定浓度范围内对病菌孢子萌发抑制作用随着药剂浓度提高而增强,对病菌的EC50分别为 1.6102、0.3038、4.4892、1.6103和 0.3896mg·L-1,多菌灵对光腥黑穗病菌的毒力高于其它4种供试药剂。通过光学显微镜和扫描电子显微镜观察表明,药剂作用下光腥黑穗病菌孢子萌发出现3种类型畸形,导致正常发育受到抑制。     

进境小麦中沙地牧草腥黑粉菌的鉴定

从上海口岸进境的澳大利亚小麦中发现一种类似小麦印度腥黑粉病菌的腥黑粉菌冬孢子，对该菌冬孢子进行了形态学特征和PCR检测，根据结果，将这种冬孢子鉴定为沙地牧草腥黑粉菌Tilletia ehghartaTle；本研究设计了T．ehrhartaea的特异引物Eh2/Eh4，结合引物Till／Til4建立了T．ehdmrtae的套式PCR检测方法。     

感染“中四”小麦条锈菌T4新菌系的致病范围测定

 为研究T4新菌系对我国条锈病流行区后备及生产品种、中四后代品种（系）的致病范围,预测T4新菌系对我国未来条锈菌群体结构的影响。在苗期和成株期,用T4菌系对供试品种进行了抗病性鉴定。结果表明：T4新菌系对我国条锈病流行区后备品种和陕西省生产品种致病范围较窄,毒性较弱;而对含有“中四”血缘的小麦品种（系）有较强的毒性,几乎能感染所有供试的“中四”衍生系品种。在现有生产品种大面积种植下,T4新菌系暂时不会构成对现有品种的威胁;但随着“中四”后代品种大面积种植,感染“中四”条锈菌新菌系将对我国条锈病持续控制构成潜在威胁,必须加强对新菌系的监测。     

Survival of Tilletia indica teliospores under European soil conditions

As part of developing a European Pest Risk Analysis (PRA) for Tilletia indica , the causal agent of Karnal bunt of wheat, teliospore survival studies were done outside under quarantine containment at three European sites (Norway, UK, Italy). At each site, experiments were set up in three consecutive years (Experiments 1, 2 & 3) to determine teliospore survival over time (1–3 years) at 5, 10 and 20 cm depths. Experiments were sampled annually and survival assessed in relation to teliospore recovery and to germination at recovery (T0) and 3 months after recovery in case of burial-induced dormancy ( T3 ). Teliospores survived at all three sites at all depths over all the time periods studied. At each site, there was no evidence of a marked decline in teliospore recovery between sampling years, except in one set of years in one Norwegian experiment. There was no consistent effect of depth on recovery. In general there was little evidence for a marked decline in teliospore germination between sampling years. There was some evidence of a decrease in germination with increasing depth in the UK, and for some time-depth interactions. After 3 years' incubation (Experiment 1), mean teliospore recovery and mean germination were: UK: 61% recovery and 31% ( 33% ) germination for T0 (and T3 ); Italy: 30% recovery and 36% ( 29% ) germination; and Norway: 12% recovery and 19% ( 49% ) germination. Germination for laboratory controls ranged from 20–59% (UK), 18–41% (Italy) and 28–59% (Norway). There was no evidence for burial-induced dormancy except in Norway. Teliospores of T. indica can survive for at least three years in European soils. This prolonged period of survival could support establishment of the pathogen if it were introduced into areas of European cereal production.     

Attempted somatic hybridization of Puccinia striiformis f. sp. tritici and P. striiformis f. sp. hordei

Attempts were made to produce somatic hybrids between isolates of Puccinia striiformis f. sp. tritici and f. sp. hordei. A mixed infection was produced on a common susceptible barley host, Fong Tien, using white-spored isolates of P. striiformis f. sp. tritici and yellow-spored isolates off. sp. hordei. Selection was made for non-parental spore colour on selective wheat and barley hosts, and variants thus isolated were analysed for virulence markers, and for isozyme and double-stranded RNA (dsRNA) markers, all of which clearly differentiated the parental isolates. Two white-spored (non-parental) isolates were found on the selective barley host which otherwise resembled the parental f. sp. hordei isolate in virulence, isozyme and dsRNA markers. The most likely explanation of the origin of these isolates is mutation to white spore colour in the f. sp. hordei isolate.