中日美栗疫病菌群体遗传结构比较

采用RFLP技术 ,对中日美 3国的 2 6个子群体共 75 7个栗疫病菌菌株的核DNA进行了群体遗传结构分析。结果表明 ,栗疫病菌的中国子群体间遗传结构有明显的分化 ,日本子群体间的遗传结构差异不明显 ;在美国和亚洲的栗疫病菌群体间没有发现基因流的迹象 ;美国栗疫病菌群体的遗传结构与日本群体的关系比较密切 ,而与中国群体间的差异较大。     

栗疫菌弱毒力特征的传递及其影响因素

栗疫菌 (Cryphonectriaparasitica)弱毒力 (hypovirulence)的本质是菌体中含有一种弱毒性病毒 (cryphonectriahypovirulenceviruses ,CHV)dsRNA(Choietal,1992 ;Morrisetal,1979)。栗疫菌的弱毒力菌株 (H菌株 )一般都具有将强毒力 (virulent)菌株 (V菌株 )转化为弱毒力菌株的能     

韩国、美国和中国栗疫病菌的遗传变异分析

用RAPD方法,对来自韩国、美国和中国的26个栗疫病菌菌株进行了遗传变异分析.使用筛选的12个随机引物,共扩增了115个0.19～3.1 kb大小的扩增片段,其中多态性片段占61.7%.聚类分析结果,相似系数为0.92时,26个菌株分为两大组,一组由21个菌株组成,包括大部分韩国菌株和美国菌株;另一组包括部分韩国菌株和中国菌株.表明美国菌株和大部分韩国菌株的遗传相似性很高,部分韩国菌株有较大的变异,而中国菌株则表现出了遗传上的远缘关系.     

基于ITS和β-tubulin基因分析的居间疫霉菌系统发育

【目的】对我国亚热带部分森林中的疫霉菌及其所致病害进行了系统调查和分析,研究疫霉菌的种类和遗传多样性,探讨疫霉菌的系统发育关系,为林木疫病的防治提供理论依据。【方法】利用健康叶片诱捕林间溪流里的疫霉菌,对有症状的叶片组织进行分离纯化,显微镜下根据其菌丝分枝和结构特征,初步判定为疫霉菌。对菌株的ITS和β-tubulin基因进行PCR扩增和测序,将序列拼接后,用MAFFT 7.0、PAUP 4.0 beta10、Mr Bayes 3.2.6及PhyML 3.0等软件进行基因序列系统发育分析。【结果】分离鉴定得到46株中国新记录种,通过进一步培养和显微镜下观察,其形态特征与居间疫霉菌Phytophthora intercalaris相吻合。拼接之后得到完整的ITS序列为847~849 bp,与参考菌株(KT163268)序列一致性为99.29%~99.53%;β-tubulin序列均为882 bp,与参考菌株(KT163336)序列一致性为99.43%~99.66%。系统发育分析结果显示供试菌株与居间疫霉菌以100%的支持率聚为一支。本研究不仅增加了居间疫霉菌的菌株数量,也扩大了该菌的分布范围,同时也增加了中国疫霉菌的种类。【结论】居间疫霉菌种内不同地理来源的菌株之间具有较高的序列一致性,但是也存在一些碱基的差异,从而形成不同的基因型。     

板栗野生居群与栽培品种间叶绿体微卫星遗传差异初探

对24对epSSR通用引物进行筛选,选用4对呈现多态性的引物对板栗的4个野生居群和9个地方品种群进行遗传分析.结果表明:4个位点在128个样本中扩增等位基因数(Na)平均为3,有效等位基因数(Ne)平均为1.635,期望杂合度(He)平均为0.381,各遗传参数值远低于核基因组对群体研究的相应值.4个等位基因共组合出8种单倍型,既有共享率超过57%的单倍型,也存在特异稀有单倍型,其中陕西汉中与安徽广德板栗天然野生居群,具有较高的单倍型多样性,分别为0.671和0.781,明显高于其他地区,显示两地是板栗的分布及遗传多样性中心.基于cpSSR数据,对板栗地方品种与天然野生居群间的遗传结构、关系及地方品种的起源进行初步探讨.     

GFP标记的4种链格孢菌对枣树的侵染研究

【目的】进一步探寻引起枣缩果病的潜在侵染性病原,为枣缩果病的有效防治提供理论依据。【方法】选取苹果斑点落叶病菌、梨黑斑病菌、马铃薯早疫病菌和番茄黑斑病菌为供试菌株,测定其对潮霉素B的敏感性后再进行GFP标记,并以枣缩果病互隔链格孢菌作为对照,将通过稳定性测试的菌株进行幼果刺伤接种和枣树花期喷雾接种试验,探明它们在枣树上的侵染途径。【结果】苹果斑点落叶病菌、梨黑斑病菌、马铃薯早疫病菌和番茄黑斑病菌对潮霉素B均较敏感,其有效中浓度EC50值分别为1.489、2.241、3.299和2.873μg·m L~(-1),4种链格孢菌均被GFP成功标记且其稳定性均良好;林间刺伤接种苹果斑点落叶病菌、梨黑斑病菌、马铃薯早疫病菌、番茄黑斑病菌和互隔链格孢菌(对照)的枣果均发病且其症状相同,其发病率分别为75.0%、87.5%、81.3%、83.3%与93.8%;将各处理病果的病组织放在含有10μg·mL~(-1)潮霉素B的PDA培养基上培养后,其均有菌丝生长,且均可观察到带有荧光的菌丝;花期喷雾接种4种链格孢菌和互隔链格孢菌后,枣果均发病,将其病组织分离培养后均有菌丝长出,且在荧光显微镜下均可观察到荧光。【结论】苹果斑点落叶病菌、梨黑斑病菌、马铃薯早疫病菌和番茄黑斑病菌均能侵染枣树,都有可能成为枣缩果病的潜在病原菌,因此,在枣树周围应避免种植上述易被链格孢菌危害的果树和作物,这样可以阻止链格孢菌的侵染。     

松球壳孢菌的致病性研究

实验证明 ,国内供试松球壳孢菌 (Sphaeropsissapinea)的致病力明显高于美国的B型菌株 ,与A型相似 ,致病性较强。B型也能无伤侵入 ,只是发病率明显低于A型。伤口并不是病菌侵入的唯一途径 ,自新梢伸长至针叶发育完全期间 ,病菌可直接侵入树木当年嫩梢并使之枯萎 ;此后 ,随着梢部组织的不断成熟与老化 ,伤口对病菌侵入与危害的作用才得以显现出来 ,无伤接种时不发病或只产生部分枯叶。气孔也是病菌侵入的途径之一。病菌不但可侵入当年新稍 ,而且还可于枝梢的 2a和 3a生处有伤侵入 ,使之染病甚至死亡。油松(Pinustabulaeformis)、赤松 (P .densiflora)、彰武松 (P .densifloravar .zhangwuensis)较樟子松 (Pinussylvestrisvar.mongolica)抗病 ,且彰武松主要表现为“耐病”。幼龄的樟子松较大龄的抗病。树势削弱的枝梢抗病性能降低 ,发病快而重。潜育期和繁殖期的长短与寄主、树势、组织的成熟程度和气温等有关     

Diversity of vegetative compatibility types,distribution of mating types and occurrence of hypovirulence of Cryphonectria parasitica in chestnut stands in NW Spain

An extensive survey on chestnut stands in NW Spain was carried out to study the population biology of Cryphonectria parasitica in order to design future biological control programmes of chestnut blight based on the field introduction of native hypovirulent strains. Five hundred and thirty-nine Cryphonectria parasitica isolates, belonging to five populations (A Coruña, Lugo, Ourense, Pontevedra and León), were obtained. The diversity of vegetative compatibility was very low. Six vc types were found, each population showing only from 2 to 4 vc types. Two vc types were the known European testers EU1 and EU66, and the other four were undescribed vc types that were named E1, E2, E3 and E4. E1 was the dominant vc type in Lugo and Ourense populations, and EU1 in Pontevedra and León. Hypovirulent isolates (a total of 15) were only detected in the León population, all but one being compatible with the vc type EU1. Hypovirulent strains belonged to the French subtype F1 of the Cryphonectria hypovirus-1 (CHV1).     

不同产区板栗病原菌的种类及其致病力研究

从北京、山东、河北、湖南、湖北、江西、安徽、广西等板栗主产区的腐烂栗实中分离出146个分离物,经鉴定归属于11个属。不同产区栗实的自然带菌情况各异,带菌量和带菌种类有所不同,南方板栗产区的病原菌种类多于北方产区。回接实验研究了其中分布较普通的6个属优势菌的致病力,表明不同菌的致病力强弱有较大差异,在相同培养条件下,Rhixoctoria使种仁的发病程度最严重,致病力最强,Penicillium sp.的致病力最弱。不同接种方式对种仁侵染率的影响不同,种仁有伤接种的侵染率最高,达90％以上,而种皮接种和无伤滚动浸涂接种则不会使种仁发病腐烂。研究中还发现,不同病原菌所致板栗腐烂的病斑特征有所不同。     

特有种野生血皮槭的生长状况

血皮槭(Acer griseum(Franch)Pax)是无患子科(Sapindaceae)槭树属(Acer)落叶乔木,为我国特有种。其树干赭褐色,树皮卷曲状剥落,秋季叶色红艳或黄色,是世界著名的观赏树种。1901年,西方植物学家威尔逊在湖北发现血皮槭,将其和珙桐一起作为园林树种引入欧洲[1],继而血皮槭又被引入美国等其他西方国家。1993年,血皮槭获得英国皇家园艺学会园艺奖,目前在国外用于庭院观赏。血皮槭不仅具有观赏价值,而且具有用材和药用价值[2-3]。血皮槭在2004年出版的《中国物种红色目     

The effects of logging and disease on American chestnut

Disturbance histories drive spatiotemporal patterns of species distributions, and multiple disturbances can have complex effects on these patterns of distribution. The introduction of the chestnut blight (Cryphonectria parasitica (Murril.) Barr.) to the eastern United States in the early 1900s coincided with an increase in logging, thus presenting an ideal situation for studying the effect of two disturbance events, logging and disease. The purpose of this study was to compare chestnut (Castanea dentata) abundance and the prevalence of chestnut blight among (1) sites that were and were not logged for chestnuts during the blight pandemic and (2) sites that varied in time since the last logging event. Current chestnut abundance and chestnut blight prevalence were assessed in areas where chestnut was known to occur before the blight. Elevation, soil pH, slope, aspect, age of canopy trees, and presence or absence of chestnut stumps indicating selective logging of chestnuts were recorded at each site. Chestnuts were more abundant on sites that had not been selectively logged for pre-blight chestnuts. Chestnut presence was more likely at high elevations (857 m ± 33 m). Chestnut abundance was greater at high elevations (>1000 m) and acidic soils (pH 4-5). Chestnut blight prevalence was not correlated with any measured environmental variable. Rather, 15.1% of all chestnut stems were infected with blight regardless of chestnut density. Thus, higher chestnut abundance is not due to lower mortality from the chestnut blight, although the temporal dynamics of blight infection and stem recovery were not within the scope of this study. This research shows that local rates of chestnut population decline differ between locations with different chestnut logging histories. Chestnut site preferences are better understood within the context of history, and thus teasing apart the effects of disease, logging, and environment will result in more successful chestnut restoration efforts.     

Mechanisms and metabolomics of the host–pathogen interactions between Chestnut (Castanea species) and Chestnut blight (Cryphonectria parasitica)

Chestnut blight is a stem‐girdling disease of Castanea caused by the fungal pathogen Cryphonectria parasitica. Chestnut blight affects all Castanea species to some degree. In Asian species, chestnut blight is a commercially relevant disease which primarily affects nut production. In American and European species, chestnut blight has caused significant declines in wild populations and continues to negatively affect nut production in the European chestnut (C. sativa). Despite the profound effect of this disease in the Castanea genus, very little is known concerning the factors involved in the host–pathogen interaction between C. parasitica and its Castanea hosts. This review summarizes information on known mechanisms and metabolites involved in the host–pathogen interaction and contributes original information on the pathogen in relation to susceptible and putatively resistant genotypes with a view to furthering research that will promote a better understanding of this devastating disease and enable its control.     

禄劝板栗疫病防治技术研究

板栗疫病是世界性栗树病害之一。云南省禄劝县2005年发现板栗疫病,通过对板栗疫病全面调查和防治,提出板栗疫病的综合防治措施,有效控制病害,提高栗农的经济收入。     

Variations in Disease Resistance of Chestnut Cultivars against Chestnut Blight Fungus,Cryphonectria parasitica

INTRODUCTION Chestnut trees cultivated worldwide are planted as fruit tree in Korea and the area is increasing annually. In the 1970s, chestnut trees were enormously planted in many provinces in Korea. However,chestnut blight occurred and increased due to lack of disease management and the aging of the trees. Blight caused by Cryphonectria parasitica is a kind of important disease and occurred in oak and maple. American chestnut is more susceptible to this pathogen than Korean or Japane…     

Low genetic diversity but frequent sexual reproduction of the chestnut blight fungus Cryphonectria parasitica in Azerbaijan

Chestnut blight was first recorded in Azerbaijan on the native European chestnut (Castanea sativa) in 2004, and since then, the disease is expanding in the country. In this study, chestnut blight was detected in seven of eight forest districts that were inspected. To characterize the local population structure of the chestnut blight fungus, 199 Cryphonectria parasitica isolates were collected and assessed for vc type, mating type and microsatellite genotype. Among these isolates, one dominant vc type was detected comprising 93% of the isolates. Six additional vc types were identified among the other isolates. The microsatellite analysis revealed a very similar pattern with 96.5% of the isolates belonging to the same multilocus genotype. Both mating types of C. parasitica were present in all seven districts with a mating type ratio not different from 1:1 in five districts. In accordance with the occurrence of both mating types, sexual fruiting bodies (perithecia) of C. parasitica were found in all districts with an overall prevalence on 20.6% of the cankers. The dominant vc type and microsatellite genotype in Azerbaijan do not occur in Europe, but have previously been found to be widespread in neighbouring Georgia. Our study reveals that sexual reproduction in the invasive C. parasitica population in Azerbaijan is frequent, although the population shows a low genetic diversity. This could favour the biological control of chestnut blight using hypovirulence, which so far does not seem to be present in Azerbaijan.     

明清板栗古树遗传多样性的SSR分析

正板栗(Castanea mollissima Blume)属于壳斗科(Fagaceae)栗属(Castanea Miller)植物,广泛分布于全国23个省(区、市)[1],年产量约213.2万吨,是我国的传统木本粮食树种和优势经济林树种。北京是华北品种群的主要分布区,板栗主要分布于怀柔、密云、昌平、延庆、房山等地,其中怀柔地区板栗栽培历史非常悠久,分布着丰富的古板栗资源,据专家考