中国咖啡锈菌(Hemileia vastatrix)生理小种研究

对我国云南、海南和广东咖啡植区收集到的58个咖啡锈菌菌株标本进行生理小种鉴定,鉴定出小种有7个。各咖啡植区除共同出现Ⅱ号生理小种外,云南咖啡植区还出现Ⅰ,XV,XXIII和XXIV号生理小种;海南则出现VI和XXII号小种;广东咖啡栽培地区未发现有新的生理小种。各咖啡植区新生成的生理小种种类有明显不同。     

中国咖啡锈菌（Hemileia vastatrix）生理小种研究

对我国云南、海南和广东咖啡植区收集到的５８个咖啡锈菌菌株标本进行生理小种鉴定，鉴定出小种有７个。各咖啡植区除共同出现Ⅱ号生理小种外，云南咖啡植区还出现Ⅰ，ＸＶ，ＸＸⅢ和ＸＸⅣ号生理小种；海南则出现Ⅵ和ＸＸⅡ号小种；广东咖啡栽培地区未发现有新的生理小种。各咖啡植区新生成的生理小种种类有明显的不同。     

菜豆炭疽菌生理小种鉴定及普通菜豆种质的抗性评价

对来源于黑龙江、吉林、内蒙古、河北、云南等8个省（市）的15个菜豆炭疽菌分离物进行生理小种鉴定,鉴别出5个菜豆炭疽菌生理小种,其中81号小种出现的频率高达67％,是中国的优势小种。用81号小种对181份菜豆进行抗性鉴定,发现高抗材料2份,抗病材料43份,高感材料33份,说明我国菜豆种质资源对炭疽菌81号小种抗感差异显著,抗病资源丰富。     

海南省香蕉枯萎菌生理小种的RAPD分析

利用随机扩增多态性DNA(RAPD)分子标记方法对海南省香蕉枯萎病菌2个生理小种(小种1和小种4)进行遗传多样性分析,以筛选出的15个随机引物对采自海南省各市县发病蕉区的分别属于1号生理小种和4号生理小种的16个代表菌株及广东省2个1号和4号生理小种对照菌株进行RAPD-PCR扩增,结果产生97个RAPD分子标记,其中多态性的条带有76条,通过聚类分析探讨了供试小种间的亲缘关系,并寻找到了1、4号生理小种的特异性条带,为在分子水平上进行香蕉枯萎病菌生理小种鉴定提供更为便利的手段。     

基于多基因序列分析对尖孢镰孢菌古巴专化型（香蕉枯萎病菌）生理小种的鉴定

由尖孢镰孢菌古巴专化型Fusarium oxysporum f. sp. cubense, Foc引起的香蕉枯萎病是香蕉生产上的毁灭性病害,自1996年以来已对我国华南地区香蕉生产造成了严重危害。传统上香蕉枯萎病菌生理小种的鉴定主要采用人工接种鉴别寄主尔后测定病菌致病性的方法,但实验周期长,且受季节影响。以来自澳大利亚的香蕉枯萎病菌生理小种1号（BW1）、2号（Race 2）、3号（Race 3）以及亚热带4号（BW4）为对照,对分离自我国华南地区主要香蕉产区（广东、广西、海南、福建等省区）的14株香蕉枯萎病菌的单孢菌株进行致病性测定,并结合热带4号小种（TR4）和亚热带4号小种（ST4）的分子特异检测方法,确定其生理小种类型;同时,利用ITS、TEF-1α、IGS、histone H3、β-tubulin等 5个主要用于镰孢菌系统发育学研究的基因,研究不同地区不同来源的Foc菌株之间的亲缘关系及其与非病原尖孢镰孢菌的关系,并评价这5个基因在香蕉枯萎病菌生理小种鉴定上的应用价值。研究结果表明：（1）来源于我国华南地区的4号小种主要为热带4号小种;（2）TEF-1α、IGS、histone H3等3个基因片段能够将Foc中不同生理小种的菌株划分成不同的系统发育谱系,与致病性测定的结果具有对应关系,也能较好地反映尖孢镰孢菌种内菌株的亲缘关系,可用于香蕉枯萎病菌生理小种鉴定;（3）我国Foc 1号生理小种的遗传多样性高于4号生理小种,Foc 1号生理小种的菌系与来自香蕉果实上的非病原尖孢镰孢菌的亲缘关系比其与Foc 4号生理小种的菌系的亲缘关系更近。     

河北省西瓜枯萎病菌致病性分化及其RAMS分析

本文对50个西瓜枯萎病菌株,(其中46个来自河北省石家庄、保定、唐山等12个西瓜种植区的代表菌株)进行了致病性测定、RAMS(Random amplified microsatellites)扩增和致病类型与RAMS类群的相关性分析。根据鉴别寄主对不同菌株的抗感反应,将50个菌株划分为3个不同的生理小种,即0号、1号和2号生理小种,分别占供试菌株的18%、64%和18%;21个RAMS引物对供试菌株扩增出188条带,其中多态性带134条,占总带数的71%。基于RAMS标记聚类分析,50个菌株被划分为3个类群(RAMSGroups,RGs)。RGI包含来自不同地区的41个菌株,以1号生理小种为主(32个),占该类群的78.1%;RGII包括来自保定、唐山和新疆的3个菌株,均为0号生理小种;RGIII包括张家口、石家庄、保定等地的6个2号生理小种菌株。RAMS类群与生理小种之间存在一定相关性,与菌株的地理来源关系不明显。     

海南省香蕉枯萎病病原菌的分离鉴定及1号、4号小种的生物学特性

香蕉枯萎病是目前国内和世界很多地区香蕉种植区的一种毁灭性病害,目前尚未找到有效的防治方法.本文采集了海南省不同地区香蕉枯萎病的病原菌,通过经典病理学与分子生物学的方法进行了鉴定,此外还优化了快速检测的方法.结果表明,通过接种巴西香蕉和粉蕉进行致病性检测以及分离菌rDNA-ITS测序结果,明确鉴定出供试的香蕉分离菌株为4号生理小种,粉蕉分离菌株为1号生理小种.为了对1号、4号生理小种有更多的了解,本文还对1号、4号小种菌株生物学特性进行了测定,确定了影响菌丝生长的最佳条件.结果显示,pH 5时最适合1号、4号生理小种的菌丝生长,适合菌丝生长的温度为19～28℃之间,温度达到37℃时菌丝不能生长,碳源对菌丝的生长影响不大.这些方法和数据可以有利于田间香蕉枯萎病病害的检测和最终确定,生物学特性的测定可以为耕作技术的改进和农药的研发提供参考依据.     

黄淮麦区重要小麦品种和种质资源材料的抗条锈性评价

采用苗期分小种和成株期混合优势小种法测定了黄淮麦区227份小麦品种和种质材料对小麦条锈菌的抗病性,结果表明,被测品种在苗期对4个条锈菌生理小种的抗病性有很大的差异,抗条中27、30、31、29号小种的品种分别占被测品种总数的93．00%、72．69%、64．76%和61．67%。成株期用6个菌株混合接种测定选出抗病品种76个,占33．48％,其中免疫的为40个,占17．62%。通过对227份小麦品种资源材料的苗期分小种鉴定及与成株期混合优势小种鉴定结果比较,筛选出了成株期和苗期均抗病的品种48个,占被测品种总数的21．14％;成株期抗病苗期感病的品种30个,占被测品种总数的13．22％。     

大豆抗灰斑病菌多个生理小种资源的筛选

用人工接种大豆灰斑病茼的方法对224份供试材料,在生理小种水平上进行了抗性鉴定,筛选出抗8个以上生理小种的多抗资源47份,占供试材料的20．98％,其中东北农业大学的材料最多,比例达46．81％;黑龙江省主栽品种有5份,占多抗材料的10．64％。供试材料中,有抗单个小种和抗多个甚至全部生理小种的品种,表明在现行大豆品种资源中,具有较丰富的专化抗性资源和广谱性的抗源。     

中国棉花枯萎菌生理小种的RAPD分析*

利用随机扩增多态性ＤＮＡ（ＲＡＰＤ）分子标记方法对我国棉花枯萎菌３个生理小种（３、７、８号）进行遗传多样性分析,以筛选出的１０个随机引物对采自我国１１个省（自治区）的２６个代表菌株及国外３个不同生理小种对照菌株进行ＲＡＰＤ－ＰＣＲ增,共产生了１４０个ＲＡＰＤ分子标记,其中８７．８％具有多态性。通过聚类分析确定了供试小种间的亲缘关系,并寻找到了我国３、７、８号小种的特异条带,为确立我国棉花枯萎菌生理小种在国际上的分类地位提供了可靠的分子证据。     

Molecular and Pathogenic Variation Identified Among Isolates of <Emphasis Type="Italic">Corynespora cassiicola</Emphasis>

Pathogenicity tests and inter simple sequence repeat (ISSR) molecular fingerprinting markers were utilized to analyze 24 Corynespora cassiicola isolates obtained from a lot of Hevea clones grown in most rubber nurseries and a few plantations in China. The C. cassiicola isolates were collected from Hainan and Yunnan provinces, China, from 2006 to 2008. The assay of 24 C. cassiicola isolates on detached leaves of four different Hevea rubber clones (genotypes PR 107, Dafeng 95, RRIM 600, and Reyan 7-33-97) indicated that 23 of the isolates were susceptible to RRIM 600, and were therefore considered race 1 except for CC-023. ISSR analysis grouped 24 C. cassiicola isolates into four clusters (A, B, C, and D). Unweighted pair-group method with arithmetic averaging (UPGMA) analysis based on Nei and Li's coefficient (calculated from the binary matrix data of 103 DNA fragments generated from 16 ISSR primers) indicated that cluster A included 19 isolates from Hainan and Yunnan (this cluster was further divided into two sub clusters (I, II), sub cluster II contained isolate CC-023); clusters B and C comprised of 1 isolates from Hainan, respectively; while cluster D encompassed 3 isolates from Hainan and Yunnan. Pathogenicity tests and ISSR analysis showed that there was no correlation between race structure, the geographical origin of the pathogen and their ISSR clusters because 23 of the isolates belonging to four distinct clusters were considered race 1 except for isolate CC-023. However, most of the isolates with different pathogenicity levels shared the same clades, and furthermore, the ISSR clusters and cology color had an exact correlation. These results should facilitate the development of rubber clones with enhanced resistance against all genetic clusters of C. cassiicola.     

警惕检疫性害虫南洋臀纹粉蚧在中国大陆扩散

南洋臀纹粉蚧,又称咖啡粉蚧、可可粉蚧、紫粉蚧,主要危害饮料作物、果树、蔬菜和园林树木,是新近入侵中国大陆的一种危险性检疫性害虫,2012年以来在中国大陆的云南、海南等地陆续被发现。本文介绍了南洋臀纹粉蚧的识别特征、危害特性、寄主植物种类、生物生态学特点、地理分布范围、传播扩散途径和防治措施等,为预防该虫在我国的进一步蔓延提供依据。     

Detection of Cochliobolus heterostrophus races in South China

Cochliobolus heterostrophus is the causal pathogen of the southern corn leaf blight (SCLB). There are three known races: race O, race C and race T. To determine which C. heterostrophus races comprise the field population in southern China and to assess diversity of these strains in terms of virulence, 200 isolates from diseased plants were collected in nine provinces/municipalities. All were race O, that is, no race T or race C isolates were found. Sixty race O isolates that sporulated well were chosen for further analysis. Virulence was measured using the integral optical density (IOD) of leaf lesions on four maize inbred lines. UPGMA cluster analysis of AFLP markers was applied to the 60 race O isolates plus control race O, T and C strains. Phylogenetic distribution, geographic location and virulence were not correlated. These results can provide valuable information for guidance in early warning and disease control.     

PHYSIOLOGIC RACES OF PHYTOPHTHORA INFESTANS (MONT.) DE BARY IN NORTHERN IRELAND*

By using the detached-leaf technique and Black's series of differential host varieties, seven physiologic races of Phytophthora infestans (Mont.) de Bary have been distinguished as occurring in Northern Ireland. Six were found at the Dunanney potato variety trial plots, namely: race 1; race 2; race 4; race I, 2; race 1,4; and race I, z, 4. The remaining race, race 0, was isolated from the commercial potato crop.
In a survey, comprising seventy-three isolates, of the physiologic races occurring in the commercial potato crop, only race o and race 4 were found (3 and 70 isolates respectively).
Certain modifications to the detached-leaf technique have given improved results, including the formation of normal lesions and the elimination of atypical infections showing sparse sporulation.
The variation in the host-parasite reaction of the detached leaves and the identity of the common race in commercial potato crops are discussed.     

Identification of Gremmeniella abietina Races with Random Amplified Polymorphic DNA Markers

Seven random amplified polymorphic DNA (RAPD) markers amplified from four oligonucleotides (10-mers) by the polymerase chain reaction were used to distinguish between the North American and European races of Gremmeniella abietina, the causal agent of Scleroderris canker of conifers. Forty-three isolates of the pathogen from 11 different host species originating from 11 countries, states, and provinces were tested; race designation was consistent with results from immunogenic and soluble-protein assays. By using RAPD markers, it was possible to identify G. abietina races by DNA amplifications directly from fruiting bodies, thus eliminating the need to culture the fungus, as is necessary with immunogenic and soluble-protein assays. Two isolates which had been previously classified as intermediate were clearly identified as belonging to either one of the two races by using RAPD markers. No interracial hybrids were detected in our survey. Patterns of amplification products from the European race in North America were identical to patterns of European isolates, further substantiating that this is an introduced race to the North American continent.     

Distribution of genetic variability in populations of two chromosomal races of Dichroplus pratensis (Melanoplinae, Acrididae) and their hybrid zone

We examined, through allozyme electrophoresis, the genetic structure of populations of the acridid grasshopper Dichroplus pratensis from two chromosomal races (Northern and Southern) and their hybrid zone in Argentina. No fixed alleles for any particular race were found, although genetic differentiation among parental races was significant (0 = 0.044, 95% CI: 0.004-0.068). Hybrid populations are genetically more similar to the Southern race (0 = 0.008, 95% CI: -0.005-0.018) than to Northern ones (0 = 0.018, 95% CI: 0.002-0.030). Differential viability or fertility of hybrids, or asymmetry in mating preferences in favour of one particular cross would cause a higher proportion of matings between hybrid individuals and those from the Southern race. This would explain the high genetic similarity between those groups, in spite of their geographical vicinity with northern race populations.     

Karyology and Oogenesis of Radopholus similis (Cobb) Thorne

Two morphologically indistinguishable races of Radopholus similis from Florida are presently identifiable only by host preference tests. One race attacks banana and other hosts, but not citrus. The other race attacks both citrus and banana, as well as other hosts. The two races normally reproduce by amphimixis. The morphology of the female reproductive systems of both races were examined and appeared to be identical. However, slight differences were observed in developmental stages of oogenesis between the two races. The two races were distinct with respect to karyotype. There were four chromosomes in the banana race and five chromosomes i n the citrus race. Karyotypic uniformity was found i n the two Florida populations of the citrus race.     

Assessment of genetic diversity of coffee leaf rust pathogen Hemileia vastatrix using SRAP markers

Coffee leaf rust caused by the fungus Hemileia vastatrix (Berk and Br.) is a major disease occurring in coffee plantations. Although the rust fungus exists in different physiological races, the genetic difference between them is meagrely understood. In this study, genetic diversity of 14 identified and two unidentified leaf rust races was determined by sequence‐related amplified polymorphism (SRAP) markers. Of 48 SRAP primer pairs tested, 35 primers are polymorphic and generated 347 distinct scorable fragments. The number of fragments ranged from 4 to 18 with a mean of 9.97 fragments per primer combination. Of the total 347 amplified fragments, 185 fragments (53.31%) are polymorphic with an average of 5.41 fragments per primer combination. The average resolving power (Rp) and the average polymorphism information content (PIC) of the 35 SRAP primer combinations were 13.60 and 0.356, respectively. Of 35 SRAP primer pairs, 15 primer pairs were more informative and generated 25 unique fragments, which are useful for race discrimination. The study demonstrated the existence of genetic variability among various leaf rust races and this information will be helpful in coffee breeding programmes.