东北春玉米区大斑病菌生理小种鉴定

对2005年采自东北玉米主产区的大斑病叶标样进行分离,经单孢纯化后获得56个菌株。通过Ht单基因鉴别寄主接种鉴定,结果表明:东北地区玉米大斑病菌生理分化已呈现复杂化,0号生理小种和1号生理小种分别占35.7%和17.9%,为优势小种,其次为123号生理小种,占12.5%,另外还存在2、3、23、123N、12和23N号生理小种。     

大豆灰斑病菌生理小种鉴定

大豆灰斑病菌生理小种鉴定胡国华，于凤瑶，程显伟，勇健康，栾怀海（黑龙江友谊县农垦科学院红兴隆所１５５８１１）大豆灰斑病（ＣｅｒｃｏｓｐｏｒａｓｏｊｉｎａＨａｒａ）广泛发生于世界大豆产区。１９１５年日本首次发现，我国以黑龙江东部地区发生严重，近年向西移...     

东北春大豆灰斑病菌生理小种鉴定结果初报

 大豆灰斑病病原菌具有高度的变异性,能分化出许多生理小种,美国的Athow 1952年首次报道了大豆灰斑病病原菌的生理分化现象。     

玉米大斑病菌生理小种研究初报

 1980年至1981年两年的试验结果表明:我国玉米大斑病菌存在着两个生理小种,即生理小种1号和生理小种2号。病菌标样采自辽宁、广西、浙江、陕西、黑龙江等地玉米大斑病菌共105个标样,病菌经分离培养接种在具有Ht₁、,Ht₂单基因抗性寄主以及多基因抗性寄主上。测定结果证明:接种在具有Ht₁、Ht₂单基因抗性寄主上表现为褪绿斑的菌株,属于生理小种1号,其毒力公式为Ht₁Ht₂/O (有效抗性基因/无效寄主基因)。接种在具Ht₁单基因抗性寄主上表现有毒力产生萎蔫斑,而对Ht₂鉴别寄主表现无毒力产生褪绿斑的菌株属于生理小种2号,其毒力公式为Ht²/Ht¹。
目前玉米大斑病菌生理小种2号只在辽宁发现,尤以丹东地区出现频率较高。     

玉米小斑病菌生理小种研究初报

 从我国不同地区采集的玉米小斑病菌(Hclminthosporium maydis),通过温室苗期接种鉴定,及其产生的毒素对玉米种子根的抑制作用,发现76-527、76-528和76-529三个分离菌系在T型细胞质雄性不育系幼苗上产生萎蔫型大病斑,而在相对应的正常系以及M、C、CA、EK、D、PS型细胞质雄性不育系幼苗上则产生坏死型小病斑。其中76-529所产生的毒素,对T型细胞质雄性不育系种子根的抑制作用远远大于相对应的正常系,因此,初步认为这些分离菌系类似国外的T小种。而76-361和76-414两个分离菌系对T型细胞质雄性不育系则无上述的特异性。因此,初步认为这些分离菌系类似国外的o小种。     

我国玉米小斑病菌的生理小种

 根据当前我国玉米生产中大面积种植的是以正常细胞质自交系配制的杂交种为主,和各地正在加速研究和发展雄性不育细胞质利用的实际情况,三年来我们用来自国内16个省、市、自治区的181个小斑病菌的标样,通过接种试验,从77个包括T、C、S型细胞质的雄性不育系和正常细胞质的自交系中,初步选出8个自交系建议作为我国玉米小斑病菌生理小种试用的鉴别寄主:T单412-2,TC103,CVa35,C二南二四,MS344,MS05,辽马43,二南二四,应用这套鉴别寄主,可以区分16个生理小种。目前用这套鉴别寄主测试来自国内不同地区的98个标样的结果,已出现12个生理小种。     

小麦白粉病菌生理小种鉴定结果初报

 近年来,我们对小麦白粉病菌生理小种的鉴定方法及我国部分麦区生理小种进行了初步的研究。现将情况简报如下。     

安徽省玉米小斑病菌生理小种鉴定及对烯唑醇的敏感性

玉米小斑病是由玉蜀黍双极蠕孢(Bipolarismaydis)引起玉米叶部发病的病害之一,该病害广泛分布在世界玉米产区,严重影响玉米生产。玉米小斑病菌存在明显生理分化现象,目前已证实在中国存在T、C、S和O共4个小种。由于近年来不育细胞质的感病玉米自交系在玉米育     

云南、贵州玉米大斑病菌生理小种分化研究

玉米大斑病是云南和贵州省玉米生产的重要病害之一。本文对2008年和2009年在云南、贵州采集分离获得的45份大斑病病菌菌株进行了生理小种鉴定,结果在云南共鉴定出12、13、3N、123、12N、13N、23N、123N等8个生理小种,其中123N小种出现频率最高,为30%;在贵州共鉴定出123、13N、23N、123N等4个生理小种,其中123N小种是主要小种类群,占53.3%。云南的大斑病菌菌株对Ht〖STBX〗1〖STBZ〗、Ht2、Ht〖STBX〗3〖STBZ〗和HtN基因的毒性频率分别为73.3%、73.3%、90%和80%,而贵州的菌株则分别为80%、80%、100%和93.3%。两省菌株的毒性随着抗性基因组合的复杂性增加而下降,对4基因组合的毒性频率分别为30%和53.3%;贵州的菌株毒性较云南菌株为高。云南的小种构成较复杂,而贵州小种的毒性更强。     

玉米大斑病菌生理小种温度效应的初步研究

对玉米大斑病菌1号和2号2个小种的4个代表菌株的温度效应研究表明,2个小种在菌丝生长速度、菌丝生长量、孢子产生量以及致病毒素产生量等生物学特性方面的温度效应存在着一定的差异。1号小种对温度的适应范围较广,其上述各生物学特性的最适温度分别是25、25、20、20～25℃;而2号小种对温度的要求较1号小种严格,其上述各生物学特性的最适温度分别是20、20、25、15℃。此外还发现在适宜的产孢温度时,2号小种的产孢量极显著地高于1号小种。结论指出,长期以来温度可能是限制2号小种扩展、蔓延的主导因素之一,温度一旦适宜,大斑病菌2号小种会成为优势小种,并迅速导致Ht_1基因玉米的抗性丧失。     

玉蜀黍平脐蠕孢拮抗细菌YB01的鉴定及拮抗作用

通过形态特征、生理生化及16S rDNA同源性序列分析对玉蜀黍平脐蠕孢（Bipolaris maydis）拮抗细菌YB01进行鉴定,结果表明,该菌为苍白杆菌属的一种（Ochrobactrum sp.）,序列号为HQ141339。YB01对玉蜀黍平脐蠕孢的拮抗作用研究表明：YB01培养液可以有效抑制玉蜀黍平脐蠕孢的生长、孢子的形成与萌发。显微镜观察结果表明,用YB01培养液处理的玉蜀黍平脐蠕孢菌丝体膨大变形,细胞质发生浓缩,表明YB01的拮抗作用主要是通过其代谢产物影响玉蜀黍平脐蠕孢细胞壁而实现的。     

橡胶狗尾草平脐蠕孢叶斑病病原菌鉴定及生物学特性研究

为明确采自西双版纳景洪地区疑似橡胶麻点病的病原菌,采用组织分离法进行病原菌分离,活体接种法进行致病性测定,通过形态学观察结合rDNA-ITS和GAPDH两个核苷酸片段序列分析,将病原菌确定为狗尾草平脐蠕孢Bipolaris setariae。通过单因子变量试验,对病原菌进行生物学特性研究,结果表明：菌丝生长最适温度为30℃,最适pH为7～8,最适培养基为PDA,菌丝致死温度为53℃,10 min。该病原菌能有效利用多种碳源和氮源,碳源以可溶性淀粉利用率最高,最适氮源为蛋白胨。24 h黑暗条件下培养更有利于菌丝生长。分生孢子萌发的最适温度为28～35℃,最适pH为7～8,28℃黑暗培养2 h后萌发率达到最大,为95.5%,分生孢子致死温度为60℃,10 min。     

Identification and Origin of Xanthomonas campestris pv. campestris Races and Related Pathovars

ABSTRACT One hundred sixty-four isolates of Xanthomonas campestris pv. campestris and other X. campestris pathovars known to infect cruciferous hosts (X. campestris pvs. aberrans, raphani, armoraciae, and incanae) were inoculated onto a differential series of Brassica spp. to determine both pathogenicity to brassicas and race. Of these, 144 isolates were identified as X. campestris pv. campestris and grouped into six races, with races 1 (62%) and 4 (32%) being predominant. Other races were rare. The remaining 20 isolates from brassicas and other cruciferous hosts were either nonpathogenic or very weakly pathogenic on the differential series and could not be race-typed. Five of these isolates, from the ornamental crucifers wallflower (Cheiranthus cheiri), stock (Matthiola incana) and candytuft (Iberis sp.), showed clear evidence of pathovar-like specificity to the hosts of origin. A gene-for-gene model based on the interaction of four avirulence genes in X. campestris pv. campestris races and four matching resistance genes in the differential hosts is proposed. Knowledge of the race structure and worldwide distribution of races is fundamental to the search for sources of resistance and for the establishment of successful resistance breeding programs.     

Two new species of Bipolaris

Two new fungal species, Bipolaris secalis , isolated from rye seed, and B. triticalis , isolated from triticale seed, arc described and shown to reduce germination of rye seed.     

Identification of Lentil Germ Plasm Resistant to Colletotrichum truncatum and Characterization of Two Pathogen Races

ABSTRACT A total of 1,771 lentil accessions from the U.S. lentil collection (U.S. Department of Agriculture-Agricultural Research Service, Pullman, WA) and the Institut für Pflanzengenetik und Kulturpflanzenforschung (Gatersleben, Germany) were screened for resistance to Colletotrichum truncatum, the cause of anthracnose. About 95% of the accessions were susceptible when inoculated with a single isolate in the field. Retesting, under controlled conditions, of accessions rated as resistant or moderately resistant in the field resulted in identification of anthracnose resistance in four accessions from the U.S. collection (PI 320937, PI 320952 [cv. Indianhead], PI 345629, and 468901), and 12 accessions from the German collection (Lens 3, 102, 104, 106, 107, 119, 122, 134, 135, 177, 195, and 209). Seven of the accessions were used as host differentials to characterize pathogenic variability of 50 single-spore isolates collected in Manitoba and Saskatchewan, Canada. The presence of two distinct races was demonstrated. Isolates of C. truncatum avirulent on cv. Indianhead, PI 320937, PI 345629, PI 468901, Lens 102, Lens 104, and Lens 195 were designated race Ct1. Isolates that were virulent on these seven entries were designated race Ct0, indicating their lack of avirulence genes. Race Ct0 was isolated more frequently from commercial seed samples than race Ct1, but the two races were isolated with similar frequency from plants in commercial fields planted to susceptible cultivars. Race Ct0, to which no resistance has yet been identified, presents a high risk to lentil production in Canada and potentially worldwide.     

条斑型玉米圆斑病病原鉴定及其生物学特性研究

 本研究通过致病性测定、形态学和分子生物学鉴定方法,首次明确陕西省发生的玉米条斑型叶斑病是玉米圆斑病的一种症状类型,由玉米生离蠕孢(Bipolaris zeicola)3号生理小种引起。供试品种豫玉22、农大108、农大3138、东单7号、沈单10号、沈单16号、户单4号、新陕资1号、高农1号和陕单9号都对3号生理小种表现感病,品种间抗病性差异不显著。此菌在PDA、PSA、OMA、CMA、WA和Czapek上均可生长,最适生长培养基为PDA。菌落生长温度为5~35℃,最适菌落生长温度为25℃。分生孢子在5~40℃均可萌发,低于5℃高于40℃萌发率极低,萌发的最适温度为28℃。孢子在pH 3~11均可萌发,萌发最适pH为5。在自来水中分生孢子可以萌发,蔗糖和葡萄糖溶液可以明显促进孢子萌发。     

The Identification of Two New Races of Pyrenophora tritici-repentis from the Host Center of Diversity Confirms a One-to-One Relationship in Tan Spot of Wheat

ABSTRACT Pyrenophora tritici-repentis, causal agent of tan spot, induces necrosis and chlorosis in its wheat host. The tan spot system conforms to the toxin model and three host-specific toxins have been identified (Ptr ToxA, Ptr ToxB, and putative Ptr ToxC). Processing of a collection of isolates, obtained in the Fertile Crescent and Caucasus regions, yielded two new virulence patterns. Isolate Az35-5 combined the virulences of races 2 and 5 and was classified in the new race 7. Isolates TS93-71B and TS93-71F had a virulence pattern that combined those of races 2, 3, and 5 and were grouped in the new race 8. Southern analysis revealed that all three isolates possessed copies of the ToxA and ToxB genes, the first time the genes were found in a common background. The production of Ptr ToxA and Ptr ToxB by the isolates was confirmed by western blotting. Virulence patterns suggested that TS93-71B and TS93-71F may also produce Ptr ToxC, even though it was not present at detectable levels in culture filtrates. The identification of races 7 and 8 complete the theoretical maximum number of races that can be differentiated by three loci in the host (2(3) = 8), assuming a one-to-one relationship. It appears that the wheat/P. tritici-repentis system is a mirror image of the classical gene-for-gene relationship.     

黑龙江省稻瘟病菌生理小种的鉴定

应用３个籼稻、４个粳稻组成的中国鉴别品种将黑龙江省１１０个稻瘟病菌菌株划分为４群７个生理小种。用日本清泽的１２个单基因抗性鉴别品种将上述菌株划分为７７个生理小种。对＋、ｔｉ－ａ、Ｐｉ－ｋ、Ｐｉ－ｚ基因致病频率高（７０．４％～８９％）的生理小种遍布全省各稻区；对Ｐｉ－ｔ、Ｐｉ－ｂ、Ｐｉ－ｚｔ基因致病频率低（０～１９．３％）的生理小种分布窄，这３个基因可用于抗病育种。试验表明应用日本清泽的１２个粳稻单基因抗性鉴别品种更适宜黑龙江省稻瘟病菌生理小种的鉴定     

Physiological Races and Vegetative Compatibility Groups of Fusarium oxysporum f. sp. lactucae Isolated from Crisphead Lettuce in Japan

One hundred and sixteen isolates of Fusarium oxysporum f. sp. lactucae obtained from 85 fields in three crisphead lettuce-producing areas in Nagano Prefecture, Japan were typed for races using differential cultivars Patriot, Banchu Red Fire and Costa Rica No. 4. They were also grouped into vegetative compatibility groups (VCGs) using complementation tests with nitrate non-utilizing (nit) mutants. Two California strains reported as F. oxysporum f. sp. lactucum, a type culture of F. oxysporum f. sp. lactucae, and 28 avirulent isolates of F. oxysporum obtained from crisphead lettuce were included for comparison. Among Nagano isolates, 66 isolates were identified as race 1, and 50 as race 2. Race 1 strains derived from Shiojiri and Komoro cities and race 2 from Kawakami village and Komoro city. All isolates of race 2 were biotin auxotrophs, and the race could be distinguished based on its requirement for biotin on minimal nitrate agar medium (MM). Pathogenic isolates were classified into two VCGs and three heterokaryon self-incompatible isolates. Strong correlations were found between race and VCG. All the race 1 strains were assigned to VCG 1 except self-incompatible isolates, and all the race 2 strains to VCG 2. The 28 avirulent isolates of F. oxysporum were incompatible with VCG 1 and VCG 2. California strains was vegetatively compatible with VCG 1, and they were assigned to race 1. Based on vegetative compatibility, these two races of F. oxysporum f. sp. lactucae may be genetically distinct, and F. oxysporum f. sp. lactucae race 1 is identical to F. oxysporum f. sp. lactucum. Received 7 May 2002/ Accepted in revised form 6 September 2002