黑龙江省马铃薯晚疫病菌交配型的研究

由致病疫霉Phytophthora infestans(Mont.)de Bary引起的晚疫病是目前危害马铃薯生产最严重的病害之一,明确A2交配型在黑龙江省的存在与否,对晚疫病防治策略的制订具有重要的指导意义。本研究将采自黑龙江省大兴安岭、嫩江、讷河、克山、海伦、绥棱、绥化、巴彦、呼兰、哈尔滨、双城、林口、望奎的马铃薯晚疫病样品进行分离纯化得到124个菌株,通过对峙培养鉴定方法进行交配型测定,结果显示:124个菌株中未发现A2交配型菌株,表明黑龙江省未出现马铃薯晚疫病A2交配型。     

黑龙江省发现马铃薯晚疫病菌(Phytophthora infestans)A2交配型

对2005~2012年间采集自黑龙江省哈尔滨、望奎、漠河、塔河、呼玛、加格达奇、嫩江、克山、甘南、鹤岗、肇东、林口12个市县的133个马铃薯晚疫病菌株进行了交配型鉴定。结果表明,采集自2005~2010年间的51个菌株均为A1交配型,未发现A2交配型;采集自2011年的52个菌株中12个为A2交配型,占23.08%;2012年鉴定的30个菌株中9个为A2交配型,占30%。这是自2004年朱杰华报道发现一株A2交配型六年后,黑龙江省首次确认在甘南、哈尔滨、肇东发现马铃薯晚疫病菌A2交配型。     

黑龙江省马铃薯晚疫病研究进展与综合防治

马铃薯晚疫病是马铃薯生产的主要病害之一,每年都有不同程度的发生和流行,已成为马铃薯产业发展的制约因素。文章重点介绍了黑龙江省在马铃薯晚疫病菌生理小种与A2交配型测定、马铃薯晚疫病检测技术研究、抗晚疫病育种及植物源杀菌剂研制等方面的研究进展,同时介绍了马铃薯晚疫病综合防治的方法,这些对今后黑龙江省开展马铃薯晚疫病的研究和防治工作具有重要的借鉴作用。     

黑龙江省和吉林省马铃薯晚疫病菌multi-locus基因型分析

2006～2008年在黑龙江省和吉林省共分离获得99株马铃薯晚疫病菌,并测定了这些菌株的交配型、瑞毒霉敏感性、同工酶基因型和mtDNA单倍型。交配型测定结果显示在吉林省和黑龙江省分离的所有菌株均为A1交配型。瑞毒霉敏感性测定结果显示敏感性菌株占14.1%,中抗菌株占7.1%,抗性菌株占78.8%,表明吉林省和黑龙江省发生的晚疫病菌已对瑞毒霉产生抗药性。黑龙江省和吉林省分离的所有菌株中发现了两种mt DNA单倍型(Ⅰa和Ⅱa)。其中,Ⅰa单倍型占11.1%,Ⅱa单倍型占88.9%。根据Gpi和Pep图谱,本试验发现了3种同工酶基因型,其中优势同工酶基因型是Gpi:100/100,Pep:100/100。根据菌株的交配型、同工酶基因型和mtDNA单倍型,共发现4种基因型,其中,multi-locus基因型A(84.9%)是黑龙江省和吉林省发现的优势基因型,但也出现了新的基因型分化。     

抗性马铃薯晚疫病菌的治理对策

<正>马铃薯晚疫病抗性种群发生的第一个原因是A~2型菌株的发生和散布.马铃薯晚疫病菌的有性繁殖阶段由A~1、A~2二类不同形态的菌丝交配而产生卵孢子.A~2型菌株的抗逆力、侵袭力、致病力远比A~1型强.A~1型菌株一般在阴雨潮湿天气使叶片、块茎致病,A~2型菌株在又干又热的天气也会使马铃薯的叶片,甚至茎秆、块茎生病.过去各地仅发生A~1菌株,只有在墨西哥发现有A~2菌株.1981年A~2菌株扩散到了瑞士、大不列颠、德国、荷兰、以色列和日本,1985年在独联体发现并扩散.A~2菌株的传入和散布使独联体马铃薯晚疫病菌的种群组成和性质发生了变化,同时又增加了卵孢子这一初侵染补充源.     

黑龙江省马铃薯晚疫病菌线粒体DNA单倍型分析

为明确黑龙江省马铃薯晚疫病菌线粒体DNA单倍型组成和分布情况,采用PCR-RFLP方法分析了2015～2020年采自黑龙江省7个马铃薯种植区的193份马铃薯晚疫病菌株的线粒体DNA单倍型及频率分布。结果表明,IIa单倍型为优势线粒体DNA单倍型,占比89.12%,Ia和Ib两种单倍型也均有发现,分别占比9.84%和1.04%,所有样品中未发现IIb单倍型。与前人研究相比较,黑龙江省线粒体DNA单倍型存在动态变化,因此,加强对晚疫病菌群体遗传结构的监测,对更好地进行马铃薯晚疫病防控具有重要意义。     

黑龙江省马铃薯晚疫病菌对甲霜灵药剂的敏感性测定

利用菌落直径法对2008年黑龙江省4个地区53株马铃薯晚疫病菌的甲霜灵药剂敏感性进行了研究,结果表明,黑龙江省马铃薯晚疫病菌中对甲霜灵药剂具有抗药性的菌株占很大比重,但是区域间抗药菌株的出现频率具有很大差异,其中牡丹江、哈尔滨地区抗药菌株达到了100%,海伦的抗药菌株为23.08%,加格达奇没有出现抗药菌株。本研究对在黑龙江省科学合理地使用苯基酰胺类杀菌剂防治马铃薯晚疫病具有重要意义。     

云南省部分马铃薯产区晚疫病菌抗药性测定

由致病疫霉菌(Phytophthora infestans)引起的马铃薯晚疫病是严重危害马铃薯生长和产量的主要病害之一。在马铃薯晚疫病的化学防治过程中,几乎所有马铃薯主产区都有马铃薯晚疫病菌抗药性的报道。对云南省马铃薯主产区晚疫病菌抗药性进行检测,明确云南省马铃薯产区晚疫病菌的抗药性情况。通过抑菌试验检测马铃薯晚疫病菌对甲霜灵、银法利和大生M-45的抗性,测定来自云南省5个马铃薯产区的53个菌株。结果表明,中甸、丽江、剑川、石林和小哨未发现对甲霜灵、银法利和大生M-45的抗性马铃薯晚疫病菌,上述药剂仍可以有效防治马铃薯晚疫病。     

马铃薯晚疫病菌对瑞毒霉与霜脲氰的交互抗性

2008~2011年在黑龙江省共分离了41个马铃薯晚疫病菌,并测定了这些菌株对瑞毒霉和霜脲氰的敏感性和交互抗性。瑞毒霉测定结果显示6个(14.63%)菌株显示为敏感性,11个(26.83%)菌株显示为中抗,24个(58.54%)菌株显示为抗性。这说明黑龙江省分离的晚疫病菌已对瑞毒霉产生抗性。对于霜脲氰,EC50值为0.0630~2.1289μg/mL,最不敏感菌株是最敏感菌株的33.79倍,敏感性基线值为0.1879μg/mL。交互抗性分析结果显示,未产生交互抗性的菌株为73.16%,产生交互抗性菌株为26.84%。以上结果说明霜脲氰和瑞毒霉不能交叉使用。     

不同割秧时期对马铃薯晚疫病的防治效果研究

<正>1 前 言 晚疫病是当前影响我国马铃薯生产发展的最严重的真菌性病害,在我国各大马铃薯产区每年都有不同程度的发生。目前,无论是国内还是国外,防治马铃薯晚疫病不外乎两种主要方式:培育抗病品种及药剂防治。随着晚疫病菌A2交配型在我国的出现,致使抗病育种的难度进一步加大,短期内难有成效,所以药剂防治仍是当前防治晚疫病的首选方式。但药剂防治也存在着一些弊端,如长期使用     

Assessment of mating types and resistance to metalaxyl of Canadian populations ofPhytophthora infestans in 1997

The distribution of A1 and A2 mating types, and of metalaxyl-sensitive (MS), metalaxyl-intermediate (MI), and metalaxyl-resistant (MR) strains ofPhytophthora infestans, the causal pathogen of late blight, were determined in Canada in 1997. Potato plants or tubers and tomato plants or fruits, suspected to have late blight infection, were received from seven Canadian provinces in 1997, and were assessed for the presence ofP. infestans. Among 220 samples suspected to have late blight,P. infestans was recovered from 132 samples (60%) received from British Columbia (BC), Manitoba, New Brunswick, Prince Edward Island, and Quebec. From the 132 samples, 364 isolates were obtained and tested for their mating type and response to metalaxyl. Populations ofP. infestans within Canadian provinces were homogeneous for mating types, except within BC, where populations comprised both A1 and A2 mating types both within fields and sometimes within samples. The A2 mating type was found in all provinces where late blight was present. The A1 mating type was found only in Manitoba (1 isolate) and in BC (38 isolates). Unlike the old A1 isolates, those found in BC in 1997 were highly resistant to metalaxyl. These A1 isolates are even more resistant than A2 isolates. Based on assays with 10 ug.ml^?1 of metalaxyl, 14% of all tested isolates were MS, 69.8% were MI and 16.2% were MR. In addition, all provinces contained MS, MI, and MR isolates. No specific mating type or metalaxyl sensitivity level were specific to tomato or potato.     

Mating Type, Virulence, Aggressiveness and Metalaxyl Resistance of Isolates of Phytophthora Infestans in Poland

A total of 93 single-lesion isolates of Phytophthora infestans were collected from late blight diseased potatoes grown in several locations in Poland, in the years 2002–2004. They were tested for mating type, virulence, aggressiveness and metalaxyl resistance. Sixty one percent of the isolates was of the A1 and 39% of the A2 mating type. Regarding virulence, complex races predominated. Most of the isolates were highly and moderately aggressive. Among isolates, tested together with 38 previously collected (1995–2001) ones, 14.5% was metalaxyl resistant, 3.5% intermediately resistant and 82.0% of the isolates was sensitive to metalaxyl. In addition, 14 isolates tested with three simple sequence repeat markers showed high genetic diversity. These data indicate that Polish population of P. infestans is diverse and aggressive, with potential for sexual recombination and spreading of fungicide insensitivity.     

Characterization and Distribution of Three New Clonal Lineages of Phytophthora infestans Causing Late Blight in Wisconsin from 2009 to 2012

Phytophthora infestans causes late blight of potato and tomato, a disease that has been estimated to cost U.S. potato growers $287.8 million annually. We collected isolates of P. infestans from Wisconsin from 2009 to 2012 and determined distribution of clonal lineages and mating types and sensitivity to the systemic fungicide mefenoxam. We also sought to evaluate the current utility of an analysis of the Glucose-6-phosphate isomerase (Gpi) allozyme locus for predicting mefenoxam sensitivity with the aim of delivering timely information to growers. Overall, 143 isolates were collected from 52 locations in 20 Wisconsin counties from 2009 to 2012. Three clonal lineages, US-22, US-23, and US-24, were identified and were novel to Wisconsin and the U.S. US-22 is of the A2 mating type and sensitive to mefenoxam, with Gpi 100/122. US-23 and US-24 are of the A1 mating type and primarily intermediately sensitive to mefenoxam, with Gpi 100/100 and 100/100/111, respectively. Because of this close correlation and the unique Gpi patterns for each lineage present, we were able to predict mefenoxam sensitivity directly from samples using the allozyme assay and quickly deliver management information to growers. Both mating types were present in Wisconsin in 2009 and 2010 but were spatially separated and no evidence of sexual recombination or soil persistence was detected. The presence of new clonal lineages of P. infestans in Wisconsin indicates a need for continued close monitoring of late blight to facilitate generation of timely information for enhanced short-term and long-term late blight management.     

Characterisation of Phytophthora infestans Isolates Collected from Potato and Tomato Crops in Tunisia During 2006–2008

Severe late blight epidemics in Tunisia in recent years prompted population studies on the pathogen responsible for this disease, Phythophthora infestans. Characterisation of 165 Tunisian P. infestans isolates collected from 2006 to 2008 was performed for the mating type and mt haplotype, while subsets were analysed for metalaxyl sensitivity (n?=?65), virulence on differential set of 11 R genes of Solanum demissum (n?=?31), aggressiveness on cv. Bintje (n?=?36) and measurement of the radial growth on agar medium at three temperatures (n?=?38). Most isolates from potato and all isolates from tomato had the A1 mating type. The A2 mating type was detected in the north-east and northern areas, but not in the north-west. All the A2 mating type isolates were metalaxyl resistant and seem to be part of a new generation of the P. infestans isolates which are more aggressive, with more complex races, and tolerant to higher temperatures. The increased severity of epidemics during 2006 to 2008 can be attributed to favourable weather conditions during growing seasons, adaptation of new genotypes, widespread phenylamide resistance in potato production regions and most probably incorrect spray programmes. In contrast to the presence of complex pathotypes in two major potato crop regions (north-east and northern areas), the P. infestans population detected in the other regions and in tomato crops was still relatively simple. Compared with the situation in Europe and the American continent, or even compared with neighbouring countries such as Algeria, the genetic changes in Tunisia are still comforting and require strict management decision on late blight control to avoid the spread of new P. infestans populations from Europe or neighbouring countries.     

Identification of mating types and metalaxyl resistance in North American populations ofPhytophthora infestans

The A² mating type ofPhytophthora infestans was first reported in the United States in 1990. Concurrently,P. infestans strains resistant to metalaxyl ere found in the Pacific Northwest. Collaborative surveys were undertaken during 1991–1993 to investigate the frequency of occurrence of A² mating types and metalaxyl resistant strains in populations ofP. infestans isolated from outbreaks of late blight in potato and tomato crops in North America.In vitro testing indicated that isolates from the northeastern U.S. and Atlantic Canada were primarily (52/55) metalaxyl sensitive and all were A¹ mating types. Among 85 isolates from late blight epidemics in Florida and Texas, greater than 61% were both metalaxyl resistant and A² mating type. Metalaxyl resistance and A² mating types were identified also in a few tomato isolates from North Carolina. Although the majority of 134 isolates from the Pacific Northwest (British Columbia and Washington) were metalaxyl resistant, only 2 isolates from Washington were A² mating types. Among 111 isolates from 2 sites in central Mexico, 63% and 77% were both metalaxyl resistant and A² mating types. The data indicate also a higher frequency of metalaxyl resistance in A² isolates, than in A¹ isolates, among isolates from Florida and Texas. Highest metalaxyl resistance levels were found, however, in A¹ isolates from California, where no A² isolates were recovered.     

Occurrence of the A2 mating type ofPhytophthora infestans in potato fields in the United States and Canada

Ten isolates ofP. infestans collected from blighted potato fields in the U.S. and Canada during the years 1983–1989 were examined for mating type on lima bean, oatmeal, and rye grain media. Two of the ten isolates produced oospores in less than 15 days when cultured in the presence of known A¹ mating types from the USA, Mexico, and Europe, indicating they are A² mating types. When the two A² isolates (one from Pennsylvania and one from Vancouver, B.C.) were cultured singly or with known A² isolates, no oospores formed after 6 weeks of culture. Pathogenicity tests showed that both isolates produced typical late blight symptoms on potato foliage and stems, and there appeared to be no difference in virulence between these two A² and the eight A¹ isolates. Inoculations with a mixture of A¹ + A² sporangia also produced oospores in host tissues. This is the first report of the presence of the A² mating type ofP. infestans in the U.S. and Canada.     

Phenotypes ofPhytophthora infestans in Nepal: mating types and metalaxyl sensitivity

Summary Potato late blight has appeared in epidemic proportions in Nepal since the mid 1990s and fungicides have been reported to be decreasingly effective in managing the disease.Phytophthora infestans isolates were collected from potato crops during 1999–2000 and analysis of 371 isolates for mating types and 270 isolates for metalaxyl sensitivity revealed the presence of both new and old populations. This is the first report on the presence of metalaxyl-resistant isolates in Nepal. The frequencies of A1 and A2 were 83 and 17%, respectively. Metalaxyl-resistant, intermediate and sensitive isolates were recorded as 10%, 12% and 78% respectively. Metalaxyl resistance was distributed in both mating types. Sites with a history of metalaxyl use had a significantly higher number of resistant and intermediate isolates ({ie337-1}, P<0.01) than sites where metalaxyl had not been used. This study confirms the changes in population structure ofP. infestans in Nepal.