玉米C群不同亚群雄性不育胞质对小斑病(Bipolaris maydis)C小种侵染的病理反应研究

以10套同核异质(N、C、Rb、ES)品系及Cms-C胞质背景的3个杂交种(F₁)为试材．对田间观测的4个病理指标的鉴定和分析结果表明：(1)除乳熟期病情指数外，其余3个病理指标的结果显示出C小种对C群CＩ亚群雄性不育胞质具有专化性侵染的特点．但在不同病理指标、不同核型之间所表观的专化性程度却有较大差别；CⅡ、CⅢ亚群胞质无专化侵染现象．(2)C小种的致病力小于Ｔ小种．     

河北省玉米小斑病菌优势生理小种鉴定及ITS序列分析

2007~2016年在河北各地采集玉米小斑病标样,对分离出的356株玉米小斑病菌菌株进行生理小种鉴定。结果表明,在鉴定的年度范围内,玉米小斑病菌T小种、C小种、S生理型、O小种的分离频率在年度间存有差异,O小种的平均分离频率94.94%,是河北省玉米小斑病菌的优势小种;O小种对主栽品种郑单958和自交系C103的致病力呈下降趋势,在C103上致病力下降幅度小于郑单958。对河北省石家庄、保定、衡水、沧州邯郸、邢台采集的45株菌株进行ITS序列分析构建UPGMA进化树,分析表明,河北省内玉米小斑病菌株的遗传进化与地域有一定关系,差异不明显。     

用叶片和种子DNA对玉米M5P型与YⅡ-1型雄性不育细胞质进行归群

利用GenBank上公布的玉米T、C、S群不育细胞质线粒体DNA特异基因T-urf13、atp6-C、orf355的片段序列设计引物,以玉米自交系B77、U8112和150为核背景的3组同核异质系(N、T、C、S、M5P型和YⅡ-1型)叶片总DNA和种子总DNA以及线粒体DNA为模板,经PCR扩增对新型雄性不育胞质MP型和YⅡ-1型进行归群研究.结果表明:①M5P型和YⅡ-1型不育胞质的PCR扩增产物与T群、S群有很大差别,与C群不育胞质的PCR扩增结果相同,M5P型和YⅡ-1型不育胞质可归为C群;②设计的胞质鉴定特异引物以从叶片中提取的总DNA和从种子中提取的总DNA为模板扩增,与以线粒体DNA为模板扩增的结果一致,表明只要提取基因组总DNA就可以用于玉米胞质类型的归群;③基于PCR策略用玉米胞质特异引物对胞质进行归群,不受供试材料核背景的影响.     

玉米C群不同亚群雄性不育胞质对小斑病（Bipolaris maydis）C小种侵染的病理反应研究

以１０套同核异质（Ｎ、Ｃ、Ｒｂ、ＥＳ）品系及Ｃｍｓ－Ｃ胞质背景的３个杂交种（Ｆ１）为试材．对田间观测的４个病理指标的鉴定和分析结果表明：（１）除乳熟期病情指数外，其余３个病理指标的结果显示出Ｃ小种对Ｃ群ＣＩ亚群雄性不育胞质具有专化性侵染的特点．但在不同病理指标、不同核型之间所表观的专化性程度却有较大差别；ＣⅡ、ＣⅢ亚群胞质无专化侵染现象．（２）Ｃ小种的致病力小于Ｔ小种．     

海南省3种油茶炭疽病菌的致病力及其生物学特性研究

为了弄清海南省不同油茶炭疽病菌致病力差异及生物学特性,采用刺伤接种法对3种油茶炭疽病菌(C.fructicola、C.siamense、C.camelliae)的致病力进行测定,发现不同病原间致病力存在显著差异,其中C.fructicola致病力最强,C.siamense致病力次之,C.camelliae致病力最弱。对3种炭疽病菌生物学特性研究发现,3种病菌最适生长温度、p H值及光照条件类似,同时均可利用多种碳、氮源,但不同病菌生长的最优碳源、氮源有一定差异。C.fructicola的产孢量、分生孢子萌发率及附着胞形成率均高于C.siamense及C.camelliae。不同油茶炭疽病菌生物学特性的差异可能与其致病力分化有关。本研究结果将为进一步研究不同油茶炭疽病菌致病差异机制提供理论依据。     

平方C群不同亚群雄性不育胞质对小斑病（Bipolaris maydis）C小种浸染…

以１０套同核异质（Ｎ，Ｃ，Ｒｂ，ＥＳ）品系及Ｃｍｓ－Ｃ胞质背景的３个杂交种（Ｆ１）为试材，对田间观测的４个病理指标的鉴定和分析结果表明，（１）除乳熟期病情指数外，其余３个病理指标的结果显示出Ｃ小种对Ｃ群ＣＩ亚群雄性不育胞质具有专化性侵染的特点，但在不同病理指标，不同核型之间所表现的专化性程度却有较大差别，ＣⅡ，ＣⅢ亚群胞质无专化侵染现象，（２）Ｃ小种的致病力小于Ｔ小种。     

大豆锈病病菌生理小种的初步研究

大豆锈病病菌(Phakopsora Rachyrhizi Syd.)的7个菌系接种在8个鉴别寄主上,按照病原的致病力强弱(病斑反应型)初步分为A、B、C、D4个生理小种,其中生理小种A的致病力最强,对各个鉴别寄主都为感病,生理小种B、C、D的致病力比较差,可通过各鉴别寄主区分开。     

香蕉枯萎病菌fga1基因的克隆与序列分析

为了解fga1基因在尖孢镰刀菌古巴专化型侵染香蕉过程中的作用,及其与尖孢镰刀菌古巴专化型生理小种1号和生理小种4号之间的致病力差异的关系,采用PCR和RT-PCR方法扩增了2个生理小种的fga1基因,并对扩增产物进行了测序及相似序列搜索和比对,还对基因编码的蛋白进行了氨基酸序列比对和功能分析.研究结果表明2个生理小种fga1基因开放阅读框均为1 062 bp,编码353个氨基酸,基因同源性为99.5%,氨基酸序列相同.推测fga1基因可能与香蕉枯萎病菌自身繁殖和附着胞的形成有关.从fga1基因序列及其编码蛋白的氨基酸序列看,2个生理小种致病力的差异与fga1基因并无明显对应关系,这为进一步研究fga1基因功能奠定了基础.     

用叶片和种子DNA对玉米M5P型与YⅡ-1型雄性不育细胞质进行归群

利用GenBank上公布的玉米T、C、S群不育细胞质线粒体DNA特异基因T-urf13、atp6-C、orf355的片段序列设计引物,以玉米自交系B77、U8112和150为核背景的3组同核异质系(N、T、C、S、M_5P型和Y_Ⅱ-1型)叶片总DNA和种子总DNA以及线粒体DNA为模板,经PCR扩增对新型雄性不育胞质M5P型和YⅡ-1型进行归群研究。结果表明：①M_5P型和Y_Ⅱ-1型不育胞质的PCR扩增产物与T群、S群有很大差别,与C群不育胞质的PCR扩增结果相同,M_5P型和Y_Ⅱ-1型不育胞质可归为C群;②设计的胞质鉴定特异引物以从叶片中提取的总DNA和从种子中提取的总DNA为模板扩增,与以线粒体DNA为模板扩增的结果一致,表明只要提取基因组总DNA就可以用于玉米胞质类型的归群;③基于PCR策略用玉米胞质特异引物对胞质进行归群,不受供试材料核背景的影响。     

玉米“辽2(L2)”型细胞质雄性不育性的选育与利用

用自选新杂交组合(开24×替423)的种子，通过钴60γ射线诱变获得雄性不育突变体，经与有关轮回亲本连年回交育出不育系，其与有关测验种的杂交育性反应，不同于T、S、双及C型，定名为L₂(辽2)型。测定结果表明，对该材料的胞质不育性，较易遇到天然恢复系，也较易找到保持系，便于三系配套应用。抗病性鉴定结果表明，L₂型不育性属于一种抗T小种小斑病侵袭的新型抗病细胞质，可适用于全恢式、掺合式或半恢式利用。     

Host range study of Argentine Nacobbus aberrans sensu Sher populations and comments on the differential host test

The existence of races within the species Nacobbus aberrans sensu Sher has been confirmed; however, there is no consensus on a consistent system for race determination. Four plant species previously used as differential hosts in some N. aberrans race tests (tomato, pepper, sugarbeet and potato) were tested for susceptibility to seven nematode populations from Argentina. Plants were inoculated with second-stage juveniles and kept under glasshouse conditions at 21 °C for 90 days. The parameters evaluated (root gall index, egg mass index, and reproduction factor) in different nematode populations and plants showed significant differences. The reproductive fitness of the nematode populations differed among the plants that showed some degree of susceptibility. The results showed that N. aberrans comprises populations differing in host preference. Based on the nematode populations’ behaviour on these hosts, two groups were distinguished: i) populations that multiplied on all hosts, ii) populations that did not multiply on potato. The present work contributes to the analysis of criteria for developing a differential host test.     

Further observations on races of potato wart in Newfoundland

Summary A race of the wart fungus,Synchytrium endobioticum corresponding in behaviour to European race 2 occurs commonly in Newfoundland. In 1970 the presence of a race which can infectUltimus but notHilla, and hence appears similar to race 8, has been confirmed. A type similar to race 1 has been isolated from a few locations. Contribution No. 25. Research Station.     

玉米大斑病菌生理小种同工酶的薄层扫描图谱

对属于玉米大斑病菌1、2号生理小种的四个标准菌株的过氧化物同工酶和酯酶同工酶进行PAGE和IEF分析研究．过氧化物同工酶扫描图谱发现1号生理小种在薄板80mm处有明显的馒头状吸收峰(G峰)，而2号小种在薄板80mm处有一微弱吸收(M峰)，紧随其后义在85mm处出现另一微小吸收峰(N峰)，可见玉米大斑病菌1、2号在生理小种的过氧化物同工酶图谱有一定的差异。酯酶同工酶扫描图谱发现，1号生理小种在薄板130m。处有一明显的窄长吸收峰(G峰)，而2号小种在此区域则无明显吸收。如果两性电解质由pH4～6换成pH3.5～10时。2号小种在薄板70mm处有一C峰出现，但1号小种没有出现该峰，可见玉米大斑病菌1、2号生理小种的酯酶同工酶也存在着差异，这将为探讨玉米大斑病菌毒素产生的遗传学和不同小种毒素的毒性成分间的关系奠定基础。     

Differential response of Cucumis melo to Fusarium oxysporum f. sp. melonis race 1.2 isolates

Fusarium wilt incited by Fusarium oxysporum f. sp. melonis (Fom) causes severe losses in melon crops. Four physiological races of Fom have been identified: 0, 1, 2 and 1.2. In most cases, resistance to race 1.2 has been described as recessive, polygenic and not race specific. However, some evidence of race-specific effects within melon resistance to race 1.2 has been reported. In this work, we study these effects and assess whether they are due to race-specific resistance. Seeds were obtained from 14 melon accessions that exhibit some level of resistance to race 1.2, and from the lines ‘Charentais-Fom1’ (resistant to races 0 and 2), ‘Charentais-Fom-2’ (resistant to races 0 and 1), and ‘Dinero F₁’ (with partial resistance to Fom race 1.2). Melon seedlings were artificially inoculated using two different procedures: ‘continuous shaking’ and ‘tray immersion’. Symptom severity was assessed on leaves using a rating scale from 0 (no symptoms) to 4 (death of the plant). Symptoms were recorded weekly over the four-week period following the first appearance of symptoms and the area under the disease progress curve (AUDPC) was calculated. Six Fom isolates (3 from pathotype Y and 3 from pathotype W) were used in the inoculation. The less aggressive ‘tray immersion’ procedure seems to be more appropriate for detecting the typically small resistance factors of this type of polygenic partial resistance. ‘Kogane Nashi Makuwa’, ‘BG-5384’, ‘Shiro Uri Okayama’, ‘C-211’ and the control, ‘Dinero F₁’, showed a high level of resistance to all Fom isolates. However, some genotype × isolate effects were also detected. ‘Baza’, when inoculated with isolate Fom 9302, and ‘Korça, when inoculated with Fom 37mls.1.2W, showed resistance levels similar to that of ‘Dinero F₁’; this effect was not observed when ‘Baza’ and ‘Korça’ were inoculated with other isolates. These results are characteristic of race-specific resistance and offer evidence for the presence of this type of resistance to Fom race 1.2 in melons.     

培养基营养成分对香蕉枯萎病尖孢镰刀菌生长的影响

通过对香蕉枯萎病发病株病组织的分离、纯化,得到香蕉枯萎病病原菌--尖镰孢菌古巴专化型[Fusarium oxysporum f.sp.cubense(E.F.Smith)Snyder et Hansen].该病原菌在不同pH值培养基上培养4 d后,发现尖孢镰刀菌菌落在pH值4.0～9.0范围内均可生长,pH值为6.0～7.0时最适,菌落直径平均在3.7～3.9 cm之间.尖孢镰刀菌在不例营养成分的培养基上培养,结果表明,N源对尖孢镰刀菌菌丝的生长影响大于C源.生长到第6天时,全糖型培养基产孢量最大,且小型分生孢子的产孢量也最大,可使香蕉苗发病率达到100%.而大型分生孢子的产生最佳培养基为低氮型培养基.     

Latent infection of potato tubers byPseudomonas solanacearum

Strains ofPseudomonas solanacearum differed in their ability to infect tubers of different resistant potato clones grown in infested soil. When eight resistant clones (Solanum phureja orS.phureja ×S. tuberosum hybrids) were grown at 24–28°C in soil infested with a race 1 or a race 3 strain of the bacterium, relatively few plants had wilt symptoms at harvest, but 26.7% and 9.2% of the tubers harvested from plants infected with the race 1 and race 3 strains, respectively, carried latent infections. Some infected clones never yielded diseased tubers, however. The development of symptoms above ground was not correlated with the incidence of tuber infection in any particular clone. No tuber infection occurred in tolerant or resistant clones grown in infested soil at cool (12–22°C) temperatures. Tubers were inoculated directly in an attempt to evaluate the ability of bacteria to multiply in these tissues at different temperatures. Highly virulent strains ofP. solanacearum survived in susceptible tubers in higher numbers and for longer periods than in resistant ones. Low temperature (4°C) had a deleterious effect on survival of the bacterium in tubers, but did not completely eliminate the pathogen even after 40 days.     

我国玉米大斑病菌生理小种及交配型组成分析

利用Ht单基因鉴别寄主对2021年采自我国10个省(自治区)57个市县的127株玉米大斑病菌进行生理小种鉴定,采用特异性引物对供试菌株进行交配型检测。生理小种鉴定结果显示,我国玉米大斑病菌主要包括0、1、2、12、3、13、23、N、1N、2N、3N、13N、23N、123N等14个生理小种,其中,0号和1号生理小种分别占供试菌株的34.65%和28.35%,为主要小种类群。我国玉米大斑病菌生理小种存在多元化,东北地区生理分化更为明显。供试菌株对Ht1、Ht2、Ht3、HtN的毒性频率分别为41.73%、9.45%、25.20%、17.32%。交配型检测结果显示,分离株中共有A、a两种交配型,且a交配型比例明显高于A交配型,不同省份玉米大斑病菌交配型组成情况存在差异。     

2009-2015年安徽省大豆试验新品系对SMV和SCN的抗性评价

利用黄淮地区广范分布的优势大豆花叶病毒(soybean mosaic virus,SMV)株系SC3、SC7和大豆胞囊线虫1号生理小种,分别对2009-2015年安徽省大豆区试和预试参试品种(系)523份(次)进行抗病性评价.结果显示:对SC3表现抗病(高抗、抗病和中抗)的材料有262份,占参试材料总数的50.1％;抗SC7的材料有274份,占52.4％;同时对SC3和SC7表现高抗的材料仅有HD21116.同时发现参加安徽省区试预试的大豆新品种(系)在不同年份间对SMV的病情指数存在显著差异.对SCN的抗性结果显示,远育8号、阜09-242和SK8-3-3等8份表现中抗,占鉴定总数的1.8％,表现中感的有43份,占9.9％,有383份材料表现高感,占鉴定总数的比率高达88.3％,说明多数大豆品种(系)对SCN的综合抗性较差.对鉴定结果的综合分析发现,只有1份新品系同时对SMV和SCN表现中抗,为SK8-3-3.