β-1,3-葡聚糖酶和几丁质酶活性与大豆对疫霉根腐病抗性的关系

 为了明确β-1,3-葡聚糖酶和几丁质酶与大豆抗疫霉根腐病的关系,测定了不同抗性大豆品种接种大豆疫霉菌后β-1,3-葡聚糖酶和几丁质酶活性的变化情况和2种酶对大豆疫霉菌的抑制作用。结果表明,大豆疫霉菌能诱导大豆β-1,3-葡聚糖酶和几丁质酶的活性增强,但2种酶在积累速度和幅度上,抗病品种和感病品种有显著的差异。与感病品种"857-1"相比,抗病品种"垦农4号"2种酶活性不仅升高的速度快、幅度大,且高活性维持的时间长。β-1,3-葡聚糖酶和几丁质酶混合液对大豆疫霉菌的菌丝生长、孢子囊形成和孢子萌发的抑制作用明显,其次是β-1,3-葡聚糖酶,而几丁质酶对大豆疫霉菌的抑制作用不明显。表明大豆对大豆疫霉根腐病的抗性与β-1,3-葡聚糖酶和几丁质酶的活性呈正相关关系。β-1,3-葡聚糖酶和几丁质酶混合对大豆疫霉菌的抑制具有协同增效作用。     

防治大豆疫霉根腐病的药剂筛选

在离体条件下测定了 8种内吸性杀菌剂对大豆疫霉菌菌丝生长的抑制作用。甲霜灵、甲霜灵锰锌、安克锰锌、杀毒矾、霜脲锰锌、克露和加瑞农为有效杀菌剂 ,霜霉威不具有抑菌效果。甲霜灵的 EC50 值为0 .4 870 μg/ m L,抑菌效果最好 ,安克锰锌、甲霜灵锰锌的 EC50 值分别为 1.4 2 6 1μg/ m L和 1.76 97μg/ m L,效果次之。在活体条件下 ,甲霜灵和甲霜灵锰锌能完全抑制大豆疫霉菌对感病大豆品种的侵入 ,并具有较长的药效期 ,安克锰锌、杀毒矾和霜霉威虽然具有明显的防治效果但药效期很短。大豆疫霉菌菌株间对甲霜灵锰锌的敏感性存在差异 ,但这种差异与菌株来源没有相关性 ,EC50 平均值为 1.830 2μg/ m L ,没有发现耐药性菌株。在我国黑龙江省目前缺乏有效抗病品种的情况下 ,建议应用甲霜灵锰锌防治大豆疫霉根腐病。     

大豆疫霉根腐病

 大豆疫霉根腐病是毁灭性病害之一,在我国近年有加重发展趋势。美国、澳大利亚和加拿大对Phytophthora sojae及大豆抗性研究较多,目前已建立了完善的生理小种体系,分离了30多个生理小种,最新定名小种为38和39号。RFLP研究表明,P.sojae的多数变异都可在小种1,7,17和19号中表现出来,因而推测其它小种可能是从这4个小种杂交派生而来,澳大利亚的P.sojae由美国传入。抗、耐病筛选方法有田间筛选法、接种体薄层法、斜板法、下胚轴接种法和豆荚接种法等。选出不少抗病材料,通过遗传研究定名了抗性基因Rps1、Rps-b、Rps-c、Rps1-d、Rps1-k、Rps2、Rps3、Rps3-b、Rps3-c、Rps4、Rps5、Rps6和Rps7等。Rps1-k是目前应用较广的抗性基因,它能抗20多个生理小种。抗性基因Rps1和Rps1-c从被利用到丧失抗性大约是8~10年的时间,按此推算几年之内Rps1-k基因也将丧失抗性,因此主张抗病基因和耐病基因结合使用,不同抗性基因结合使用。     

中国大豆疫霉根腐病和大豆种质抗病性研究

 大豆疫霉根腐病在中国的发生区域逐渐扩大,局部地区发生严重。大豆疫霉菌1号生理小种是黑龙江省的优势小种,同时也存在其它已知生理小种和新生理小种。不同大豆生态区之间大豆疫霉菌生理小种差异显著。在总体上,中国大豆种质的抗病性不强,长江流域大豆中抗病种质比率最高,其次为黄淮海流域种质,而东北地区抗病种质较少。按省归类,大豆种质抗性由强至弱依次为河南、江苏、湖北、山西、河北、辽宁、吉林、黑龙江、山东。吉林和黑龙江选育推广品种中,感病品种分别高达80%和73%;在462份大豆品系中,也表现出南方材料抗病性高于北方材料的趋势;地方品种中感病类型也高达60%以上。     

大豆疫霉选择性分离技术研究

 由大豆疫霉(Phytophthora spiae)引起的大豆疫霉根腐和茎腐病广泛分布于世界大豆主产区。是大豆毁灭性病害之一。     

黑龙江省大豆疫霉根腐病调查与病原分离

１９９６年对黑龙江省东部和中部大豆产区２３个市、县的大豆苗期疫霉根腐病进行了调查、研究,应用ＰＢＮＩＣ疫霉选择性培养基分离大豆疫霉根腐病病原菌,从牡丹江、穆棱、林口和佳木斯豆田具疫霉根腐症状的大豆植株上分离到大豆疫霉根腐病菌,并从根腐病株上单独或与大豆疫霉菌同时分离到终极腐霉菌,研究进一步证实我国黑龙江省有大豆疫霉根腐病。调查发现,大豆疫霉根腐病和终极腐霉根腐病主要发生在土质粘重、土壤含水量高或易积水的田块。     

大豆疫霉病研究进展

本文对大豆疫霉菌的检测和分离、生理小种和遗传多样性、抗性以及侵染和田间流行特点等方面的研究进展和取得的新成果进行了综述,从检疫、农业防治和化学防治等方面提出了该病的防治对策.     

大豆疫霉根腐病在我国的发生及防治对策

由大豆疫霉根腐病菌Ｐｈｙｔｏｐｈｔｈｏｒａｓｏｊａｅ引起的大豆疫霉根腐和茎腐病１９４８年发现于美国印第安纳州,１９５１年俄亥俄州首次报道,此病目前已传播到世界各国大豆产区,是严重影响大豆生产的主要病害之一［１］。鉴于大豆疫霉菌的破坏性和毁灭性,１９８...     

大雄疫霉与大豆疫病

前言大雄疫霉为藻菌纲、霜霉目、腐霉科、疫霉属真菌的一个种。在近代分类史上,真菌学家们虽根据其孢子形态和致病性等对此菌进行了多次分类与修订,在种内又区分出几种形态和致病性不同的类型,而大豆疫病菌仅是其中的一种。伴随着大雄疫霉菌的分类进展,致使大豆疫病菌的命名也发生了相应的变化:由Phvtophthora megasperma 发展为 P.     

大豆疫霉菌部分生物学特性及其药剂筛选研究

采用大豆疫霉菌在不同条件下菌丝生长速度法研究了大豆疫霉菌的部分生物学特性,并应用杀菌剂室内生测、盆栽药剂防效对药效作了评价。研究结果表明,大豆疫霉菌营养生长的最适温度为25～30℃;最适pH为6;光暗交替有利于该菌营养体的生长,在Rye或CA培养基上生长最快。室内药效测定结果表明,烯酰吗啉EC₅₀为0.165 4μg/mL,抑菌效果最好,甲霜灵、甲霜灵.锰锌和氟吗啉.锰锌的EC_{50分别为0.261 00、.451 0和0.984 2μg/mL,效果次之。盆栽试验结果表明,几种药剂在活体条件下对大豆疫病的防治效果较好,并有较长持效期。}     

大豆疫霉病发生危害及影响其发生因素的探讨

经1995～1998年对黑龙江省大部分大豆产区调查明确,大豆疫霉病在黑龙江大豆产区的发生面积及危害程度有逐年扩大和加重趋势,田间发病率一般为3%～5%,严重达75%,甚至绝产。其发病严重原因除受品种抗病性的因素影响外,主要取决于降水的多少及土壤积水时间的长短。此外,耕作、栽培方式、茬口等因素也不同程度影响发病。大豆在整个生育期间都可受到疫霉菌的侵染。     

Management of phytophthora root rot in radiata pine seedlings

Chemical and biological agents were evaluated for their ability to suppress root rot, caused by Phytophthora cactorum , in field-grown radiata pine seedlings in New Zealand. Trials were conducted over two seasons in an area of a forest nursery with a natural infestation of P. cactorum , and a history of root rot. In each season, symptoms of root rot developed during April, one month after root pruning, when seedlings were approximately six months old. In trial one, root rot incidence by mid July 2007 was 9·1% in untreated plots and 8·4% in plots that had been treated with metalaxyl-M/mancozeb (14 kg ha⁻¹) at seedling emergence. Disease incidence was lowest (2·1%) in plots that received seven monthly applications of phosphorous acid (6·5 L ha⁻¹). Other treatments, including seed coating with thiram or Trichoderma spp., and foliar applications of methyl jasmonate, did not control disease. In trial two, effects of treatment timing relative to root pruning were investigated. By late June 2008, three months after root pruning, root rot incidence was 22·2% in the untreated plots. Phosphorous acid was the most effective treatment and almost completely suppressed disease (0·1% incidence) when applied fortnightly from February until May (seven applications). Metalaxyl-M/mancozeb (15 kg ha⁻¹) was not effective (21·4% incidence) when applied five months before root pruning. However, disease incidence was reduced when the chemical was applied one week after root pruning (14·9% incidence) and greater control was achieved (8·2% incidence) when the application rate was increased to 50 kg ha⁻¹.     

Identification of isolate‐specific resistance QTLs to phytophthora root rot using an intraspecific recombinant inbred line population of pepper (Capsicum annuum)

Quantitative trait loci (QTL) for resistance to phytophthora root rot caused by Phytophthora capsici were investigated using two Korean P. capsici isolates and 126 F₈ recombinant inbred lines derived from a cross of Capsicum annuum line YCM334 (resistant parent) and local cv. Tean (susceptible parent). The experimental design was a split plot with two replications. Highly significant effects of pathogen isolate, plant genotype, and genotype × isolate were detected. QTL mapping was performed using a genetic linkage map covering 1486·6 cM of the pepper genome, and consisted of 249 markers including 136 AFLPs (Amplified Fragment Length Polymorphisms), 112 SSRs (Simple Sequence Repeats) and one CAPS (Cleaved Amplified Polymorphic Sequence). Fifteen QTLs were detected on chromosomes 5 (P5), 10 (P10), 11 (P11), Pb and Pc using two data processing methods: percentage of wilted plants (PWP) and relative area under the disease progress curves (RAUDPC). The phenotypic variation explained by each QTL (R²) ranged from 6·0% to 48·2%. Seven QTLs were common to resistance for the two isolates on chromosome 5 (P5); six were isolate‐specific for isolate 09‐051 on chromosomes 10 (P10) and Pc, and two for isolate 07‐127 on chromosomes 11 (P11) and Pb. The QTLs in common with the major effect on the resistance for two isolates explained 20·0–48·2% of phenotypic variation. The isolate‐specific QTLs explained 6·0–17·4% of phenotypic variation. The result confirms a gene‐for‐gene relationship between C. annuum and P. capsici for root rot resistance.     

抗菌肽和几丁质酶基因提高烟草对黑胫病菌和赤星病菌的抗性研究

 通过农杆菌介导法将加信号肽修饰的人工合成杂合抗菌肽CEMA基因(SPCEMA),苜蓿防御素基因(AFP),苦瓜几丁质酶基因(CHI)以及SPCEMA-CHI、AFP-CHI、AFP-SPCEMA双价基因导入本明烟(Nicotiana benthamiana),并对转基因烟草T₀和T₁代进行了抗病性检测,比较了不同转基因植株的抗病效果。研究结果表明,转基因烟草对黑胫病菌(Phytophthora parasitica var.nicotianae)、赤星病菌(Alternaria alternata)的抗性均强于非转基因烟草,病情指数差异达极显著水平,其中转AFP-CHI双价基因烟草具有较强的抗性,与单价转基因烟草的抗性差异达显著水平。但各单价转基因以及双价转基因烟草之间对上述病菌并未表现出显著的抗病性差异。结果表明植物源的抗菌肽基因与几丁质酶基因在抗植物真菌病害中具有协同增效作用。     

Changes in biochemistry and cellular ultrastructure support different resistance mechanisms to Phytophthora sojae in nonhost common bean and host soybean

Phytophthora root and stem rot of soybean caused by Phytophthora sojae is a destructive disease affecting soybean production worldwide. In nature, soybean is the only economically important cultivated host of P. sojae. The aim of this study was to explain different resistance mechanisms to P. sojae in nonhost common bean and host soybean as a basis for the control of Phytophthora root and stem rot of soybean via nonhost resistance. Observations and measurements of disease resistance-related variables showed slight differences in structural and biochemical resistance mechanisms between common bean and soybean. P. sojae infection induced a stronger hypersensitive response in nonhost common bean than in host resistant soybean. Moreover, phytoalexin phaseollidin synthesis-related vestitone reductase gene was extremely highly up-regulated, and phytoalexin glyceollin synthesis-related isoflavone reductase gene was slightly less up-regulated in common bean than in soybean, which resulted in a higher level of phaseollidin and a lower level of glyceollin in common bean. Phaseollidin had stronger inhibitory effects on mycelial growth and oospore formation of P. sojae than glyceollin, and more cell wall depositions and callose accumulated in common bean, which are probably related to the stronger resistance of nonhost common bean to P. sojae.     

Recombinant inbred line differential identifies race-specific resistance to phytophthora root rot in Capsicum annuum

A differential series is the normal method for identification of races within a plant pathogen and a host interaction. A host differential is extremely useful for phytopathological as well as breeding purposes. A set of recombinant inbred lines (RILs) were developed and characterized for race differentiation of Phytophthora root rot caused by Phytophthora capsici. The highly resistant Capsicum annuum accession Criollo de Morelos-334 was hybridized to a susceptible cultivar, Early Jalapeno, to generate the RIL population. The host differential characterized 17 isolates of P. capsici into 13 races. The establishment of a stable host differential for the P. capsici and C. annuum interaction will assist researchers in understanding the complex inheritance of resistance to Phytophthora root rot and to develop resistant cultivars.     

玉米根系分泌物中关键抑菌物质对大豆疫霉的抑菌活性

间作是控制作物土传病害的有效手段,根系分泌物对病原菌生长的影响是间作具备控病效果的重要原因。本文研究了玉米根系对大豆疫霉游动孢子行为特征的影响,鉴定了玉米根组织中的关键抑菌活性物质,测定其对大豆疫霉菌丝生长和游动孢子行为的影响。结果表明,大豆与玉米间作能够显著降低大豆疫霉根腐病的发生,玉米根系和根系分泌物能够显著减弱根际大豆疫霉游动孢子的游动和根际大豆疫霉休止孢的萌发能力。通过HPLC对玉米根组织进行分析,发现玉米根组织中存在门布和苯并噻唑这两种抑菌物质,两者能显著抑制大豆疫霉游动孢子的游动和其休止孢的萌发能力;在浓度为500μg/mL时,其游动抑制率均达到100%;而萌发抑制率分别为100%和81%。同时,门布和苯并噻唑都能显著抑制大豆疫霉的菌丝生长。在浓度为500μg/mL时,其抑制率分别为100%和62.49%。综上所述,玉米根系组织中产生和分泌的门布和苯并噻唑对大豆疫霉具有抑菌活性,生产上可以利用玉米/大豆间作降低大豆疫病的危害。