江浙地区葡萄霜霉病菌的致病性差异研究

为明确江苏、浙江不同地区葡萄霜霉病菌的致病性分化情况,采用单斑分离法和叶盘接种法,对分离得到的不同葡萄霜霉病菌单斑菌株进行致病性测定。结果表明,分离获得的80个葡萄霜霉病菌株都有致病性,且2个省份均有半数以上的菌株的病情指数在40~60之间。致病力聚类分析表明,2个省份的菌株都可以聚类为强、中、弱3种致病力类型,江苏以强致病力菌株为优势菌株,浙江以中等致病力菌株为优势菌株。对同一省份的菌株进行致病力分析发现,江苏树山和浙江永福的菌株致病力明显强于同省其他地区,而江苏新坊和浙江上钱的菌株与同省其他地区相比,致病力最弱。同时,构建菌株的系统发育树,结果显示,同源性相同的菌株间有致病力不同的情况,致病力相同的菌株间也存在rDNA-ITS序列有差异的情况。综上,江苏、浙江的葡萄霜霉病菌都存在致病力分化现象,这种分化现象与菌株的亲缘关系远近没有相关性,但同一省份不同地区间的菌株致病力差异与菌株的地理来源有一定的相关性。     

鲜食葡萄品种对霜霉病的抗性及抗病机理研究

采用田间自然发病调查，田间接种鉴定和离体葡萄叶圆片室内接种鉴定鲜食葡萄品种对霜霉病的抗性及其抗性机理研究表明，品种间对霜霉病的抗性存在显著差异。可依感病病级分为三类，低感品种有“z工伊豆”、“奥林匹亚”、“山东早红”、“森田尼”、“早玛瑙”。几乎所有的无核品种均高感霜霉病，葡萄对霜霉病的抗性与叶内可滴定酸、还原糖、游离氨基酸含量无显著相关，与叶背气也密度、气孔开度也无相关，而外施高浓度邻苯二酚却显著降低了霜霉病发病程度。     

黄瓜和葡萄霜霉病菌对不同内吸杀菌剂的交互抗药性

为了确定甲霜胺、乙磷铝与恶唑烷酮、霜脲氰、安克和硫代磷酰胺酯之间的交抗型,在叶盘上共测试了黄瓜霜霉(PC)和葡萄霜霉(PV)的27个分离系对6种内吸杀菌剂的抗药水平,结果证实了在两种目标真菌上甲霜胺和乙磷铝之间的非交抗关系,甲霜胺和恶唑烷酮之间的正交互抗药性,在PC上甲霜胺和霜脲氰之间的非交抗关系。试验还表明在PC上甲霜胺和安克之间以及乙磷铝和霜脲氰之间的非交抗关系,在PV上甲霜胺和乙磷铝与硫代磷酰胺酯之间的非交抗关系。此外,试验发现了霜脲氰和安克在叶盘上对抗甲霜胺分离系具有很高的杀菌活性。     

Interactions between Plasmopara helianthi, Glomus mosseae and Two Plant Activators in Sunflower Plants

Interactions between Plasmopara helianthi, Glomus mosseae and two plant activators DL--amino-n-butyric acid (BABA) and CGA 245704 (acibenzolar-S-methyl (BTH)) in sunflower plants susceptible to downy mildew were studied in four experiments using different methods of treatment and pathogen inoculation. Both chemicals were applied as soil drenches and foliar sprays, whereas P. helianthi infection was obtained by root and cotyledon inoculations of the seedlings. Soil drenches at the rates of 50 and 100mgkg^–1 soil of BABA and BTH given 1 and 3 days before P. helianthi inoculation, respectively to mycorrhizal plants, provided moderate protection against the pathogen (about 50–55%). Morphological changes and decrease in mycorrhizal colonization in roots of BTH-treated plants and in BTH-treated mycorrhizal plants were also observed. Delay in the emergence and reduction of the root systems were more evident at the highest concentration but decreased with time. These effects were absent with the BABA treatment.Foliar spray treatment of BABA and BTH, applied at 4000 and 200µgml^–1, respectively (1 day post-inoculation) to mycorrhizal plants provided good protection (about 80%) against P. helianthi foliar infections. No effects on mycorrhizal colonization or on root systems were observed. In vitro tests on the effect of the compounds on the mycorrhizal fungus showed that the germination of G. mosseae sporocarps increased with BABA treatment whereas it was greatly inhibited by BTH treatment.     

Intraspecific Relationship of Plasmopara halstedii Isolates Differing in Pathogenicity and Geographic Origin Based on ITS Sequence Data

Sequence parts of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA were analysed to screen for the intraspecific variability of a non-coding genomic region in 15 Plasmopara halstedii populations of different pathotype and geographic origin. Samples revealed uniformity in a ca. 790 Bp fragment comprising of the ITS-1, 5.8S and front parts of the ITS-2. In contrast, clear differences were found in a ca. 810 Bp fragment of the ITS-2 thus allowing differentiation between populations of pathotype 100, 310 and 330 and a group of populations representing pathotypes 700, 701, 703, 710 and 730. Samples of pathotypes 700 to730 originated from Slovakia, France, and Germany, but were uniform in both ITS sequence parts, thus indicating very recent origin of these highly aggressive physiological races. The potential use of ITS sequences for pathotype differentiation and phylogenetic studies in P. halstedii is discussed.     

An Aqueous Extract of the Dry Mycelium of Penicillium chrysogenum Induces Resistance in Several Crops under Controlled and Field Conditions

We have examined the effect of Pen, an aqueous extract of the dry mycelium of Penicillium chrysogenum, on plant–pathogen interactions. Pen controlled a broad range of pathogens on several crop plants under greenhouse and field conditions. Pen protected grapevine from downy and powdery mildew (caused by Plasmopara viticola and Uncinula necator), tomato from early blight (caused by Phytophthora infestans), onion from downy mildew (Peronospora destructor) and apple trees from apple scab (caused by Venturia inaequalis) to a similar extent as fungicides such as copper and sulphur or well-known inducers such as benzothiadiazole or β-aminobutyric acid. Pen had no major direct fungicidal effect and is thus supposed to protect plants by activating their defense mechanisms. The raw material for extraction of Pen was available in constant quality, a prerequisite for commercial application. Under certain conditions, Pen caused phytotoxic side effects. The symptoms mostly consisted of small necrotic spots or, more rarely, of larger necrotic areas. The development of the symptoms was dependent on several parameters, including concentration of Pen, the number of applications, the persistence on the plant tissue, the plant species and variety and environmental conditions. In grapevine, a partially purified fraction of Pen was much less toxic than the crude Pen extract, but protected the plants to a similar extent against P. viticola. Our data show that Pen has interesting and unique properties as a plant protection agent, but more research is needed to further reduce its phytotoxic side effects.     

过氧化物酶活性及其同工酶与葡萄对霜霉病抗性的关系

采用盆栽接种的方法研究了不同抗病类型的葡萄品种感染霜霉病菌(Plasmopara viticola)后,过氧化物酶(POD)活性及同工酶酶谱的变化与葡萄抗霜霉病的关系.结果表明,霜霉病菌侵染后各品种的POD活性都有一个明显的消长过程,但抗病品种的酶活性升高的幅度大,持续的时间长.酶谱分析表明,不同抗性类型的葡萄感染霜霉病菌后,POD同工酶的数目、颜色与对照相比均有所增加.     

欧亚种葡萄对霜霉病与白粉病的抗性及关系

通过田间自然感病调查，利用配对设计方法，研究了7个欧亚种葡萄品种对霜霉病与白粉病的抗性关系。结果表明，在7个供试品种中，以藤稔、红宝石无核、矢富罗莎最抗霜霉病和白粉病，其它品种对这两种病害均无明显的抗性。欧亚种葡萄对霜霉病与白粉病的抗性之间存在极显著的直线正相关。     

银柴胡主要病虫害研究初报

对宁夏全区银柴胡病虫种群的构成、发生规律及田间虫种消长进行系统调查,并对为害银柴胡主要病害(根腐病、霜霉病、白粉病)、虫害(无翅黑金龟幼虫、银柴胡蚜)的生物学特性进行初步研究。     

葡萄白粉病与霜霉病抗性机理分析与探讨

近 8年来对葡萄白粉病与霜霉病抗性研究的基础上 ,结合前人的研究成果 ,从组织结构抗病性与生物化学物质抗病性两方面对葡萄植物抗白粉病与霜霉病的机理进行了分析与探讨 ,旨在为葡萄抗白粉病与霜霉病品种选育及病害防治提供依据