厚皮香枯梢病病原菌鉴定

厚皮香枯梢病在上海地区发生严重。本研究对上海地区的厚皮香枯梢病进行了病原菌的分离与致病性鉴定,得到其病原菌菌株2017SHTg。根据病原菌的形态特征将其鉴定为小新壳梭孢Neofusicoccum parvum。扩增病原菌2017SHTg的rDNA-ITS序列和翻译延伸因子EF-1α基因序列,进行BLAST序列比对与小新壳梭孢相似性分别为99%和100%;基于rDNA-ITS序列构建系统发育进化树,其在系统发育树上与小新壳梭孢的类群处于同一分支,此结果与形态学鉴定结果一致。     

辣椒溶杆菌NF87-2防治瓜类蔬菜蔓枯病的研究

由黑腐球壳菌Didymella bryoniae引起的瓜类蔬菜蔓枯病是一种重要真菌土传病害,造成瓜类蔬菜生产上重大的经济损失。本研究以蔓枯病菌DB-20为靶标菌,采用平板对峙培养法,测定了拮抗细菌及其代谢产物对蔓枯病菌菌丝生长和孢子萌发的的室内抑制作用,拮抗细菌和蔓枯病菌同时接种后,测定西瓜种子的发芽率和出苗率,采用盆栽试验研究拮抗细菌对黄瓜蔓枯病的防治效果。结果表明,辣椒溶杆菌Lysobacter capsici NF87-2对蔓枯病菌菌丝生长的室内抑制率为81.6%,菌株NF87-2及其次生代谢物对蔓枯病菌孢子萌发的抑制率分别为59.4%和67.2%。蔓枯病菌DB-20处理的京欣一号西瓜种子发芽率和出苗率分别为48%和38%,菌株NF87-2＋DB-20同时接种处理组的西瓜种子发芽率和出苗率分别为83%和82%。菌株NF87-2发酵液及其代谢产物对黄瓜蔓枯病的盆栽防治效果分别为81.6%和66.5%。辣椒溶杆菌NF87-2是一株具有较好生防应用潜力的拮抗菌株,有望开发成防治瓜类蔬菜蔓枯病的生物杀菌剂。     

玉米灰斑病菌的遗传多样性研究

 玉米灰斑病是由玉蜀黍尾孢菌(Cercospora zeae-maydis Tehon&Daniels)引起的世界性病害,近年来中国北方玉米发生较为严重。关于该病菌是否存在遗传变异现象在国内始终未见深人的报道,为此本研究通过RAPD技术,从DNA分子水平来研究玉米灰斑病菌群体内遗传变异的情况,为深入研究病菌致病性分化的机理和病菌一寄主互作的机理奠定基础。     

西瓜蔓枯病菌子实体的诱导及抗性鉴定

在26～28℃,12h光照/12h黑暗的条件下,西瓜蔓枯病菌Didymella bryoniae在西瓜叶汁B培养基上培养3周左右,能形成大量黄褐色的小点即分生孢子器;而在21～23℃,12h光照(40W荧光灯)/12h黑暗的条件下培养,在西瓜叶汁C培养基能大量形成黑色小点即子囊座。来源不同的蔓枯病菌对西瓜的致病力差异显著。用致病力最强的蔓枯病病菌菌株XD-99-04-29-01 2～4×10~5孢子/ml孢子液,喷雾接种3～4叶期的西瓜苗,保湿120h,20个被鉴定的国内外西瓜组合/品种的蔓枯病病情指数在15～50,差异明显。对美国的4个品种的抗病性鉴定结果与先前的报道一致。     

在水稻悬浮细胞系中非亲和白叶枯病菌繁殖受到抑制的现象及其机理的研究

 研究了水稻白叶枯病菌在水稻悬浮细胞系中的繁殖动力学特征以及悬浮细胞胞外液中各类物质对白叶枯病菌繁殖的影响。结果表明,水稻-白叶枯病菌非亲和互作与亲和互作相比病原菌繁殖的数量明显减少。胞外液中粗提蛋白对白叶枯病菌繁殖不具有抑制作用。非亲和互作胞外液中二元酚含量显著增高,并且水稻细胞防卫反应基因的转录和翻译活性明显增强。表明非亲和互作中白叶枯病菌繁殖受到抑制与水稻细胞防卫反应的启动相关。     

江苏省水稻品种细菌性条斑病抗性评价与病原菌致病力分化

采用针刺接种法,在水稻孕穗期接种3个不同致病型的细菌性条斑病菌,鉴定134个不同类型的水稻品种对细菌性条斑病的抗感性,并使用6个鉴别品种测定江苏徐淮地区82个细菌性条斑病菌的致病力.结果表明:粳稻品种对细菌性条斑病的抗性明显高于籼稻,常规稻和杂交稻对细菌性条斑病的抗性没有明显差异;根据病菌与鉴别品种的互作反应,将供试菌株区分为8个致病型,大多数菌株和鉴别品种表现为弱互作关系,少数菌株与鉴别品种存在强互作关系;第1致病型的菌株致病力强,6个鉴别品种均呈感病反应,并占供试菌株总数的40.2%.     

苹果炭疽叶枯病菌CgCMK1基因的克隆与功能分析

 苹果炭疽叶枯病是由胶孢炭疽菌(Colletotrichum gloeosporioides)引起的苹果重要叶部病害,严重威胁苹果树的生长。CMK1-MAPK途径在植物病原真菌致病过程中具有重要的作用。本研究从苹果炭疽叶枯病菌中克隆了黄瓜炭疽病菌(C. lagenarium)CMK1的同源基因CgCMK1。CgCMK1基因ORF全长1 068 bp,编码355个氨基酸。CgCMK1敲除后不影响苹果炭疽叶枯病菌营养生长、色素沉积以及脂滴的转运。ΔCgCMK1突变体产孢能力显著下降、分生孢子萌发但不产生附着胞,外源添加cAMP不能诱导ΔCgCMK1突变体形成附着胞,在ΔCgCMK1突变体中,过表达cAMP信号途径依赖的蛋白激酶催化亚基基因CgCPK1也不能恢复突变体形成附着胞。CgCMK1基因参与氧化胁迫的应答反应,但不参与离子胁迫的应答反应。ΔCgCMK1突变体对苹果叶片完全丧失致病性,即使有伤接种也不能产生病斑。CgCMK1在苹果炭疽叶枯病菌分生孢子和附着胞中均有表达,定位于细胞质。上述结果表明,CgCMK1参与调控苹果炭疽叶枯病菌的分生孢子产量、附着胞的形成、氧化胁迫应答及致病性。     

苹果炭疽叶枯病菌CgCMK1基因的克隆与功能分析

 苹果炭疽叶枯病是由胶孢炭疽菌(Colletotrichum gloeosporioides)引起的苹果重要叶部病害,严重威胁苹果树的生长。CMK1-MAPK途径在植物病原真菌致病过程中具有重要的作用。本研究从苹果炭疽叶枯病菌中克隆了黄瓜炭疽病菌(C. lagenarium)CMK1的同源基因CgCMK1。CgCMK1基因ORF全长1 068 bp,编码355个氨基酸。CgCMK1敲除后不影响苹果炭疽叶枯病菌营养生长、色素沉积以及脂滴的转运。ΔCgCMK1突变体产孢能力显著下降、分生孢子萌发但不产生附着胞,外源添加cAMP不能诱导ΔCgCMK1突变体形成附着胞,在ΔCgCMK1突变体中,过表达cAMP信号途径依赖的蛋白激酶催化亚基基因CgCPK1也不能恢复突变体形成附着胞。CgCMK1基因参与氧化胁迫的应答反应,但不参与离子胁迫的应答反应。ΔCgCMK1突变体对苹果叶片完全丧失致病性,即使有伤接种也不能产生病斑。CgCMK1在苹果炭疽叶枯病菌分生孢子和附着胞中均有表达,定位于细胞质。上述结果表明,CgCMK1参与调控苹果炭疽叶枯病菌的分生孢子产量、附着胞的形成、氧化胁迫应答及致病性。     

甜瓜营养液栽培中蔓枯病的发生与防治技术

潮州市东山农业科技开发有限公司从１９９７年开始利用营养液栽培甜瓜,取得比较满意的效果。但由于近２ａ连作严重,蔓枯病也时有发生。发病轻时影响瓜的品质,严重时可导致死秧,整棚无收,对发展甜瓜生产影响较大。１发病症状及有关因素该病病菌发育生长温度以平均气温...     

广西一点红真菌性病害病原鉴定续报

在已报道的一点红真菌性病害病原菌鉴定的基础上,对最新研究和鉴定的真菌性病害病原菌鉴定进行续报,它们分别是枝枯病、菌核病和炭疽病。枝枯病的病原为洋扁豆大褐斑病菌[Diaporthe phaseolorum(Cke.et Ell.)Sacc.],菌核病的病原为核盘菌[Sclerotinia sclerotiorum(Lib.)de Bary],炭疽病的病原为围小丛壳菌(Glomerella cingulata),其无性态为胶孢炭疽菌(Colletotrichum gloeosporioides)。     

西瓜蔓枯病分子诊断技术研究

 本文测定西瓜上的西瓜蔓枯病菌(Didymella bryoniae)、西瓜炭疽病菌(Colletotrichum orbiculare)及西瓜枯萎病菌(Fusarium oxysporum f. sp. niveum)的rDNA的ITS序列,比对近缘种及西瓜上不同病菌的ITS序列同源性,设计出特异性上游引物XM-2和下游引物XM-R2。经过对XM-2/XM-R2引物的PCR扩增条件的优化,可以扩增出一条344bp的西瓜蔓枯病菌特异性DNA条带。上述方法可以检测到pg以上的蔓枯病菌基因组DNA,并且可以准确扩增出西瓜蔓枯病自然病样中特异性的DNA片段。本文建立了一项西瓜蔓枯病分子检测技术,该方法准确、快速、可靠,可用于西瓜蔓枯病田间的快速诊断。     

Internal Transcribed Spacer Regions 1 and 2 and Random Amplified Polymorphic DNA Analysis of Didymella bryoniae and Related Phoma Species Isolated from Cucurbits

ABSTRACT Didymella bryoniae (anamorph Phoma cucurbitacearum) is the causal agent of gummy stem blight, although other Phoma species are often isolated from cucurbit plants exhibiting symptoms of the disease. The molecular and phylogenetic relationships between D. bryoniae and these Phoma species are unknown. Isolates of D. bryoniae and Phoma obtained from cucurbits grown at various geographical locations in the United States were subjected to random amplified polymorphic DNA (RAPD) analysis and internal transcribed spacer (ITS) sequence analysis (ITS-1 and ITS-2) to determine the molecular and phylogenetic relationships within and between these fungi. Using RAPD fingerprinting, 59 isolates were placed into four phylogenetic groups, designated RAPD group (RG) I, RG II, RG III, and RG IV. D. bryoniae isolates clustered in either RG I (33 isolates), RG II (12 isolates), or RG IV (one isolate), whereas all 13 Phoma isolates clustered to RG III. There was greater than 99% sequence identity in the ITS-1 and ITS-2 regions between isolates in RG I and RG II, whereas isolates in RG III, P. medicaginis ATCC 64481, and P. exigua ATCC 14728 clustered separately. On muskmelon seedlings, a subset of RG I isolates were highly virulent (mean disease severity was 71%), RG II and RG IV isolates were slightly virulent (mean disease severity was 4%), and RG III isolates were nonpathogenic (disease severity was 0% for all isolates). The ITS sequences indicate that RG I and RG II are both D. bryoniae, but RAPD fingerprints and pathogenicity indicate that they represent two different molecular and virulence subgroups.     

一种大豆对拟茎点茎枯病抗性鉴定技术体系的构建

 由Phomopsis longicolla(或Diaporthe longicolla)等拟茎点霉(间座壳)属真菌引起的拟茎点茎枯病是我国黄淮海等地大豆生产中的一种重要茎部病害。利用抗病品种是防控该病最为经济有效的措施。为构建一种大豆对拟茎点茎枯病的室内抗性鉴定技术体系,用于抗病资源的快速筛选,本研究比较了下胚轴创伤接种法、切茎接种法、黄化苗接种法、种子接种法和菌丝块贴茎法等5种接种方法,发现下胚轴创伤接种法具有操作简单、试验周期短、易于判定结果、结果稳定性好的优点。选取5个具有毒力强弱和地域代表性的P. longicolla菌株为鉴别菌株系,建立了抗性结果评价标准,形成了抗性鉴定技术体系。对2020年从黄淮海等地收集的62份大豆主栽品种进行抗性鉴定,发现对强毒力菌株DT3-3-1和弱毒力菌株ZZ1-1高抗的品种分别占31%和68%,有13个品种同时高抗5个菌株(占21%),表明我国大豆主栽品种中存在对拟茎点茎枯病的抗性种质资源。本研究为挖掘大豆对拟茎点茎枯病的抗性资源提供了新的候选方法。     

Correlation of trichome density and length and polyphenol fluorescence with susceptibility of five cucurbits to Didymella bryoniae

Journal of Plant Diseases and Protection - The fungal pathogen Didymella bryoniae causes gummy stem blight and black rot on a broad spectrum of cucurbits. However the substantial differences in...     

Screening for resistance to Didymella bryoniae in rootstocks of melon

Glasshouse evaluations of rootstocks of melon for resistance to Didymella bryoniae were conducted on different cucurbits previously selected as resistant or partially resistant to race 1,2 of Fusarium oxysporum f. sp. melonis. Cucumis anguria, C. ficifolius, C. figarei, C. metuliferus, C. zeyheri and Benincasa hispida showed a very high degree of resistance to D. bryoniae both on leaves and stems. Among the commercial rootstocks, Cucurbita hybrids ELSI, ES 99-13, RS 841, displayed a similar level of resistance. Stem inoculation of three cucurbit species grafted with susceptible melon cv. Proteo determined the occurrence of limited symptoms, but the lesions remained confined in the rootstock not affecting the grafted plant. Cultivation of susceptible melon cultivars grafted on resistant rootstocks may represent an efficient method for controlling Didymella crown rot and Fusarium wilt.     

Characterization and host range evaluation of Pseudomonas viridiflava from melon, blite, tomato, chrysanthemum and eggplant

The fluorescent bacterium Pseudomonas viridiflava (Burkholder) Dowson was identified as the causal agent of bacterial leaf blight of melon, tomato, blite, eggplant and of pith necrosis of chrysanthemum plants. Koch's postulates were fulfilled on greenhouse-grown or on potted plants under controlled environmental conditions. Twenty seven cultivated and one weed species, when artificially inoculated, were found to be susceptible to a strain of the bacterium isolated from cucumber. In cross-inoculation tests on potted plants, each strain induced the disease symptoms, independently of the host of origin. To our knowledge, melon and blite have not been previously reported as natural hosts of P. viridiflava. Also this is the first record of the bacterium as a foliar pathogen of melon, tomato, eggplant and blite and as a stem pathogen of chrysanthemum in Greece.     

广东省新推广大豆品种病害的初步调查

本文采用普查和定点调查以及传统的植物病害鉴定方法,在2006年6月至2010年10月对广东省新推广高产优质大豆品种的病害种类、发生危害及分布进行了调查.发现病害共有12种,其中真菌病害9种,分别是锈病、霜霉病、红冠腐病、丝核菌叶枯病、炭疽病、白绢病、白粉病、镰刀菌根腐病和煤烟病;细菌性病害、线虫病害和病毒病害各1种,分别为细菌性叶斑病、根结线虫病和花叶病.主要病害为锈病、霜霉病、红冠腐病、花叶病、丝核菌叶枯病和炭疽病等.不同季节大豆的主要病害发生情况不同.春大豆以霜霉病发生较为严重;而夏大豆则以红冠腐病、锈病、花叶病毒病和丝菌核叶枯病发生较严重.     

Assessment of the impact of mid-season late blight infection on disease development and yield of potato variety Russet Norkotah in Maine

Development of late blight of potatoes caused by Phytophthora infestans (US 8 fungal genotype, A2 mating type) was monitored in two Russet Norkotah commercial fields at Fort Fairfield in 1996 and Duncan Farm in 1997. Experimental plots representing various disease treatments (low, moderate, high and random late blight severity levels) were established in two fields in 1996. In 1997, only low and high disease treatments were established. The application of fungicides for late blight control was conducted in both years. Late blight incidence and severity were assessed in each plot of each treatment. Components of late blight disease development, tuber blight incidence and tuber yields were determined from each plot. Progress of late blight disease was rapid in 1996 but not in 1997. During the 1996 cropping season, mean disease incidence and severity in the random disease treatment plots were 84 and 21% respectively within 10 days of disease detection. In 1997, low levels of late blight severity were detected in the field plots. Average numbers of late blight leaf and stem lesions on infected plant and fungal sporangia on the diseased leaf were not significantly affected by disease treatment. Late blight foliar severity significantly affected potato tuber yields. Lowest tuber yield was obtained in plots with high disease levels and highest yields were recorded in plots with low late blight severity in 1996. Late blight severity was significantly correlated with tuber yield but not with per cent tuber blight.     

中国香瓜与菜瓜地方品种资源白粉病抗性评价

春秋2个季节在温室利用风媒接种方法对搜集的102份香瓜和14份菜瓜种质资源进行了白粉病抗性评价,结果鉴定出7份香瓜和1份菜瓜高抗白粉病,其病情指数为零,1份菜瓜抗病,其病情指数0.9,表明我国香瓜和菜瓜地方品种资源中蕴涵着潜在的改良甜瓜白粉病抗性的基因资源。     

Pectolytic enzymes produced in vitro and during colonization of melon tissues by Didymella bryoniae

Pectolytic enzymes produced by Didymella bryoniae in a liquid medium containing pectin as sole carbon source and in inoculated etiolated hypocotyls of 10 melon cultivars, as well as those constitutively expressed in spores, were studied by isoelectric focusing, quantitatively and qualitatively. Five constitutive pectin lyase (PNL) isoenzymes differing in isoelectric joint (pI), one acidic (pI 3.9) and four basic (pI 8.4, 8.9, 9.3, 9.9) were expressed in extracts from spores. The same PNL isoenzyme pattern was detected in culture filtrates and in infected tissues of all the melon cultivars tested. Polygalacturonase (PG) activity, represented by a single inducible acidic band (pI 4.6) was detected only in culture filtrates. A single constitutive basic pectin methylesterase (PME) isoenzyme (pI > 10.0) was also found in spores, culture filtrates and inoculated melon tissues. All cultivars were susceptible at the seedling growth stage, but with differences in disease severity; cultivars Amarillo Oro and Juane Canari were, respectively, the least and most susceptible. Pectin lyase activity was highly correlated with disease severity. In rotted tissues and culture filtrates, an increase in pH to values over 7.0 was recorded, values optimal for PNL activity. In this plant–pathogen interaction, PNL activity represents the principal pectolytic component and these isoenzymes were associated with the onset of disease, disease severity and an increase in pH of infected tissue.