硫酸链霉素对番茄斑疹病病菌的毒力测定

为明确硫酸链霉素对番茄斑疹病病菌的毒力及对病害的防效,采用平板菌落计数法测定其毒力,并对温室内番茄植株进行人工接菌后喷施药剂,测定其防效。结果表明,硫酸链霉素对番茄斑疹病病菌的毒力(EC_50)为0.060 8μg/m L;温室防治试验中,72%硫酸链霉素可溶性粉剂3 500~6 000倍液处理对发病植株的病指防效为95.24%~77.78%,除最低用量6 000倍液处理外,均极显著高于对照药剂46.1%氢氧化铜水分散粒剂1 250倍液处理。从沈阳地区保护地发病番茄上采集的供试斑疹病病菌对硫酸链霉素高度敏感,未产生抗药性。     

四霉素对番茄叶霉病菌的毒力效应及田间防治效果

为评价四霉素对番茄叶霉病的防治效果,采用菌丝生长速率法和孢子萌发法分别测定了四霉素对9株不同地区来源的叶霉病菌（Passalora fulva）菌丝生长、孢子萌发以及芽管伸长的毒力,并进行了田间药效试验。结果表明:四霉素对番茄叶霉病菌具有较高的抑制活性,其中抑制孢子萌发、芽管伸长的活性较高,其EC50值分别为0.002 30~0.012 7 μg/mL、0.000 50~0.013 μg/mL;对菌丝生长抑制活性略低,其EC50值为0.601 6~1.394 μg/mL。显微观察发现:经四霉素处理后,番茄叶霉病菌新生菌丝生长受阻、部分菌丝末端分支增多、变粗;分生孢子萌发受抑制,芽管膨大变粗、生长受阻。田间试验结果表明:经四霉素有效成分6.75和20.25 g/hm2处理后,对番茄叶霉病的保护防效分别为74.40%和83.09%,治疗防效分别为67.92%和76.68%,均显著高于对照药剂甲基硫菌灵（有效成分540 g/hm2）的处理防效。     

六种三唑类杀菌剂对番茄叶霉病菌的毒力及其安全性和田间防效评价

为筛选出有效防治番茄叶霉病的药剂,采用生长速率法及平板涂布法测定6种三唑类杀菌剂对番茄叶霉病菌菌丝生长及分生孢子萌发和芽管伸长的毒力,评价其对番茄植株的安全性和对叶霉病的田间防效。结果表明,己唑醇、苯醚甲环唑、戊唑醇和氟硅唑对番茄叶霉病菌菌丝生长的毒力均较高,EC_(50)分别为0.50、0.55、0.80、2.42 mg/L,其次为腈菌唑和四氟醚唑,EC50分别为6.92、15.08 mg/L。6种杀菌剂抑制病菌分生孢子萌发及芽管伸长的作用均较弱,对芽管伸长的抑制活性高于对孢子萌发的抑制活性;戊唑醇和四氟醚唑抑制孢子萌发的作用相对较强,100 mg/L处理的抑制率为60%~70%,戊唑醇、四氟醚唑和己唑醇抑制芽管伸长的作用相对较强,100 mg/L处理的抑制率均在70%以上。己唑醇和戊唑醇200 mg/L处理番茄植株,显著抑制其株高,苯醚甲环唑和腈菌唑对其影响相对较小,这4种杀菌剂对番茄植株的叶色及形态均无明显影响;且这4种杀菌剂对番茄叶霉病的田间预防效果均高于治疗效果,其中150 mg/L己唑醇的预防效果和治疗效果均最高,分别为90.67%和85.58%;苯醚甲环唑的最低,300 mg/L时预防效果为80.16%,治疗效果为71.68%。     

不同杀菌剂对番茄早疫病菌的室内毒力测定

番茄早疫病由真菌茄链格孢菌侵染所致的一种病害,也是武汉地区番茄生产中发生最为普遍的一种病害,5月下旬到6月,是早疫病发生高峰期,发病严重时引起落叶、落果和断枝,对产量影响很大,常年减产20%～30%,严重时达50%以上,甚至绝收.     

火把对柑桔炭疽病菌的室内毒力试验

采用菌丝生长速率法,用杀菌剂火把对柑桔炭疽病菌进行了室内毒力测定,测得火把对柑桔炭疽病的EC50值为0.8110μg/mL,EC98值为10.5435μg/mL,确定了其在室内有效抑菌浓度。本试验有利于指导进一步的室外药效试验以确定实际应用中的最佳施用浓度。     

不同杀菌剂对柑橘果实采后炭疽病菌室内毒力测定

[目的]为筛选出防治柑橘炭疽病的有效药剂.[方法]采用菌丝生长速率法测定了9种杀菌剂对柑橘炭疽病菌(Colletotrichum gloeosporioides)的毒力作用.[结果]25％吡唑醚菌酯、95％肟菌酯、96％戊唑醇、95％苯醚甲环唑、40％双胍三辛烷基、75％百菌清、75％肟菌酯戊唑醇、80％代森锰锌和70...     

不同杀菌剂对烟草赤星病菌室内毒力测定

[目的]筛选防治烟草赤星病的有效药剂.[方法]采用菌丝生长速率法和孢子萌发法测定7种杀菌剂对烟草赤星病菌(Alternaria alternata)的毒力作用.[结果]菌丝生长速率法中56％啶酰·肟菌酯、50％啶酰菌胺、30％肟菌·戊唑醇、72％霜脲·锰锌、80％戊唑醇、30％丙硫菌唑、50％氯溴异氰尿酸的EC50值分别为0.1525,0.1603,0.2420,1.8137,4.5663,14.8457,86.9761 mg/L,孢子萌发法中50％啶酰菌胺、50％氯溴异氰尿酸、56％啶酰·肟菌酯、72％霜脲·锰锌、80％戊唑醇、30％肟菌·戊唑醇、30％丙硫菌唑的EC50值分别为0.1272,0.1333,0.2088,1.3191,1.8218,3.1282,27.0458 mg/L.供试的7种杀菌剂中对菌丝生长的抑制效果最好的是56％啶酰·肟菌酯,EC50值为0.1525 mg/L;对孢子萌发的抑制效果最好的是50％啶酰菌胺,EC50值为0.1272 mg/L.[结论]56％啶酰·肟菌酯和50％啶酰菌胺可优先作为烟草赤星病田间防治实验用药,72％霜脲·锰锌和30％肟菌·戊唑醇可用作交替使用杀菌剂.     

甲霜灵·霜霉威复配剂对棉疫病菌的联合毒力

在实验室条件下,测定了甲霜灵和霜霉威复配剂对棉疫病菌(Phytophthora boehmeriae)的联合毒力。结果表明,复配剂MPA、MPB、MPC对棉疫病菌的EC50分别为0.055 5、0.104 4μg/mL和0.084 5μg/mL,对照单剂甲霜灵和霜霉威对棉疫病菌的EC50分别为0.039 1μg/mL和10.618 3μg/mL;联合毒力分析表明,甲霜灵和霜霉威按1∶1.5复配有增效作用,按1∶1和1.5∶1复配有相减作用。     

9种杀菌剂对苹果斑点落叶病菌和轮纹病菌的毒力比较

在室内比较测定了己唑醇等9种杀菌剂对苹果斑点落叶病菌和苹果轮纹病菌的抑菌毒力。结果表明:苹果斑点落叶病菌对三唑类杀菌剂己唑醇、戊唑醇、腈菌唑、氟硅唑和苯醚甲环唑的敏感性依次下降,EC50值均在1μg/mL以下,EC90值均低于10μg/mL;上述药剂与异菌脲的毒力相当,高于多氧霉素。苹果轮纹病菌对供试5种三唑类杀菌剂的敏感性略低于斑点落叶病菌,其中仍以己唑醇毒力最高,其次是戊唑醇、氟硅唑、腈菌唑、苯醚甲环唑,异菌脲与苯醚甲环唑的毒力水平相当,表明上述药剂对轮纹病有兼治作用,而多氧霉素对该病菌的毒力相对较低。2种病菌对甲氧基丙烯酸酯类的醚菌酯敏感性均较低,而硫酸铜的抑菌毒力最低。     

9种杀菌剂对西瓜炭疽病菌的室内毒力测定及配比试验

为筛选防治西瓜炭疽病的高效低毒杀菌剂, 缓解和治理生产中病菌对药剂的抗性, 在室内离体条件下采用生长速率抑制法及孢子萌发抑制法测定了9种杀菌剂对西瓜炭疽病菌( Colletotrichum orbiculare )的毒力。结果表明, 嘧菌酯、咪鲜胺和甲基硫菌灵对病原菌菌丝生长的EC50在0.093 3~0.118 2 mg/L之间, 均小于1 mg/L, 表明西瓜炭疽病菌对上述杀菌剂比较敏感; 百菌清、烯肟菌酯和戊菌唑的EC50在2.310 1~5.925 9 mg/L, 病菌对药剂的敏感程度相对较低; 代森锰锌、恶霉灵和多菌灵的EC50分别为36.876 3、74.466 6和99.898 5 mg/L, 抑菌活性较差。孢子萌发试验中, 嘧菌酯、咪鲜胺和甲基硫菌灵对病菌孢子萌发的抑制活性最高, EC50在0.069 4~0.167 2 mg/L之间; 百菌清、烯肟菌酯、代森锰锌的抑制活性次之, EC50在1.853 0~9.503 9 mg/L之间; 多菌灵的抑制活性相对最低, EC50为99.335 3 mg/L。将两种不同作用机理的杀菌剂嘧菌酯与咪鲜胺按照2∶1的比例混配, 联合毒力测定和评价结果表明两者混配对抑制西瓜炭疽病菌具有增效作用。     

Similarity between Copper Resistance Genes from Pseudomonas syringae pv. actinidiae and P. syringae pv. tomato

Twenty-eight strains of Pseudomonas syringae pv. actinidiae isolated in 1984, 1987 and 1988 from kiwifruit orchards in Japan were tested for their resistance to copper sulfate. All strains isolated in 1984 were copper sensitive with a minimum inhibitory concentration (MIC) of cupric sulfate of 0.75 mM. However, some strains isolated in 1987 and 1988 were resistant, with the MIC ranging from 2.25 to 3.0 mM. All copper-resistant strains contained at least one of two plasmids, pPaCul (about 70.5 kb) or pPaCu2 (about 280 kb), or both. In a copper-resistant strain Pa429, the location of the copper-resistance gene(s) was examined by insertional inactivation with Tn5. The MIC of copper sulfate in the copper-sensitive mutant obtained by Tn5 tagging decreased from 2.75 to 0.75 mM. The 14.5 kb BamHI fragment, designated pPaCuB14, containing the same locus mutagenized with Tn5 was cloned from pPaCu1. However, pPaCuB14 did not confer copper resistance in the transformant of copper-sensitive strain Pa21R, suggesting that this clone did not contain a full set of copper-resistance gene(s). Then a cosmid library of pPaCu1 was constructed and six cosmid clones hybridized with pPaCuB14 were selected. One of the six cosmids, designated pPaCuC1, conferred a near wild-type level of copper resistance in the transformant of the copper-sensitive strain. pPaCuC1 had a homologous region that hybridized with all of the PCR-amplifled fragments of copA, copB, copR, and copS genes of P. syringae pv. tomato. DNA sequence analysis of the homologous region revealed the existence of four open reading frames (ORF A, B, R and S) oriented in the same direction. The predicted amino acid sequences of ORF A, B, R and S had 80, 70, 97 and 95% identity with CopA, B, R and S of P. syringae pv. tomato, respectively. Received 5 July 2001/ Accepted in revised form 27 September 2001     

Comparison of ethylene-producing Pseudomonas syringae strains isolated from kudzu (Pueraria lobata) with Pseudomonas syringae pv. phaseolicola and Pseudomonas syringae pv. glycinea

The relationships among strains of Pseudomonas syringae pv. glycinea (Psg) and Pseudomonas syringae pv. phaseolicola (Psp) isolated from kudzu ( Pueraria lobata) and bean ( Phaseolus vulgaris) were investigated. All strains tested showed a close phenotypic similarity, with the exception of the utilization of inositol and mannitol as well as the production of toxins. On this basis the strains could be divided into three groups. Group 1 consists of all strains of pathovar glycinea, group 2 includes all Psp strains isolated from kudzu, and all Psp strains isolated from bean belong to group 3. This grouping was also reflected in the genetic fingerprints using the polymerase chain reaction (PCR) with primers that anneal to dispersed repetitive bacterial sequences (rep-PCR). The rep-PCR generated fingerprints were unique for each of the three groups. The strains of group 2, Psp strains isolated from kudzu, possess certain characteristics of group 1 (ethylene production) and group 2 (phaseolotoxin production). The Psp strains from kudzu can be clearly differentiated from Psp strains isolated from bean. They utilize mannitol, produce ethylene, and are strongly pathogenic to kudzu, bean, and soybean. The results obtained show that the Psp strains from kudzu should be separated from the pathovar phaseolicola and should represent their own pathovar.     

番茄细菌性叶斑病菌超分支滚环扩增快速检测技术

根据番茄细菌性叶斑病菌(Pseudomonas syringae pv. tomato,Pst)的一段特异蛋白基因序列,按照锁式探针的设计原理设计探针和扩增引物,优化系列反应条件,建立了特异性的Pst超分支滚环扩增技术。试验结果表明：该检测技术能够从供试的10种不同的病原菌中特异性地检测出番茄细菌性叶斑病菌,DNA检测的最低浓度为500 fg/μL,检测灵敏度高于常规PCR。     

应用PCR方法快速检测黄瓜细菌性角斑病菌

黄瓜细菌性角斑病是黄瓜上的一种重要细菌病害,其病原为丁香假单胞菌黄瓜致病变种(Pseudomonas syringae pv.lachrymans),目前未见到该病害特异性PCR检测方法的报道。通过分析丁香假单胞菌(P.syringae)不同致病变种glyceraldehyde-3-phosphate dehydrogenase 1(gap1)基因序列设计得到一对Psl特异性PCR引物。利用该引物对丁香假单胞菌不同致病变种、假单胞菌属其他种及其他属的共46株菌株进行了PCR扩增,结果表明,所有不同来源的12株黄瓜细菌性角斑病菌均得到179bp的目标片段,而所有其他参试菌株均无扩增条带,PCR检测的灵敏度为7.5×103cfu/mL。利用该方法可从接种后发病的黄瓜叶片总DNA中检测到特异条带,而健康叶片无条带。该引物的PCR检测方法可直接用于植株总DNA的检测,无需进行病原菌的分离培养,快速简便,适用于进出境检验检疫及种苗健康检测等。     

Leaf necrosis and twig dieback of sweet persimmon (Dyospiros kaki L.) caused by Pseudomonas syringae pv. syringae in Italy

In spring 1996, extensive leaf necrosis and twig dieback were observed on young sweet persimmon (Dyospiros kaki L.) trees, cultivars O'Gosho, Hachija, Mercatelli and Kaki-tipo planted in the Abruzzo region (central Italy). Many trees were killed. When the dieback reached the trunk, in many cases, new vegetation was noticed above the graft point. The cultivar Jiro-C was not affected by the disease. During 1997, no symptoms were observed on any plant. The orchard was planted in a clay soil with a very low content of organic matter. Biochemical, nutritional and pathogenicity tests indicated Pseudomonas syringae pv. syringae van Hall as the causal agent of the disease. This is the first report of this bacterium as a pathogen of sweet persimmon in Europe.     

猕猴桃溃疡病菌在中国的适生性分析

通过分析猕猴桃溃疡病菌在中国的适生性,为科学制定有效的检疫监管措施,防范其入侵和扩散,确保猕猴桃产业健康发展提供理论依据。本研究根据前人研究结果,采用模糊数学综合评判的原理和方法,定量分析猕猴桃细菌性溃疡病菌(Pseudomonas syringae pv.actinidiae)在我国各个地区的适生性。猕猴桃溃疡病菌在我国最适宜的省份主要分布在四川、云南、贵州、福建、安徽、湖南、湖北、河南、江西、陕西、浙江、重庆、西藏。鉴于该病具有发生发展迅速,危害性强,防治难度大等特点,应当加强猕猴桃种苗等繁殖材料的检疫,加强对果园的管理和病害监测,积极采取有效的防治措施并加强抗病育种方面的研究。     

Persistence and translocation of a benzothiadiazole derivative in tomato plants in relation to systemic acquired resistance against Pseudomonas syringae pv tomato

A reproducible and accurate procedure, based on HPLC analysis, has been developed to determine simultaneously acibenzolar‐S‐methyl (CGA 245 704) and its acid derivative (CGA 210 007) in tomato leaves. The limit of detection and quantification of the method are 0.015 and 0.15 mg litre^?1 for CGA 245 704 and 0.030 and 0.30 mg litre^?1 for CGA 210 007. In tomato plants treated with 250 µM CGA 245 704, it was found that the inducer rapidly translocates from treated leaves (cotyledons, 1st and 2nd) to untreated leaves (3rd to 5th), with the maximum translocation (40% of the total quantity found) occurring 8 h after the treatment. CGA 245 704 residues decreased as time elapsed in both treated and untreated tomato leaves, reaching negligible values 72 h after treatment. The acid derivative, CGA 210 007, was formed in tomato plants as early as 2 h after CGA 245 704 treatment, albeit only in the treated leaves. CGA 210 007 residues decreased in treated tomato leaves with a trend similar to that observed for CGA 245 704. Treatment of tomato plants with CGA 245 704 or CGA 210 007 at 250 µM systemically protected the plants against Pseudomonas syringae pv tomato attacks, the causal agent of bacterial speak disease. Evidence of this were reductions in the degree of infection, the bacterial lesion diameter and the bacterial growth in planta. Since neither CGA 245 704 nor CGA 210 007 inhibited bacterial growth in vitro and the protection against bacterial speak of tomato was observed when the two compounds were completely degraded, the protection must be due to the activation of the plant's defence mechanisms. © 2001 Society of Chemical Industry     

中国4省猕猴桃细菌性溃疡病菌的生物型检测和遗传多样性分析

由丁香假单胞菌猕猴桃致病变种Pseudomonas syringae pv. actinidiae (Psa)侵染引起的猕猴桃细菌性溃疡病(kiwifruit bacterial canker)是全球猕猴桃生产上最具毁灭性的细菌病害。为探明福建、安徽、四川和陕西4省Psa菌株的生物型和遗传多样性,用5对PCR特异性引物PsaJ-F/-R、PsaK-F/-R、Tac-F/-R、Con002-F/-R和avrRps4-F1/-R2检测Psa菌株的生物型;用4对PCR引物27F/1492R、PsaF1/PsaR2、gapA-Fps/Rps和rpoD+364s/-1222ps分别扩增16S rRNA、ITS、gapA和rpoD基因,进行多基因联合分析Psa菌株的遗传多样性。结果表明,特异性引物Tac-F/-R从47株Psa菌株中均能扩增出一条545 bp的特异条带,其他4对引物未扩增出任何条带,说明供试Psa菌株的生物型均为biovar 3。多基因联合分析表明,4省Psa存在丰富的遗传多样性,4个群体共检测出27个单倍型,单倍型多样性为0.955。安徽、福建、四川和陕西群体的单倍型数差异较大,分别为1、8、12个和12个。4个群体的多态性位点数、核苷酸多样性和平均核苷酸差异数差异极显著(P<0.01),其中福建群体的多态性最丰富,而安徽群体的多态性最低。AMOVA分析表明,3.6%的遗传变异来源于种群间,而96.4%的遗传变异来源于种群内,说明种群内变异是遗传变异的主要来源。遗传分化分析表明,安徽省Psa群体与其他3个群体间的遗传分化极高(Fst>0.175),福建、四川和陕西群体间的遗传分化水平较低(Fst<0.017)。研究结果有利于了解福建省Psa的来源,为阻断Psa的传播和猕猴桃细菌性溃疡病的长期可持续控制提供了理论参考。     

云南省烟草野火病菌生理小种分化的研究

 通过从云南省主要产烟区收集到的45个烟草野火病菌菌株在15个供试烟草品种上的接种试验研究,筛选到一套烟草野火病菌生理小种鉴别寄主体系.同时,以发病率作为抗感划分标准,可将供试菌株划分为4个生理小种(即生理小种Ⅰ、Ⅱ、Ⅲ、Ⅳ).