不同新型作用机制杀菌剂对梨树主要病菌毒力及防治流程应用

 为明确多种新型作用机制杀菌剂与引起梨树褐斑病、黑星病、白粉病等病原菌的有效对靶关系及制定梨树主要病害防治流程,采用菌丝生长速率法、离体叶片法与田间药效方法研究新型杀菌剂对靶标病原菌的毒力、对靶标病害的防效及其田间有效应用,建立替代梨树主要病害传统化学杀菌剂的防治流程技术。结果显示,双胍三辛烷基苯磺酸盐在离体叶片法下对褐斑病的防效大于85%,田间药效验证3次用药后7 d防效大于85%、30 d防效大于80%、90 d防效仍大于60%,兼治轮纹病菌其毒力EC₅₀值均小于1 μg·mL^-1。双胍三辛烷基苯磺酸盐、辛菌胺醋酸盐、吩嗪α-2羧酸在离体叶片法下对黑星病防效大于90%且毒力EC₅₀值小于1 μg·mL^-1;田间药效验证1次用药后7 d防效大于80%、30 d防效仍大于75%。噻肟菌酯、硝苯菌酯、丙硫菌唑在离体叶片法下对白粉病的防效大于85%;田间药效验证3次用药后7 d铲除效果大于70%、30 d仍大于60%。丙硫菌唑对黑斑、轮纹病菌毒力EC₅₀值均小于1 μg·mL^-1;吩嗪α-2羧酸同时对褐斑、黑斑、轮纹病菌毒力EC₅₀值小于1 μg·mL^-1。针对梨树主要病害发生期,选用新型杀菌剂替代传统杀菌剂制定防治技术流程,其综合防效达到88.94%。不同新型作用机制杀菌剂在防治梨树主要病害上的应用,能够降低抗药性产生,同时达到有效防治的目的。     

四种杀菌剂对小麦根病病原菌的室内药效试验

室内药效试验表明：麦根宁1号、敌力脱对小麦根腐病菌的生长均有良好的抑制作用。麦根宁Ⅰ号稀释300倍时，平均抑菌圈直径最大；敌力脱稀释800倍时，平均抑菌圈直径最大。同时，麦根宁Ⅰ号、敌力脱Ⅱ号，粉锈宁对小麦全蚀病菌生长也有明显的抑制作用。粉锈宁，麦根宁Ⅰ，Ⅱ号在稀释10000倍时，抑菌率均达100％；敌力脱在稀释15000倍时，平均抑菌率仍达89．7％。     

Sensitivity of four Yeasts to Fungicides and CO2 Concentrations and Their Antagonistic Ability in Combination with Fungicide to pathogenic Fungi in vitro

The yeasts Cryptococcus laurentii,Trichosporon pullulans,Rhodotorula glutinis and Trichosporon sp.were used to investigate their sensitivity to four fungicides and different concentrations of CO2,as well as their antagonistic ability to Penicilliumexpansum and Alternaria alternata in vitro when applied with fungicide.There were significant differences in sensitivity to the fungicides among the different yeasts(P = 0.05).R.glutinis was more sensitive to Deccocil,Iprodione and Stroby as compared to other yeasts.Combination antagonistic yeasts with fungicide could more significantly enhance biocontrol ability of the yeasts against the pathogenic fungi in vitro(P = 0.05).C.laurentii was the most effective antagonist among the four yeasts and could completely control spore germination of P.expansum and A.alternata when combined with Stroby at the concentration of 100 μL L-1.The yeasts,except R.glutinis,could grow well on nutrient yeast dextrose agar (NYDA) after 8 d incubation even at 20% CO2 concentration at 25℃.Particularly Trichosporon sp.showeda better adaptability to low temperature as compared to other antagonists.     

甲氧基丙烯酸酯类杀菌剂的应用、开发现状及展望

本文对甲氧基丙烯酸酯类杀菌剂的开发现状及应用前景进行了简要的介绍。文中涉及甲氧基丙烯酸酯类杀菌剂的化学结构、生物活性、登记与专利和开发公司等。     

Secretion of Natural and Synthetic Toxic Compounds from Filamentous Fungi by Membrane Transporters of the ATP-binding Cassette and Major Facilitator Superfamily

This review provides an overview of members of the ATP-binding cassette (ABC) and major facilitator superfamily (MFS) of transporters identified in filamentous fungi. The most common function of these membrane proteins is to provide protection against natural toxic compounds present in the environment of fungi, such as antibiotics produced by other microorganisms. In plant pathogenic fungi, these transporters can also be an important determinant of virulence on host plants by providing protection against plant defence compounds or mediating the secretion of host-specific toxins. Furthermore, they play a critical role in determining base-line sensitivity to fungicides and other antimycotic agents. Overexpression of some of these transporters can lead to the development of resistance to chemically-unrelated compounds, a phenomenon described as multidrug resistance (MDR). This has been observed in a variety of organisms and can impose a serious threat to the effective control of pathogenic fungi.     

十种常用农药与球孢白僵菌的生物学相容性

球孢白僵菌孢子粉与10种常用农药相容性的测定结果显示,随着孢子浓度上升,所试农药对孢子的抑制作用均有不同程度的增强。在1/10田间常规使用浓度下,百菌清和代森锰锌均能抑制或杀死孢子(萌发率<1％)。除阿维菌素外,所有杀虫剂均与白僵菌孢子相容,在常规使用浓度的10倍稀释液中孢子萌发率达90％以上。吡虫啉、蚜虱灵、灭多威和氟虫腈与孢子的相容性最好,其中吡虫啉和蚜虱灵对孢子萌发率的影响不明显随药剂浓度的变化而变化,即使在田间常规使用浓度下孢子萌发率也在95％以上,而阿维菌素与白僵菌的相容性极差。因此,应用白僵菌制剂防治害虫,选择生物学相容性好的农药以低剂量与白僵菌制剂混用,既可使菌剂增效,又可大幅度降低化学药剂用量。     

Functional Analysis of ABC Transporter Genes From Botrytis cinerea Identifies BcatrB as a Transporter of Eugenol

The role of multiple ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporter genes from the plant pathogenic fungus Botrytis cinerea in protection against natural fungitoxic compounds was studied by expression analysis and phenotyping of gene-replacement mutants. The expression of 11 ABC (BcatrA–BcatrK) and three MFS genes (Bcmfs1, Bcmfs2 and Bcmfs4) was studied. All genes showed a low basal level of expression, but were differentially induced by treatment with cycloheximide and the plant defence compounds camptothecin, eugenol, psoralen, resveratrol and rishitin. The latter compounds induced expression of BcatrB at a high level. Eugenol was more toxic to BcatrB gene-replacement mutants than to the control isolates. Eugenol also caused an instantaneous increase in mycelial accumulation of the fungicide fludioxonil, a known substrate of BcatrB. However, there was no difference in virulence between the wild-type and BcatrB gene-replacement mutants on Ocimum basilicum, a plant known to contain eugenol. The results indicate that BcatrB is a transporter of lipophilic compounds, such as eugenol, but its role in virulence remains uncertain.     

油菜菌核病菌对多菌灵和乙霉威的抗药性机理

生物测定结果表明,油菜菌核病菌田间菌株对多菌灵(MBC)敏感性表型呈多样性,即存在MBCS、MBCLRLR、MBCHRHR和MBCVHR表型.而对乙霉威(DIE)则只检测到DIES和DIEHR表型.MBCS、MBCLR和MBCHR菌株中除JD2-3菌株为DIES外,其余菌株均为DIEHR,MBCVHR菌株对DIE表现为DIES.MBC和DIE之间存在典型的负相关交互抗性.序列分析结果表明,表型为MBCVHRDIES菌株的β-微管蛋白基因,第198位氨基酸由Glu(GAG)突变为Ala(GCG);表型为MBCHRDIEHR菌株的β-微管蛋白基因的突变位点在第200位,由Phe(TTC)突变为Tyr(TAC);而表型为MBCSDIES和MBCLRDIEHR的菌株在所扩增的β-微管蛋白基因片段中未发生突变.初步表明,β-微管蛋白基因198和200位氨基酸的突变是引起油菜菌核病菌对多菌灵抗药性呈多样性的分子机理.     

菌核净、代森锰锌及其混剂对烟草赤星病菌毒力测定

运用Horsfall毒力试验设计方案和孢子萌发抑制法分别测定菌核净、代森锰锌及其混剂对烟草赤星病菌(Alternaria alteranta)的毒力，并分别用Wadley方法、Gowing方法、Abbott方法和孙云沛方法等多种评价方法评价所配混剂的增效作用，结果表明，当它们按EC50剂量7：3的比例混配时所得混剂表现明显的增效作用．4种增效作用评价方法所得结果一致，田间防治结果也证明该混剂可有效防治赤星病。     

Repression of deoxynivalenol accumulation and expression of Tri genes in Fusarium culmorum by fungicides in vitro

A defined medium was developed in which to monitor deoxynivalenol (DON) accumulation, fungal growth and expression of genes involved in trichothecene biosynthesis (designated Tri genes). In liquid culture, DON accumulated shortly after maximum expression of Tri6 and coincident with expression of Tri5. This was generally 96 h after inoculation. The effects of sublethal concentrations of the fungicides azoxystrobin, trifloxystrobin, kresoxim-methyl and tebuconazole on biosynthesis of the trichothecene DON by Fusarium culmorum were studied using this medium. The strobilurin fungicides trifloxystrobin and azoxystrobin significantly reduced the accumulation of DON in culture medium at a range of concentrations. Kresoxim-methyl, also a strobilurin, and tebuconazole, a triazole, did not significantly reduce the accumulation of DON, although levels were lower than those in nonamended cultures. Trifloxystrobin significantly reduced the accumulation of DON when added to cultures before initiation of trichothecene biosynthesis. RT-PCR assays of the expression of Tri6 and Tri5 genes indicated that trifloxystrobin acted by inhibiting the initiation of trichothecene biosynthesis.