啶酰菌胺和咯菌腈复配对草莓灰霉病菌的室内毒力测定及田间防效

采用生长速率法测定了啶酰菌胺、咯菌腈及其复配物对草莓灰霉病菌的室内毒力,通过Wadley法进行增效作用评价,并验证了复配物对草莓灰霉病的田间防效。结果表明:啶酰菌胺和咯菌腈以质量比1∶1、5∶1、3∶1、2:1、3∶2复配对草莓灰霉病菌表现增效作用,以质量比1∶3、1∶4、1∶5、4∶1复配则表现相加作用。其中3∶1复配的增效作用最明显,增效系数为4.47,田间对草莓灰霉病的最佳防效可达74.40%。     

啶酰菌胺对黄瓜灰霉病防治效果的综合评价

利用菌丝生长速率法检测了6株灰葡萄孢(Botrytis cinerea)对6种药剂的抗性背景,发现它们对啶酰菌胺具有不同水平的抗性。同时结合盆栽试验和田间试验评价了50%啶酰菌胺水分散粒剂对黄瓜灰霉病的防治效果。盆栽试验中,50%啶酰菌胺水分散粒剂对具有低等抗性的2株灰葡萄孢的防治效果分别为53.49%和53.04%,对3株高等抗性的灰葡萄孢的防治效果分别为50.16%、51.67%和32.24%。说明灰葡萄孢的抗性发展已经严重影响了啶酰菌胺的杀菌活性。2013年和2014年的田间试验中,50%啶酰菌胺水分散粒剂施药量为375g·(667m2)-1时,防治效果分别为94.34%和90.39%。在施药量为300g·(667m2)-1时,50%啶酰菌胺水分散粒剂与对照药剂50%腐霉利可湿性粉剂的防治效果都很显著。综上所述,现阶段啶酰菌胺对黄瓜灰霉病仍具有很好的防治效果。     

保护地番茄灰霉病分生孢子飞散动态

对生长季保护地空气中番茄灰霉病分生孢子进行逐日、逐小时捕捉和分析研究 ,发现保护地内空气温、湿度影响孢子的飞散量。一天中各小时的孢子飞散量与空气温度呈显著正相关 (R =0 92 95 ,P <0 0 1 ) ,与空气相对湿度呈显著负相关 (R =- 0 80 91 ,P <0 0 1 ) ;病原菌分生孢子是病害发生的先决条件 ,病害发生与天气状况密切相关 ,连续阴雨日 2d以上 ,孢子大量产生 ,发生严重侵染 ;晴朗的天气对灰霉病有抑制作用。     

草莓病害生物防治初探

用平板稀释法从２０份根围土样中分离出６７株芽孢杆菌,用异步培养法筛选出对草莓灰霉菌和立枯丝菌核有强拮抗作用的菌株２２个,其中对２种病原菌有一强一弱拮抗作用的菌株９个,对２种病原菌均有强拮抗作用的菌株５个。朱１０,１２,３４和６３还对梨轮纹病菌和玉米大斑病有拮抗作用,表现为广谱抗菌丝,其中菌株１０和１２对４种病原真菌均有强拮抗作用。     

Significance of ABC transporters in fungicide sensitivity and resistance

ATP-binding cassette (ABC) transporters are members of a protein superfamily which can be responsible for efflux of drugs from cells of target organisms. In this way, the transporters may provide a mechanism of protection against cytotoxic drugs. In laboratory-generated mutants of fungi, overproduction of ABC transporters can cause multi-drug resistance to azoles and other non-related toxicants. The impact of this mechanism of resistance in field populations with decreased sensitivity to azoles remains to be established. Inhibitors of ABC transporter activity may synergize activity of azoles to populations of both sensitive and azole-resistant pathogens. The natural function of ABC transporters in plant pathogenic fungi may relate to transport of plant-defence compounds or fungal pathogenicity factors. Therefore, inhibitors of ABC transporter activity may act as disease control agents with an indirect mode of action. ©1997 SCI     

3种植物免疫诱抗剂对番茄灰霉病菌的抑制作用

为明确植物免疫诱抗剂对番茄灰霉菌的抑菌效果,选用3%氨基寡糖素水剂、0.5%几丁聚糖水剂和1%香菇多糖水剂3种常规植物免疫诱抗剂,分别配制高、中、低3个浓度,采用含药培养基的方法开展室内抑菌试验,明确3种植物免疫诱抗剂相应最佳抑菌浓度后,在番茄生育期开展田间诱导抗灰霉病试验。室内抑菌试验结果表明：3种植物免疫诱抗剂均可抑制番茄灰霉菌的生长,其中,1%香菇多糖水剂对番茄灰霉病菌具有较好的速效性和持效性,1%香菇多糖水剂20倍液接菌1d后的抑菌率为36.1%,4d后抑菌率为67.43%;3%氨基寡糖素水剂抑菌效果次之,3%氨基寡糖素水剂100倍液接菌1d后抑菌率为22.1%;0.5%几丁聚糖水剂抑菌效果相对较低,抑菌率维持在0.0%～14.3%。田间诱导抗病试验结果表明：0.5%几丁聚糖水剂200倍液对番茄灰霉病具有较好的诱抗效果,连续施用4次后,番茄灰霉病防效达61.83%。     

解淀粉芽孢杆菌菌株P-r21抑菌广谱性及对番茄灰霉病的防治

为明确内生解淀粉芽孢杆菌(Bacillus amyloliquefaciens)菌株P-r21的抑菌广谱性及对番茄灰霉病的防治效果,本研究优化了菌株P-r21发酵条件,利用平板对峙法测定了该菌株对6种病原菌的抑菌活性及对番茄灰霉病菌(Botrytis cinerea)孢子萌发的抑制作用,并通过离体接种试验研究了对番茄灰霉病的防效。结果表明：菌株P-r21最佳发酵条件为在PYJ中培养初始pH 6.0,培养时间为12 h。菌株P-r21对供试的6种植物病原菌(Botrytis cinerea、Fusarium proliferatum、Rhizoctonia cerealis、Gaeumannomyces graminis、Fusarium graminearum、Colletotrichum karstii)的生长均表现出抑制作用;对C. karstii和B.cinerea抑制作用最强,抑菌率达到88.0%和84.5%。发酵滤液对B. cinerea孢子萌发抑制率达80.6%,对叶片和果实灰霉病的防效达到100%和80.0%;发酵液10倍稀释后防效也可达到67.1%和60.7%。本研究明...     

拟南芥转录因子IDD4不同突变体对灰葡萄孢菌的抗性分析

为明确IDD家族IDD4基因在拟南芥Arabidopsis thaliana抵抗灰葡萄孢菌Botrytis cinerea侵染过程中的作用,通过统计病情指数检测拟南芥野生型（wild type,WT）植株、过表达植株IDD4-OE和缺失突变体idd4植株感染灰葡萄孢菌情况,利用组织染色检测叶片细胞死亡和H₂O₂的积累情况,采用实时荧光定量PCR（real-time quantitative-PT-PCR,qRT-PCR）技术分析灰葡萄孢菌肌动蛋白基因Bc. ACTIN在3种植株叶片中的表达情况,并施加0.1 mmol/L外源水杨酸（salicylic acid,SA）后测定IDD4-OE植株的病情指数。结果显示,不同株系对灰葡萄孢菌的抗性由高到低依次为idd4＞WT＞IDD4-OE,IDD4-OE植株中病原菌感染部位的寄主细胞死亡程度比idd4植株严重。染色结果表明,病原菌侵染拟南芥后4 h,接种部位已有H₂O₂积累。qRT-PCR反应结果显示,Bc. ACTIN在IDD4-OE中比在idd4植株中的表达水平更高,表明灰葡萄孢菌在IDD4-OE植株中的繁殖速率更快。对IDD4-OE植株外源施加SA后,其病情指数、Bc. ACTIN表达量与WT植株间均无显著差异,说明SA能将感病植株的抗性提高至WT植株的水平,表明IDD4作为负调控因子参与了拟南芥对灰葡萄孢菌的抗性调控,SA在其中发挥着重要作用。     

Fusaricidins in Paenibacillus polymyxa A21 and their antagonistic activity against Botrytis cinerea on tomato

Four kinds of antifungal compounds from an extract of Paenibacillus polymyxa A21 with molecular masses of 883.56, 897.59, 947.55, and 961.58 Da were characterized as the members of fusaricidin-type of antibiotics according to LC-MS analysis. Fusaricidins isolated from culture filtrate displayed high antagonistic activity against several plant fungal pathogens, especially Botrytis cinerea, the causal agent of gray mold. The fusaricidins biosynthetic gene cluster (BGC) from A21 was cloned by PCR and comparative cluster analysis revealed that gene fusTE, the 3′ boundary of the fusaricidin BGC in strain PKB1, was not present in fusaricidin BGC of A21, indicating that fusTE is not necessary for fusaricidin synthesis. Fusaricidin extract from A21 significantly reduced gray mold disease incidence and severity on tomato. The mRNA levels for three patho-genesis-related proteins (PRs) revealed that treatment of tomato leaves with fusaricidin extract induced the expression of PR genes to different levels, suggesting that one reason for the reduction of gray mold infection by fusaricidin is induction of PR proteins, which lead to increased resistance to pathogens. This is the first report of the application of fusaricidins to control tomato gray mold and the comparative cluster analysis provides important molecular basis for research on fusaricidin biosynthesis.     

Long‐lasting β‐aminobutyric acid‐induced resistance protects tomato fruit against Botrytis cinerea

Minimizing losses to pests and diseases is essential for producing sufficient food to feed the world's rapidly growing population. The necrotrophic fungus Botrytis cinerea triggers devastating pre‐ and post‐harvest yield losses in tomato (Solanum lycopersicum). Current control methods are based on the pre‐harvest use of fungicides, which are limited by strict legislation. This investigation tested whether induction of resistance by β‐aminobutyric acid (BABA) at different developmental stages provides an alternative strategy to protect post‐harvest tomato fruit against B. cinerea. Soil‐drenching plants with BABA once fruit had already formed had no impact on tomato susceptibility to B. cinerea. However, BABA application to seedlings significantly reduced post‐harvest infection of fruit. This resistance response was not associated with a yield reduction; however, there was a delay in fruit ripening. Untargeted metabolomics revealed differences between fruit from water‐ and BABA‐treated plants, demonstrating that BABA triggered a defence‐associated metabolomics profile that was long lasting. Targeted analysis of defence hormones suggested a role of abscisic acid (ABA) in the resistance phenotype. Post‐harvest application of ABA to the fruit of water‐treated plants induced susceptibility to B. cinerea. This phenotype was absent from the ABA‐exposed fruit of BABA‐treated plants, suggesting a complex role of ABA in BABA‐induced resistance. A final targeted metabolomic analysis detected trace residues of BABA accumulated in the red fruit. Overall, it was demonstrated that BABA induces post‐harvest resistance in tomato fruit against B. cinerea with no penalties in yield.