Effects of milsana and benzothiadiazole on the ultrastructure of powdery mildew haustoria on cucumber.
Effects of milsana and benzothiadiazole on the ultrastructure of powdery mildew haustoria on cucumber.
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DOI：
10.1094/phyto.1999.89.9.728
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发表时间：
1999-09
期刊：
影响因子：
3.2
通讯作者：
K. Wurms;C. Labbé;N. Benhamou;R. Belanger
中科院分区：
文献类型：
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作者：
K. Wurms;C. Labbé;N. Benhamou;R. Belanger
疾病评估和细胞学研究提供了两种预防化合物Milsana和苯并噻二唑（BTH）对长黄瓜上白粉病发展的作用模式和效力的有价值的信息。通过诱导局部抗性，相对于接种对照，Milsana应用显著降低了疾病发生率。显微镜观察显示，大多数吸器在局部Milsana处理中已经塌陷，并被电子不透明物质浸渍的无定形材料包裹。吸器崩溃的速度（在4天内的治疗应用）与包裹的电子致密物质染成蓝色的甲苯胺蓝O表明，酚类物质可能参与Milsana防御反应。用麦胚凝集素/卵类粘蛋白-金复合物对几丁质进行细胞化学标记，结果表明，在菌丝体和吸器壁中的几丁质不受干扰的情况下，真菌的细胞完全解体。这可能表明几丁质分解活性在米尔萨纳激活的防御反应中并不重要。应用高剂量的BTH诱导偶尔细胞壁增厚和积累的化合物，染色紫色甲苯胺蓝O，但防御反应弱，零星，不足以减少黄瓜白粉病感染。对BTH的反应无法在首次应用的时间或系统性方面进行区分。
ABSTRACT Disease assessments and cytological investigations provided valuable information on the modes of action and efficacies of two prophylactic compounds, Milsana and benzothiadiazole (BTH), against powdery mildew development on long English cucumber. Milsana application significantly reduced disease incidence relative to inoculated controls through induction of localized resistance. Microscopic observations showed most haustoria had collapsed in the localized Milsana treatment and were encapsulated by an amorphous material impregnated by electron-opaque substances. The rapidity of haustorial collapse (within 4 days of treatment application) together with the encasement by electron-dense substances stained blue by toluidine blue O suggest that phenolics are possibly involved in the Milsana defense response. Cytochemical labeling of chitin with a wheat germ agglutinin/ovomucoid-gold complex showed that complete cellular disorganization of the fungus had occurred without disturbance to chitin in the walls of mycelia and haustoria. This may indicate that chitinolytic activity is not important in the Milsana-activated defense response. Application of high doses of BTH induced occasional cell wall thickening and accumulation of a compound that stained purple by toluidine blue O, but the defense response was weak, sporadic, and insufficient to reduce powdery mildew infection on cucumber. Responses to BTH could not be differentiated in terms of timing of the initial application or systemicity.