Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
Mol Plant Pathol. 2004 Nov 1;5(6):537-47. doi: 10.1111/j.1364-3703.2004.00251.x.
SUMMARY The obligate biotrophic fungal pathogen of barley, Blumeria graminis f.sp. hordei (Bgh), elicits a burst of H(2)O(2) in its host barley at sites of germ tube invasion. To evaluate whether this specialized pathogen has any antioxidant response to this oxidative burst, the Bgh catB gene was characterized and transcript-profiled together with other genes implicated in the management of oxidative stress (catalase-peroxidase, cpx; glutathione peroxidase, gpx; superoxide dismutase, sod1) and in comparison with the constitutively expressed Bghbeta-tubulin and elongation factor1 (ef1) genes. Gel-based and real-time RT-PCR revealed enhanced numbers of catB transcripts at mature primary germ tube and appressorium germ tube (AGT) stages in a susceptible host. Moreover, an anti-CATB polyclonal antibody, from Aspergillus fumigatus, which recognizes both native and recombinant Bgh CATB, revealed an intense circle of immunofluorescence at the host-pathogen interface at the AGT tip and within the halo area surrounding the host papilla. A new diaminobenzidine-based 'scavenger' assay revealed areas of H(2)O(2) clearing at sites of fungal invasion, provoking speculation that Bgh catalase activity may contribute to pathogenicity in Bgh.
摘要 大麦专性活体营养真菌病原体禾本科布氏黑粉菌（Bgh）在其宿主大麦的芽管入侵部位引发 H ₂ O₂ 的爆发。为了评估这种专门的病原体是否对这种氧化爆发有任何抗氧化反应，对 Bgh catB 基因进行了特征描述，并与其他与氧化应激管理（过氧化氢酶过氧化物酶、cpx；谷胱甘肽过氧化物酶、gpx；超氧化物歧化酶、sod1）相关的基因一起进行了转录谱分析，并与组成型表达的 Bghbeta-微管蛋白和伸长因子 1（ef1）基因进行了比较。凝胶基和实时 RT-PCR 显示，在易感宿主中，成熟的初级芽管和附着孢芽管（AGT）阶段的 catB 转录本数量增加。此外，一种来自烟曲霉的抗 CATB 多克隆抗体可识别天然和重组 Bgh CATB，在 AGT 尖端和宿主乳突周围的晕圈区域的宿主-病原体界面处显示出强烈的免疫荧光圈。一种新的基于二氨基联苯胺的“清除剂”测定法显示在真菌入侵部位有 H₂O₂清除区域，这引发了人们的猜测，即 Bgh 过氧化氢酶活性可能有助于 Bgh 的致病性。
