Genetic and physiological determinants of Streptomyces scabies pathogenicity
Genetic and physiological determinants of Streptomyces scabies pathogenicity
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DOI：
10.1111/j.1364-3703.2009.00561.x
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发表时间：
2009-09-01
影响因子：
4.9
通讯作者：
Beaulieu, Carole
中科院分区：
文献类型：
--
作者：
Lerat, Sylvain;Simao-Beaunoir, Anne-Marie;Beaulieu, Carole
黑斑病是一种危害薯类块根作物和块茎的世界性严重病害。它是由土壤传播的丝状细菌引起的，属于链霉菌属。链霉菌通常是腐生微生物，但少数种类已经获得了感染地下植物组织的能力。马铃薯疥疮的主要致病因子是疥疮链霉菌。一种被称为抗结痂素的植物毒素的产生对常见的结痂病原体的毒性至关重要。参与萨氏菌素生物合成途径的基因和其他毒力基因聚集在一个巨大的致病岛上。致病岛可以被动员并转移到非致病亲缘，导致新的致病链霉菌的出现。在大多数致病性链霉菌物种中，thaxtomin A是发现的主要形式。thaxtomin A合成的调控是复杂的。虽然植物来源的化合物纤维素二糖现在被认为是遗传水平上的thaxtomin A合成的诱导剂，但其他分子（包括芳香氨基酸和一些次级代谢物）对毒素的产生有抑制作用。本文综述了常见的疥疮，重点介绍了疥疮及其毒力机制。分类学：疥疮链霉菌兰伯特和洛里亚；王国的细菌;门放线菌;类放线菌;放线菌目;家庭链霉菌科;属链霉菌属;种疥疮或疥疮。寄主范围：疥疮链霉菌具有广泛的寄主范围，包括块茎蔬菜和大多数根茎作物。疥疮链霉菌在马铃薯（Solanum tuberosum）、甜菜（Beta vulgaris）、胡萝卜（Daucus carota）、防风草（Pastinaca sativa）、萝卜（Raphanus sativus）、芜菁（Brassica nabbrassica）和萝卜（Brassica rapa）上引起常见的痂。疾病症状：常见的结痂症状表现为随机分布的浅、凸起或深凹坑状软木状病变。它们的大小和颜色变化很大，但病变通常为棕色，直径为几毫米。由于受结痂感染的植物的空中组织保持健康，因此没有地上症状显示该疾病的存在。疥疮链霉菌也抑制单子叶和双子叶植物幼苗的生长。有用的网站：http://www.sanger.ac.uk/Projects/S_scabies, http://www.potatodiseases.org/scab.html, http://www.uri.edu/ce/factsheets/sheets/potatoscab.html。
P>Common scab is a severe disease worldwide affecting tap root crops and potato tubers. It is caused by soil-borne filamentous bacteria belonging to the genus Streptomyces. Streptomycetes usually are saprophytic microorganisms, but a few species have acquired the ability to infect underground plant tissues. The predominant causal agent of potato scab worldwide is Streptomyces scabies. The production of phytotoxins called thaxtomins is essential for the virulence of common scab-causing agents. The genes involved in the biosynthetic pathway of thaxtomins and other virulence genes are clustered on a large pathogenicity island. The pathogenicity island can be mobilized and transferred to nonpathogenic relatives, leading to the emergence of new pathogenic streptomycetes. In most pathogenic Streptomyces species, thaxtomin A is the predominant form found. The regulation of thaxtomin A synthesis is complex. Although the plant-derived compound cellobiose is now recognized as the inducer of thaxtomin A synthesis at a genetic level, other molecules (including aromatic amino acids and some secondary metabolites) show inhibitory effects on the production of the toxin. This paper is an overview of common scab with a focus on S. scabies and its virulence mechanisms.Taxonomy:Streptomyces scabies (Thaxt.) Lambert and Loria; Kingdom Bacteria; Phylum Actinobacteria; Class Actinomycetes; Order Actinomycetales; Family Streptomycetaceae; genus Streptomyces; species scabies or scabiei.Host range:Streptomyces scabies (syn. S. scabiei) has a broad host range comprising tuber vegetables and most tap root crops. Streptomyces scabies causes common scab on potato (Solanum tuberosum), beet (Beta vulgaris), carrot (Daucus carota), parsnip (Pastinaca sativa), radish (Raphanus sativus), rutabaga (Brassica napobrassica) and turnip (Brassica rapa).Disease symptoms:Common scab symptoms appear as randomly distributed shallow, raised or deep-pitted corky lesions. Their size and colour are quite variable, but lesions typically are brown with a diameter of a few millimetres. No above-ground symptoms disclose the presence of the disease as aerial tissues of scab-infected plants remain healthy. Streptomyces scabies also inhibits the growth of seedlings in monocot and dicot plants.Useful websites:http://www.sanger.ac.uk/Projects/S_scabies, http://www.potatodiseases.org/scab.html, http://www.uri.edu/ce/factsheets/sheets/potatoscab.html.