Molecular Aspects of Specificity in Interaction of Arabidopsis and Host-Specific Toxin Produced by Alternaria brassicicola

拟南芥与芸苔链格孢产生的宿主特异性毒素相互作用的分子方面的特异性

• 批准号: 06660053
• 负责人: OTANI Hiroshi
• 金额: $ 1.28万
• 依托单位: Tottori University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06660053/
• 关键词: Alternaria brassicicola; Host-Specific Toxin; Cruciferae; Arabidopsis thariana; Plasma Membrane; 特異性決定; 突然変異体; 実生根伸長阻害活性; 感染誘発活性

Black leaf spot of Cruciferae caused by Alternaria brassicicola is a major disease in cultivated Brassica plants. Recently, we found that the pathogen produces host-specific toxin (HST), named AB-toxin. The toxin was released from the germinating spores only when spores were inoculated on host leaves, indicating that the production of AB-toxin by the pathogen is induced by substances in host leaves. Interestingly, the activity of AB-toxin was retained by membranes with a molecular weight cutoff of 5,000. In addition, the activity was heat unstable, and was lost by treatment with proteinase. Thus, unlike other HSTs, AB-toxin has a high molecular weight and is probably a protein (s). As a protein, AB-toxin may offer the advantage of being a direct gene product.Arabidopsis thariana which is known as a model plant for molecular biology, belongs to Cruciferae. Therefore, responses to the pathogen and AB-toxin of A.thariana were investigated. When the spores of the pathogen were inoculated on leaves of 7 ecotypes of A.thariana, black spot lesions appeared on 6 ecotypes except an ecotype RLD.AB-toxin was examined for biological activity on A.thariana. The toxin was toxic to 6 ecotypes, but was harmless to RLD.These results indicate that there are ecotypes susceptible and resistant to the pathogen and AB-toxin. To investigate hereditary background of the responses of A.thariana, susceptible and resistant ecotypes were crossed. The responses of the crossed plants indicated that the resistance is determined by a single dominant gene. On the other hand, AB-toxin induced electrolyte leakage from susceptible ecotype leaves within 1 hr after treatment, indicating that AB-toxin has a primary effect on the plasma membranes of host cells.

十字花科植物黑叶斑病是由芸苔链格孢菌引起的十字花科植物黑斑病，是栽培芸苔属植物的主要病害。最近，我们发现该病原体产生宿主特异性毒素（HST），命名为AB-毒素。只有当孢子接种在寄主叶片上时，萌发的孢子才会释放毒素，这表明病原体产生AB毒素是由寄主叶片中的物质诱导的。有趣的是，截留分子量为 5,000 的膜保留了 AB 毒素的活性。此外，该活性对热不稳定，并且通过蛋白酶处理而丧失。因此，与其他 HST 不同，AB 毒素具有高分子量，并且可能是一种蛋白质。作为一种蛋白质，AB-毒素可能具有直接基因产物的优势。拟南芥属十字花科植物，被誉为分子生物学的模式植物。因此，研究了拟南芥对病原体和 AB 毒素的反应。将病原菌孢子接种于7个生态型的拟南芥叶片上，除1个生态型RLD外，其余6个生态型均出现黑斑病斑。检测AB毒素对拟南芥的生物活性。该毒素对6个生态型有毒，但对RLD无害。这些结果表明存在对该病原体和AB毒素敏感和抗性的生态型。为了研究拟南芥反应的遗传背景，将敏感生态型和抗性生态型进行了杂交。杂交植物的反应表明，抗性是由单个显性基因决定的。另一方面，AB 毒素在处理后 1 小时内诱导易感生态型叶片电解质渗漏，表明 AB 毒素对宿主细胞的质膜具有主要影响。

项目成果

Otani,H.: "Molecular Aspects of Pathogenicity and Host Resistance (Edited by Mills,D.and Kunoh,H.)" APS Press (The American Phytopathological Society) ,St.Paul (in press), (1996)

Otani,H.：“致病性和宿主抗性的分子方面（由 Mills,D. 和 Kunoh,H. 编辑）”APS Press（美国植物病理学会），St.Paul（印刷中），（1996 年）

Otani, H.et al.: "Molecular Aspects of Pathogenicity and Host Resistance (Edited by Mills, S.and Kunoh, H.)." APS (The American Phytopathological Society) Press, ST.Paul. (in press). (1996)

Otani, H.等人：“致病性和宿主抗性的分子方面（由 Mills, S. 和 Kunoh, H. 编辑）。”

Otani, H.: "Molecular Aspects of Pathogenicity and Host Resistance (Edited by Mills, D. and Kunoh, H.)" APS Press (The American Phytopathological Society), St. Paul (in press), (1996)

Otani, H.：“致病性和宿主抗性的分子方面（由 Mills, D. 和 Kunoh, H. 编辑）” APS Press（美国植物病理学会），St. Paul（印刷中），（1996 年）