Studies on the development of control methods for plant virus diseases by antiviral agents and attenuated virus strains

该项目包括以下方面的研究：1）来自微生物和植物的抗病毒剂，2）2,4-二氧六氢-1,3,5-三嗪（DHT）和苯菌灵（甲基，2苯并咪唑氨基甲酸酯；MBC）的抗病毒活性，3）减毒病毒株的保护作用。得到的结果如下： 1． Sclerotinia sclerotiorum (Lib.)De Bary 和 Mirabilis jalapa L. 的提取物对烟草花叶病毒 (TMV) 和其他病毒表现出高抑制活性。经证明前者的成分为粘多糖，后者的成分为碱性蛋白（MAP）（M.W.24200）。 MAP在田间试验中对TMV表现出极高的预防效果。从感染黄瓜花叶病毒(CMV)(AgX)的烟草植株中提取的症状抑制物质，经田间试验表明对烟草和番茄植株有症状抑制活性。 2． DHT 或 MBC 处理可减轻感染 TMV(DHT,MBC) 和马铃薯 Y 病毒坏死株 (MBC) 的烟草和番茄植株的症状。 DHT 和 MBC 联合治疗未观察到协同作用。在同时感染蚕豆病毒属病毒和马铃薯蒂病毒属病毒的广藿香（Pogostemon patchouli）分生组织培养中，培养基中添加DHT，即使从4毫米长的分生组织尖端也很容易获得无病毒的植物。 3.电子显微镜超微结构观察显示，与野生株相比，TMV减毒株感染的宿主细胞中病毒颗粒数量较少，分布有限，细胞病变效应较小。通过用紫外光照射感染植物的粗汁液获得CMV减毒株。从菊花轻度斑驳病毒（Cucumovirus）中发现了对症状具有抑制作用的卫星RNA，这是对该病毒的首次描述。

This project is composed of studies on 1)antiviral agents from microbes and plants, 2)antiviral activity of 2,4-dioxohexahydro-1,3,5-triazine(DHT) and benomyl(methyll,2benzimidazole carbamate;MBC),3)protection with attenuated virus strains. The results obtained were as follows;1. Extracts of Sclerotinia sclerotiorum (Lib.)De Bary and Mirabilis jalapa L.showed high inhibi- tory activities against tobacco mosaic virus (TMV) and other viruses. Ingradient of the former was proved to be mucopolysaccharide, and of the latter was basic protein(MAP)(M.W.24200). MAP showed extremely high preventive effect on TMV in the field exsperiment. The symptom suppressive substance extracted from tobacco plant infected with cucumber mosaic virus(CMV) (AgX) indicated suppressive activity of symptoms on tobacco and tomato plants in the field test.2. Treatments with DHT or MBC caused reduction of symptoms on tobacco and tomato plants, infeted with TMV(DHT,MBC) and potato virus Y necrotic strain (MBC). No synergistic effect was observed by combined treatment of DHT and MBC. In meristem culture of patchouli plan (Pogostemon patchouli) infected with both of a Fabavirus and a Potyvirus, addiction of DHT into the medium made it easy to get virus free plant,even from 4 mm long meristem tip.3.Ultrastructural observations with electronmicroscope showed less number and limited distributions of virus particles and less cytopathic effect in the host cells infected with attenuated strains of TMV than those with wild strains. An attenuated strain of CMV was obtained by irradiation with UV light onto crude sap of infected plan. A satellite RNA which has suppressive effectg on symptoms was found from chrysanthemum mild mottle virus (Cucumovirus) as first description for this virus.