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

本项目包括微生物和植物源抗病毒药物的研究、2，4-二氧六氢-1，3，5-三嗪（DHT）和苯菌灵（甲基1，2-苯并咪唑氨基甲酸酯;MBC）的抗病毒活性研究、减毒病毒株的保护作用研究。结果如下：1.核盘菌Sclerotinia sclerotiorum（Lib.）De Bary和紫茉莉（Mirabilis jalapa L.）对烟草花叶病毒（TMV）等病毒具有较强的抑制活性。前者为粘多糖，后者为碱性蛋白（MAP）（分子量24200）。田间试验表明，MAP对TMV有极高的防治效果。从受黄瓜花叶病毒（CMV）侵染的烟草植株中提取的症状抑制物质（AgX）在田间试验中对烟草和番茄植株表现出症状抑制活性.用双氢睾酮或多菌灵处理烟草和番茄植株，感染TMV（双氢睾酮，多菌灵）和马铃薯病毒Y坏死株（多菌灵）的症状减轻。DHT与MBC联合应用无协同作用。在同时感染两种病毒的广藿香茎尖培养中，加入双氢睾酮（DHT）后，即使在4 mm长的茎尖上也能获得无病毒植株。3.电镜观察表明，TMV弱毒株感染的寄主细胞中病毒颗粒数量少，分布范围窄，细胞病变程度轻。用紫外线照射黄瓜花叶病毒（CMV）的粗汁液，获得一株CMV弱毒株。从菊花轻斑驳病毒（Cucumovirus）中发现了一种对症状有抑制作用的卫星RNA，这是该病毒的首次描述。

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.