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

该项目包括1)来自微生物和植物的抗病毒药物，2)2，4-二氧六氢-1，3，5-三嗪(DHT)和苯菌灵(MBC)的抗病毒活性，3)弱毒株的保护作用。结果表明：1.核盘菌和紫茉莉提取物对烟草花叶病毒(TMV)等病毒有较高的抑制活性。前者梯度为粘多糖，后者为碱性蛋白(MAP)(M.W.24200)。田间试验表明，MAP对烟草花叶病毒有极高的防治效果。田间试验表明，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对烟草和番茄植株具有抑制活性。在感染烟草花叶病毒(DHT，MBC)和马铃薯Y病毒坏死株系(MBC)的烟草和番茄上，DHT或MBC处理能减轻症状。DHT与MBC联用未见协同作用。在同时感染花叶病毒和马铃薯Y病毒的广藿香分生组织培养中，加入DHT后，即使从4 mm长的分生组织顶端也能获得脱毒植株。3.超微结构观察表明，与野生株相比，TMV弱毒株侵染的宿主细胞中病毒粒子数量较少，分布有限，对细胞的致病作用较小。用紫外光照射感染计划的粗汁液，获得了CMV减毒株系。首次从菊花温和斑驳病毒(黄瓜病毒)中发现了一种对症状有抑制作用的卫星RNA。

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.