RUI: Analysis of the Synergistic Interaction Between African Cassava Mosaic Virus and East African Cassava Mosaic Cameroon virus

双生病毒是对世界各地许多粮食作物的生产力和质量的主要威胁，因此已成为一个严重的经济问题。在喀麦隆的木薯中分离出两种这样的病毒：非洲木薯花叶病毒（ACMV-[CM]）和东非木薯花叶喀麦隆病毒（EACMCV）。被ACMV-[CM]感染的木薯植物表现出恢复的表型，这让人想起病毒诱导的基因沉默（VIGS），由此病毒感染引起与感染病毒共享同源性的植物RNA的序列特异性下调。然而，当植物被ACMV-[CM]和EACMCV共感染时，发生协同反应，与单独被任一病毒单独感染的植物相比，引起更严重的疾病症状。这种协同作用已映射到EACMCV组分A。在本项目中，将确定引起这种协同相互作用的特定基因。EACMCV编码的基因能增强ACMV-[CM]的复制，EACMCV编码的基因能抑制ACMV-[CM]的复制。 由于大多数基因沉默抑制研究都集中在转基因植物上，大多数已鉴定的抑制因子在疾病流行中的自然作用尚未阐明。此外，这些研究都是针对RNA病毒的。该项目将重点关注DNA病毒在恢复中的作用，从而扩大对这些机制的研究。特拉华州州立大学是一所历史悠久的黑人本科院校，少数民族入学率为76%;因此，该项目将为少数民族本科生提供研究和培训机会，并将帮助他们更有效地竞争学术和生物技术方面的就业机会。该项目还将巩固在特拉华州州立大学建立功能性病毒和分子生物学研究和培训实验室的努力。

Geminiviruses are a major threat to the productivity and quality of many food crops around the world and have therefore emerged as a serious economic problem. Two such viruses were isolated in cassava in Cameroon: African cassava mosaic virus (ACMV-[CM]) and East African cassava mosaic Cameroon virus (EACMCV). Cassava plants infected by ACMV-[CM] exhibit a recovered phenotype reminiscent of virus induced gene silencing (VIGS), whereby virus infection causes sequence specific down-regulation of plant RNA sharing homology with the infecting virus. However, when plants are co-infected by ACMV-[CM] and EACMCV, a synergistic reaction occurs, causing more severe disease symptoms compared with plants singly infected by either virus alone. This synergism has been mapped to EACMCV component A. In this project the specific gene causing this synergistic interaction will be determined. Furthermore the mechanism involved will also elucidated based on two hypotheses: 1) EACMCV encodes a suppressor of gene silencing that blocks the plant defense mechanism, 2) EACMCV encoded gene(s) enhance the replication of ACMV-[CM]. Because most gene silencing suppression studies have focused on transgenic plants, the natural role of most of the identified suppressors in disease epidemics has not been elucidated. Moreover, these studies have been on RNA viruses. This project will focus on the role of DNA virus on recovery, thus expanding research on these mechanisms. Delaware State University is a historically black undergraduate institution with a 76% minority enrollment; therefore this project will provide research and training opportunities to minority undergraduate students and will help them to compete more effectively for job opportunities in academics and biotechnology. The project will also consolidate efforts to establish a functional virus and molecular biology research and training laboratory at Delaware State University.