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

Delaware State University, Dover DE

Investigators

Abstract

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.