A plant virus-based vector system for gene function studies in pepper

While pepper (Capsicum annuum L.) is a highly recalcitrant species for genetic transformation studies, plant virus-based vectors can provide alternative and powerful tools for transient regulation and functional analysis of genes of interest in pepper. In this study, we established an effective virus-based vector system applicable for transient gain- and loss-of-function studies in pepper using broad bean wilt virus 2 (BBWV2). We engineered BBWV2 as a dual-gene expression vector for simultaneous expression of two recombinant proteins in pepper cells. In addition, we established enhanced and stable expression of recombinant proteins from the BBWV2-based dual vector via co-expression of a heterologous viral suppressor of RNA silencing. We also developed a BBWV2-based virus-induced gene silencing (VIGS) vector, and we successfully silenced the phytoene desaturase gene (PDS) using the BBWV2-based VIGS vector in various pepper cultivars. Additionally, we optimized the BBWV2-based VIGS system in pepper by testing the efficiency of PDS gene silencing under different conditions. This BBWV2-based vector system represents a convenient approach for rapid and simple analysis of gene functions in pepper.