Recent Advances in In Planta Transient Expression and Silencing Systems for Soybean Using Viral Vectors

Abstract

Transient methods for overexpressing and silencing plant genes enable rapid analysis of gene function and gene regulation. Several methods that avoid the traditional time- and labor-intensive generation of stable transgenic plants have been used recently in soybean and other plants to express or silence genes. In this post-genomic era, the sequences of the soybean genome and many other crop genomes are readily available. Genome sequences coupled with transient expression and silencing systems enable large-scale screens to associate genes with traits, or more detailed characterization of gene products and regulatory sequences. Recombinant plant viruses that can carry genetic payloads of whole genes or gene fragments provide convenient platforms as vectors for transient gene expression and silencing in soybean. This chapter focuses on seven viral vector systems that have been used in soybean for overexpression and/or virus-induced gene silencing (VIGS) applications. We discuss the features of the viral genomes, strategies for their use, applications in gene expression and/or VIGS, and future prospects to expand the utility of viral vectors for soybean improvement.