A Foxtail mosaic virus-based vector for virus-induced gene silencing in maize
Y. MEI (1), C. Zhang (2), J. Hill (1), S. Whitham (1) (1) Iowa State University, U.S.A.; (2) Alcorn State University, U.S.A.

Plant viruses have been widely used as vectors for foreign gene expression and virus-induced gene silencing (VIGS). Viral vectors capable of expressing heterologous proteins and silencing endogenous plant genes provide valuable tools to complement conventional genetic technologies. Maize is an important crop plant and a model for genetic studies, and although its genome is sequenced, current functional genomics approaches limit the throughput of gene function analyses. Here, we describe a VIGS system derived from Foxtail mosaic virus (FoMV) that is able to establish systemic infection and silencing of endogenous maize genes. To demonstrate the utility of the FoMV vector for VIGS applications, ~200 – 300 bp fragments of four genes, phytoene desaturase (pds, functions in carotenoid biosynthesis), lesion mimic 22 (les22, encodes a key enzyme of the porphyrin pathway), iojap (ij, functions in plastid development), and brown midrib 3 (bm3, caffeic acid O-methyltransferase) were cloned into the vector, and these constructs were inoculated onto seedlings of the sweet corn line Golden x Bantam. The FoMV clones systemically infected sweet corn plants and reduced the mRNA expression of the target genes by 60% to 90% or more in the fourth - sixth leaves. Further, we demonstrate that the FoMV infectious clone establishes systemic infection in several maize inbred lines, sorghum, and green foxtail, indicating the potential applications of the FoMV vector for functional genomics studies in maize and other monocots.

Abstract Number: P9-289
Session Type: Poster