A Ligation-Independent Cloning Tobacco Rattle Virus Vector for High-Throughput Virus-Induced Gene Silencing Identifies Roles forNbMADS4-1and -2in Floral Development

Virus-induced gene silencing (VIGS) is a widely used, powerful technique for reverse genetics. VIGS vectors derived from the Tobacco rattle virus (TRV) are among the most popular for VIGS. We have developed a TRV RNA2 vector that allows the insertion of gene silencing fragments by ligation-independent cloning (LIC). This new vector has several advantages over previous vectors, particularly for applications involving the analysis of large numbers of sequences, since TRV-LIC vectors containing the desired insert are obtained with 100% efficiency. Importantly, this vector allows the high-throughput cloning of silencing fragments without the use of costly enzymes required for recombination, as is the case with GATEWAY-based vectors. We generated a collection of silencing vectors based on 400 tomato (Solanum lycopersicum) expressed sequence tags in this TRV-LIC background. We have used this vector to identify roles for SlMADS1 and its Nicotiana benthamiana homologs, NbMADS4-1 and -2 in flowering. We find that NbMADS4-1 and -2 act nonredundantly in floral development and silencing of either gene results in loss of organ identity. This TRV-LIC vector should be a valuable resource to the plant community.