Virus-Induced Gene Silencing for Nodulation Analysis in Soybean.

Virus-induced gene silencing (VIGS) is a powerful reverse genetics tool that enables the transient knockdown of gene expression in plants by exploiting their natural antiviral defense mechanisms. This chapter presents a detailed protocol for applying a Cowpea severe mosaic virus (CPSMV)-based VIGS system to study gene function in soybean (Glycine max), with a focus on symbiotic root nodulation. VIGS allows systemic silencing of target genes, making it especially valuable to study pathways involving systemic signaling. The protocol includes Agrobacterium-mediated propagation of CPSMV variants in Nicotiana benthamiana, followed by mechanical inoculation of soybean plants and nodulation analysis. Detailed steps for vector construction, viral amplification, plant infection, and downstream molecular and phenotypic analyses are provided. This protocol is reproducible, accessible, and suitable for functional genomics studies in soybean, particularly for genes involved in nodulation but also in other developmental or stress-related processes.