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Iowa State University researchers have developed an improved genetic tool for researching and understanding soybean genomics.

Highly reliable and efficient silencing of a variety of soybean genes, including those required for protein translation, defense signaling pathways, cytoskeleton, and roots, has been demonstrated.  The utility of the DNA-based BPMV VIGS vector in characterizing gene function has been shown using soybean homologues of Arabidopsis defense signaling pathways.

Virus-induced gene silencing (VIGS) is a new approach to so-called reverse genetics.  Using this technology, the expression of a known gene (or sequence) is altered and the resulting effect on plant phenotype is investigated.  VIGS is being increasingly used as a reverse genetics tool to study and identify functions of specific plant genes, especially in plants such as soybean that are refractory to other methods, such as transformation.  While RNA-based VIGS vectors have been developed for investigating gene function(s) in soybean, they are subject to RNA degradation, are not facile to manipulation, require in vitro RNA transcription, and are costly and time consuming.  As a result, these systems are not suitable for high-throughput genomics applications.  To overcome these drawbacks, ISU researchers have developed a highly reliable soybean gene expression and silencing vector. This second generation improvement over a previously described system is based on DNA inoculation and uses a Cauliflower mosaic virus (CaMV) promoter driven Bean pod mottle virus (BPMV) vector. Because the DNA-based BPMV vector is designed to silence multiple genes using a single construct, simultaneous testing of different combinations of genes to address questions related to genetic redundancy or epistasis is possible.  In addition, the vector can be used in soybean to validate the function of Arabidopsis gene homologues.

• Amenable to high through-put gene manipulation

• Highly efficient: obviates the need for in vitro transcription and infection using unstable RNA inoculation

• Enables silencing of multiple genes using a single construct

• Facilitates functional validation of Arabidopsis gene homologues

• Economical: eliminates the need for chemical stabilization of transcribed RNA

Soybean functional genomics