The "one-step" Bean pod mottle virus (BPMV)-derived vector is a functional genomics tool for efficient overexpression of heterologous protein, virus-induced gene silencing and genetic mapping of BPMV R-gene in common bean (Phaseolus vulgaris L.).

Stéphanie Pflieger,Fanny Mary,Valérie Geffroy,Manon M S Richard,Vincent Thareau,Sophie Blanchet,Chouaib Meziadi,Céline Mazoyer

doi:10.1186/s12870-014-0232-4

Abstract

BackgroundOver the last two years, considerable advances have been made in common bean (Phaseolus vulgaris L.) genomics, especially with the completion of the genome sequence and the availability of RNAseq data. However, as common bean is recalcitrant to stable genetic transformation, much work remains to be done for the development of functional genomics tools adapted to large-scale studies.ResultsHere we report the successful implementation of an efficient viral vector system for foreign gene expression, virus-induced gene silencing (VIGS) and genetic mapping of a BPMV resistance gene in common bean, using a “one-step” BPMV vector originally developed in soybean. With the goal of developing this vector for high-throughput VIGS studies in common bean, we optimized the conditions for rub-inoculation of infectious BPMV-derived plasmids in common bean cv. Black Valentine. We then tested the susceptibility to BPMV of six cultivars, and found that only Black Valentine and JaloEEP558 were susceptible to BPMV. We used a BPMV-GFP construct to detect the spatial and temporal infection patterns of BPMV in vegetative and reproductive tissues. VIGS of the PHYTOENE DESATURASE (PvPDS) marker gene was successfully achieved with recombinant BPMV vectors carrying fragments ranging from 132 to 391 bp. Finally, we mapped a gene for resistance to BPMV (R-BPMV) at one end of linkage group 2, in the vicinity of a locus (I locus) previously shown to be involved in virus resistance.ConclusionsThe “one-step” BPMV vector system therefore enables rapid and simple functional studies in common bean, and could be suitable for large-scale analyses. In the post-genomic era, these advances are timely for the common bean research community.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0232-4) contains supplementary material, which is available to authorized users.

Highlights

Over the last two years, considerable advances have been made in common bean (Phaseolus vulgaris L.) genomics, especially with the completion of the genome sequence and the availability of RNAseq data
We evaluated the efficiency of direct rub-inoculation of P. vulgaris cv
The Bean pod mottle virus (BPMV)-0 and BPMV-green fluorescent protein (GFP) constructs were introduced into plants by rub-inoculation of primary leaves using a mix of BPMV RNA1 and RNA2 infectious plasmids

Summary

Introduction

Over the last two years, considerable advances have been made in common bean (Phaseolus vulgaris L.) genomics, especially with the completion of the genome sequence and the availability of RNAseq data. Common bean (Phaseolus vulgaris L.) is the most important grain legume for direct human consumption in the world. This crop, a major source of dietary protein, minerals and certain vitamins, plays a significant role in human nutrition in developing and underdeveloped countries [1]. Transcriptome analysis in common bean using high-throughput sequencing of RNA transcripts (RNA-seq) has provided data on gene expression profiles in different tissues (seeds, pods, leaves, roots, and nodules) at different development stages (http://www.phytozome.org). These recent advances have successfully resulted in the identification of a large number of genes. Genetic transformation of common bean is feasible, it has a low transformation efficiency, and is not suitable for high-throughput functional genomics (reviewed in [3])

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