Review articleGenetic resistance against viruses in Phaseolus vulgaris L.: State of the art and future prospects

- Common bean is an agronomically relevant crop that is infected by many viruses.
- Many dominant or recessive resistance genes that confer resistance to viruses have been identified in common bean.
- Resistance phenotypes to viruses in common bean vary from extreme resistance to local or systemic necrosis.
- Temperature variation is an important factor that may influence resistance phenotypes.
- Common bean is good plant model to study plant-virus interactions at a molecular level.

Viruses are obligate parasites that replicate intracellularly in many living organisms, including plants. Consequently, no chemicals are available that target only the virus without impacting host cells or vector organisms. The use of natural resistant varieties appears as the most reliable control strategy and remains the best and cheapest option in managing virus diseases, especially in the current ecological context of preserving biodiversity and environment in which the use of phytosanitary products becomes limited. Common bean is a grain legume cultivated mainly in Africa and Central-South America. Virus diseases of common bean have been extensively studied both by breeders to identify natural resistance genes in existing germplasms and by pathologists to understand the molecular bases of plant-virus interactions. Here we present a critical review in which we synthesize previous and recent information concerning 1) main viruses causing diseases in common bean, 2) genetic resistance to viruses in common bean, 3) the different resistance phenotypes observed and more particularly the effect of temperature, 4) the molecular bases of resistance genes to viruses in common bean, and 5) future prospects using transgenic-engineered resistant lines.

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