©Pascal Xicluna/Min.Agri.Fr

In order to meet the challenge of feeding a growing global population in a healthy and sustainable way, one of the tools is to strengthen the natural defenses of plants against pathogens, and particularly viruses. Among resistant plant varieties, natural mutations were selected for a study on this topic by the French National Institute of Agronomic Research (INRA).

They were selected by transforming certain genes into “virus neutralizers.” These genetic mutations are largely used for selected resistant varieties by crossbreeding. However, certain cultivated plants do not have such natural resistance. To study this, researchers from INRA evaluated how a modification of protein in host plants could lead to a large and efficient resistance to a family of viruses called Potyvirus without modifying the yield.

Potyviruses represent one of the largest groups of viruses that attack plants and that cause significant losses in harvests. The genetic analysis of resistance to these viruses in cultivated plants allowed to identify the central role of protein in plants, not only for the synthesis of proteins in plants, but also for plant resistance to viruses. When a plant is infected by a Potyvirus, the viruses recruit these factors in the host plant to multiply.

Among numerous wild and cultivated species, mutations of a particular gene were selected, leading to a change in several amino acids of the protein eIF4EI, imparting a plant resistance to Potyviruses. Even when mutated, the gene remains functional and plays its natural role in the synthesis of proteins in the plants. Different natural mutations leading to Potyvirus resistance were identified, notably in cultivated peppers, tomatoes, and peas.

Researchers from INRA showed that targeted modifications of the protein could be reproduced and transferred to a plant that does not have natural resistance in order to transfer this ability without affecting the development of the plant. This work demonstrates that the use of natural genetic resistance in certain plants can allow to introduce genetic resistance in other plants without negatively affecting the development of the plant or reducing its yield.