Resistance to viruses of potato: current status and prospects

Abstract

The potato (Solanum tuberosum), one of the most important food crops in the world, is infected by various viruses, nine of which have great economic significance, causing substantial losses in the yield and quality of the crop. To minimize consequences of virus infections, in developed countries specific phytosanitary measures have been established and are being improved to monitor the spread of viruses and certify seed potato material using virus diagnostics and production of virus-free potato cultivars. However, in the longer-term, the development and deployment of potato cultivars resistant to viruses would be a priority. Some new potato cultivars and lines resistant to many viruses have already been generated using either traditional breeding methods or genetic engineering. For this purpose, natural resistance genes, primarily from wild Solanum species, or virus derived nucleotide sequences have been used as sources of resistance. However, these approaches have essential limitations because the acquired resistance is highly specific (against individual viruses only), is not durable, can be overcome by viruses and, finally due to regulatory bans on genetically modified organisms. Recently developed new genome editing technologies with the potential to be a powerful tool for gene design open up broad opportunities for development of next-generation resistance genes. The most promising approaches are (1) site-directed mutagenesis of the genes conferring specific resistance to make their action much broader and (2) the use of non-specific (nonhost) resistance to generate plants resistant to unrelated viruses and, in some cases, to other pathogens and even abiotic stresses. Identification of genes involved in mechanisms of non-host resistance is just beginning. The cell nucleus is a new source of novel factors involved in various signaling pathways resulting in defence response to virus infection. This review focuses on the approaches and challenges related to the development of potato plants resistant to virus infections.