Virus resistance in potato: Current state and prospects

Abstract

The potato (Solanum tuberosum), one of the world’s most important food crops, is infected by numerous viruses, nine of which are of major economic importance as they cause significant yield losses and reduce the quality of the crop. To mitigate the consequences of viral infections, countries with highly developed agriculture are improving and promoting sanitary measures, which include constantly monitoring viruses and certification of potato seed material based on virus diagnostics and improved potato cultivars. However, the development of virus-resistant potato cultivars seems to be a preferable choice in the long term. By employing conventional breeding techniques and genetic engineering approaches using natural virus resistance genes, normally obtained from the wild growing Solanum species, or virus-specific sequences, a number of potato cultivars/lines, which are resistant to the majority of known potato viruses, have already been obtained. However, the above-mentioned techniques have certain limitations, which are determined, in particular, by the high virus specificity of the acquired resistance (against certain viruses only), its short duration, and the ability of the virus to overcome it, as well as the regularly declared bans on the use of genetically modified plants. In the modern era, the novel technologies allowing us to edit genomes for the purposes of gene design have created the possibility to engineer a new generation of resistance genes. The most promising approaches are thought to be the directed mutagenesis of resistance genes, which allows broadening the spectrum of the effects of the gene and the use of nonhost resistance (NHR) (nonspecific resistance) genes, allowing engineering plants resistant to unrelated viruses and in certain cases, to other pathogens and even abiotic stresses. The identification of genes involved in the mechanisms of NHR has only just begun. The nucleus is now being considered as a new source of still unknown factors involved in diverse signal pathways controlling the plant’s defensive response against virus infection. The review describes the approaches which are used to generate virus-resistant potato plants and the challenges faced in this path.