Cultivated potato (Solanum tuberosum) is a major crop worldwide. It occupies the second place after cereals (corn, rice, and wheat). This important crop is threatened by the Oomycete Phytophthora infestans, the agent of late blight disease. This pathogen was first encountered during the Irish famine during the 1840s and is a reemerging threat to potatoes. It is mainly controlled chemically by using fungicides, but due to health and environmental concerns, the best alternative is resistance. When there is no disease, no treatment is required. In this study, we present a summary of the ongoing efforts concerning resistance breeding of potato against this devastating pathogen, P. infestans. This work begins with the search for and selection of resistance genes, whether they are from within or from outside the species. The genetic methods developed to date for gene mining, such as effectoromics and GWAS, provide researchers with the ability to identify genes of interest more efficiently. Once identified, these genes are cloned using molecular markers (MAS or QRL) and can then be introduced into different cultivars using somatic hybridization or recombinant DNA technology. More innovative technologies have been developed lately, such as gene editing using the CRISPR system or gene silencing, by exploiting iRNA strategies that have emerged as promising tools for managing Phytophthora infestans, which can be employed. Also, gene pyramiding or gene stacking, which involves the accumulation of two or more R genes on the same individual plant, is an innovative method that has yielded many promising results. All these advances related to the development of molecular techniques for obtaining new potato cultivars resistant to P. infestans can contribute not only to reducing losses in agriculture but especially to ensuring food security and safety.

Cultivated potato (Solanum tuberosum L.) is one of the most important crops worldwide. Phytophthora infestans (Mont.) de Bary is the oomycete pathogen responsible for the famous Irish famine (1840s). It is still the most important pathogen affecting potato crops, causing the late blight disease on potato and tomato. It is mainly controlled by fungicides. Breeding for disease resistance is the best alternative to chemical control of the disease. One of the strategies used is to stack many resistance genes in the same genotype. Here, we wanted to test the effect of the stacked resistance gene (R) from S. demissum on the infection process by the virulent race EU_13_A2. Four potato genotypes were tested, each one harboring, respectively, one, two, three or four R genes. All the tested genotypes were sensitive. However, the sensitivity degree was negatively correlated with the number of genes harbored by each genotype. There was a delay of two days of symptoms manifestation for the genotype with 4Rs, and the pathogen produced less spores on the detached leaf test. In addition, the amount of phenolic compounds produced is higher in the genotypes with multiple R genes.

The potato (Solanum tuberosum) is the 3rd most important crop worldwide, and Phytophthora infestans is the most devastating pathogen to potato crops. In this study, it has identified markers for resistance and susceptibility to late blight using potato genotypes that differ in their resistance/susceptibility to Phytophthora infestans. Using Fourier transform infrared spectroscopy, many absorbance bands have been identified as specific to resistant potato plants, and others were specific to susceptible potato plants. For each case (resistance/susceptibility), three bands were identified: 941-1180 cm-1, 1336-1483 cm-1, and 1483-1703 cm-1 and 1056-1294 cm-1, 1442-1585 cm-1, and 1585-1832 cm-1, respectively. As it is a simple, rapid, and inexpensive technology, FTIR (Fourier Transform Infrared) spectroscopy offers an excellent opportunity for studying potato resistance/susceptibility to late blight.

Cultivated potato (Solanum tuberosum) is susceptible to many pests and pathogens, but the most important threat to potato production is, so far, the late blight disease, caused by the oomycete Phytophthora infestans. Resistance genes from the wild Solanum sp. have been used by breeders to develop late-blight-resistant cultivars. Two sets of Black differentials potato genotypes (R1, R2, …, R11) were used to identify a new marker for resistance gene R11 of potato to late blight. RAPD polymorphic bands were isolated, cloned, and converted into SCAR primers. By amplification of genomic DNA with SCAR primers followed by enzymatic digestion with HinfI restriction enzyme, and verified by Southern blotting, a marker of R11 resistance gene of potato to Phytophthora infestans was identified.