Excellent germplasm resources are the foundation for cultivating high-quality, disease-resistant, and stress-tolerant varieties. In this study, simple sequence repeat (SSR) markers were used to identify 138 potato accessions collected from worldwide, and genetic cluster analysis was used to characterize the genetic diversity of the tested germplasm resources. The Potato virus Y (PVY) resistance of these potato accessions was identified by artificial friction inoculation combined with molecular marker detection, and potato accessions with different PVY resistance were screened based on disease index and incidence rate. Using SSR markers, 138 potato accessions were identified, and the results showed that the genetic distances between the tested potato germplasm resources ranged from 0.025 to 0.660, and the genetic similarity coefficients ranged from 0.489 to 0.975. The 138 accessions could be clustered into five subgroups using Unweighted Pair-Group Method with Arithmetic Mean (UPGMA). Among them, Z173, Biyin No. 4, Suyin No. 2, XN995, XN987, Biyin No 22, Bibiao104, Sarpo mira, XN996, XN979, Desiree, RUNSHI, Actrice, Jia 1219, Heyin No 12, and Moyin No.1 have relatively distant genetic relationship with another 122 accessions. Based on the disease index, the following different accessions were screened: five highly resistant, 11 resistant, 45 moderately resistant, 35 susceptible, and 42 highly susceptible. Fourteen resource materials with good resistance (disease index ≤ 33.74%, and a grading of high resistance (HR) or medium resistance (MR); incidence rate ≤ 67.58%) were identified. By combining genetic cluster analysis and PVY resistance identification, six accessions showed PVY resistance and had distant genetic relationships with other accessions selected which provided important materials for disease resistance breeding and quality improvement of potato. In this study, the genetic diversity and PVY resistance of global potato germplasm resources was explored, and potato germplasm materials with important utilization value were screened. The results obtained in this study could provide important references for the research and utilization of global potato germplasm resources.

Abstract [Objective] The study aims to provide a theoretical basis for potato disease resistance breeding by investigating the characteristics of the potato defensin gene StPSK4 and conducting a functional analysis of its role in potato disease resistance. [Methods] The authors utilized bioinformatics method for a systematic analysis of StPSK4, and conduct transcriptome sequencing analysis to examine the tissue-specific expression pattern of StPSK4 under biotic and abiotic stress, assessing the plant innate immune response to Pseudomonas syringae in StPSK4 overexpressing plants. [Results] The full length CDS of StPSK4 was 457 bp, encoding 100 amino acids. StPSK4 contained a signal peptide, with its tertiary structure mainly composed of α-helices and random coils. The C-terminus of PSK4 contains the defensin sequence DYIYTQ, and the similarity between StPSK4 and Solanaceae crops was above 80%. StPSK4 was highly expressed in potato sprouts and petioles, and showed strong response to biotic and abiotic stress such as high temperature, salt, P . syringae, and Phytophthora infestans. Overexpression of StPSK4 suppressed ROS burst in potato and defensed marker gene expression, and enhanced resistance to P . syringae. [Conclusion] StPSK4 responds to various stress conditions such as high temperature and bacterial wilt infestans. Overexpression of StPSK4 inhibits ROS burst, defense marker gene expression, and resistance to bacterial wilt in potato, confirming the suppressive role of StPSK4 in potato disease resistance.

Potato scab, a global soil-borne disease caused by <i>Streptomyces</i>, is pivotal in developing resistant cultivars due to its complex resistance mechanisms. This study investigates the transcriptomic responses in potato to common scab using resistant variety CS10 and susceptible CS11 post <i>S. scabie</i> inoculation (0 d and 10 d, 12 cDNA libraries). Differential expression analysis identified 147 key DEGs (Differentially Expressed Genes) essential in disease recognition, signal transduction, and defense. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses revealed several significant metabolic pathways, such as ADP binding, heme binding, chloroplast thylakoid membrane, photosynthesis, glutathione metabolism, and homologous recombination, among others. Notably, the correlation between chloroplast pathways (GO:0019745) and photosynthesis (map00195) highlights photosynthesis’s role in potato scab response, while the oxygen transport (GO:0031408)-related glutathione metabolism pathway (map00480) emphasizes antioxidant defenses. Furthermore, three potential resistance genes were validated: Ethylene Response Factor ERF010 (<i>LOC102589042</i>), Disease Resistance Protein RPP13 (<i>LOC102605863</i>), and Cytochrome P450 83B1 (<i>LOC102604056</i>), demonstrating the linkage between metabolic pathways and pathogen response. These findings offer insights into potato’s molecular resistance mechanisms against potato scab, supporting the breeding of resistant varieties and comprehensive disease management, thus advancing sustainable agriculture.

This document outlines the proposed design for an adoption and impact study of potato variety UNICA, developed by the International Potato Center (CIP) and launched in Peru in 1998. UNICA stands out as a remarkable agricultural innovation due to its high productivity, resistance to diseases, and adaptability to diverse climates. Originally bred from the Lowland Tropics Virus Resistance (LTVR) breeding population, it was designed to enhance food security and improve farmers' incomes globally. Its ability to thrive in both mountainous and lowland environments, coupled with resistance to potato viruses and late blight—a devastating disease—has contributed to its widespread success. The design aims at answering the following research questions: What are the effects of adopting UNICA on farmers’ income, livelihoods, and employment? What factors promote the adoption of the UNICA variety, and what elements contribute to ensuring its long-term sustainability?

Potato is an important crop, used not only for food production but also for various industrial applications. With the introduction of the potato as a staple food strategy, the potato industry in China has grown rapidly. However, issues related to bacterial wilt, exacerbated by factors such as seed potato transportation and continuous cropping, have become increasingly severe in the primary potato cultivation regions of China, leading to significant economic losses. The extensive genetic diversity of <i>Ralstonia solanacearum</i> (<i>R. solanacearum</i>), which is the pathogen of bacterial wilt, has led to a lack of highly resistant potato genetic resources. There is a need to identify and cultivate potato varieties with enhanced resistance to reduce the adverse impact of this disease on the industry. We screened 55 accessions of nine different wild potato species against the bacterial wilt pathogen <i>R. solanacearum</i> PO2-1, which was isolated from native potato plants and belongs to phylotype II. Three accessions of two species (ACL24-2, PNT880-3, and PNT204-23) were identified with high resistance phenotypes to the tested strains. We found these accessions also showed high resistance to different phylotype strains. Among them, only PNT880-3 was capable of flowering and possessed viable pollen, and it was diploid. Consistent with the high resistance, decreased growth of <i>R. solanacearum</i> was detected in PNT880-3. All these findings in our study reveal that the wild potato PNT880-3 was a valuable resistance source to bacterial wilt with breeding potential.

Abstract The integration of molecular markers in the realm of potato genetics has opened new avenues for accelerating genotype analysis and developing improved varieties. Many markers linked to important features have been discovered so far and are consistently distributed across 12 chromosomes (× = 12) of potato. Notably, the genes allied to disease resistance stand out as significant and prevalent. Molecular markers associated with these genes have revolutionized selection processes, making them faster and more effective. Besides, advanced technologies such as kompetitive allele-specific PCR, high-resolution melting assay, SNP-array, genotyping by sequencing, and genome-wide association study, are emphasizing the use of those molecular markers with greater accuracy to detect R genes aligning with the phenotypes. This review discusses advances in potato breeding for resistance against common stresses, focusing on progress made through molecular marker-assisted selection.

Background. Phytophthora infestans (Mont.) de Bary is a well-known serious pathogen that affects a wide range of currently grown potato cultivars. Control of the disease, including the breeding process, is complicated by the fact that leaf resistance to P. infestans is often unrelated to tuber resistance, resulting in the need to identify individual plants with leaf and/or tuber resistance to be used in breeding programs. In view of this, research efforts to identify such sources are quite relevant. The objective was to assess the occurrence of plants with resistance in both organs among different wild species and analyze the relationship between leaf and tuber resistance within them.Material and methods. Assessment of leaf and tuber resistance in 97 accessions belonging to 36 species was carried out under artificial inoculation. Using the data obtained on each individual plant, the connection between leaf and tuber resistance was analyzed by means of the Wilcoxon matched-pairs test and Spearman’s rank-order correlations.Results. The species with more frequent occurrence of plants combining leaf and tuber resistance and the species with the predominance of leaf or tuber resistance were identified. The statistical analysis did not show complete (100%) correlations between leaf and tuber resistance in any of studied species. In some cases, a significant positive or negative correlation between these characters was found. The assessment results for the studied species/accessions can facilitate the search for leaf and/or tuber resistance sources capable of improving potato cultivars susceptible to late blight.

Late blight disease caused by the fungus Phytophthora infestans is the main yield limiting factor amongstthe diseases of potato in India and across the globe. Potato Cyst Nematode/PCN (Globodera spp.) is another biotic factorof economic importance and is a quarantine organism. Exploitation of genetic resistance is the most preferred managementstrategy. In the present study, indigenous potato genotypes collected from different parts of the country along with checkswere evaluated for their resistance against late blight under natural epiphytotic field conditions and in laboratory underartificially inoculated conditions including detached leaf and tuber slice assays and PCN through Root ball techniqueduring 2020-2023. The converted field scale values i.e. average AUDPC value ranged from 7 in highly resistant genotypeRangpuria to 1596 in susceptible accession AGR/56. The field blight response was comparatively more correlated (r =0.63)with susceptibility levels measured in the detached leaf assay compared to that with tuber slice assay (r =0.48). GenotypesKanpuria Safed, JG-1, Rangpuria and Desi Aloo showed resistance to late blight both under laboratory and field conditions.For PCN, Garlentic, Jeevan Jyoti and JG-1 have combined resistance (0 female/root ball) over the years to both the species.Majority of the studied genotypes have medium to high pollen viability with desirable tuber traits and yield advantage.The identified resistant genotypes excel their usage as parental lines in breeding for biotic stress resistance specificallyfor late blight and PCN.

Most food crops are susceptible to necrotrophic bacteria that cause rotting and wilting diseases in fleshy organs and foods. All varieties of cultivated potato (Solanum tuberosum L.) are susceptible to diseases caused by Pectobacterium species, but resistance has been demonstrated in wild potato relatives including S. chacoense. Previous studies demonstrated that resistance is in part mediated by antivirulence activity of phytochemicals in stems and tubers. Little is known about the genetic basis of antivirulence traits, and the potential for inheritance and introgression into cultivated potato is unclear. Here, the metabolites and genetic loci associated with antivirulence traits in S. chacoense were elucidated by screening a sequenced S. tuberosum x S. chacoense recombinant inbred line (RIL) population for antivirulence traits of its metabolite extracts. Metabolite extracts from the RILs exhibited a quantitative distribution for two antivirulence traits that were positively correlated: quorum sensing inhibition and exo-protease inhibition, with some evidence of transgressive segregation, supporting the role of multiple loci and metabolites regulating these resistance-associated systems. Metabolomics was performed on the highly resistant and susceptible RILs that revealed 30 metabolites associated with resistance, including several alkaloids and terpenes. Specifically, several prenylated metabolites were more abundant in resistant RILs. We constructed a high-density linkage map with 795 SNPs mapped to 12 linkage groups, spanning a length of 1,507 cM and a density of 1 marker per 1.89 cM. Genetic mapping of the antivirulence and metabolite data identified five quantitative trait loci (QTLs) related to quorum sensing inhibition that explained 8-28% of the phenotypic variation and two QTLs for protease activity inhibition that explained 14-19% of the phenotypic variation. Several candidate genes including alkaloid, and secondary metabolite biosynthesis that are related to disease resistance were identified within these QTLs. Taken together, these data support that quorum sensing inhibition and exo-protease inhibition assays may serve as breeding targets to improve resistance to nectrotrophic bacterial pathogens in potato and other plants. The identified candidate genes and metabolites can be utilized in marker assisted selection and genomic selection to improve soft- rot and blackleg disease resistance.

Cultivated potato (<i>Solanum tuberosum</i>) is a major crop worldwide. It occupies the second place after cereals (corn, rice, and wheat). This important crop is threatened by the Oomycete <i>Phytophthora infestans</i>, 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, <i>P. infestans</i>. 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 <i>Phytophthora infestans</i>, which can be employed. Also, gene pyramiding or gene stacking, which involves the accumulation of two or more <i>R</i> 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 <i>P. infestans</i> can contribute not only to reducing losses in agriculture but especially to ensuring food security and safety.