Search Results (5)

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. Full article

Drought stress is one of the most limiting abiotic stresses for plant growth and development. Potato (Solanum tuberosum L.), due to its shallow root system, is considered sensitive to drought. In potato breeding, the wild Solanum species may represent a good resource for disease and abiotic stress resistance genes, but their transfer is limited by sexual incompatibilities. Somatic hybrids (SH) between potato and the wild species Solanum bulbocastanum, sexually incompatible with potato, proved to be late-blight-resistant in laboratory and field assays. The aim of this study was to screen a series of somatic hybrids and derived backcrosses for drought stress tolerance. In vitro stress exposure (with 5% and 15% PEG 6000) allowed the selection of several tolerant genotypes in a short time. The eleven selected genotypes were tested by using a semi-automated plant phenotyping platform at the Biological Research Centre in Szeged, Hungary, where the plants’ biomass accumulation and photosynthesis under long-term drought conditions were monitored. The findings of this study affirm that the somatic hybrids between potato and S. bulbocastanum, along with their backcrosses, constitute valuable pre-breeding material. This is attributed to their possession of both late blight resistance and drought stress tolerance. Full article

We applied a genomic in situ hybridization (GISH) to analyze the genomic constitution of and meiotic pairing in interspecific somatic hybrids, and in a wide subset of backcrossing derivatives (BC₁–BC₅), from three interspecific combinations involving the cultivated potato, Solanum tuberosum (AAAA genome), and three diploid (1 EBN) wild Mexican potato species (genome BB)—S. tarnii, S. pinnatisectum, and S. bulbocastanum. The theoretically expected genomic composition was detected in the somatic hybrids (AAAABB) and in the BC₁ progeny (AAAAB), whereas in the subsequent BC₂–BC₄ generations, the partial loss of alien chromosomes was observed and almost all the BC₅ genotypes showed a complete chromosome elimination of wild species. GISH revealed a homoeologous pairing between the chromosomes of the A- and the B-genomes in each of the hybrid progenies. Using GISH, we selected introgression lines with a single chromosome of the wild species in a potato genome background, as well as introgression lines with intergenomic recombinant chromosomes. Moreover, via molecular screening, BC hybrids with diagnostic markers for the R-genes conferring resistance to late blight disease and to the quarantine pest of the potato–Columbia root-knot nematode—were selected. The potential application of the results obtained for the planning of introgressive schemes directed to the breeding of advanced lines with multiple disease and pest resistance is discussed. Full article

Global climate change, especially when involving drought and salinity, poses a major challenge to sustainable crop production, causing severe yield losses. The environmental conditions are expected to further aggravate crop production in the future as a result of continuous greenhouse gas emissions, causing further temperature rise and leading to increased evapotranspiration, severe drought, soil salinity, as well as insect and disease threats. These suboptimal growth conditions have negative impact on plant growth, survival, and crop yield. Potato is well known as a crop extremely susceptible to drought, which is primarily attributed to its shallow root system. With potato being the fourth major food crop, increasing potato productivity is thus important for food security and for feeding global population. To maintain a sustainable potato production, it is necessary to develop stress tolerant potato cultivars that cope with the already ongoing climate change. The aim of our study is to analyze the response of potato somatic hybrids to drought and salt stress under in vitro conditions; the somatic hybrids studied are the wild relative Solanum chacoense (+) Solanum tuberosum, with or without mismatch repair deficiency (MMR). Upon this selection of drought and salt tolerant genotypes, somatic hybrids and their parents were phenotyped on a semi-automated platform, and lines tolerant to medium water scarcity (20% compared to 60% soil water capacity) were identified. Although none of the parental species were tolerant to drought, some of the MMR-deficient somatic hybrids showed tolerance to drought and salt as a new trait. Full article

Interspecific somatic hybridization is a noteworthy breeding strategy that allows the production of novel genetic variability when crossing barriers exist between two parental species. Although the genetic consequences of somatic hybridization have been well documented, little is known on its impact at the epigenetic level. The objective of our research was to investigate the epigenetic changes, in particular DNA methylation, occurring in a population of potato somatic hybrids. The analysis of 96 Solanum × michoacanum (+) S. tuberosum somatic hybrids from five fusion combinations and their parents was carried out by methylation-sensitive amplified polymorphism (MSAP) and high-performance liquid chromatography (HPLC) methods. Six MSAP primer combinations generated 622 unique bands, of which 295 were fully methylated. HPLC analysis showed from 15.5% to 16.9% total cytosine methylation within the parental forms. Overall, the MSAP and HPLC methods indicated an increase in DNA methylation in the somatic hybrids in comparison to their parents. Among the latter, a lower degree of DNA methylation in the wild S. × michoacanum species than S. tuberosum was found. Our findings indicated that somatic hybridization changed the level of cytosine methylation in the studied potato somatic hybrids. Full article