This study’s aim was to evaluate the genetic diversity of European plum (Prunus domestica) cultivars and hybrids in Lithuania using SSR markers. In total, 107 plum genotypes (including 68 European plum cultivars and 39 hybrids) from the genetic resources collection of the Institute of Horticulture of the Lithuanian Research Centre for Agriculture and Forestry (LRCAF IH) were evaluated using nine microsatellite markers (SSRs) previously published and suggested by the European Cooperative Programme for Plant Genetic Resources (ECPGR). Up to six alleles per locus with each primer pair were generated for some genotypes due to the hexaploidy of plums. The number of alleles in each primer ranged from 18 to 30, with an average of 24.33. The highest number of alleles was generated with the PacA33 primer pair (30). The most informative primer, according to the PIC value, was BPPCT007. Sixty-two unique alleles (representing 39.5% of all polymorphic alleles) have been detected in the plum germplasm developed in Lithuania. According to UPGMA cluster analysis, 58 European plum genotypes were separated into eight groups without any relation to fruit color or shape. By genetic diversity (UPGMA) and structure (Bayesian) analysis, European plum hybrids were grouped into clusters according to their pedigree.

Brown rot caused by Monilinia spp. fungi causes substantial losses in stone and pome fruit production. Reports suggest that up to 90% of the harvest could be lost. This constitutes an important worldwide issue in the food chain that cannot be solved by the use of chemical fungicides alone. Biocontrol agents (BCAs) based on microorganisms are considered a potential alternative to chemical fungicides. We hypothesized that endophytic bacteria from Prunus domestica could exhibit antagonistic properties towards Monilinia fructigena, one of the main causative agents of brown rot. Among the bacteria isolated from vegetative buds, eight isolates showed antagonistic activity against M. fructigena, including three Pseudomonas spp. isolates that demonstrated 34% to 90% inhibition of the pathogen’s growth when cultivated on two different media in vitro. As the stimulation of plant growth could contribute to the disease-suppressing activity of the potential BCAs, plant growth promoting traits (PGPTs) were assessed for bacterial isolates with M. fructigena-suppressing activity. While all isolates were capable of producing siderophores and indole-3-acetic acid (IAA), fixating nitrogen, mineralizing organic phosphate, and solubilizing inorganic phosphate and potassium, only the Pseudomonas spp. isolates showed 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. Overall, our study paves the way for the development of an eco-friendly strategy for managing M. fructigena pathogens by using BCAs including Pseudomonas spp. bacteria, which could also serve as growth stimulators.

The aim of this study was to evaluate phenotypic traits and genetic diversity of the 13 tomato (Solanum lycopersicum L.) varieties and 6 hybrids developed at the Institute of Horticulture Lithuanian Research Centre for Agriculture and Forestry (LRCAF IH). For the molecular characterisation, seven previously published microsatellite markers (SSR) were used. A24 and 26 alleles were detected in tomato varieties and hybrids, respectively. Based on the polymorphism information content (PIC) value, the most informative SSR primers for varieties were TMS52, TGS0007, LEMDDNa and Tom236-237, and the most informative SSR primers for hybrids were SSR248 and TMS52. In UPGMA cluster analysis, tomato varieties are grouped in some cases due to genetic relationships, as the same cluster cultivars ‘Viltis’ (the parent of cv. ‘Laukiai’) and ‘Aušriai’ (the progeny of cv. ‘Jurgiai’) are present. The grouping of all hybrids in the dendrogram is related to the parental forms, and it shows the usefulness of molecular markers for tomato breeding, as they can be used to trace the origin of hybrids and, eventually, varieties accurately. The knowledge about the genetic background of Lithuanian tomato cultivars will help plan targeted crosses in tomato breeding programs.

European plum production is affected by mostly harm Monilinia spp., causing full pathogen brown-rot infections. The plums are the susceptible to the Monilinia fructigena pathogen, which is the most common in Europe. This study aims to analyze the gene expression profiles and signaling pathways of the European plum, cv. Victoria, inoculated with the M. fructigena pathogen at 24, 48, and 72 h post inoculation. By transcriptome sequencing, the number of differentially expressed genes (DEGs) increased over time, with the highest number at 72 hpi, showing the tendency to involve more genes in the response to prolonged exposure to the pathogen. Pathogenesis-related (PR) family and mildew resistance locus O (MLO-like) proteins were expressed the most during plum response to the pathogen. The plum initiates complex defense responses by significantly activating 23 pathways according to Kyoto Encyclopedia of Genes and Genomes (KEGG). In this study, expressed genes over the infection were in response to stress, defense, cell death, and disease resistance. The findings of this study could be used as the basis for further research of markers linked to resistance or susceptibility to disease in plum hybrids at an early age, which will improve the plum breeding process.

Strawberry anthracnose is becoming more important from a scientific and economic standpoint. The Colletotrichum spp. pathogen complex includes C. fragariae, C. gloeosporioides and C. acutatum. The aim was to use microsatellite (SSR) markers to assess the genetic diversity of Colletotrichum species. We used seven SSR primer pairs previously developed for the C. acutatum (3) and C. gloeosporioides (4) species. To analyze the genetic diversity of C. fragariae, it was discovered that SSR primer pairs created for C. gloeosporioides were helpful. SSR molecular markers were used in this study for the first time to identify the species of C. fragariae. The average polymorphism information content (PIC) value across all SSR primer pairs was 0.72, making them all informative. The most informative SSR primers were CG22 and CG30, with PIC values of 0.83 and 0.82, respectively. We believe these primers are suitable for the genetic diversity analysis of C. fragariae species. Therefore, the SSR primer pairs CG20 and CG30 are suggested for the genetic investigation of C. acutatum and C. gloeosporioides. A higher incidence of Colletotrichum spp. polymorphism in Lithuania can be linked to adaptation to survival in our environment, according to this study’s findings on the number of alleles and the degree of genetic diversity, which are higher than the results reported in the literature.

European plum (Prunus domestica) is among the most important stone fruits cultivated worldwide. However, its production is significantly affected by fungal brown rot disease, caused by Monilinia spp. pathogens, which threaten the crop throughout the entire vegetation period. This study aimed to visually assess brown rot resistance and susceptibility in European plum and to perform whole-genome sequencing (WGS) of selected cultivars and hybrids grown in Lithuania, with the goal of identifying candidate single-nucleotide polymorphisms (SNPs) associated with disease response. WGS was performed for 20 European plum cultivars and hybrids with known resistance or susceptibility profiles, generating over 1,4 million SNPs. These SNPs were filtered to identify genetic variants associated with brown rot disease. Three candidate SNPs were found to be significantly associated with disease response (located on chromosomes G5 and G8) and one linked to susceptibility (on chromosome G5). Identified SNPs were located in genes encoding alcohol dehydrogenase family enzymes (resistant cultivars, G5 chromosome) and beta-glucosidase family enzymes (variants found in both resistant and susceptible cultivars, G5 chromosome), which are important for plant biotic stress response. The findings of this study provide a valuable foundation for the development of molecular markers for identifying resistant and susceptible cultivars and may inform future European plum breeding programs.