Plant microbiota contributes to nutrient absorption, and the production of hormones and vitamins, and plays a crucial role in responding to environmental stress. We hypothesized that Vaccinium spp. harbour a unique microbiota that enables them to coexist in extreme environments such as saline, nutrient-poor, and waterlogged conditions. Upon examining Bacillus spp. endophytes isolated from blueberries, cranberries and lingonberries in vitro, we identified B. halotolerans (Bil-LT1_1, Bil-LT1_2) and B. velezensis (Cran-LT1_8, Ling-NOR4_15) strains that inhibit the growth of five pathogenic fungi and five foodborne bacteria. Whole-genome sequencing provided insights into genome organization and plasticity, helping identify mobile elements and genes potentially acquired through horizontal gene transfer. Functional annotation identified genes associated with plant colonization, stress tolerance, biocontrol activity, and plant growth promotion. Comparative genomic analyses revealed key biosynthetic gene clusters (BGCs) responsible for producing antifungal metabolites, including lipopeptides and polyketides. Genes supporting plant nutrition, growth, and environmental adaptation were present also in these strains. Notably, isolated endophytes exhibited particularly high levels of genomic plasticity, likely due to horizontal gene transfer involving gene ontology (GO) pathways related to survival in polymicrobial and foreign environments.

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.

Monilinia spp., which causes brown rot, is one of the most damaging pathogens in stone fruits. Researchers are exploring epiphytic and endophytic microorganisms with the potential to suppress pathogens, control pathogenic microorganisms, and/or promote plant growth. In this study, microorganisms with antagonistic activity against three Monilinia species were isolated from plum orchard soil and plum fruits. Antagonism tests in vitro showed strong antagonistic properties of six strains of bacteria and two yeast-like fungi against M. fructigena, M. fructicola, and M. laxa, with growth inhibition from 45.5 to 84.6%. The antagonists were identified and characterized at the genetic level using whole genome sequencing (WGS). Genes involved in antibiotic resistance, virulence, secondary metabolite synthesis, and plant growth promotion were identified and characterized through genome mapping, gene prediction, and annotation. None of the microorganisms studied were predicted to be pathogenic to humans. The results of this study indicate that the bacteria Bacillus pumilus, B. velezensis, two strains of Lysinibacillus agricola, Pseudomonas chlororaphis isolated from stone fruit orchard soil, and the yeast-like fungus Aureobasidium pullulans, isolated from plums, are promising candidates for the biological control of Monilinia spp.

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.