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A novel negative-sense single-stranded RNA virus showing genetic similarity to viruses of the genus Rubodvirus has been found in raspberry plants in the Czech Republic and has tentatively been named raspberry rubodvirus 1 (RaRV1). Phylogenetic analysis confirmed its clustering within the group, albeit distantly related to other members. A screening of 679 plant and 168 arthropod samples from the Czech Republic and Norway revealed RaRV1 in 10 raspberry shrubs, one batch of Aphis idaei, and one individual of Orius minutus. Furthermore, a distinct isolate of this virus was found, sharing 95% amino acid identity in both the full nucleoprotein and partial sequence of the RNA-dependent RNA polymerase gene sequences, meeting the species demarcation criteria. This discovery marks the first reported instance of a rubodvirus infecting raspberry plants. Although transmission experiments under experimental conditions were unsuccessful, positive detection of the virus in some insects suggests their potential role as vectors for the virus. [ABSTRACT FROM AUTHOR]

Systemic infections with phytoplasmas and viruses threaten the production of healthy plant material under the fruit species certification system. We tested the possibility of sanitation using in vitro culture and cryotherapy. The starting material of the cultivars Golden Delicious (clones A and B), Virginia Crab, and Panenské zlepšené was taken from in vivo plants that tested positive for apple proliferation phytoplasma. The Táborita cultivar was obtained from already established in vitro cultures that had tested positive for apple proliferation phytoplasma, apple mosaic virus, and apple chlorotic leaf spot virus. Cultivars Golden Delicious A, Virginia Crab, and Panenské zlepšené were sanitated from the phytoplasma in the first step, i.e., by sterilization and a subsequent transfer to in vitro conditions. Golden Delicious B remained infected with the phytoplasma, and both viruses, after the in vitro culture phase and together with Táborita, were subjected to cryotherapy by vitrification. In Golden Delicious B, three out of thirteen initial shoot tips regenerated after a liquid nitrogen treatment. Four mericlones were regenerated from 10 initial cryopreserved shoot tips of Táborita. None of the three pathogens were detected by PCR in the regenerated Golden Delicious B mericlones. On the contrary, in the case of Táborita, infection with all the pathogens was detected after regeneration. The results obtained indicate the potential applicability of in vitro cultivation techniques or, if necessary, subsequent cryopreservation as a method for sanitizing against systemic microbial contamination. However, further research on the relationship between pathogens and specific genotypes is needed. [ABSTRACT FROM AUTHOR]

In sweet cherry (Prunus avium L.), quantitative trait loci have been identified for fruit maturity, colour, firmness, and size to develop markers for marker-assisted selection. However, resolution is usually too low in those analyses to directly target candidate genes, and some associations are missed. In contrast, genome-wide association studies are performed on broad collections of accessions, and assemblies of reference sequences from Tieton and Satonishiki cultivars enable identification of single nucleotide polymorphisms after whole-genome sequencing, providing high marker density. Two hundred and thirty-five sweet cherry accessions were sequenced and phenotyped for harvest time and fruit colour, firmness, and size. Genome-wide association studies were used to identify single nucleotide polymorphisms associated with each trait, which were verified in breeding material consisting of 64 additional accessions. A total of 1 767 106 single nucleotide polymorphisms were identified. At that density, significant single nucleotide polymorphisms could be linked to co-inherited haplotype blocks (median size ~10 kb). Thus, markers were tightly associated with respective phenotypes, and individual allelic combinations of particular single nucleotide polymorphisms provided links to distinct phenotypes. In addition, yellow-fruit accessions were sequenced, and a ~ 90-kb-deletion on chromosome 3 that included five MYB10 transcription factors was associated with the phenotype. Overall, the study confirmed numerous quantitative trait loci from bi-parental populations using high-diversity accession populations, identified novel associations, and genome-wide association studies reduced the size of trait-associated loci from megabases to kilobases and to a few candidate genes per locus. Thus, a framework is provided to develop molecular markers and evaluate and characterize genes underlying important agronomic traits. [ABSTRACT FROM AUTHOR]

Sweet cherry is a vegetatively propagated, self-incompatible, perennial plant with a high level of heterozygosity and ancient breeding history. Maintenance and conservation of genetic resources are necessary for future breeding programmes, growers and fruit production stability. The knowledge about S-allele constitution of cultivars is very important for fruit growers and breeders. DNA molecular genetic methods were used for evaluation of genetic variability and S-genotyping within sweet cherry genetic resources. Totally, 13 different S-alleles in 29 S-locus combinations for 24 individual incompatibility groups within 153 sweet cherries accessions were detected. S3 (88 cultivars), S1 (60 cultivars) and S4 (54 cultivars), followed by S2 (34 cultivars) and S6 (28 cultivars) were the most frequent S-alleles. S-alleles distribution linked to ripening time was also analysed. A total of 117 microsatellite SSR and EST-SSR polymorphic markers were used for molecular-genetic analyses. The hierarchical cluster analysis divided sweet cherry cultivars into seven clusters. Genetic relationships of individual cultivars corresponded with genealogical and geobotanical characteristics and known breeding history. Genetic population structure analyses in seven clusters (K= 7) supported hierarchical clustering results and involved ripening period, fruit colour and country of origin to genetic diversity evaluation of germplasm collection. [ABSTRACT FROM AUTHOR]

The airborne gamma-ray spectrometry images from the Czech and German parts of the Carboniferous Altenberg-Teplice Volcanic Complex (ATVC) - both obtained during independent surveying campaigns - were merged to display the structure of the caldera fill (dominated by rhyolitic ignimbrites) and associated intrusive bodies. The airborne systematic measurements were supported by the ground- and laboratory gamma-ray spectrometry analyses (K, U, Th) of representative lithologies from outcrops and drill-cores. Significant differences were identified between the younger and older (post- and pre-caldera respectively) intrusive complexes related to the ATVC. The younger Schellerhau granite displays 1.5-3.0× higher concentrations of radioactive elements than the older Fláje granite. The ATVC was found to be split by the NW-SE trending Altenberg Fault into a southern and a northern segment that expose different stratigraphic levels of the caldera's fill. The individual types of rhyolite ignimbrites defined in the Czech part of the ATVC are characterized by distinct concentrations of natural radioactive elements which enable identification of the individual types from the airborne gamma-spectrometry image. These characteristics were compared to data obtained from the German part, and several lithological types were unified to common units. A single Th-rich unit (Pramenáč type in Czech part, Lugstein type in Germany and Teplice Rhyolite TR3a in Mi-4 borehole) can be traced across the entire caldera and may serve as the principal correlation member. Inclusion of the Vrchoslav type into this TR3a unit remains speculative due to lack of data, and further petrological research is required. On the other hand, Vlčí kámen and Medvědí vrch types from opposite sides of the caldera display identical properties allowing to merge them into a common unit TR3b overlain by the youngest unit TR4 (Přední Cínovec type) - restricted to the Czech territory. This result may suggest partly synclinal structure within the southern ATVC segment. The TR4 unit has a strong compositional tendency towards the post-ignimbrite granite porphyry intrusions. Some lithotypes in the northern segment (e.g., Buschmühle) do not have counterparts on the Czech side and most likely represent an independent volcanic unit in the northern, presumably older, part of the caldera. The uniform composition of the rhyolitic rocks observed in the entire profiles of the drillings located in the Town Teplice (TP-39 reaching 1170 m depth) may suggest that the main feeding conduit system for the TR4 ignimbrite was located within the Teplice-Lahošť horst area. [ABSTRACT FROM AUTHOR]