Genetic diversity among twelve grape cultivars indigenous to the Carpathian Basin revealed by RAPD markers

Twelve cultivars (Vitis vinifera L.) were subjected to RAPD analysis in order to estimate the genetic diversity among these genotypes and to analyse their genetic relationships. The study was performed using 28 primers that generated 120 polymorphic fragments. There was genetic variation among the cultivars with values of genetic diversity ranging from 0.419 to 0.642 using the Jaccard coefficient. UPGMA analysis of distance matrix resulted in a dendrogram with three clusters. The dendrogram shows that the cultivars of our study can be distinguished to a relatively high degree. Results were compared with the taxonomic classification and with the synonyms of the cultivars. The RAPD technique was useful for identification and discrimination of these grape cultivars

Novel pathogen-specific primers for the detection of Agrobacterium vitis and Agrobacterium tumefaciens

To detect agrobacteria causing crown gall disease of grapevine novel virulence and oncogene specific primer combinations were tested on Agrobacterium vitis and Agrobacterium tumefaciens strains including most opine types found in grapevines. Reproducible detection of all the tested pathogens in a single reaction was only possible with multiplex PCR using mixtures of virulence-, or oncogene specific primers. A primer combination including pehA, virF and virD2 gene-specific oligonucleotides amplified the corresponding fragments from nearly all strains included and distinguished A. vitis and A. tumefaciens strains carrying octopine or nopaline pTis and A. vitis vitopine strains. A second set of primers designed to amplify the T-DNA auxin genes iaaH and iaaM detected all of the tested pathogens and, as in the case of virF-, and virD2-specific primers, A. vitis vitopine strains formed also a distinct group. These data were further confirmed using opine synthase-, or 6b gene-specific primers that also allowed the identification and distinction of octopine and nopaline as well as vitopine isolates of A. vitis. Thus, a wide range of agrobacteria occurring on grapevine were detected and identified. On the other hand, our results confirm that vitopine-type agrobacteria form a distinct group within the genus Agrobacterium.

Novel pathogen-specific primers for the detection of Agrobacterium vitis and Agrobacterium tumefaciens

Summary To detect agrobacteria causing crown gall disease of grapevine novel virulence and oncogene specific primer combinations were tested on Agrobacterium vitis and Agrobacterium tumefaciens strains including most opine types found in grapevines. Reproducible detection of all the tested pathogens in a single reaction was only possible with multiplex PCR using mixtures of virulence-, or oncogene specific primers. A primer combination including pehA, virF and virD2 gene-specific oligonucleotides amplified the corresponding fragments from nearly all strains included and distinguished A. vitis and A. tumefaciens strains carrying octopine or nopaline pTis and A. vitis vitopine strains. A second set of primers designed to amplify the T-DNA auxin genes iaaH and iaaM detected all of the tested pathogens and, as in the case of virF-, and virD2-specific primers, A. vitis vitopine strains formed also a distinct group. These data were further confirmed using opine synthase-, or 6b gene-specific primers that also allowed the identification and distinction of octopine and nopaline as well as vitopine isolates of A. vitis. Thus, a wide range of agrobacteria occurring on grapevine were detected and identified. On the other hand, our results confirm that vitopine-type agrobacteria form a distinct group within the genus Agrobacterium. K e y w o r d s

Silencing Agrobacterium oncogenes in transgenic grapevine results in strain-specific crown gall resistance

Crown gall disease of grapevine induced by Agrobacterium vitis or Agrobacterium tumefaciens causes serious economic losses in viticulture. To establish crown gall-resistant lines, somatic proembryos of Vitis berlandieri × V. rupestris cv. 'Richter 110' rootstock were transformed with an oncogene-silencing transgene based on iaaM and ipt oncogene sequences from octopine-type, tumor-inducing (Ti) plasmid pTiA6. Twentyone transgenic lines were selected, and their transgenic nature was confirmed by polymerase chain reaction (PCR). These lines were inoculated with two A. tumefaciens and three A. vitis strains. Eight lines showed resistance to octopine-type A. tumefaciens A348. Resistance correlated with the expression of the silencing genes. However, oncogene silencing was mostly sequence specific because these lines did not abolish tumorigenesis by A. vitis strains or nopaline-type A. tumefaciens C58

Partitioning of genetic (Rapd) variability among sexes and populations of the Barn Owl (Tyto alba) in Europe

The white Barn Owl subspecies (Tyto alba alba) is found in southern Europe and the reddish-brown subspecies (T a. guttata) in northern and eastern Europe. In central Europe, the two subspecies interbreed producing a large range of phenotypic variants. Because of the different ratios of the subspecies in different geographic regions, we predict that genetic variation should be greater in Switzerland than in Hungary. We tested this hypothesis by measuring genetic variation with the RAPD method. As predicted, the genetic differentiation within a Swiss population of Barn Owls was significantly greater than the variation within a Hungarian population. This suggests that gene flow is greater in central Europe than at the eastern limit of the Barn Owl distribution in Hungary. In both countries genetic variation was more pronounced in females than in males. As in other birds, this is probably because female Barn Owls are less philopatric than males. The number of migrants between Hungary and Switzerland is ca. 1 individual per generation; if calculated separately for the sexes, then 0.525 for males and ca. I for females (Nm values). The difference in the number of migrants between genders again is likely a consequence of higher male philopatry. The sexual differentiation is greater in the Swiss population than in the Hungarian and the genetic substructuring of the populations of the species is substantial. The reason for the considerable population substructuring could be the nonmigratory behavior and socially monogamous pairing of the species, as well as the geographical barriers (Alps) between the populations examined

Novel pathogen-specific primers for the detection of Agrobacterium vitis and Agrobacterium tumefaciens

Summary To detect agrobacteria causing crown gall disease of grapevine novel virulence and oncogene specific primer combinations were tested on Agrobacterium vitis and Agrobacterium tumefaciens strains including most opine types found in grapevines. Reproducible detection of all the tested pathogens in a single reaction was only possible with multiplex PCR using mixtures of virulence-, or oncogene specific primers. A primer combination including pehA, virF and virD2 gene-specific oligonucleotides amplified the corresponding fragments from nearly all strains included and distinguished A. vitis and A. tumefaciens strains carrying octopine or nopaline pTis and A. vitis vitopine strains. A second set of primers designed to amplify the T-DNA auxin genes iaaH and iaaM detected all of the tested pathogens and, as in the case of virF-, and virD2-specific primers, A. vitis vitopine strains formed also a distinct group. These data were further confirmed using opine synthase-, or 6b gene-specific primers that also allowed the identification and distinction of octopine and nopaline as well as vitopine isolates of A. vitis. Thus, a wide range of agrobacteria occurring on grapevine were detected and identified. On the other hand, our results confirm that vitopine-type agrobacteria form a distinct group within the genus Agrobacterium. K e y w o r d s