Yazar "Ipek, M." seçeneğine göre listele

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    Association of reversible inactivation of the maize transposable element Ds with tissue-specific processing of the 35S:TPase transcript in carrot (Daucus carota L.)
    (Taylor & Francis Ltd, 2006) Ipek, A.; Ipek, M.; Simon, P. W.
    An Ac/Ds-based two-element transposon tagging system has been introduced into carrot. F-1 progeny containing both the 35S-Ac-transposase gene (35S:TPase) and the Ds element were derived from crosses between 35S:TPase- and Ds-bearing parents. While excision of Ds was not detected in any F-1 plants carrying both 35S:TPase and the Ds element, calli initiated from these F-1 plants had the Ds element excised, indicating Ds transposition. Reverse transcriptase-PCR analysis revealed that the 35S:TPase gene was expressed in both F-1 plants and calli, and that introns 1, 2, and 3 were spliced correctly. Although intron 4 was also spliced correctly in calli, incorrectly spliced intron 4 was detected in F-1 plants. Sequence analysis of incorrectly spliced reverse transcriptase-PCR products demonstrated the presence of a cryptic intron donor site within intron 4 of the 35S:TPase transcript. This probably competed with the proposed intron donor site during maturation of the major 35S:TPase transcript. These results suggested that the major transcript of 35S:TPase was incorrectly processed and, consequently, that the Ds element was reversibly inactivated in the somatic tissues of carrot plants, whereas this inactive Ds element was remobilised during tissue culture, where the 35S:TPase transcript was spliced correctly. These observations point to an important role for tissue-specific 35S:TPase transcript processing for successful transposition of Ds in carrot. Therefore, successful processing of the 35S:TPase transcript in carrot callus may indicate strategies to increase Ac transposition in other tissues.
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    Microsatellite and morphological markers reveal genetic variation within a population of Sclerotinia sclerotiorum from oilseed rape in the Canakkale Province of Turkey
    (Wiley, 2007) Mert-Turk, F.; Ipek, M.; Mermer, D.; Nicholson, P.
    The genetic variation among a population of Sclerotinia sclerotiorum collected from oilseed rape fields in the Canakkale Province of Turkey was assessed using molecular and morphological markers. Seven microsatellite primer pairs (out of eight) revealed 32 clear polymorphic alleles among the 36 fungal isolates examined. An unweighted pair-group mean analysis dendrogram was generated using the genetic distance matrix with the 32 microsatellite alleles. The level of similarity was as low as 15% between some isolates indicating a high level of genetic diversity within the fungal population; 23 distinct isolates were found (at a genotypic diversity level of 63%). Among the collection of 36 isolates, 19 mycelial compatibility groups (MCGs) were identified; 10 MCGs included at least two isolates. Molecular and morphological data suggest that most of the isolates within a single MCG were identical; however, the isolates belonging to the MCG2 and MCG4 had variable microsatellite haplotypes and were morphologically dissimilar. The data suggest that there is possibly a high rate of outcrossing as well as evolutionary potential within the population of the pathogen in oilseed rape fields. This is the first report demonstrating the genetic and morphological variation within a population of S. sclerotiorum in Turkey.