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The karyotypes of southern Italian samples of three species of the genus Allium L. belonging to the section Allium, were analyzed using Feulgen staining and C-banding techniques. Karyomorphological affinities and C-banding patterns clearly denote close phyletic relationships between A. commutatum Guss., A. ampeloprasum L. and A. atroviolaceum Boiss. Nevertheless, the karyotypes of the two tetraploid species revealed notable differences in the amount and distribution of C-banded heterochromatin. Marker chromosomes were identified which helped tracing evolutionary relationships among the three taxa considered. The results of morphological and karyological examinations allow the proposition of a possible phyletic pathway between the diploid species A. commutatum and the tetraploid ones A. ampeloprasum and A. atroviolaceum. The latter species seems to be particularly well adapted to southern Italian environments and might therefore contribute useful traits to closely related crops, such as leeks. 相似文献
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Pablo?Lunello Daniel?Ducasse Vilma?ConciEmail author 《European journal of plant pathology / European Foundation for Plant Pathology》2005,112(4):371-378
Protocols for producing virus-free Allium plants require an indexing system that is more sensitive than DAS-ELISA and can detect low virus concentrations in infected plants. In the present work, degenerate primers were designed and a one-step IC-RT-PCR protocol was developed to differentiate between Leek yellow stripe virus (LYSV) and Onion yellow dwarf virus (OYDV) in single and mixed infections in several Allium spp. A 566-bp band was observed for LYSV, a 489-bp band for OYDV in single infections, and two bands of the same sizes in mixed infections in different species of Alliaceae. A 508-bp band of Shallot yellow stripe virus and a 594-bp band of Turnip mosaic virus were also amplified with the same primers. RT-nested-PCR was also conducted directly in microtitre plate wells after negative or questionable reactions were produced in an ELISA experiment. The detection limit of the DAS-ELISA for LYSV was 16.5–27.3 ng ml−1. The RT-nested-PCR done after DAS-ELISA was 102 times more sensitive than the DAS-ELISA alone. In parallel, an IC-RT-nested-PCR in microcentrifuge tubes was 104 times more sensitive than the DAS-ELISA. The DAS-ELISA-RT-nested-PCR enables the initial screening of samples by DAS-ELISA to eliminate a high percentage of virus-positive plants, considerably reducing the number of plants to analyze further by RT-PCR. 相似文献
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