BACKGROUND: Interspecific hybridisation resulting in polyploidy is one of the major driving forces in plant evolution. Here, we present data from the molecular cytogenetic analysis of three cytotypes of Elytrigia ×mucronata using sequential fluorescence (5S rDNA, 18S rDNA and pSc119.2 probes) and genomic in situ hybridisation (four genomic probes of diploid taxa, i.e., Aegilops, Dasypyrum, Hordeum and Pseudoroegneria). RESULTS: The concurrent presence of Hordeum (descended from E. repens) and Dasypyrum + Aegilops (descended from E. intermedia) chromosome sets in all cytotypes of E. ×mucronata confirmed the assumed hybrid origin of the analysed plants. The following different genomic constitutions were observed for E. ×mucronata. Hexaploid plants exhibited three chromosome sets from Pseudoroegneria and one chromosome set each from Aegilops, Hordeum and Dasypyrum. Heptaploid plants harboured the six chromosome sets of the hexaploid plants and an additional Pseudoroegneria chromosome set. Nonaploid cytotypes differed in their genomic constitutions, reflecting different origins through the fusion of reduced and unreduced gametes. The hybridisation patterns of repetitive sequences (5S rDNA, 18S rDNA, and pSc119.2) in E. ×mucronata varied between and within cytotypes. Chromosome alterations that were not identified in the parental species were found in both heptaploid and some nonaploid plants. CONCLUSIONS: The results confirmed that both homoploid hybridisation and heteroploid hybridisation that lead to the coexistence of four different haplomes within single hybrid genomes occur in Elytrigia allopolyploids. The chromosomal alterations observed in both heptaploid and some nonaploid plants indicated that genome restructuring occurs during and/or after the hybrids arose. Moreover, a specific chromosomal translocation detected in one of the nonaploids indicated that it was not a primary hybrid. Therefore, at least some of the hybrids are fertile. Hybridisation in Triticeae allopolyploids clearly and significantly contributes to genomic diversity. Different combinations of parental haplomes coupled with chromosomal alterations may result in the establishment of unique lineages, thus providing raw material for selection.
- Klíčová slova
- Allopolyploidy, Chromosomal alterations, Elymus repens, FISH, GISH, Higher polyploids, Hybridisation, Thinopyrum intermedium,
- MeSH
- cytogenetické vyšetření MeSH
- DNA rostlinná analýza MeSH
- genotyp * MeSH
- hybridizace genetická * MeSH
- hybridizace in situ fluorescenční MeSH
- hybridizace in situ MeSH
- lipnicovité genetika MeSH
- polyploidie * MeSH
- RNA ribozomální 18S analýza MeSH
- RNA ribozomální 5S analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- DNA rostlinná MeSH
- RNA ribozomální 18S MeSH
- RNA ribozomální 5S MeSH
We have determined the sequences of 5S rRNA and spliced leader (SL) RNA genes, and adjacent intergenic regions for representatives of all known trypanosomatid genera parasitizing insects. The genetic loci have been analyzed separately as well as by a combined approach. Several isolates, assigned by morphology to different genera (Leptomonas spp., Blastocrithidia spp.), seem to belong to a single species with an unexpectedly wide host and geographical range. An unnamed trypanosomatid isolated from rats in Egypt was found to belong to the genus Herpetomonas, so far associated with insect hosts only. It is closely related to Herpetomonas ztiplika, a parasite of a blood-sucking biting midge. Apparently several different trypanosomatid species can infect one insect species, as exemplified by Leptomonas sp. PL and Wallaceina sp. Wsd, which were isolated from different specimens of Salda littoralis on the same locality and day. However, since the same species of Leptomonas was obtained from insect hosts belonging to different genera, some insect trypanosomatids may have low host specificity. Our data revealed additional discrepancies between molecular phylogenetic data and cell morphology, rendering current trypanosomatid taxonomy unreliable.
- MeSH
- fylogeneze MeSH
- genetická variace * MeSH
- hmyz parazitologie MeSH
- intergenová DNA MeSH
- molekulární sekvence - údaje MeSH
- protozoální geny MeSH
- RNA protozoální genetika MeSH
- RNA ribozomální 5S analýza chemie genetika MeSH
- RNA se sestřihovou vedoucí sekvencí analýza genetika MeSH
- Trypanosomatina klasifikace cytologie genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Názvy látek
- intergenová DNA MeSH
- RNA protozoální MeSH
- RNA ribozomální 5S MeSH
- RNA se sestřihovou vedoucí sekvencí MeSH
