A detailed examination of 45 pea (Pisum sativum L.) simple sequence repeat (SSR) loci revealed that 21 of them included homologous sequences corresponding to the long terminal repeat (LTR) of a novel retrotransposon. Further investigation, including full-length sequencing, led to its classification as an RLC-Angela-family-FJ434420 element. The LTR contained a variable region ranging from a simple TC repeat (TC)(11) to more complex repeats of TC/CA, (TC)(12-30), (CA)(18-22) and was up to 146 bp in length. These elements are the most abundant Ty1/copia retrotransposons identified in the pea genome and also occur in other legume species. It is interesting that analysis of 63 LTR-derived sequences originating from 30 legume species showed high phylogenetic conservation in their sequence, including the position of the variable SSR region. This extraordinary conservancy led us to the proposition of a new lineage, named MARTIANS, within the Angela family. Similar LTR structures and partial sequence similarities were detected in more distant members of this Angela family, the barley BARE-1 and rice RIRE-1 elements. Comparison of the LTR sequences from pea and Medicago truncatula elements indicated that microsatellites arise through the expansion of a pre-existing repeat motif. Thus, the presence of an SSR region within the LTR seems to be a typical feature of this MARTIANS lineage, and the evidence gathered from a wide range of species suggests that these elements may facilitate amplification and genome-wide dispersal of associated SSR sequences. The implications of this finding regarding the evolution of SSRs within the genome, as well as their utilization as molecular markers, are discussed.

• MeSH
• DNA rostlinná genetika   MeSH
• Fabaceae genetika   MeSH
• genom rostlinný * MeSH
• hrách setý genetika   MeSH
• koncové repetice MeSH
• mikrosatelitní repetice * MeSH
• molekulární sekvence - údaje MeSH
• retroelementy * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA rostlinná MeSH
• retroelementy * MeSH

The distinctness, uniformity and stability (DUS) requirements involve expensive, space- and time-consuming measurements of morphological traits. Moreover, for a majority of traits, interactions between genotype and environment complicate the evaluation. Molecular markers have a potential to facilitate this procedure, increase the reliability of decisions, and substantially save the time and space needed for experiments. We chose 25 varieties of pea (Pisum sativum L.) from the list of recommended varieties for cultivation in the Czech Republic, and made both a standard classification by 12 morphological descriptors and a classification by biochemical-molecular markers. Two isozyme systems, 10 microsatellite loci, 2 retrotransposons for multilocus inter-retrotransposon amplified polymorphism (IRAP), and 12 retrotransposon-based insertion polymorphism (RBIP) DNA markers were analysed. The main objective of the study was to examine the potential of each method for discrimination between pea varieties. The results demonstrate a high potential and resolving power of DNA-based methods. Superior in terms of high information content and discrimination power were SSR markers, owing to high allelic variation, which was the only biochemical-molecular method allowing clear identification of all varieties. Retrotransposon markers in RBIP format proved to be the most robust and easy to score method, while multilocus IRAP produced informative fingerprint already in a single analysis. Isozyme analysis offered a fast and less expensive alternative. The results showed that molecular identification could be used to assess distinctness and complement morphological assessment, especially in cases where the time frame plays an important role. Currently developed pea marker systems might serve also for germplasm management and genetic diversity studies.

• MeSH
• biologické markery * MeSH
• DNA rostlinná genetika   MeSH
• druhová specificita MeSH
• hrách setý genetika   metabolismus   MeSH
• mikrosatelitní repetice genetika   MeSH
• polymorfismus genetický MeSH
• retroelementy MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biologické markery * MeSH
• DNA rostlinná MeSH
• retroelementy MeSH