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Advisor(s)
Abstract(s)
The genus Avena comprises four distinct genomes organized in diploid (AA or CC), tetraploid
(AABB or AACC) and hexaploid species (AACCDD), constituting an interesting model
for phylogenetic analysis. The aim of this work was to characterize 45S rDNA intergenic
spacer (IGS) variability in distinct species representative of Avena genome diversity±A.
strigosa (AA), A. ventricosa (CvCv), A. eriantha (CpCp), A. barbata (AABB), A. murphyi
(AACC), A. sativa (AACCDD) and A. sterilis (AACCDD) through the assessment of the 5'
external transcribed spacer (5'-ETS), a promising IGS region for phylogenetic studies poorly
studied in Avena genus. In this work, IGS length polymorphisms were detected mainly due
to distinct 5'-ETS sequence types resulting from major differences in the number and organization
of repeated motifs. Although species with A genome revealed a 5'-ETS organization
(A-organization) similar to the one previously described in A. sativa, a distinct organization
was unraveled in C genome diploid species (C-organization). Interestingly, such new organization
presents a higher similarity with other Poaceae species than A-genome sequences,
supporting the hypothesis of C-genome being the ancestral Avena genome. Additionally,
polyploid species with both genomes mainly retain the A-genome 5'-ETS organization, confirming
the preferential elimination of C-genome sequences in Avena polyploid species.
Moreover, 5'-ETS sequences phylogenetic analysis consistently clustered the species studied
according to ploidy and genomic constitution supporting the use of ribosomal genes to
highlight Avena species evolutive pathways.
Description
Research Article
Keywords
Avena genus genome
Pedagogical Context
Citation
Publisher
PLOS one