IBONE   05434
INSTITUTO DE BOTANICA DEL NORDESTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Novel diversity in wild peanut relatives and the importance of their conservation in South America
Autor/es:
SAMOLUK S.; CARÍSIMO D.; ROBLEDO, G.; SEIJO G.
Lugar:
Bento Gonçalves
Reunión:
Congreso; 6th International Crop Science Congress; 2012
Institución organizadora:
International Crop Science Society
Resumen:
DIVERSITY AND CHROMOSOMAL DISTRIBUTION OF LONG INTERSPERSED NON- LTR
ELEMENTS (LINES) IN THE A GENOME OF ARACHIS SPECIES
Samoluk,S; Carisimo,D; Robledo,G; Seijo,JG;
Instituto de Botánica del Nordeste; Instituto de Botánica del Nordeste; Instituto de Botánica del Nordeste; Instituto de Botánica del Nordeste;
Retroelements constitute part of the repetitive DNA and play an important role in both the evolution
and structure of plant genomes. Section Arachis has 31 species grouped in five genomes (A,B,D,F
and K), 29 are wild diploids and two are allotetraploids. Even though there is a conserved colinearity
of different molecular markers among Arachis species with different genomes, GISH analysis
suggested a large divergence at the sequence level. On these bases, it has been hypothesized that
the repetitive fraction may have driven or participated in the genome differentiation of Arachis.
Considering that, and as a first step to test this hypothesis, the diversity of a group of LINEs
retroelements in Arachis species belonging to the A genome (A. duranensis, A. cardenasii and A.
helodes) was analyzed. For this purpose, 20 sequences of the conserved region of the reverse
transcriptase gene were amplified from genomic DNA of the three species using degenerate
primers. The amplified sequences showed 81% of variable sites and stop codons in 40% of them.
However, they had high homology at the amino acid level. These sequences also showed high
homology with the amino acid motifs of the reverse transcriptase of LINEs present in other
angiosperms and in gymnosperms. Despite the wide distribution of these elements in different
groups of plants, the N-J dendrogram revealed that the Arachis sequences form a unique cluster,
although nonspecific subclusters were observed for each species. This clustering suggests that the
diversification of the elements present in Arachis took place before the origin of the A genome. The
fluorescent in situ hybridization revealed a dispersed pattern of weak signals over most of the
chromosomes of the three species, suggesting that even though these elements are ubiquitous,
they have a low representation in the A genome.