Characterization of Brazilian accessions of wild Arachis species of section Arachis (Fabaceae) using heterochromatin detection and Fl uorescence in situ hybridization (FISH).

CUSTODIO, AR; VALLS, JFM; SEIJO, JG

Brasilia

Congreso; 5th International Conference of the Peanut Research Community on Advances in Arachis through Genomics and Biotechnology (AAGB).; 2011

AAGB

Twelve Brazilian accessions of five Arachis species were characterized using FISH and heterochromatin detection. 5S and 45S rDNA loci, syntenic sites, and chromosomes with heterochromatic bands were observed. Arachis glandulifera V14730 presented eight 45S sites, two intense 5S sites and possibly two faint ones, seven chromosome pairs with mainly pericentromeric, but also interstitial heterochromatic bands, quite similar to the pattern described from Bolivian accessions. Arachis valida accessions V9153 and V13514 presented six 45S and two 5S sites, with synteny in one chromosome pair. Centromeric heterochromatic bands were absent, although a telomeric band could be present in one chromosome pair of V13514, as described from the type. Accessions of A. gregoryi V6389, V14743 and V14957 had two 5S and two 45S sites, not syntenic, similar to previous information on V14753. Five Brazilian accessions identified as A. magna did not show heterochromatic bands. All five presented two 5S sites, as for the type. They varied concerning 45S sites, two in V13748, V14727, V14750, four in V13765, six in V14724. None exactly repeated the 45S pattern of the type collection. Identified as A. hoehnei, accession V9146 presented four 45S and four 5S sites, in two syntenic chromosome pairs, and centromeric heterochromatic bands in all pairs. This accession shows a small chromosome pair, which however does not seem to behave as the A pair. It is possible that two types of plants, morphologically similar but with significant cytogenetic differences, are filed under A. hoehnei, of which those not corresponding to the type should be segregated.