Karyotype characterization reveals an up and down of 45S and 5S rDNA sites in Crotalaria (Leguminosae-Papilionoideae) species of the section Hedriocarpae subsection Macrostachyae

Autor(es)

Morales, A. G. ^[1] ; Aguiar-Perecin, M. L. R. ^[1] ; Mondin, M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Escola Super Agr Luiz de Queiroz, Dept Genet, BR-13400970 Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Genetic Resources and Crop Evolution; v. 59, n. 2, p. 277-288, FEB 2012.
• Citações Web of Science: 10

Resumo

The genus Crotalaria is one of the largest within the family Leguminosae-Papilionoideae, with more than 600 species. However, few karyotypes have been described. In the present paper, five species belonging to the section Hedriocarpae were studied (subsection Machrostachyae), in order to better understand chromosomal evolution in Crotalaria. The results reveals that all species presented 2n = 2x = 16 with symmetrical karyotypes, and slight differences in the chromosome morphology. A secondary constriction was identified at short arm of the pair 1. The 45S rDNA was mapped in the secondary constriction and adjacent heterochromatin (NOR-heterochromatin) and a minor site was identified in C. ochroleuca. The 5S rDNA was mapped linked to 45S rDNA at chromosome 1 short arm in all species. Additional sites for 5S rDNA were identified in C. pallida, C. striata and C. mucronata. Heterochromatin blocks around the centromeres are not CMA(+) neither DAPI(+). The karyotypes of the subsection Macrostachyae are characterized by an inversion at chromosome pair one in relation to previous specialized floral species analyzed. Additional sites of 45S and 5S rDNA were assumed to be a result of transposition events by different ways. The results suggest heterochromatin differentiation and the position of ribosomal genes indicates chromosomal rearrangements during evolution. Karyotype characteristics corroborate the morphological infrageneric classification. (AU)

• Processo FAPESP: 98/01170-5 - Análise da organização do genoma de alguns grupos de plantas através de técnicas de hibridação molecular in situ para mapeamento de sequências repetitivas de DNA (FISH) e análise de DNA genômico (GISH)
• Beneficiário: Margarida Lopes Rodrigues de Aguiar-Perecin
• Modalidade de apoio: Auxílio à Pesquisa - Temático