Análise cariotípica em espécies dos gêneros Solanum, Lycianthes e Vassobia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The Solanum genus comprises about 1.400 species of shrubs, trees and wines, found preferentially in the tropical regions. Some of these with economic interests, as the potato. In relation to the cytogenetical features, this group is interesting by the fact of the karyotypes be sufficiently conserved in chromosome number and shape, with diversity in the repetitive DNA. The objective of this study was to characterize species of Solanum and two species of next genera, Lycianthes australe and Vassobia breviflora, using cytogenetic parameters (conventional staining, C-CMA3/DAPI banding and FISH with 45S and 5S rDNA. We have been seen that all the species had presented 2n = 24, confirming the counting for the majority of the species study here. In Solanum scuticum, S. gemellum, S. amygdalifolium and Lycianthes australe the counting was new. All the species had presented arreticulated nuclei with early condensed proximal in prophase and little variation in the karyotype symmetry. However, S. corymbiflorum exhibited chromosomes approximately three bigger times in relation to the other species. GC-rich heterochromatin had been found in the terminal region of all the chromosomes in the majority of the species of Solanum. In the other species, including related genera, only the one pair was detected, while in S. corymbiflorum two pairs had been found. AT-rich regions had been evidenced in the centromerics regions of all the chromosomes in L. australe and centromerics regions of the two largest pairs in S. amygdalifolium. 45S rDNA sites were coincident with C/CMA3 + regions (satellites) which were found in just one pair, but with variation in the carrier pair. Solanum corymbiflorum presented two chromosomic pairs with 45S rDNA. The FISH with 5S rDNA showed signals in the pericentromeric region of one chromosome pair, generally in the short arms of the smaller chromosomes of each complement, with exception of S. trachytrichium that it presented two marked pairs. The results indicates that the mechanisms of karyotype differentiation involve changes in the pairs carrier rDNA sites, location and number of GC- and AT-rich bands, as well as changes in the shape and size of chromosomes and karyotypes. The results in S. corymbiflorum, that already it was considered Cyphomandra corymbiflora, can suggests that the Cyphomandra and Solanum genera represent two distinct groups in contrast of that they suggest some taxonomical studies, when its consider a just one taxonomic group.

ASSUNTO(S)

plantas - biologia molecular plant genetics plant molecular biology genética vegetal

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