Análise de sequências de DNA cloroplástico de espécies do gênero Capsicum.

Peppers are originated in America where great natural genetic variability is observed. More than 25 Capsicum species were already described in the American continent, in their great majority wild species, many of them met in the Atlantic forest and Amazon. Five species are domesticated and largely utilized as food and condiment in the world (C. annuum var. annuum, C. baccatum var. pendulum, C. chinense, C. frutescens e C. pubescens). Other 10 species are yet semi-domesticated and less commercially utilized. The knowledge of phylogenetic relationship of domesticated and wild species is still limited. This knowledge is fundamental for germplasm organization, characterization and conservation and, mainly, for the utilization of existent genetic resources in viable crossings in breeding programs. Recent collection expeditions in Brazilian southeast turned possible the discovery of pepper natural populations. The botanic descriptors studied until now indicated that these populations possibly represent new species met in Atlantic forest remainings. A sample of 54 accessions of wild, semidomesticated and cultivated peppers and sweet pepper were studied in polymorphic regions of chloroplast genome to establish phylogenetic relations among accessions. DNA samples of Capsicum evolutionary distant species (Nicotiana tabacum, Physalis sp, Lycopersicon esculentum and Atropa belladonna) were used as outgroups. The study was based in the molecular clock hypothesis through the evaluation of observed polymorphism in chloroplastic DNA specific regions by CAPS –(“cleaved amplified polymorphic sequence”). The phenetic analysis of cpDNA 8 Analise de Sequencias de DNA Cloroplastico de Especies do Genero Capsicum polymorphisms indicated, initially, a division of analyzed accessions in two main groups, one corresponding to accessions of Capsicum genus and the other to outgroup species confirming the monophyletic relation among Capsicum species. The Capsicum genus group, was subdivided in two subgroups, one containing the cultivated and semi-domesticated Capsicum species and another one with the wild species. In the first subgroup the C. annuum, C. frutescens e C. chinense accessions grouped together while C. baccatum accessions were grouped in an independent division. The second Capsicum subgroup was divided in two groupings, one containing the wild species recently collected in the Atlantic forest and other containing wild species classified in other studies: C. villosum, C. bufforum, C. dusenii e C. campilopodium. One of the Atlantic forest accessions (sp6), however, grouped with C. bufforum accession. Two of the recently collected accessions (sp2 e sp3) presented very similar cpDNA haplotype. The data corroborated botanic evidences that some of the new accessions recently collected in the Atlantic forest represent new species of the genus.