Filogeografia, diferenciação geográfica e caracterização citogenética de populações naturais de Psychotria ipecacuanha das florestas Atlântica e Amazônica

• Ano de defesa: 2007
• Autor(a) principal: Rossi, Ana Aparecida Bandini
• Orientador(a): Oliveira, Luiz Orlando de
• Banca de defesa: Caixeta, Eveline Teixeira , Viccini, Lyderson Facio
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Genética e Melhoramento
• Departamento: Genética animal; Genética molecular e de microrganismos; Genética quantitativa; Genética vegetal; Me
• País: BR
• Palavras-chave em Português: Filogeografia; Diversidade genética; Planta medicinal
• Palavras-chave em Inglês: Phylogeography; Genetic diversity; Medicinal plant
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA MOLECULAR E DE MICROORGANISMOS
• Link de acesso: http://locus.ufv.br/handle/123456789/1374

Ipecac (Psychotria ipecacuanha) is a small perennial shrub, which grew abundantly under shady areas of tropical rain forests of Brazil. The species was employed by native Brazilians who taught the medicinal properties to European settlers. Ipecac roots have achieved worldwide usefulness as an expectorant, amoebicide, and vomitive agent because of its pharmacological active isoquinoline alkaloids. However, overharvesting of wild plants and negligence in replanting ipecac plants after uprooting has led to a severe decline of native ipecac populations. Remaining populations occur naturally in the understory of tropical forests from three widely discrete regions: 1) Central America and adjacent parts of South America; 2) Southwestern part of the Brazilian Amazon; and 3) Atlantic Rain Forest along the Brazilian coast. The studies carried out in the present investigation used a combined approach that included molecular phylogeography based on cpDNA, population structure via ISSR, and cytogenetics to characterize natural populations of ipecac from the Atlantic and Amazon forests of Brazil. The analyses allowed us to develop and evaluate hypotheses on the historical and ecological factors that shaped the distribution of extant populations and added a substantial amount of information to the understanding the evolutionary history of this important medicinal species. Both nested clade analyses and ISSR analyses revealed remarkable differences between forests. Diversity of cpDNA haplotype was much higher in the Atlantic Forest, which harbor 11 out of the 12 haplotypes found. Only a single haplotype was uncovered in the Amazon Forest. None of the haplotypes was shared across forest types, which indicated the presence of reciprocal monophyly. The nested clade analyses pointed allopatric fragmentation as the main causal force that shaped the differences between forests. When compared to the Amazon Forest, the Atlantic Forest exhibited higher levels of genetic diversity as shown by the greater values of HE, HB and I, both as a mean of populations and as a group, as revealed by the ISSR analyses. AMOVA revealed that most of the genetic diversity was partitioned between forest types. Gene flow between forests is negligible at the present time. The flow cytometry analyses evidenced two groups with distinct DNA amount (2C = 1.24 pg and 2C = 2.05 pg). Ipecac showed a karyotype consisting of 11 chromosome pairs (2n = 22), of which 4 are metacentric and 7 are submetacentric. The cytogenetic analyses reveled that natural populations may be experiencing polyploidization and suggested that this species can be a tetraploid. Overall, the analyses indicated a recent colonization event as the origin of the populations found in the Amazon Forest and an ancient origin for the populations of the Atlantic Forest. The later forest was considered as a center of diversity for ipecac. Implications for conservation are discussed.