Avaliação da estrutura e diversidade genética de Coleocephalocereus purpureus, uma espécie ameaçada de extinção

Abstract

Coleocephalocereus purpureus is a critically endangered cactus. Its distribution is restricted to a fragment of the Caatinga biome in Minas Gerais, occurring in rocky outcrops where intense exploitation of ornamental granite usually occurs. Its habitat is severely compromised due to mining processes. Thus, this research aimed to analyze the structure and genetic diversity of four populational groups of C. purpureus located in different locations of Itinga (MG) and the elaboration of the Genetic Management Plan for the specimens present in the RPPN Pasmado as well as the elaboration of conservation actions for the other three groups as a way to retain the remaining genetic diversity of the species. Thus, a molecular marker was developed to access the genetic structure to estimate the genetic variability of C. purpureus populations. To evaluate the genetic diversity, 132 samples were collected from representatives of the four groups, DNA was extracted and the microsatellite molecular markers were genotyped. Molecular data were interpreted and the most genetically valuable individuals were identified. From the obtained molecular markers it was possible to estimate the heterozygosity of the sampled groups, certifying that the developed markers were adequate to be used in future population studies of C. purpureus diversity and population structure. It was verified that the genetic diversity estimates presented moderate levels of gene variability and it was possible to define two distinct populations isolated by Jequitinhonha River. From the results obtained, the Genetic Management Plan was elaborated for the species. It was concluded that: (1) the higher the heterozygosity found between grouping, the greater the genetic variability and, consequently, the better the population balance and the lower the risk of extinction of the species by genetic factors; (2) the markers developed are extremely useful for genetic studies with the species in question; (3) there was a lack of in-depth conservation studies of C. purpureus; (4) for the implementation of the Genetic Management Plan it will be necessary to elaborate complementary studies on the reproductive biology of C. purpures, as well as studies on the respective pollinators. Therefore, it was inferred that this research collaborates effectively with the conservation of the species, since it brings to the public an important molecular tool for access to genetic structure and diversity, subsidizing the Genetic Management Plan, which has important potential for rehabilitate and reconstruct declining C. purpureus grouping