Caracterização genética de bacurizeiros (Platonia insignis Mart.) por meio do marcador molecular ISSR da Bacia Hidrográfica do Munim - Maranhão

Abstract

The bakuri tree (Platonia insignis Mart.), a plant native to the Brazilian Amazon, is distributed in the state of Maranhão in the regions of Amazonia Maranhense, Baixada Maranhense and in the Cerrados of the extreme south and Baixo Parnaíba and occurs in areas of intense agricultural activity, where deforestation and fires are common, leading to a rapid reduction in the number of individuals and a decrease in genetic variability. Studies of a genetic-molecular nature are scarce for the species, making it difficult to recognize the real genetic loss. Soon the objective of this work was to genetically characterize populations of bacurizeiros (P. insignis Mart.) Existing in the municipalities of Chapadinha, Morros, Axixá, Santa Rita and Urbano Santos, belonging to the Munim Hydrographic Basin in the state of Maranhão, by means of molecular markers ISSR. Surveys were carried out on the occurrence of natural populations and sample collection in the municipalities of Chapadinha, Urbano Santos, Morros, Axixá and Santa Rita. The samples were sent to the Warwick Estevan Kerr Genetics and Molecular Biology Laboratory (LabWick) for processing the DNA extraction and amplification steps. The DNA was extracted according to the CTAB protocol and the polymerase chain reactions (PCR) were performed with the ISSR UBC 808, 809, 810, 811, 825 and 840 primers. All the primers used amplified, the ISSR UBC 808 was what presented the smallest amount of locus, n = 3, but with 100% polymorphism. The ISSR UBC 811 and 825 primers amplified the largest number of loci, n = 7. The Molecular Analysis of Variance (AMOVA) showed low diversity between populations and high within populations, 11.41% and 88.58%, respectively. The Fst diversity index was 0.17192, indicating moderate genetic differentiation between populations. The genetic diversity index of Nei (He) was 0.435 (Morros population) to 0.348 (Urbano Santos population), showing high average rates of heterosigozity. However, a genetic bottleneck process was observed for the ISSR UBC 809 and 810 primer loci in the Urbano Santos samples and for the ISSR UBC 810 primer locus in the step mutation model (SMM) for the Morros samples, indicating possible loss of alleles and population decrease in the short term. The analysis of Principal Coordinates (PCoA) revealed interaction between all studied samples, indicating a possible exchange of genes between individuals in the Munim Basin and the clusters formed in the dendogram also show this, however it shows low correlation by the index used in the work, r = 0.6753. The results in general point to measures of conservation in situ of this species mainly in the localities where bottleneck process was observed