Caracterização genética de populações de bacurizeiros (platonia insignis mart.) nos biomas amazônico e cerrado do Maranhão

Abstract

The bacuri tree (Platonia insignis Mart.) belongs to the Clusiaceae family and to the genus Platonia, being the only species in this genus. It is one of the most popular fruit and timber species in the Amazon and Northeast regions. Despite being a species of economic and cultural importance, bacuri forests have been suffering constant destruction, resulting in the loss of genetic variability of the species. Thus, the objective of this work is to genetically characterize populations of bacuri trees (Platonia insignis Mart.) existing in the cities of São Luís, Axixá, Santa Rita, Morros and Urbano Santos in Maranhão State using ISSR markers. A survey of the occurrence of natural populations of bacuri trees was carried out in São Luís, Axixá, Santa Rita, Morros and Urbano Santos in Maranhão State, collecting 15 samples of leaf tissue from São Luís, 13 from Axixá, 14 from Santa Rita, 15 from Morros and 15 from Urbano Santos. About ten leaves were collected from each sample. Samples were sent to the Laboratory of Genetics and Molecular Biology Warwick Estevan Kerr (LabWick) for processing the DNA extraction and amplification steps. DNA was extracted according to the CTAB protocol. Polymerase Chain Reactions (PCR) were performed with the primers: UBC 807, UBC 808, UBC 809, UBC 810, UBC 811, UBC 817, UBC 825, UBC 826, UBC 827, UBC 828 and UBC 834, after (PCR) reaction the products generated by the ISSR markers were converted into a binomial matrix (0/1), used to carry out genetic characterization analysis, between and within populations. Data were processed using Arlequin 3.11, PAST 4.03, Bottleneck 1.2 and Fingerprint Analysis with Missing Data 1.31 (FAMD) software. All tested primers amplified, with a total of 149 locus. In AMOVA, the genetic structuring results showed greater genetic diversity within populations, with 73.58% and less diversity between populations, with 26.41%. For the Fst index, the value of 0.26411 was obtained, indicating high genetic diversity. Principal coordinate analysis (PCoa) revealed interaction among all studied individuals. The cophenetic correlation coefficient calculated in the distance matrix was 0.8396. The dendrogram formed 19 groups, the largest group contained 15 samples, of these 15 samples only individuals from the same population were observed. Nei's genetic diversity index for the populations studied ranged from 3.426 to 2.346, an average of 3.636 indicating a high genetic diversity. Primers 817 and 828 did not present a genetic bottleneck for any of the populations in the model (A.I.M). In the model (S.S.M) a genetic bottleneck process was observed for all primers. The bacuri populations studied show high genetic diversity based on the evaluated parameters. However, it is worth noting that these populations are undergoing a genetic bottleneck process, so it is necessary that remaining genetic diversity be collected and preserved in situ and ex situ in order to guarantee the survival of this species to serve as a basis for management studies seeking its domestication.