Caracterização da fração repetitiva do genoma de Hancornia speciosa Gomes

Abstract

The mangabeira is a native species of Brazil, widely distributed and that presents socioeconomic importance mainly in the Northeast and Center-West regions of the country. In Brazil, H. speciosa occurs in the Caatinga, in the Cerrado, in the Coastal Tracks and in the Restingas. Its fruits contain vitamin C and have the highest levels of protein and iron and its leaves have medicinal properties being used to control blood pressure and to treat diabetes. Due to the real estate expansion, use of native areas for cultivation of large crops and fragmentation of the forests, the species has suffered significant genetic erosion. Despite its importance and vulnerability genetic and genomic studies in H. speciosa and therefore projects with the purpose of knowing and studying the genomic and genetic characteristics of the species are important in order to contribute to the conservation and genetic improvement of the species. Plants generally contain high proportions of repetitive DNA, which are important elements of gene regulation and that appear along the evolution causing mutations that can change phenotypically the organism in question. In this sense, the objective of this work was to characterize the repetitive fraction of H. speciosa providing the first genomic study in the species which will contribute in future to techniques applied to genetic improvement involving genomic association. Mangrove individuals from the State of Pernambuco were collected and their DNA extracted and later fragmented to construct the new generation sequencing paired-end-reads (NGS) library, using the Illumina HiSeq2500 platform. Genome size was estimated using flow cytometry and the repetitive fraction was analyzed using the RepeatExplorer and TAREAN software. Three species genetically related to H. speciosa were used to compare the results and to evaluate if the amount of repetitive DNA is related to the genetic proximity of the species. The genome of H. speciosa has a small size (430 Mb) and a small amount of repetitive DNA (15%) which comes mainly from LTR / Gypsy elements and from rDNA sequences. The species does not present satellite DNA sequences and we suggest that the role of this element in the genome is assumed by LTR / Gypsy chromovirus sequences which have a large proportion in genomes, especially in centromeric regions. The information obtained in the present study provides initial information to the genomic studies in H. speciosa which will contribute to the genetic improvement of the mangaba.