Mitochondrial genome of Hancornia speciosa gomes: intergenic regions containing retrotransposons and predicted genes.

Abstract

Plant mitochondrial genomes are characterized by high homologous recombination, extensive intergenic spacers, conservation in DNA sequences, and gene content. The Hancornia genus belongs to the Apocynaceae family, with H. speciosa Gomes being the sole species in the genus. It is an siganificant commercial fruit crop; however, only a number of studies have been conducted. In this study, we present the mitochondrial genome of H. speciosa and compare it with other mitochondrial genomes within the Apocynaceae family. A total of 2.8Gb of Illumina paired-end reads were used to obtain the mitogenome,resulting in 22 contigs that were merged using 6.1Gb of Illumina mate-pair reads to obtain a circular chromosome.The mitochondrial genome of H. speciosa is circular, containing 63 predicted functional genes, spanning a length of 741,811bp, with a CG content of 44%. Within the mitogenome, 50 chloroplast DNA sequences, equivalent to 1.72% of the genome, were detected. However, intergenic spaces accounted for 703,139bp (94.79% of the genome), and 287 genes were predicted, totaling 173,721bp. This suggests the incorporation of nuclear DNA into the mitogenome of H. speciosa and self duplication. Comparative analysis among the mitogenomes in the Apocynaceae family revealed a diversity in the structure mediated by recombination, with similar gene content and large intergenic spaces.