AVALIAÇÃO DA VARIAÇÃO SOMACLONAL DURANTE A MICROPROPAGAÇÃO DE MANGABEIRA (Hancornia speciosa Gomes) POR MEIO DE MARCADORES MOLECULARES ISSR E SSR

Abstract

Somaclonal variation refers to genetic and epigenetic changes that can occur regenerated plants by vegetal tissue culture techniques .The present work evaluated the clonal fidelity and the genetic diversity of micropropagated mangabeira seedlings using ISSR and SSR molecular markers. There were used direct and indirect shoot organogenesis strategies for micropropagation where obtained plantlets were subcultured every 30 days, totalizing six subcultures performed. Visual analysis of the eletrophoretic pattern for selected SSR and ISSR markers was performed to assess the occurrence of somaclonal variants, by the existence or not of polymorphism in the amplificated locus, comparing the subcultivated seedlings/calli with their respective parent plant. For genetic diversity analysis, the dissimilarity matrix obtained by the complement of the Jaccard Index (ISSR) and the complement of the Weighted Index (SSR) were calculated using the GENES software. Hierarchical grouping (UPGMA) was used to plot a dendrogram. The cophenetic correlation coefficient (CCC) and the polymorphic information content (PIC) were also calculated. Homogenous plantlets (absence of somaclonal variation) were obtained in both, direct and indirect, regeneration pathways. These results can be explained by the genetic constitution of the individuals, as well as, by the use of low phytoregulators concentrations during the subcultures. For genetic diversity, a low dissimilarity value was observed among the analyzed matrices, with a minimum value found for ISSR of 0.016 and SSR of 0, indicating a low genetic variability among the evaluated individuals.