Estrutura e diferenciação genética entre morfos de Minaria cordata (Apocynaceae) utilizando marcadores ISSR

Abstract

Minaria currently has 21 species, with a center of diversity in the Espinhaço Range, located in eastern Brazil, related to the rupestrian fields and cerrado areas. The core of Minaria is composed of two clades, one with seeds without coma and another with comosa seeds. In this last clade occurs the complex Minaria parva, a group of difficult taxonomic resolution, with divergences such as the inclusion of M. abortiva in M. cordata and the segregation of morphs in M. cordata var virgata. Minaria cordata has the widest distribution in the genus, with diverse floral variation, whose morphs eventually overlap. One way to resolve these taxonomic divergences may be molecular characterization. ISSR (Inter Simple Sequence Repeats) markers can be used for a variety of purposes, for example in the discrimination and molecular characterization of individuals. Within this context the objective of the present work is to describe the diversity and genetic structure of Minaria cordata based on ISSR markers comparing distinct datasets, one with 14 populations of M. cordata and another with 7 populations of M. cordata and M. abortive, evaluating if there are genetic differences between the two molds to the point of indicating independent evolutionary units. Two data sets were used, one with 14 populations, generatedin this work, and another with 7 populations plus M. abortiva, compiled in 2011. The PIC (content of polymorphic information) was verified for each primer used, parameters of diversity and structure. Genetics of populations of “virgata” and “cordata” morphs were measured. The M. cordata species presented low genetic diversity and moderate structure, the Bayesian analysis from the two data sets illustrate the occurrence of three distinct genetic groups, with some mixture between the analyzed morphs, but which may represent distinct evolutionary units. The COR03 and COR10 populations of the “virgata” morphotype, occurring outside the Espinhaço Chain, show greater similarity with M. abortiva. The “virgata” morphotype, present in Espinhaço, has some similarity to the “cordata” morph, which is the most structured group, regardless of the place of occurrence. These results may help in the taxonomic delimitation of M. cordata, providing genetic proof for the observed morphological variation.