ESTRUTURA GENÉTICA-POPULACIONAL DA PLANTA MEDICINAL Achyrocline flaccida (Weinm.) DC. BASEADA EM MARCADORES ISSR

Abstract

The Atlantic Forest has a high plant diversity due to its various vegetation types. Among these vegetation formations in southern Brazil highlights the "Campos". Despite the importance of the Atlantic Forest and their vegetation types, genetic studies with plants of this biome are insufficient. Achyrocline flaccida (Weinm.) DC., popularly known as Macela, is a native plant of the grasslands that despite their ecological and medicinal importance, has no genetic data in the literature. Currently, the molecular markers is the most appropriate tool for obtaining genetic-population data. In the literature many ISSR primers (Inter-simple Sequence Repeat) are available. But, to obtain reliable data and with resource savings is necessary to use robust primers for the species under study. The objective of this study was to select the best ISSR primers for genetic studies in Achyrocline flaccida and assess the diversity and genetic structure of populations of this species from southern Brazil. To selection of ISSR primers were tested 42 primers in a population of 20 plants and for each primer was calculated the following attributes: Polymorphism Information Content (PIC), Marker Index (MI) and Resolution Power (RP). Among the 42 ISSR primers tested, 35 showed amplification and of these, based on the results obtained with the index PIC, MI and RP were selected the top 10 primers for the species. With these primers were evaluated the genetic diversity and structure of seven Macela populations (131 samples) from southern Brazil. The AMOVA showed greater genetic variability in (64.7) than between populations (33.96), with the variability unevenly distributed among populations (Fst 0.33). Gene flow between populations ranged from 5.2 to 1.68, being 1.39 for all populations. The evaluation of the loci grouping, as well as the data of presence and absence of exclusive loci reveals that exclusive absences may be contributing significantly to the differentiation of populations. The Mantel test indicated a positive correlation between genetic and geographic distance. The PCoA analysis, the of data of grouping loci, the Nei genetic distance and Bayesian analysis corroborate showing weak structuring among populations and confirm the high levels of gene flow between populations. These results show high genetic diversity in the species. The diversity among populations, the structure and gene flow between the populations of Achyrocline flaccida indicate that it occurs and / or there is a high gene flow among populations of southern Brazil. Probably this gene flow is increased by the anthropic action. The data obtained here may be important for understanding the genetic basis of species and development of conservation strategies and / or rational exploitation of the species.