Variability and genetic differentiation by ISSR markers in M. dolens (Mimosa, Leguminosae)

BESSEGA C.; MORALES M; FORTUNATO R. H.

Melbourne

Congreso; IBC 2011, XVIII International Botanical Congress; 2011

Australian botanical community

Mimosa dolens (Leguminosae) constitutes a morphological complex growing in tropical and subtropical regions of southern Southamerica.. Within Subserie Dolentes intra-specific taxa were proposed in M. dolens. Previous morphological and cytological studies indicated that M. dolens subsp. rigida and acerba, (NE from Argentina, Paraguay and S of Brasil); M. dolens subsp. acerba var. rudis (4x); M. dolens subsp. rigida and M. dolens subsp. callosa (8x) (from NE de Paraguay) lives in sympatry and intermediate individuals between them can be found. The objective of this study was to analyze the genetic variability, population structure and phenetic relationships among Mimosa dolens populations using ISSR (Inter Simple Sequence Repeat) markers in order to help in the understanding of these complex taxa. DNA of 34 seedling from two different populations from Paraguay were analyzed. A total of 81 loci were scored using three ISSR primers and analyzed with AFLPsurv software. A high level of genetic variability was found in San Pedro and Porteira Ortiz populations (He= 0.19 - 0.29; P= 33% - 86% respectively). The analysis of genetic structure indicated that the interpopulation genetic diversity (37%) was lower than the intrapopulation genetic diversity (62%). Genetic differentiation among populations (FST=0.3687) was highly significant. The UPGMA analysis based on DICE coefficient grouped the individuals from San Pedro population but split the individuals from Pereira Ortiz. The PCA analysis (performed with Genalex 6) explained the 86% of the variation in the 3 first axis and is consistent with phenogram obtained. The relationships can be explained by the morphological criteria and in those cases where external traits makes difficult the classification the ISSR technique can help in the delimitation of the taxa. Future experiments including more populations and loci can be performed to find diagnostic loci.