Variabilidade genética de Arrabidaea bilabiata com marcadores moleculares AFLP e teste de extratos em fungos fitopatogênicos

Abstract

The grass pasture degradation is one of most serious problems to animal production in Amazonia. Weeds occur on pastures and cause some problems, livestock poisoning is a serious problem. Specially in the north states of Brazil when toxic plants cause large deaths on cattle and the large amount of this deaths is caused by Arrabidaea bilabiata in river Amazonas floodplains. Otherwise weeds are potential source of secondary metabolites and another compound with biotechnological potential. Some weeds of Arrabidaea are studied for your medicinal, antifungal and toxic activities. A. bilabiata extracts were assayed for in vitro activity against Escherichia coli, Klebsiella pneumonae, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus sp. and Candida albicans. All microbial strains were found to be resistant to the extracts with the exception of C. albicans, suggesting a possible antifungal activity. The main goal of this work was to evaluate the genetic variation between A. bilabiata from Autazes, Itacoatiara and Parintins (AM) and evaluate in vitro antifungal activity of A. bilabiata aquous and alcoholic extracts on BDA. The four combinations of AFLP markers used yielded 309 bands in 65 analyzed plants, with most (98.5%) being polymorphic, indicating a large level of genetic diversity. The minimum and maximum number of bands per primer was respectively, 59 and 85 bands and the minimum and maximum similarity coefficient was 14,28% and 88,50%. The lower similarity coefficient was chosen between Autazes and Itacoatiara and Parintins plants (14,28% to 17,08%). The greatest genetic variability in Autazes, Itacoatiara and Parintins A. bilabiata plants occurred between those places. The UPGMA dendrogram indicate two isolated groups the first one with Autazes plants and the second one with Itacoatiara and Parintins plants together. The results of this study indicate that AFLP markers were efficient in measuring the genetic variability amongst A. bilabiata plants and suggest the existence of low reproductive propagation tax and low seed dispersion efficiency. More studies about reproductive biology and seeds dispersion of this specie is valuable to help explain how this specie evolved and create diversification. More studies which large populations can improve more information about which factors contribute to genetic variation in A. bilabiata. The aquous extract of A. bilabiata don t show antifungal effect against C. cassicola; in S. rolfsii it reduces in 50% this fungus species growth on 40% concentration. In C. casiicola the aquous extract reduce in 20% and 40% concentration, 62% and 70% esporulation, respectively. The alcoholic extracts don t show antifungal effect against evaluated fungus. The C. casiicola esporulation reduction suggests the aquous extracts potential in biologic control. For S. rolfsii we don t indicate A. bilabiata extract because it has stimulated effects on this fungus sclerodium production.