Diversidade genética de isolados do agente etiológico da fusariose do abacaxizeiro no Brasil

Abstract

In order to know the genetic diversity in the population of Fusarium guttiforme, causal agent of Fusarium resinose pineapple, were analyzed in VCG, AFLP and morphological characterization of isolates of F. guttiforme from different Brazilian states. All 130 isolates showed the typical markers of F. guttiforme. In the analysis of VCG using nit mutants were identified 17 groups of 40 isolates. Four VCGs harbored more than one isolate. Two groups were formed by isolates from different geographical regions, two isolates of several municipalities of the Holy Spirit. The other VCGs had only one isolate. The dendrogram generated from AFLP analysis, based on the difference of band patterns generated by two combinations of primers, revealed the presence of three groups. The main group was subdivided into six subgroups, with isolates of 63% to 100% similarity, including most of the isolates and type species. The similarity indices were calculated using the coefficient of Dice. The presence of isolates from different regions in the same VCG and AFLP group indicates that the transport of infected plants may be the main route of spread of the pathogen. Both techniques showed high genetic diversity in the population. Thus, the possibility of the occurrence of sexual reproduction in species can not be ruled out. Morphological characterization and grouping obtained in the AFLP analysis confirmed that the main pathogen of Fusarium wilt of pineapple is F. guttiforme. The observation of two groups with a similarity below 40% in relation to main group suggests that there may be distinct populations causing wilt in pineapple in Brazil.