Molecular characterization of endophytic strains of Fusarium verticillioides (= Fusarium moniliforme) from maize (Zea mays. L)

The species Fusarium verticillioides (= F. moniliforme) is often found in maize seeds, constituting an important source of inoculum in the field. Fusarium spp., associated with symptomatic and asymptomatic plants, may be a primary causal agent of disease, a secondary invader or an endophyte. In the present work, endophytic fungi were isolated from two populations of Zea mays (BR-105 and BR-106) and their respective inbred lines. Within different inbred lines of maize, Fusarium was found at a frequency of 0 to 100% relative to the number of total isolated fungi. The frequency with which the genus occurred was practically the same in the two field sites (around 60%). Twenty-one F. verticillioides strains were analysed using the random amplified polymorphic DNA (RAPD) technique, employing 10 random primers. Variability analysis of endophytic isolates via RAPD showed genome polymorphism taxa of species around 60%. Endophytic isolates were clustered by their sites of origin. RAPD analysis clustered the endophytic isolates by their maize inbred lines hosts (Mil-01 to Mil-06), whereas at site A they clustered into two major groups related to the maize gene pool (BR-105 or BR-106 population). All strains isolated from seeds collected in Site A, except strains L9 and L10, were sub-grouped according to maize inbred lines. The analysis showed a discrete sub-grouping at site B. Results obtained here could be explained by a co-evolution process involving endophytic isolates of F. verticillioides and maize inbred lines.