Characterization of Gibberella fujikuroi complex isolates by fumonisin B-1and B-2 analysis and by RAPD and restriction analysis of PCR-amplified internal transcribed spacers of ribosomal DNA

Twenty nine isolates of Fusarium spp. (twenty four of them belonging to the Gibberella fujikuroi complex) isolated from banana and corn from different geographical regions were analyzed for their ability to produce fumonisins B-1 and B-2 and for genetic relatedness using random amplified polymorphic DNA (RAPD) and restriction analysis of PCR amplification products of the 5 .8s ribosomal DNA-intervening internal transcribed spacer regions (ITS I-5. 8S-ITS II). For RAPD analysis, six of twenty oligonucleotide primers were s elected after testing with five Fusarium spp. isolates and used to characte rize 24 additional isolates. DNA fragments from the 29 isolates of Fusarium spp., which were approximately 560 bp, were amplified with the universal p rimers ITS1 and ITS4. The restriction enzymes HaeIII, MboI, HpaII and MspI were useful for distinguishing the isolates. The RAPD analysis permitted to find interspecific differences among the isolates of Fusarium spp., betwee n isolates with low and high capacity of fumonisin production and among iso lates from different hosts. The restriction fragment length polymorphism (R FLP-PCR) analysis permitted to distinguish among different species of Fusar ium. In combination with morphological analysis, the results of this resear ch may find an application for the diagnosis of unknown Fusarium spp. and, particularly, for the characterization of fumonisin-producing isolates, whi ch may be very useful in the food technology field.