SUMMARY

Endopolygalacturonases (endoPGs) are fungal en-zymes secreted during the infection in order to degrade plant cell wall pectins. In Fusarium spp., endoPGs are among the first enzymes produced during infection and play a crucial role in plant tissue penetration and colo-nization. The endoPG of F. phyllophilum strain FC-10, previously classified as F. verticillioides, is the best char-acterized Fusarium cell wall degrading enzyme. In this work we have carried out a phylogenetic analysis of the endoPG (pg) gene sequence that confirms the classifica-tion of the FC-10 strain as F. phyllophilum, and also shows an unexpected divergence of the pg gene of F. phyllophilum strain NRRL 25305. This gene and the biochemical characteristics of the encoded product ap-pear more closely related to those of F. verticillioides pg. This observation and the evidence that endoPGs have experienced positive selection indicate that selective pressure acting on these enzymes may limit the use of their gene sequences as reliable markers for phylogenet-ic studies