Cloning and partial characterization of endopolygalacturonase genes from Botrytis cinerea

Botrytis cinerea is a plant-pathogenic fungus infecting over 200 different plant species. We use a molecular genetic approach to study the process of pectin degradation by the fungus. Recently, we described the cloning and ch aracterization of an endopolygalacturonase (endoPG) gene from B. cinerea (B cpg1) which is required for full virulence. Here we describe the cloning an d characterization of five additional endoPG-encoding genes from B. cinerea SAS56. The identity at the amino acid level between the six endoPGs of B. cirerea varied from 34 to 73%. Phylogenetic analysis, by using a group of 3 5 related fungal endoPGs and as an outgroup one plant PG, resulted in the i dentification of five monophyletic groups of closely related proteins. The endoPG proteins from B, cinerea SAS56 could be assigned to three different monophyletic groups. DNA blot analysis revealed the presence of the complet e endoPG gene family in other strains of B, cinerca, as well as in other Bo trytis species. Differential gene expression of the gene family members was found in mycelium grown in liquid culture with either glucose or polygalac turonic acid as the carbon source.