Characterization of a multigene family encoding an endopolygalacturonase in Sclerotinia sclerotiorum

Sclerotinia sclerotiorum produces several polygalacturonases which together with other pectinolytic enzymes are involved in the degradation of pectin. A number of different genomic clones were isolated by screening a genomic DNA library in phage EMBL3. Southern-blot and restriction mapping indicate that seven genes constitute two subfamilies of a multigene family encoding endopolygalactutonase. Using pulsed-field gel electrophoresis to separate S. sclerotiorum chromosomes each subfamily was found to hybridize to a different chromosome. A comparison of the nucleotide sequence for the coding region of three members of the gene family reveals surprisingly few base substitutions suggesting that this gene family arose from recent multiple duplication events.