CHARACTERIZATION OF A MULTIGENE FAMILY ENCODING AN ENDOPOLYGALACTURONASE IN SCLEROTINIA-SCLEROTIORUM

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