THE MAJOR SECRETED CELLULASE, CELV, OF ERWINIA-CAROTOVORA SUBSP CAROTOVORA IS AN IMPORTANT SOFT-ROT VIRULENCE FACTOR

CelV is the major secreted beta-1,4-endoglucanase of the phytopathogen Erwinia carotovora subsp. carotovora. Its role in virulence was inves tigated by comparing the ability of a cellulase-deficient mutant to ca use soft rot of potato tubers with that of the wild type. A significan t role was demonstrated despite the inability of CelV to effect soft r ot when expressed in Escherichia coli. This established the major cell ulase of E. carotovora subsp. carotovora as a virulence factor and pro vided evidence for a synergistic relationship between the various clas ses of exoenzyme in attack of potato tubers.