Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/1997
Publication Date: N/A
Technical Abstract: Fusarium solani is one of the most prominent pathogens involved in pre- and post-harvest decay of cantaloupe fruit. The mechanisms of the decay process caused by F. solani are poorly understood. Production of polygalacturonase (PG) by F. solani was studied in vitro and in vivo. The fungus produced at least 13 PG isozymes with pIs of 4.1 to 7.3 in shake culture using pectin as the sole carbon source. Only one PG isozyme was detected in extract from decayed fruit tissues and purified to homogeneity. The molecular weight of the purified isozyme was estimated to be 38 kDa based on SDS-PAGE with endo-PG activity. The pI was equal to or greater than 10 according to IEF-PAGE. The optimum pH for enzyme activity was 5. The Km and Vmax of the enzyme on polygalacturonic acid were 1.3 mg/ml and 7.9 units per micro gram protein, respectively. Purified PG effectively macerated mature cantaloupe fruit tissues. This study indicates that the production of PG isozymes by F. solani in vitro is very different from those produced in vivo. PG is presumed to be an important enzyme involved in the fruit decay process.