identification and genetic variation of fusarium species in isfahan, iran, uning pectic zymogram technique

the genus fusarium is a species rich genus. different media are required to study themorphological characters and classify different species, a time consuming technique. in this study pecticzymograms were used to identify species and form species of fusarium isolates. fusarium isolates (318) wereobtained from different areas and hosts in isfahan province, iran. isolates were identified to species based onmorphological characters. a pectic enzyme solution was prepared for each isolate using liquid mediacontaining citrus pectin as the sole carbon source. electrophoresis was performed using acrylamide gelcontaining 0.2% citrus pectin as the enzyme substrate. the gels were incubated in 0.1m malic acid beforestaining overnight in 0.02% ruthenium red, to visualize enzyme electrophoretic patterns. several zymogramphenotypes were obtained for polygalacturonase and pectin esterase. in total, 12 zymogram patterns weredetermined for the 318 isolates tested. the results showed that there is considerable intraspecific variation infusarium species. there were 3, 5 and 2 zymogram electrophoretic patterns for fusarium oxysporum, f.solani and f. culmorum respectively. however, there was only one zymogram pattern for f. subglutinans andalso one for f. equiseti. although the intraspecific variation based on pectic zymograms was not correlated tothe form species of fusarium, species of fusarium could be distinguished using this technique as there wasno common zymogram pattern among species.