PECTIC ENZYME PATTERNS OF FUSARIUM OXYSPORUM VIRULENT ISOLATES FROM CHICKPEA IN IRAN

The pectic enzymes produced in vitro by 8 isolates (5 Highly virulent and 3 Weakly virulent) of Fusarium oxysporum , were detected by spectrophotometry, and characterized by polyacrylamide gel electrophoresis with substrate-containing gels (zymogram). Analysis of the polygalacturonase (PG) isozyme banding patterns (zymogram) identified two distinct phenotypes among the isolates from chickpea (Cicer arietinum), F. oxysporum zymogram group one (FOZG-1) and FOZG-2. Of the 8 isolates tested, 5 isolates had the FOZG-1 phenotype, and 3 isolates had the FOZG-2 phenotype. There were two virulent groups among these isolates: highly virulent (HV) and weakly virulent (WV). The HV isolates were all FOZG-1 and WV isolates were FOZG-2. Analysis of the pectic enzyme activity of different isolates on PZ medium demonstrated that PG and pectin lyase (PNL) were the predominant enzyme activities in FOZG1 (HV) compared with FOZG2 (WV) isolates, while the pectate lyase (PL) showed enzyme activity in both FOZG1 and FOZG2 groups. Therefore, from these results it can be hypothesized that PG and PNL enzymes may be important in pathogenicity of F. oxsporum isolates in Iran.