In vitro and in vivo production of polygalacturonase, polymethylgalacturonase and cellulase enzymes by Alternaria solani at different incubation periods

The production of polygalacturonase (PG), polymethylgalacturonase (PMG) and cellulase (Cx) enzymes have been studied at different incubation period. The fruit rot pathogen of tomato Alternaria solani was cultured at 28°C on semi ripe tomato fruit broth medium for 2, 4, 6,  8, 10 and 12 days. Isolated pathogen A. solani has a capability of producing PG, PMG and Cx enzyme within short incubation period, that is, 2 days incubation. Production of these enzymes gradually increased by increasing the length of incubation period up to 6 days and further increase in length of incubation up to 12 days, did not show any effect on the production of PG, PMG and Cx. The 6 days incubation was found to be the best incubation period for the production of all these three enzymes. The production of PG and Cx was also more in comparison with PMG enzyme. The enzyme activity in healthy and diseased semi ripe tomato fruits was also assayed at different incubation periods and it was found to be maximum in diseased tomato fruits in comparison with healthy tomato fruits. It was also found that PG and PMG enzymes were produced in higher concentration than the Cx enzyme. Among six incubation periods, 6 days incubation period was found best for maximum production of all these three enzymes.   Key words: Alternaria solani, semi ripe tomato fruit medium, semi ripe tomato fruit, incubation period.