Isozyme polymorphism of endo-beta-1,4-glucanase in Aspergillus nidulans.

An electrophoretic survey of the natural populations of Aspergillus nidulans, the A. nidulans group, and various species belonging to the genus Aspergillus from diverse geographical areas of India was carried out to determine the isozyme polymorphism of endoglucanase. The data revealed the presence of three forms of endoglucanase designated EG I, EG II, and EG III. In some isolates, EG I and EG II were present separately; in others, instead of two separate bands, one thick band was detected, which was designated EG I. In natural isolates of A. nidulans and the A. nidulans group, EG III was detected in most, but not all, isolates, while EG I and EG II were always present. However, in various other species of the genus Aspergillus, EG II was totally lacking. In all the populations at the EG I and EG II region, seven electrophoretic variants each were detected, and at the EG III region four variants were seen. The data suggest that there may be two structural genes for endoglucanase, one coding for proteins in the EG I/EG II zone and another for protein in the EG III zone.