Variability in Indian isolates of Sclerotium rolfsii by SDS-PAGE

The variability among 14 different Indian isolates of Sclerotium was studied on the basis of protein profile generated by Polyacrylamide Gel–Electrophoresis (SDS-PAGE). Different characteristics taken into account while studying the variability were sclerotia formation, non-formation, basidial stage formation and non-formation and type of disease symptom, viz. spotted leaf rot and collar rot. A comparison was done between mycelium of the different isolates as well as the sclerotia of the same isolate. All the 14 isolates showed a significant variation among themselves with respect to number and intensity of major and minor bands. It was intriguing to note that isolate L-Brl showed quiet different pattern from the rest of the isolates. A strong induction of a protein band of ∼15 kDa, probably responsible for the sclerotial development, was observed on comparing the protein profile of mycelium with the protein profile of sclerotia of all the isolates taken into consideration. A 66 kDa protein was prominently present in the isolate (L-Sph) which invariably forms basidiospores, but this protein was not present in the mycelial protein profile. A protein band with molecular weight greater than 98 kDa was prominently present in the total protein profile of isolates which does not form sclerotia in its life cycle. Furthermore, a protein band of ∼12 kDa was consistently present in the isolate which causes collar rot and this protein was absent in isolates which cause spotted leaf rot. Two closely placed distinct protein bands of 43 kDa and 46 kDa were invariably present in all the isolates causing spotted leaf rot. The dendrogram constructed with the help of protein profile so obtained was found to be divided into two prominent clusters. The representative isolate (L-Sph) was also investigated for pectinase, cellulase and xylanase production. The presence of hydrolytic enzymes is significant for contributing pathogenicity to the fungus.