Confined enzymatic activity of S. scitamineum and U. esculenta at the Smut Gall during Infection

Abstract

We aimed to evaluate the enzymatic abilities of U. esculenta and S. scitamineum to degrade cellulose, pectin and lignin and explain the possible confinement of the smut - fungi in the smut-gall. S. scitamineum and U. esculenta were isolated from the smut gall of S. spontaneum and Z. latifolia plants, respectively. The teliospores were inoculated into a culture flask containing various concentrations (3%-10%) of pure cellulose powder to check the degradation ability of the fungi. The fungi were sub-cultured onto modified Czapek Dox Agar (CDA) supplemented with 0.3% carboxy methyl cellulose (CMC) followed by Gram’s Iodine test to determine the relative cellulolytic activity index (RCAI). Extracellular proteins were harvested and profiled by SDS-PAGE and subsequently zymography was carried out with regular 0.1% substrate infiltration to determine cellulolytic, pectinolytic and laccase activities. The fungi were capable of producing cellulase and pectinase but lacked the laccase enzyme required to degrade the lignin, perhaps as an essential evolutionary requirement for the completion of their life cycle in the host. Importantly, the lack of laccase activity by U. esculenta and S. scitamineum could partially explain why the fungal colonization remains localized in the topmost part of S. spontaneum and Z. latifolia.