A biochemical method for estimating viability of teliospores of Tilletia controversa

A rapid biochemical test was developed to assess indirectly the viability of teliospores of Tilletia controversa, the cause of dwarf bunt of wheat, that contaminate wheat grain. Lipase activity was detected consistently in extracts from viable teliospores by a fluorescein diacetate (FDA) assay. No fluorescence activity was observed in extracts from autoclaved spores. By comparison, lipase detection was inconsistent when 4-methyl- umbelliferyl-palmitate was used as substrate. Extracts of teliospores that did not germinate on soil extract agar exhibited no lipase or glucosidase activity. Viability of individual teliospores could not be assessed by lipase assay because spore coats were impermeable to FDA. The FDA assay reduced the time needed to assess the average viability of a teliospore population from 2 mo to 1 hr