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Title: ASSAY OF BETA-GLUCURONIDASE ACTIVITY IN INTACT TRANSFORMED FUNGAL CELLS

Author
item LI, WEI - UNIVERSITY OF WISCONSIN
item YOURMAN, LEONARD - UNIVERSITY OF WISCONSIN
item Leong, Sally
item SPEAR, RUSSELL - UNIVERSITY OF WISCONSIN
item ANDREWS, JOHN - UNIVERSITY OF WISCONSIN

Submitted to: Fungal Genetics Newsletter
Publication Type: Research Notes
Publication Acceptance Date: 5/5/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: The ecology or relationship of microorganisms and their environment is important to understand as microorganisms play an important role in processes that affect our ability to survive on earth. One area of special concern is how microorganisms such as fungi cause and prevent plant disease on leaves. We are studying the ecology of the fungus Aureobasidium pullunans on apple leaves in order to better define the potential role of this fungus in biological control of apple foliar diseases. We have introduced the "GUS" enzyme marker into the fungus which has enabled us to determine how much and where the fungus is growing on apple leaves. Moreover, we have defined a rapid procedure to assess GUS activity in whole cells of the fungus growing on apple leaves. Our results suggest this method may be applicable to the study of other fungi living in a variety of environments.

Technical Abstract: Aureobasidium pullulans was transformed with genes encoding Beta- glucuronidase (gusA) and GUS expression was assayed fluorometrically. The total GUS activity in intact, permeabilized fungal cells very closely approximated the sum of the GUS activity in the cell-free extract and pellet fractions. Inoculation of apple leaf surfaces with A pullulans blastospores showed that GUS activity increased with cell concentration over the range of 10**3-10**5 cells. The association between log GUS activity and log cell number is well described by a linear relationship or, somewhat better, by a quadratic relationship. Our results suggest that GUS can be monitored quickly, simply, and quantitatively in intact cells of A pullulans, and perhaps other fungi, without the need for homogenization.