July 2008: Highlights of Jan's, Astrid's and Teresa's projects
Jan and Astrid recently graduated and Teresa finished her project and returned to Spain. This is a good reason to recall some of the highlighs of their work.
Jan clarified the role of mycotoxin zearalenone in the interaction of zearalenone-producing Fusarium spp. with mycoparasite Gliocladium roseum and proved a new paradigm for its ecological role. Jan's work was based on experiments with fungi growing in the presence of zearalenone, performed by Petr Karlovsky in 1998:
Photos of this and other agar plates were kept for 9 years in the drawer before being published in our 2007 Appl. Env. Microbiol. paper.
Jan knocked out the gene for zearalenone esterase in G. roseum a showd that the mutants became susceptible to zearalenone:
Left: HPLC profile of zearalenone after incubation with G. roseum. (A): w.t. strain, hydrolyzed and decarboxylated product of zearalenone is shown. (B): G. roseum with deactivated esterase. Half of zearalenone is still intact (arrow). Peak at 5.6 min originated from an unknown metabolite, Husam is in process of purifying it for structure elucidation. Right: Growth inhibition shown by zearalenone esterase mutant (zes2) on medium with zearalenone.
Astrid investigated xylem sap of Brassica napus infected with Verticillium longisporum. She found metabolites suppressed and other enhanced by infection. Most interestingly, some metabolites only appeares in infected plants and are never found in healthy plants or pure fungal cultures:
Teresa worked with Awais on the chemical interaction between G. roseum and Fusarium species in the rhizosphere. We don't show there results fully here as they are too recent, but stay tuned - we will reveal them eventually. You can see that they worked with pot cultures, using maize (in the picture below) and wheat.
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