SBIR-STTR Award

Low molecular weight metabolites produced by the rust mycoparasite, Aphanocladium album, can convert infective urediniospores in rusts to non-infective teliospores. Teliospore-inducing factor (TIF) and their associated analogs will be isolated and chemically characterized in this Phase I study. APPROACH: Testing the feasibility of novel mechanism of action may potentially provide an approach for managing rust diseases with mycoparasite metabolites by suppressing subsequent urediniospore and rust disease development. Isolation of the teliospore-inducing factor (TIF) would greatly facilitate basic research efforts aimed at understanding the complex life cycles of rust fungi and could potentially reveal additional mechanisms for managing rust diseases. Recent results of experiments conducted in our laboratory with A. album and its metabolites caused urediniospores of the oat rust fungus (Puccinia coronata) to convert to teliospores on excised oat leaves in the laboratory and on oat plants in greenhouse experiments. Similar observations have been shown for the wheat rust fungus, P. recondita. We hypothesize that this early induction of non-infective teliospores will reduce disease development in the field. NON-TECHNICAL SUMMARY: If teliospores could be prematurely induced by the mycoparasite metabolite treatment, the rust disease cycle would be curtailed, thus blocking the spread of disease and lessening economic losses. The chemistry of the teliospore-inducing compound (TIC) and analogs would facilitate the control of cereal rusts. Knowledge of chemical structure of the TIC would also permit synthesis and testing of analogs. In addition, isolation of the teliospore-inducing compound(s) would greatly facilitate basic research efforts aimed at understanding the complex life cycles of the rusts. The PhytoMyco Research Corporation's (PMRC) strategic plan is to combine expertise in microbiology, plant pathology, biochemistry, and chemistry to provide environmentally safe bio-fungicides from natural products that can manage plant diseases.The market value for a well-defined mycoparasite metabolite with a novel mechanism of action could potentially be worth millions of dollars worldwide.

Keywords:
rust disease; mycoparasite; fermentation; secondary metabolites; urediniospores; teliospores

Low molecular weight metabolites produced by the rust mycoparasite, Aphanocladium album, can convert infective urediniospores to non-infective teliospores. The teliospore-inducing factor (TIF) has been isolated, identified and demonstrated in proof-of concept experiments to convert infective urediniospores to non-infective teliospores of the oat rust fungus, Puccinia coronata. During Phase II, we will synthesize the teliospore inducing compound, oosporein and its analogs. The analogs and synthesized compounds of oosporein will be evaluated under greenhouse and field conditions for their ability to convert infective urediniospores to non-infective teliospores. OBJECTIVES: 1. Preparation of analogs (derivatization) and total synthesis of the teliospore inducing compound, Oosporein 2. Screening the analogs and synthesized compounds in greenhouse studies and optimization of the conditions for field evaluation 3. Field trials of the most potent derivative or the synthesized compound based on the greenhouse results. APPROACH: In summary, a number of viable and well precedented reaction pathways exist for the preparation of oosporein and structurally related compounds. These should provide ready access to usable quantities of these compounds so that their biological activity may be investigated.