Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 1, 1995
Publication Date: N/A
Interpretive Summary: Germination at will of resting spores of plant disease fungi would permit development of better ways to control plants diseases. Volatile aroma chemicals were shown to stimulate the germination of resting spores of the bean rust fungus, Uromyces appendiculatus. These compounds were volatile and effective at very low concentrations. Related chemicals, calcium propionate, used to prevent mold in bread, and acetaldehyde ammonia also stimulated germination of these spores. Both compounds are water soluble and non-volatile. Active compounds which are soluble in water present a controllable way to use germination stimulators for practical purposes. They may be used to permit studies of the resting spores for research purposes, or be adapted to new kinds of disease control of the bean rust disease. These compounds represent additions to our library of active compounds which may be tested for getting spores of other problem-causing fungi to germinate at will, and perhaps aid in solving plant pest problems.
Technical Abstract: Methyl isobutyrate and isobutyraldehyde and some related derivatives were reported previously to stimulate germination of teliospores of Uromyces appendiculatus (J. Agric. Food Chem. 41:1743-7, 1993). Extension of the study to smaller compounds indicated stimulatory activity in acetaldehyde and propionaldehyde and some related derivatives. Acetaldehyde stimulated germination to 76% (control 22%) at 21 days, at 10 ul/L. Propionaldehyde stimulated germination to 78% (control 22%) at 21 days, at 25 ul/L. Two water-soluble, non-volatile derivatives, calcium propionate and acetaldehyde ammonia, stimulated germination to 70% (control 17%) at 1000 ul/L, and to 80% (control 9%) at 50 ul/L, respectively, at 21 days. Teliospores exposed to vapor from 25% aqueous acetaldehyde for 5 min germinated 53% (control 12%) at 21 days. Compounds such as these may play a role in activating these teliospores under natural conditions