Pichia anomala as a biocontrol agent of Penicillium roquefortii in high-moisture wheat, rye, barley, and oats stored under airtight conditions

摘要

P. anomala inhibited the growth of P. roquefortii in high-moisture winter wheat, barley and oats in cases where a malfunctioning airtight feed-storage system allowed air to leak in. To imitate air leakage to such a storage system, grain was inoculated, packed in glass tubes with a restricted air supply, and incubated at 25deg C. Yeast and mold colony forming units (CFU) were counted on selective media after 14 days. P. anomala reached a density of about 5X107 CFU/g on all tested cereals except in spring wheat (cv. Dragon), where a density of 109 CFU/g was reached. In winter wheat cv. Kosack, P. roquefortii reached a density of 106 CFU/g in grain that had not been inoculated with yeast, and 105 CFU/g in co-culture with 5X103 CFU/g of P. anomala. At 5X104 P. anomala, growth of P. roquefortii was totally inhibited. Similar results were obtained with spring wheat cv. Dragon, barley cv. Golf and oat cv. Svea. However, spring wheat cv. Dragon was generally much less conducive to growth of P. roquefortii.On rye cv. Motto, P. roquefortii did not grow in monoculture or when co-cultured with P. anomala. No differences in antagonistic activity of P. anomala or sensitivity of P. roquefortii, respectively, occurred between the 3 isolates tested of each species.