Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2000
Publication Date: N/A
Technical Abstract: Fusarium head blight or scab is a common cereal disease that is generally caused by F. graminearum and/or culmorum. The plants are most susceptible to the disease during anthesis, when fungal spores enter the developing kernel. Histological studies with wheat have shown that the endosperm protein matrix and starch granules are damaged in diseased kernels, implying that the fungus uses the grain storage reserves for its growth. The fungus presumably must produce hydrolytic enzymes in order to utilize these nutrients. We are studying a proteinase that the fungus may use for degrading the barley proteins. We have shown that three Fusarium species produced alkaline proteinases when grown on media that contained either gluten or autoclaved barley grain. Similar proteinase activities were present in vivo in developing barley kernels that were inoculated with F. graminearum or culmorum spores. There are proteins in barley grain that can inhibit the activities of various microbial proteinases and these may protect the grain from certain diseases. We have isolated and characterized an F. culmorum alkaline proteinase and shown that it is inhibited by compounds extracted from barley grain. The inhibitors are being identified so that we can study their interactions with the fungal proteinase. This will clarify whether the proteinase inhibitors can be used to improve the resistance of barley to fungal attack.