Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2003
Publication Date: 3/27/2003
Citation: KIMURA, M., TOKAI, T., O DONNELL, K., WARD, T.J., FUJIMURA, M., HAMAMOTO, H., SHIBATA, T., YAMAGUCHI, I. ISOLATION AND CHARACTERIZATION OF THE TRI5-CLUSTER OF FUSARIUM GRAMINEARUM F15 REQUIRED FOR 3-O-ACETYLDEOXYNIVALENOL BIOSYNTHESIS. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. 2003. V. 539 (1-3). P. 105-110. Interpretive Summary: Fungi within the Fusarium graminearum species complex cause a variety of diseases on cereal crops worldwide, including scab of wheat and barley, and ear and stem rots of maize. Taken together, these diseases result in billion dollar losses to agriculture each year. In addition, these fungi contaminate cereal grains with a variety of trichothecene mycotoxins that increase the virulence of these pathogens on their plant hosts, and also pose a serious threat to animal health and food safety. Effective disease control programs that minimize the threat of these mycotoxigenic pathogens to the producers, processors, and consumers of cereal crops worldwide require a detailed understanding of the biological mechanisms underlying mycotoxin biosynthesis and the genetic basis for observed mycotoxin diversity. The result of this research provides information critical to the development of intervention strategies to disrupt the production of trichothecenes, and also enable the development of direct genetic methods to determine the mycotoxigenic potential of individual pathogens. Such methods will enhance disease surveillance and control programs, and will facilitate efforts to prevent introductions of pathogens with novel mycotoxigenic potential into the U.S.
Technical Abstract: We have cloned cosmids containing the trichothecene gene cluster from Fusarium graminearum F15 (i.e. FgTri5-cluster) and characterized the toxin cluster genes. In the 41,224 bp region sequenced, there were three genes (Tri8, Tri3, and pseudo-Tri13) that may not function in 3-O-acetyldeoxynivalenol (3-ADON) biosynthesis. In contrast to other strains, however, Tri7 was completely missing from the cluster. Similarity searches and Southern blot analyses suggested that a putative tyrosinase an polysaccharide deacetylase gene define the ends of the cluster. The number of pathway genes in the complete FgTri5-cluster is less that half the total number of steps necessary for 3-ADON biosynthesis.