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Associate Professor of Plant Biology
Plant Biology Department
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Research
My laboratory studies the biology of mycotoxigenic fungi using molecular genetics, genomics and biochemical techniques. We are currently studying Gibberella zeae (anamorph: Fusrium graminearum). G. zeae is a pathogen of corn, wheat and barley and produces two mycotoxins, deoxynivalenol and zearalenone. Through the study of the pathogen life cycle, we are working on developing novel strategies to control these toxin-producing organisms.
The group of fungi known as the Ascomycota produce their meiotic products, ascospores, in a sac-like structure called an ascus. The ascus evolved as a tubular gun used to shoot ascospores into the air. Forcible discharge enables these fungi to propel their propagules into air currents where they are carried many miles to (hopefully) fertile new territories. In the spring, G. zeae uses this technique to move its spores from the previous season's crop to emerging wheat, barley and corn flowers. This new generation of ascospores infects the flowers and initiates another cycle of the devastating head blight disease. The ascospores are produced in flask-shaped structures called perithecia (Figure 1) that contain hundreds of spore-filled asci. When conditions are right, each ascus pushes through the "mouth" of the perithecium and fires its contents into the air (Figure 2). The empty ascus withdraws into the perithecium and another ascus protrudes. We have developed a model of ascus function that accounts for our physiological and gene disruption experiments. Rigorous testing of this model in underway. The discharge mechanism will most likely be conserved among all ascomycetes which forcibly discharge their spores.
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Cross section of a mature perithecium showing darkly stained ascospores contained in thin asci (8 spores per ascus). A single ascus is pushing up through the "mouth" of the perithecium, ready to discharge its spores into the air. Spores may be carried on air currents for many miles. Copyright Mycologia, 2000. |
Spores discharged onto a slide from perithecium on the left. The mechanism of discharge is currently under investigation. |
Using histological techniques, we have described the development and differentiation of the fungus during plant colonization. We are now characterizing gene expression associated with colonization and sexual development using microarray technology, mutant characterization, and genetic manipulation. Differentiation in planta is triggered by cell type and plant developmental stage. Our findings indicate a much closer dependence of the fungus on the host life cycle than was previously thought to exist.
My laboratory has been involved with sequencing and annotating the genome of G. zeae . Information on the genome sequencing project can be currently found at : http://mips.gsf.de/genre/proj/fusarium/. and http://www.broad.mit.edu/annotation/fungi/fusarium Together with colleagues, we have recently begun generation of a genome microarray with Affymetrix.
Gaffoor, I., and F. Trail. 200-. Characterization of two polyketide synthase genes involved in zearalenone biosynthesis in Gibberella zeae. Appl. and Environ. Microbiol. Accepted.
Trail, F., I. Gaffoor, J. Guenther, and H. Hallen. 2005. Using genomics to understand the disease cycle of the Fusarium head blight fungus, Gibberella zeae (anamorph Fusarium graminearum). Can. J. Plant Path. December issue. Gaffoor, I., Brown, D. W., Plattner, R., Proctor, R. H., Qi, W., and Trail, F. 2005. Functional analysis of the polyketide synthase genes in the filamentous fungus Gibberella zeae (anamorph Fusarium graminearum). Euk Cell. 4:1926-1933. Trail, F., Gaffoor, I., and Vogel, S. 2005. Ejection mechanics and trajectory of the ascospores of Gibberella zeae (anamorph Fusarium graminearum). Fungal Genetics and Biology: 42:528-533 Guenther, J. and Trail, F. 2005. The development and differentiation of Gibberella zeae (anamorph: Fusarium graminearum) during colonization of wheat. Mycologia 97 (1): 232-240. Miller, M.J., Roze, L.V., Trail, F., and Linz, J.E. 2005. Role of cis-acting sites NorL, a TATA Box and AflR1 in nor-1 transcriptional activation in Aspergillus parasiticus. Applied and Environmental Microbiology 71:1539-1545.
Patents and Patent applications
A method to screen for compounds that inhibit expression of genes of secondary metabolism.
F. Trail, R. Hammerschmidt, J. Linz, H. X, L. Velasquez, S. Annis. Application for patent submitted 9/00.
Use of an insertional mutant of Gibberella zeae to increase yields of wheat and barley grain.
F. Trail, Iffa Gaffoor, John Guenther, Kim Hammond-Kosack. Patent application initiated.
"The Trail lab is well funded from Federal and other sources. To inquire about availability of research assistantships and postdoctoral fellowships, please contact me." e-mail:trail@msu.edu
PLB 402 Biology of the Fungi
Iffa Gaffoor
Luis Velasquez
John Guenther
Walid Fakhouri
Heather Hallen
Undergrads:
Aditi Pandya
Olynthia Ann Chancy.
