William Neal Reynolds Distinguished Professor and Head, Dept. Plant & Microbial Biology
Research efforts in my laboratory focus on the molecular biology of interactions between fungal pathogens of plants and their hosts, with an emphasis on the role of toxins and reactive oxygen species in pathogenicity. One major area of interest focuses on fungi in the genus Cercospora and the role of their photoactivated toxin cercosporin in disease development. Cercosporin generates reactive oxygen species that damage host cells and allow for successful pathogenesis. We are isolating and characterizing genes from the fungus that encode resistance to cercosporin, both to understand the molecular basis of toxin resistance as well as a possible novel strategy for engineering Cercospora-resistant plants. We are also studying the fungus Mycosphaerella fijiensis, causal agent of the Black Sigatoka (or Black Leaf Streak) disease of banana. Light has been shown to be important in symptom development, and we are investigating the possible production of light-activated toxins by M. fijiensis and their role in colonization and disease development.
Selected Publications (last 10 years)
De Souza, A., Herrero, S., Maffia, L. A., and Daub, M. E. 2014. Methods for Cercospora coffeicola protoplast isolation and genetic transformation with green fluorescent protein. Eur. J. Plant Pathol. 139:241-244.
Daub, M. E., Herrero, S., and Chung, K. R. 2013. Reactive oxygen species in plant pathogenesis: the role of perylenequinone photosensitizers. Antiox. Redox. Signal. 19:970-989.
Rueschhoff, E. E., Gillikin, J. W., Sederoff, H. W., and Daub, M. E. 2013. The SOS4 pyridoxal kinase is required for maintenance of vitamin B6 – mediated processes in chloroplasts. Plant Physiol. Biochem. 63:281-291.
Herrero, S., Gonzalez, E., Gillikin, J. W., Velez, H., Daub, M. E. 2011. Identification and characterization of a pyridoxal reductase involved in the vitamin B6 salvage pathway in Arabidopsis. Plant Mol. Biol. 76:157 – 169.
Daub, M. E., Herrero, S., and Taylor, T. V. 2010. Strategies for the development of resistance to cercosporin, a toxin produced by Cercospora species. pp. 157 -172 In: Cercospora Leaf Spot of Sugar Beet and Related Species. R. T. Lartey, J. J. Weiland, L. Panella, P. W. Crous, and C. E. Windels, eds. APS Press, St. Paul, MN.
Daub, M. E., and Chung, K. R. 2009. Photoactivated perylenequinone toxins in plant pathogenesis. Chapt. 11 in: The Mycota V, Plant Relationships, 2nd Edition. H. Deising, Ed. Springer-Verlag, Berlin Heidelberg
Amnuaykanjanasin, A., and Daub, M. E. 2009. The ABC transporter ATR1 is necessary for efflux of the toxin cercosporin in the fungus Cercospora nicotianae. Fung. Genet. Biol. 46:146-158.
Velez, H., Glassbrook, N. J., and Daub, M. E. 2008. Mannitol biosynthesis is required for pathogenicity of Alternaria alternata . FEMS Microbiol. Lett. 285-122-129.
Gonzalez, E., Danehower, D., and Daub, M. E. 2007. Vitamer levels, stress response, enzyme activity, and gene regulation of Arabidopsis lines mutant in the pyridoxine/pyridoxamine 5’-phosphate oxidase (PDX3) and the pyridoxal kinase (SOS4) genes involved in the vitamin B6 salvage pathway. Plant Physiol. 145:985-996.
Herrero, S., Amnuaykanjanasin, A., and Daub, M. E. 2007. Identification of genes differentially expressed in the phytopathogenic fungus Cercospora nicotianae between cercosporin toxin-resistant and -susceptible strains. FEMS Microbiol. Lett. 275:326-337.
Chen, H., Lee, M. H., Daub, M. E., and Chung, K. R. 2007. Molecular analysis of the cercosporin biosynthetic gene cluster in Cercospora nicotianae. Molec. Microbiol. 64:755-770.
Denslow, S. A., Rueschhoff, E. E., and Daub, M. E. 2007. Regulation of the Arabidopsis thaliana vitamin B6 biosynthesis genes by abiotic stress. Plant Physiol. Biochem. 45:152-161.
Herrero, S. and Daub, M. E. 2007. Genetic manipulation of vitamin B6 biosynthesis in tobacco and fungi uncovers limitations to up-regulation of the pathway. Plant Sci. 172:609-620.
Velez, H., Glassbrook, N. J., and Daub, M. E. 2007. Mannitol metabolism in the phytopathogenic fungus Alternaria alternata. Fungal Genet. Biol. 44:258-268.
Taylor, T. V., Mitchell, T. K., and Daub, M. E. 2006. An oxidoreductase is involved in cercosporin degradation by the bacterium Xanthomonas campestris pv. zinniae. Appl. Environ. Microbiol. 72:6070-6078.
Choquer, M., Dekkers, K. L., Chen, H. Q., Cao, L., Ueng, P. P., Daub, M. E., and Chung, K. R. 2005. The CTB1 gene encoding a fungal polyketide synthase is required for cercosporin biosynthesis and fungal virulence ofCercospora nicotianae. Molec. Plant Microbe Interact. 18:468-476.
Denslow, S. A., Walls, A. A., and Daub, M. E. 2005. Regulation of biosynthetic genes and antioxidant properties of vitamin B6 vitamers during plant defense responses. Physiol. Molec. Plant Pathol. 66:244-255.
Daub, M. E., Herrero, S., and Chung, K. R. 2005. Photoactivated perylenequinone toxins in fungal pathogenesis of plants. FEMS Microbiol. Lett. 252:197-206.
Wetzel, D.K., Ehrenshaft, M., Denslow, S. A., and Daub, M. E. 2004. Functional complementation between the PDX1 vitamin B6 biosynthetic gene of Cercospora nicotianae and pdxJ of Escherichia coli. FEBS Lett. 564: 143-146.