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Stephen M. Marek
Oklahoma State University
Assistant Professor, Department of Entomology and Plant Pathology
Address: 127 Noble Research Center, OSU, Stillwater, OK 74078
Phone: 405-744-3090 Fax: 405-744-6039
Email: stephen.marek@okstate.edu
URL: http://www.ento.okstate.edu/profiles/marek.html
Ph.D., Plant Pathology, 2001, University of California, Davis Lab Photo
Postdoctoral: Plant Pathology, 2001-03, University of California, Davis
Research Emphasis: Molecular plant-microbe interactions; functional genomics of plant pathogenic fungi; mycology
Related Activities:
 
Research Description:

The broad focus of my research is to understand the basic biology of fungal pathogenesis. I believe questions regarding the molecular, cellular and biochemical interactions of plants and fungi must be framed in a system-specific context. While broad themes can be made based on the pathogenic lifestyle (e.g. necrotrophic vs. biotrophic, soilborne vs. foliar, etc.) of a fungus, the phylogenetic uniqueness of each interaction must be recognized. I have chosen to study the cell biology and biochemical signaling of fungal pathogenicity using an insertional mutagenesis system for fungi based on Agrobacterium-mediated “T-DNA tagging” to generate loss-of-function or dominant activation mutants. Also, the increased rate of homologous recombination of this technique speeds mutant complementation studies and the production of single-gene and large-fragment knockout lines. Libraries of transformants altered in the production of putative virulence/pathogenicity factors will facilitate the identification of pathogenic pathways occurring in fungi through epistasis, biochemical complementation, and/or transcriptome and proteome analyses.
I am presently using Agrobacterium-mediated transformation to generate transformants of Monilinia fructicola, the causal agent of brown rot of stone fruits. I hope to use this method to tag genes in M. fructicola involved in the switch from quiescence to infection. I am currently developing a research program based on fungal pathogens of Medicago truncatula. Preliminary experiments suggest Agrobacterium-mediated transformation is widely applicable to numerous phytopathogenic fungi infecting M. truncatula, including Botrytis cinerea, Fusarium spp., and Verticillium spp.
In addition to studying the pathogenic mechanisms of fungi, I also have a deep interest in trying to understand other aspects of fungal biology including, morphogenetic processes involving programmed cell death (PCD) and mycoparasitism.
 
Recent Publications:

Dhulipala MR, Enis JN, Casanova S, Marek SM (2006) Transformation of Leptosphaerulina trifolii and its interaction with Medicago. Phytopathology 96: S29.

Kamenidou S, Casanova S, Dhulipala MR, Enis JN, Cavins TJ, Marek SM (2006) Transformation of Botrytis cinerea with GFP - A tool to study the cytology of silicon-induced resistance against gray mold. Phytopathology 96: S57.

Lee HK, Marek SM, Young C, Sledge M (2006) Variation for Phymatotrichopsis omnivora alfalfa (Medicago sativa L.) Phytopathology 96: S65.

Marek SM, Cavins TJ, Kamenidou S (2006) Soluble silicon-based disease management of floricultural crops. Greenhouse Product News 16: 62.

Marek SM, Muller RM, Walker NR (2006) First report of ergot of bermudagrass caused by Claviceps cynodontis in Oklahoma. Plant Disease 90: 376.

Walker NR, Mitchell TK, Morton AN, Marek SM (2006) Influence of temperature and time of year on colonization of bermudagrass roots by Ophiosphaerella herpotricha. Plant Disease 90:1326-1330.

 
Selected Additional Publications:

Lee HK, Marek SM, Sledge MK (2005) Growth chamber assay for Phymatotrichum root rot of Medicago species. Phytopathology 95: S1112.

Lee HK, Marek SM, Sledge MK (2005) Effects of culture media on the growth of Phymatotrichopsis omnivora. Phytopathology 95: S1112.

Lee HK, Marek SM, Sledge MK (2005) Scanning electron microscopy of infection of alfalfa roots by Phymatotrichopsis omnivora. Phytopathology 95: S1112.

Littlefield LJ, Marek SM, Tyrl RJ, Winkelman KS (2005) Morphological and molecular characterization of Puccinia lagenophorae, now present in central North America. Annals of Applied Biology 147: 35-42.

Marek, SM (2005) Molecular phylogeny of Phymatotrichopsis omnivora. Phytopathology 95: S65.

Walker, NR, Marek, SM, and Taliaferro, CM (2005) Colonization of bermudagrass roots produced from stolons by Ophiosphaerella herpotricha. Phytopathology 95: S107.

Dhulipala M, Enis JN, Marek SM (2004) Agrobacterium-mediated transformation of Phoma medicaginis. Phytopathology 94: S25.