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Jacqueline Fletcher
Oklahoma State University
Sarkeys Distinguished Professor, Department of Entomology and Plant Pathology
Address: 127 Noble Research Center, OSU, Stillwater, OK 74078
Phone: 405-744-9948 Fax: 405-744-6039
Email: jacqueline.fletcher@okstate.edu
URL: http://www.ento.okstate.edu/profiles/fletcher.htm
Ph.D., Plant Pathology, 1979, Texas A&M University Lab Photo
Postdoctoral: Plant Pathology, 1980-83, University of Illinois
Research Emphasis: Host-pathogen interactions of the phytopathogenic mollicutes
Insect transmission of walled and wall-less bacterial plant pathogens
Related Activities: President of the American Phytopathological Society (2002-2003)
 
Research Description:

My research interests center on prokaryotic plant pathogens, including wall-less bacteria (spiroplasmas and phytoplasmas) and bacteria with walls. Both of these groups provide exciting avenues for evaluation of disease processes, transmission factors, host resistance, and the genetic mechanisms that control these processes.

Phytopathogenic mollicutes are transmitted by phloem-feeding leafhoppers. They pass through the insect’s gut epithelia, hemolymph, and salivary glands. The insect serves as an alternate host, as the pathogen multiplies in its body. A major focus in my laboratory is to determine the molecular factors involved in the movement of spiroplasmas through these insect cellular barriers. Experimental approaches include the creation and study of non-transmissible spiroplasma mutants, molecular genetic analysis of the spiroplasma genome, serological and physical protein analysis, transmission experiments and electron microscopy. We will apply our findings to the development of strategies for controlling insect-transmitted plant pathogens.

Another project focuses on cucurbit yellow vine disease (CYVD), an emerging problem causing severe losses in pumpkin, watermelon, cantaloupes and squash. Recently, our research team developed CYVD-specific PCR primers and identified the causal agent as the ubiquitious, multi-niche bacterium, Serratia marcescens. We also determined that the pathogen is transmitted by a very unusual insect vector, the squash bug, Anasa tristis. Current work focuses on characterizing this unusual microbe, its pathogenicity determinants, mode of transmission and epidemiology.
 
Recent Publications:

Bruton BD, Mitchell F, Fletcher J, Pair SD, Wayadande A, Melcher U, Brady J, Bextine B, Popham TH (2002) Serratia marcescens, a phloem-colonizing, squash bug-transmitted bacterium, is the causal agent of cucurbit yellow vine disease. Plant Dis (in press).

Berg M, Melcher U, Fletcher J (2001) Spiroplasma citri adhesion related protein SARP1 is a member of a novel protein domain designated sarpin. Gene 275:57-64.

Yu J, Wayadande AC, Fletcher J (2000) A microtiter plate assay for characterization of Spiroplasma citri adhesion to cultured cells of the vector leafhopper, Circulifer tenellus. Phytopathology 90:716-722.

Fletcher, J (1999) Interactions of phytopathogenic mollicutes with insect and plant hosts. First Internet Conference on Phytopathogenic Mollicutes.

Fletcher J, Wayadande AC, Melcher UK, Ye F (1998) The phytopathogenic mollicute – insect vector interface: A closer look. Phytopathology 88:1351-1358.
 
Selected Additional Publications:

Avila FJ, Bruton BD, Fletcher J, Sherwood JL, Pair SD, Melcher U (1998) Polymerase chain reaction and phylogenetic characterization of an agent associated with yellow vine disease of cucurbits. Phytopathology 88:428-436.

Bruton BD, Fletcher J, Pair SD, Shaw M, Sitterz-Bhatkar H (1998) The association of a bacteriumlike organism with yellow vine disease in cucurbits. Plant Dis 82:512-520.

Wayadande AC, Fletcher J (1998) Development and use of an established cell line of the leafhopper, Circulifer tenellus, to characterize Spiroplasma citri-vector interactions. J Invert Pathol 72:126-131.

Ye F, Melcher UK, Fletcher J (1997) Molecular characterization of a gene encoding a membrane protein of Spiroplasma citri. Gene 189:95-100.

Ye F, Rascoe JE, Melcher UK, Fletcher J (1996) Chromosomal aberrations in Spiroplasma citri strain BR3. Biochem Genet 34:269-286.