Dr. Donald M. Walker

Assistant Professor

Dr. Donald M. Walker
(615) 898-2847
Room 2127, Science Building (SCI)
MTSU Box 60, Murfreesboro, TN 37132

Degree Information

  • Ph.D., Rutgers, The State University of New Jersey (2012)
  • B.S., SUNY College of Environmental Science and Forestry (2007)
  • A.S., SUNY Niagara County Community College (2005)

Biography

I received my Ph.D. from Rutgers University in 2012. I conducted doctoral research on the systematics, ecology, and evolutionary biology of plant pathogenic fungi in the Gnomoniaceae (Diaporthales) under advisors Amy Rossman, Lisa Castlebury, and Jim White. My research expertise lies in the areas of molecular evolution and molecular ecology of microorganisms with an emphasis on fungi. Past research projects have focused on the evolution of plant-fungal pathogen relationships and utilized syst...

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I received my Ph.D. from Rutgers University in 2012. I conducted doctoral research on the systematics, ecology, and evolutionary biology of plant pathogenic fungi in the Gnomoniaceae (Diaporthales) under advisors Amy Rossman, Lisa Castlebury, and Jim White. My research expertise lies in the areas of molecular evolution and molecular ecology of microorganisms with an emphasis on fungi. Past research projects have focused on the evolution of plant-fungal pathogen relationships and utilized systematics, phylogenetics, and molecular marker development to integrate evolutionary biology, host/fungus associations, and ecological vicariance events. More recently my lab group has concentrated on using metabarcoding and high-throughput sequencing to study host-microbiome-pathogen associations and the synergistic to antagonistic interactions within these systems. Emerging infectious fungal pathogens are threatening wildlife species world-wide, therefore, we are interested to answer questions of theoretical importance centered on the spatiotemporal patterns of the host microbiome. We also assess the functional importance of the microbiome by learning about the antimicrobial products synthesized by the resident host bacteria. The southeastern United States is a global ‘hotspot’ for biological biodiversity and serves as a foundation for our field studies. 

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Publications

2018

(28) Grisnik, M., Leys, J.E., Bryan, D., Hardman, R.H., Miller, D.L., Cobb, V.A., Ogle, C., Simpson, C., Campbell, J.R., Appelgate, R.D., Allender, M.C., Nordberg, E.J., Hoekstra, A.A., Walker, D.M. 2018. Host and geographic range of snake fungal disease in Tennessee, USA. Herpetological Reviews. In press.  

(27) Minoshima, A., Walker, D.M., Takemoto, S., Hosoya, T., Walker, A.K., Ishikawa, S., Hirooka...

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2018

(28) Grisnik, M., Leys, J.E., Bryan, D., Hardman, R.H., Miller, D.L., Cobb, V.A., Ogle, C., Simpson, C., Campbell, J.R., Appelgate, R.D., Allender, M.C., Nordberg, E.J., Hoekstra, A.A., Walker, D.M. 2018. Host and geographic range of snake fungal disease in Tennessee, USA. Herpetological Reviews. In press.  

(27) Minoshima, A., Walker, D.M., Takemoto, S., Hosoya, T., Walker, A.K., Ishikawa, S., Hirooka, Y. 2018. Pathogenicity and taxonomy of Tenuignomonia styracis gen. et sp. nov., a new monotypic genus of Gnomoniaceae on Styrax obassia in Japan. Mycoscience. https://doi.org/10.1016/j.myc.2018.08.001  

(26) Walker, D.M., Murray, C.M., Talbert, D., *Tinker, P., Graham, S.P., Crowther, T.A. 2018. salamander's top down effect on fungal communities in a detritivore ecosystem. FEMS Microbiology Ecology. https://doi.org/10.1093/femsec/fiy168

(25) Malone, E.W., Perkin, J.S., Leckie, B.M., Kulp, M.A., Hurt, C.R., Walker, D.M. 2018. Which species, how many, and from where: Integrating habitat suitability, population genomics, and abundance estimates into species reintroduction planning. Global Change Biology.  doi.org/10.1111/gcb.14126

(24) *Hayes, D.H., Grisnik, M., *Stone, S.A., *Tarter, Z.W., *Ritter, K., *Yanckello, L.M., *Oatman, L.E., *Myers, L.E., *Pellegrino, C.C., Camp, C.D., Walker, D.M., Wooten, J.A. 2018. The culturable skin microbiome of the Ocoee Salamander, Desmognathus ocoee. Tennessee Journal of Herpetology 1: 4–10.  

(23) Tanguay, P., Blais, M., Potvin, A., Stewart, D., Walker, D.M., Nadeau-Thibodeau, N., DesRochers, P., Rioux, D. 2018. qPCR quantification of Ophiognomonia clavigignenti-juglandacearum from infected butternut trees under different release treatments. Forest Pathology https://doi.org/10.1111/efp.12418

2017  

(22) Hill, A., Leys, J.E., Bryan, D., Erdman, F.M., Malone, K.S., Russell, G.N., Applegate, R.D., Fenton, H., Niedringhaus, K., Miller, A.N., Allender, M., Walker, D.M. 2017. Common cutaneous bacteria isolated from snakes inhibit growth of Ophidiomyces ophiodiicola. EcoHealth doi: 10.1007/s10393-017-1289-y. (21) Tanguay, P., Blais, M., Potvin, A., Stewart, D., Walker, D.M., Nadeau-Thibodeau, N.,

(21) Walker, D.M., Smouse, P.E., Reginato, M., Struwe, L. 2017. Cladal divergence in fungal Ophiognomonia (Gnomoniaceae, Diaporthales) shows evidence of climatic niche vicariance. Biological Journal of the Linnean Society doi.org/10.1093/biolinnean/blx043

(20) Walker, D.M., Leys, J.E., *Dunham, K.E., *Oliver, J., *Schiller, E.E., *Stephenson, K., *Kimrey, J., Wooten, J., Rogers, M.W. 2017. Methodological considerations for detection of terrestrial small-body salamander eDNA and implications for biodiversity conservation. Molecular Ecology Resources DOI: 10.1111/1755-0998.12667

(19) Talbert, D., *Tinker, P., Crowther, T., Walker, D.M. 2017. Using Machine Learning to Understand Top-Down Effects in an Ecosystem: Opportunities, Challenges, and Lessons Learned. Association for the Advancement of Artificial Intelligence.  

2016  

(18) Hibbett, D., Abarenkov, K., Chai, B., Crous, P., Helgason, T., Herr, J.R., Lueschow, S., O’Donnell, K., Nilsson, R.H., Oono, R., Schoch, C., Smyth, C., Walker, D.M., Andrea, P-A., Taylor, J.W., Geiser, D.M. 2016. Sequence based classification and identification of fungi. Mycologia 108: 16–30.

(17) Shetty, K.G., Rivadeneira, D.V., Jayachandran, K., Walker, D.M. 2016. Isolation and molecular characterization of the fungal endophytic microbiome from conventionally and organically grown avocado trees in South Florida. Mycological Progress doi:10.1007/s11557-016-1219-3  

2015  

(16) Shuttleworth, L.A., Walker, D.M., Liew, E.C.Y., Guest, D.I. 2015. The chestnut (Castanea spp.) pathogen Gnomoniopsis smithogilvyi (Gnomoniaceae, Diaporthales) and its synonyms. Mycotaxon 130: 929–940.

(15) Walker, D.M., *Lawrence, B.R., *Esterline, D., *McAndrew, M., *Edelbrock, J., Graham, S.P., Kelehear, C. 2015. A novel protocol for removing environmental microbes from amphibian skin. Herpetological Reviews 46: 349–353.

(14) Rossman, A.Y., Adams, G.C., Cannon, P.F., Castlebury, L.A., Crous, P.W., Gryzenhout, M., Jaklitsch, W.M., Mejia, L.C., Stoykov, D., Udayanga, D., Voglmayr, H., Walker, D.M. 2015. Recommendations of generic names in Diaporthales competing for protection or use. IMA Fungus DOI: 10.5598/imafungus.2015.06.01.09

(13) Combs, J., *Grisnik, M., *Baldauf, K., *Sigg, M., *Swanson, T., *Amos, R., White, C.M., Schwaner, T.D., Walker, D.M., Wooten, J.A. 2015. A report of ranavirus infecting midland painted turtles with novel localities for frog infection in northwest Ohio. Herpetological Reviews 46: 361–363.

(12) Nilsson, R.H., Tedersoo, L., Ryberg, M., Kristiansson, E., Hartmann, M., Unterseher, M., Porter,T.M., Bengtsson-Palme, J., Walker, D.M., de Sousa, F., Gamper, H.A., Larsson, E., Larsson, K-H., Kõljalg, U., Edgar, R., Abarenkov, K. 2015. A comprehensive, automatically updated fungal ITS sequence dataset for reference-based chimera control in environmental sequencing efforts. Microbes & Environments DOI:10.1264/jsme2.ME14121  

2014

(11) Walker, D.M., *Lawrence, B.R., *Esterline, D., Graham, S.P., Edelbrock, M.A., Wooten, J.A. 2014. A metagenomics-based approach to the top-down effect on the detritivore food web; a salamander’s influence on fungal communities within a deciduous forest. Ecology and Evolution DOI: 10.1002/ece3.1259

(10) Schoch, C.L., Robbertse, B., Walker, D.M., and 96 others. 2014. Finding needles in haystacks: linking scientific names, reference specimens and molecular data for Fungi. DATABASE DOI: 10.1093/database/bau061

(9) Walker, A., Hirooka, Y., Walker, D.M. 2014. Ophiognomonia acadiensis. Persoonia 32, 290.

(8) Walker, D.M., *Lawrence, B.R., Castlebury, L.A., Rossman, A.Y. 2014. Five new species of the highly diverse genus Plagiostoma (Gnomoniaceae, Diaporthales) from Japan. Mycological Progress DOI: 10.1007/s11557-014-0993-z

(7) Walker, D.M., Castlebury, L.A., Rossman, A.Y., Struwe, L. 2014. Host conservatism or host specialization? Patterns of fungal diversification are influenced by host specificity in Ophiognomonia (Gnomoniaceae, Diaporthales). Biological Journal of the Linnean Society 111, 1–16. DOI: 10.1111/bij.12189  

2013  

(6) Wooten, J.A., Camp, C.D., *Combs, J.R., *Dulka, E., Reist, A., Walker, D.M. 2013. Re-evaluating niche conservatism versus divergence in the woodland salamander genus Plethodon Tschudi 1838: a case study of the parapatric members of the Plethodon glutinosus (Green 1818) species complex. Canadian Journal of Zoology 91, 883–892. DOI: 10.1139/cjz-2013-0097  

2012  

(5) Walker, D.M., Rossman, A.Y., Adams, G.C., Longa, C.M.O., Maresi, G. 2012. Valsalnicola oxystoma. Persoonia 29, 148.

(4) Walker, D.M., Castlebury, L.A., Rossman, A.Y., Mejía, L.C., White, J.F. 2012. Phylogeny and taxonomy of Ophiognomonia (Gnomoniaceae, Diaporthales), including twenty-five new species in this highly diverse genus. Fungal Diversity 57, 85–147.

(3) Walker, D.M., Castlebury, L.A., Rossman, A.Y., White, J.F. 2012. New molecular markers for fungal phylogenetics: Two genes for species-level systematics in the Sordariomycetes (Ascomycota). Molecular Phylogenetics and Evolution 64, 500–512.

(2) Rossman, A.Y., Melgar, J.C., Walker, D.M., Gonzales, A., Ramirez, T., Rivera, J.M. 2012. First report of Dolabra nepheliae causing stem canker of rambutan and pulasan in Honduras. Plant Disease 96, 765.  

2010  

(1) Walker, D.M., Castlebury, L.A., Rossman, A.Y., Sogonov, M.V., White, J.F. 2010. Systematics of genus Gnomoniopsis (Gnomoniaceae, Diaporthales) based on a three-gene phylogeny, host associations and morphology. Mycologia 102, 1479–1496.

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Awards

2018   Natural Resources Conservation Service. Assessing the Restoration Success of WRP Easements in the Lower Mississippi River Valley. Co-PI with Dr. Justin Murdock. Total award: $1,650,016. MTSU subaward to conduct microbiome work: $257,649

2018   Tennessee Wildlife Resources Agency, State Wildlife Grant. Understanding the impact of snake fungal disease on species of greatest conservation need in Tennessee. PI, $10...

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2018   Natural Resources Conservation Service. Assessing the Restoration Success of WRP Easements in the Lower Mississippi River Valley. Co-PI with Dr. Justin Murdock. Total award: $1,650,016. MTSU subaward to conduct microbiome work: $257,649

2018   Tennessee Wildlife Resources Agency, State Wildlife Grant. Understanding the impact of snake fungal disease on species of greatest conservation need in Tennessee. PI, $109,000.

2017  Tennessee Wildlife Resources Agency, State Wildlife Grant. The probiotic microbiome of endangered Tennessee bats: implications for biodiversity conservation and development of WNS biocontrol agents. PI, $81,000.

2016  Tennessee Wildlife Resources Agency, State Wildlife Grant. The origin, host, and geographic range of snake fungal disease with an emphasis on species of greatest conservation need in Tennessee. PI, $7,700.

2016  Great Smoky Mountains Conservation Association Campbell Fellowship. Keystone community members in the microbiome of salamander skin affect pathogenicity of chytrid fungi (Batrachochytrium spp.). Co-PI with Aubree Hill, $5,000.  

2014  Ohio Environmental Protection Agency. Wetland Rehabilitation at The Rieck Center for Habitat Studies. Co-PI with Benjamin Dolan and Bethany Henderson-Dean, $93,500.

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