My research focuses on population genetics of fungal plant pathogens, population biology, forest health, forest pathology, and diversity and conservation efforts of native plants. Our lab is interested in understanding complexity of host-pathogen-vector interactions and its associated microbial communities within the phytobiome across both introduced and native ranges. Increases in both native and introduced pathogens as a result of climate change have provided numerous opportunities in basic and applied research. My program’s main goal is to utilize novel genetic and genomic tools to integrate molecular data into pragmatic management decisions and provide solutions for preservation of biodiversity, conservation of native species and overall tree improvement programs. In addition, my research goal is to contribute to hunger eradication efforts on the African continent by preserving biodiversity of indigenous and nutritional plants adapted to climate change. This will not only provide regional food security, but will promote science literacy, and recruit and educate the next generation of science ambassadors in sub-Saharan African countries.

Research Focus

Host-Pathogen-Vector Interactions
My primary research centers on understanding host-pathogen-vector interactions with a focus on Thousand Cankers Disease (TCD) complex. The fungus, Geosmithia morbida, vectored by the walnut twig beetle, Pityophthorus juglandis, has been associated with disease outbreaks in walnut trees, Juglans spp., known as TCD. Read More The unique relationship of the host-pathogen-vector complex can result in significant evolutionary pressure for the pathogen, thus shaping the genome of G. morbida in unique ways that have not yet been documented in fungi. We are investigating a genome-enabled approach focused on G. morbida that will provide a better understanding of the biology of the pathogen involved in TCD and identify candidate genes and functions required for pathogenesis. Most evolutionary studies have focused on pathogens of crops that are not insect vectored, making this research a unique contribution in determining co-evolutionary history, and shedding light on emergence of new pathogenic fungi that continue to be a threat to fruit, nut, and forest trees worldwide.

Phytobiomes of Trees
The complexity of host genetics and its associated microbial communities within the phytobiome (plant itself + environment + micro- and macro-organisms living in, on, or around the host plant) can vary across a plant’s introduced and native ranges, resulting in higher ecosystem multifunctionality and functional redundancy. Host phytobiome plays an important role in host plant defenses, nutrient acquisition, and stress tolerance, serving critical functions in the interaction between plants and the environment. Using walnut trees as a non-model system, we are evaluating the impact of the complex disease system, Thousand Cankers Disease (TCD), on host genetic diversity and examining the correlation between phytobiome and disease severity in both introduced and native ranges.

Conservation Genetics and Biodiversity
An additional component of my research program focuses on conservation efforts of native trees, preservation of biodiversity in North American forests, and overall forest and tree health and protection on a global scale. We intend to devote research and teaching efforts to limit the impact of forest diseases and provide an understanding of the evolutionary dynamics, diversity and disease ecology of environmentally, socially and economically, significant trees. Read More Currently, our lab is involved in a number of conservation genetics projects focused on endangered and endemic plants in the U.S.A. and Ghana, Africa, including food security crops. In that capacity, we are involved with conservation efforts of Pityopsis ruthii, Ruth’s Golden Aster, an endangered species from the Hiwassee and Ocoee Rivers in Tennessee; Helianthus verticillatus (whorled sunflower), federally endangered plants species in Tennessee, Alabama and Georgia; and the biodiversity and preservation of an antimalarial plant endemic to Ghana, Cryptolepis sanguinolenta.

Population Genetics
In my lab, we have a number of projects related to population biology/genetics of native and/or economically important plants, as well their pathogens. We are interested in a number of different factors including, but not limited to, understanding the basic biology of the host-pathogen interactions, host-pathogen coevolution, how spatial distribution influences genetic diversity, their population structure and patterns of gene flow. Using these tools can expand our understanding of the ecological and evolutionary dynamics and elucidate historical processes that are a result of the past or current disease outbreak(s).


Extension and outreach focus

Tell me and I forget. Teach me and I remember. Involve me and I learn.” The best way to share your passion is to teach and educate others. That is why I am involved in STEM outreach for both high school and college students. An undergraduate research opportunity I was given as a student was the sole reason I continued my scientific exploration through further education. As a result, I became the person I am today – someone who loves science and loves sharing that passion, enthusiasm and inspiration with students, through both research and teaching. I am a firm believer that the best way to learn is to teach and that one’s education is never ending.


Teaching focus

I strongly believe that a teacher is a role model, advisor, guide, inspiration, and someone who is fundamentally involved and entirely dedicated to their student’s success. A teacher leads by example, motivates and encourages students to be the best they can be, and to go beyond their limits and even their own expectations. I feel fortunate and humble that I am able to do a job where I can share my passion and enthusiasm while fostering the educational growth of students. Teaching is an incredible gift, but also an enormous responsibility. As a teacher and researcher, I would like to have the same impact on students that my teachers and role models have had on me. I would like to be the change and inspiration to improve the world we live in by supporting future generations of environmental stewards and scientists.


EPP 411 – Forest Insects and Diseases (3 credits)

EPP 604 – Genomics of Forest Pest and Pathogens (3 credits; Co-teaching special topics class with Dr. Meg Staton)

EPP 531 – Special Problems in Entomology, Nematology, and Plant Pathology – Population Genetics (3 credits)

From left to right: Beant Kapoor, Aaron Onufrak, [insert name]. Dr. Denita Hadziabdic Guerry, [insert name], and Meher Ony
Hadziabdic Lab 2019

Denita Hadziabdic Guerry

Assistant Professor, Fulbright Scholar to Ghana 2018-2019
main office (865) 974-7135
fax (865) 974-4744

137 Plant Biotechnology Building
2505 EJ Chapman Drive
Knoxville, TN 37996-4560

B.S., Agriculture-Horticulture, Tennessee Tech University
M.S., Plant Pathology & Entomology, University of Tennessee
Ph.D., Plants, Soils & Insects (Population Genetics), University of Tennessee

90% Research, 10% Teaching

Graduate program concentrations
Bioinformatics, Genomics, and Molecular Interactions
Organismal Biology, Ecology, and Systematics

Areas of expertise
Forest health and forest pathology, population genetics of fungal pathogens, population biology, genetic diversity and conservation of native plants, molecular detection of pest and pathogens, phytobiome (plant host, their environment, and associated communities of macro and microorganisms), food security

Key words
Population genetics and genomics, pathogen spread, diversity and spatial distribution, thousand cankers disease, Geosmithia spp., host-pathogen-vector interactions, phytobiome, molecular detection

I am currently not accepting NEW graduate students. However, I am interested in internally motivated students and others who feel comfortable working well past the minimum target. Please contact me if you are interested in learning more about research opportunities in my laboratory.

Creative Art Microscope image

Research questions in our laboratory

How and why do disease outbreaks occur?

How do fungal pathogen disperse across wider geographical ranges, and how do those processes influence species genetic architecture?

How can we utilize novel genomic approaches to develop molecular diagnostic tools for invasive pathogens?

What genomic changes occur in a host during fungal invasion?

What is the regional influence of disease severity on host diversity and the host’s associated phytobiome?

What integrative approaches can be utilized for development of conservation and best management practices of native species in the U.S. and globally?


Current Lab Members

Selected Publications

Students and postdocs from Hadziabdic lab are underlined.M.S./Ph.D. committee member**


  1. Ony M, Nowicki M, Boggess S, Klingeman W, Zobel J, Trigiano R, Hadziabdic D (2020) Habitat fragmentation influences genetic diversity and differentiation: Fine‐scale population structure of Cercis canadensis (eastern redbud). Ecology and Evolution 10:3655-3670.
  2. Edwards T, Trigiano R, Ownley B, Windham A, Wyman C, Wadl P, Hadziabdic D (2020) Genetic diversity and conservation status of Helianthus verticillatus, an endangered sunflower of the Southern United States. Frontiers in Genetics 11:440.
  3. Parra P, Dantes W, Sandford A, De la Torre C, Pérez J, Hadziabdic D, Schaffer B, Gazis R (2020) A protocol for the rapid detection of the laurel wilt pathogen from woody samples. Plant Health Progress. Accepted.
  4. Onufrak A, Williams G**, Klingeman W, Cregger M, Klingeman M, DeBruyn J, Ginzel, M, Hadziabdic D (2020) Regional differences in the structure of Juglans nigra phytobiome reflect geographical differences in Thousand Cankers Disease severity. Phytobiomes Journal XX:1-17.


  1. Spring O, Gomez-Zeledon J, Hadziabdic D, Trigiano R, Thines M, Lebeda A (2019) Biological characteristics and assessment of virulence diversity in pathosystems of economically important biotrophic Oomycetes. Critical Reviews in Plant Sciences: 37(6):439-495.
  2. Chahal K**, Gazis R, Klingeman W, Hadziabdic D, Lambdin P, Grant J, Windham M (2019) Assessment of alternative candidate subcortical insect vectors from walnut crowns in habitats quarantined for Thousand Cankers Disease. Environmental Entomology. doi: 10.1093/ee/nvz064
  3. Wyman C**, Hadziabdic D, Boggess S, Rinehart T, Windham A, Wadl P, Trigiano RN (2019) Low genetic diversity suggests the recent introduction of dogwood powdery mildew to North America. Plant Disease:
  4. Wadl P, Mack B, Beltz S, Moore G, Baird R, Rinehart T, Molnar T, Staton M, Hadziabdic D, Trigiano R (2019) Development of genomic resources for the powdery mildew, Erysiphe pulchra. Plant Disease: 103:804-807.
  5. Nowicki M, Zhao Y, Boggess S, FluessH, Payá-MilansM, Staton M, Houston L, Hadziabdic D, Trigiano R (2019) Taraxacum kok-saghyz (Russian dandelion) genomic microsatellite loci: cross-species amplification and population genetics applications. Scientific Reports 9: 1915.
  6. Klingeman B, Bernard E, Boggess S, Pietsch G, Hadziabdic D, Trigiano R (2019) First Report of Honeysuckle leaf blight on Amur Honeysuckle (Lonicera maackii) caused by Insolibasidium deformans in Tennessee. Plant Disease:


  1. Gazis R, Poplawski L, Boggess S, Klingeman W, Boggess S, Trigiano R, Graves A, Seybold S, Hadziabdic D (2018) Mycobiota associated with insect galleries in walnut with thousand cankers disease reveals a potential natural enemy against Geosmithia morbida.Fungal Biology 122(4): 241-253.
  2. Oren E, Klingeman W, Gazis R, Moulton J, Lambdin P, Coggeshall M, Hulcr J, Seybold S, Hadziabdic D (2018) A novel molecular toolkit for rapid detection of the pathogen and primary vector of thousand cankers disease. PLOS One13(1): e0185087.
  3. Blood B, Klingeman W, Paschen M, Hadziabdic D, Couture J, Ginzel M (2018) Behavioral responses of Pityophthorus juglandis (Coleoptera: Curculionidae: Scolytinae) to volatiles of black walnut and Geosmithia morbida, the causal agent of thousand cankers disease. Environmental Entomology 47(2): 412-421.
  4. Hatmaker A, Staton M, Dattilo A, Hadziabdic D, Rinehart T, Schilling E, Trigiano R, Wadl P (2018) Population structure and genetic diversity within the endangered species Pityopsis ruthii (Asteraceae). Frontiers in Plant Science 9: 943.
  5. Nowicki M, Boggess S, Saxton A, Hadziabdic D, Xiang Q-Y, Molnar T, Huff M, Staton M, Zhao Y, Trigiano R (2018) Haplotyping ofCornus florida and kousa chloroplasts: insights into species-level differences and patterns of plastic DNA variation in cultivars. PLOS One 13(10): e0205407.
  6. Hua L, Hadziabdic D, Amissah N, Nowicki M, Boggess S, Staton M, Teng N, Trigiano R (2018) Characterization of fifteen microsatellite loci and genetic diversity analysis for the Ghanaian food security crop Solenostemon rotundifolius (Frafra potato). African Journal of Biotechnology 17(47): 1352-1357.


  1. Edwards T, Trigiano R, Wadl P, Ownley B, Windham AS, Hadziabdic D (2017) First report of Alternaria alternata causing leaf spot on Ruth’s Golden Aster (Pityopsis ruthii) in Tennessee. Plant Disease 101(2): 383.
  2. Edwards T, Trigiano R, Wadl P, Ownley B, Windham A, Hadziabdic D (2017) First report of Alternaria alternata causing leaf spot on whorled sunflower (Helianthus verticillatus) in the southeast United States. Plant Disease 101(4): 632.
  3. Mantooth K*, Hadziabdic D*, Boggess S, Windham M, Miller S, Cai G, Spatafora J, Zhang N, Staton M, Ownley B, Trigiano R (2017) Confirmation of independent introductions of an exotic plant pathogen of Cornus species, Discula destructiva, on the east and west coasts of North America and subsequent population bottlenecks. PLOS One 12(7): e0180345. *Equal author contributors.


  1. Daniels D, Nix K, Wadl P, Vito L, Wiggins G, Windham M, Ownley B, Lambdin P, Grant J, Merten P, Klingeman W, Hadziabdic D (2016) Thousand Cankers Disease Complex: A forest health issue that threatens Juglans species across the U.S. Forests 7(11): 260.
  2. Amissah J, Wadl P, Hadziabdic D, Boggess S, Trigiano R (2016) Characterization of thirteen microsatellite loci from the West African antimalarial plant Cryptolepis sanguinolenta. Journal of Medicinal Plants Research 10:183-187.
  3. Trigiano R, Bernard E, Hadziabdic D, Dattilo A, Wadl P (2016) First report of powdery mildew on whorled sunflower (Helianthus verticillatus) caused by Golovinomyces ambrosiae. Plant Disease 100 (5): 1017.
  4. Rinehart T, , Hadziabdic D, Wadl P, Trigiano R (2016) Molecular tools for studying genetic diversity in plant pathogens. In: Ownley, B.H. and R.N. Trigiano, eds. Plant Pathology, Concepts and Laboratory Exercises, 3rd CRC Press, Boca Raton, FL. pp 517-539.


  1. Dean D, Wadl P, Hadziabdic D, Klingeman W, Ownley B, Rinehart T, Dattilo A, Scheffler B, Trigiano R (2015) Analysis of genetic diversity and population structure for the US native shrub Viburnum rufidulum in Tennessee and Kentucky. Journal of the American Society for Horticultural Science 140(6): 523–531.
  2. Hadziabdic D*, Wadl P*, Staton M, Klingeman W, Moulton J, Pscheidt J, Wiggins G, Grant J, Lambdin P, Windham M, Faccoli M, Merten P, Trigiano R (2015) Development of microsatellite loci in Pityophthorus juglandis, a vector of thousand cankers disease in Juglans. Conservation Genetics Resources 7(2): 431-433. * Equal author contributors.


  1. Boggess S, Wadl P, Hadziabdic D, Scheffler B, Windham A, Klingeman W, Trigiano R (2014) Characterization of 12 polymorphic microsatellite loci of Pityopsis graminifolia latifolia. Conservation Genetics Resources6(4): 1043-1045.
  2. Wiggins G, Grant J, Lambdin P, Merten P, Nix K, Hadziabdic D, Windham M (2014) Discovery of walnut twig beetle, Pityophthorus juglandis, associated with forested black walnut, Juglans nigra, in the eastern U.S.Forests5: 1185-1193.
  3. Hadziabdic D, Vito L, Windham M, Pscheidt J, Trigiano R, Kolarik M (2014) Genetic differentiation and spatial structure of Geosmithia morbida, the causal agent of thousand cankers disease in black walnut (Juglans nigra). Current Genetics 60: 75-87.
  4. Hadziabdic D, Windham M, Baird E, Vito L, Cheng Q, Grant J, Lambdin P, Wiggins G, Windham A, Merten P, Taylor G (2014) First report of Geosmithia morbidain North Carolina: the pathogen involved in thousand cankers disease of black walnut. Plant Disease 98: 992.


  1. Dean D, Wadl P, Hadziabdic D, Wang X, Trigiano R (2013) Analyzing microsatellites using the Qiaxcel system. In: Methods in molecular biology: Microsatellites. Springer Science, U.S.A. 1006:223-243. doi: 10.1007/978-1-62703-389-3_16.


  1. Trigiano RN, Wadl PA, Dean D, Hadziabdic D, Scheffler BE, Runge F, Telle S, Thines M, Ristaino J, Spring O (2012) Ten polymorphic microsatellite loci identified from a small insert genomic library for Peronospora tabacina. Mycologia 104(3): 633-640.
  2. Hadziabdic D, Wang X, Wadl P, Rinehart T, Ownley B, Trigiano R (2012) Genetic diversity of flowering dogwood in the Great Smoky Mountains National Park. Tree Genetics & Genomes 8: 855-871.
  3. Hadziabdic D, Wadl P, Vito L, Boggess S, Scheffler B, Windham M, Trigiano R (2012) Development and characterization of sixteen microsatellite loci for Geosmithia morbida, the causal agent of thousand canker disease in black walnut (Juglans nigra). Conservation Genetics Resources 4: 287-289.


  1. Wadl P, Dean D, Li Y, Vito LM, Scheffler B, Hadziabdic D, Windham M, Trigiano R (2011) Development and characterization of microsatellites for switchgrass rust fungus (Puccinia emaculata). Conservation Genetics Resources 3: 185-188.
  2. Wadl P, Reed S,Hadziabdic D (2011) Production of haploid tobacco and potato plants using anther culture. In: Trigiano, R.N. and D.J. Gray, eds. Plant Tissue Culture, Development and Biotechnology, CRC Press, Boca Raton, FL.
  3. Hadziabdic D, Reed SM, Wadl PA (2011) Haploid cultures. In: Trigiano, R.N. and D.J. Gray, eds. Plant Tissue Culture, Development and Biotechnology, CRC Press, Boca Raton, FL.
  4. Trigiano R, Vito L, Windham M, Boggess S, Hadziabdic D (2011) Direct shoot organogenesis from leaf explants of chrysanthemum and african violets. In: Trigiano, R.N. and D.J. Gray, eds. Plant Tissue Culture, Development and Biotechnology, CRC Press, Boca Raton, FL.

For complete list of publications please visit my