Lab: LIFE B470

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Undergraduate students, graduate students, and postdocs are highly encouraged to contact Dr. Horn by email to inquire about openings in various projects aiming to study biochemical pathways for producing high value bioproducts, abiotic stress, membrane biology, and/or other topics that may be of mutual interest.

Degrees:

• Postdoctoral Associate, Department of Biology and Plant Research Laboratory, Michigan State University, 2018
• Doctor of Philosophy, Biochemistry, University of North Texas, 2013
• Bachelor of Science, Biochemistry, The University of Texas at Austin, 2008

Research Interests:

1. Identifying and Characterizing Enzymes in Plant Metabolism and Bioproduct Production:

The plant kingdom produces an astonishing number of chemically and functionally diverse metabolites that contribute to a plant's survival, growth and development, defense, and evolutionary selection. Identifying and characterizing all the genes, and their encoded proteins, that produce these metabolites and modulate their levels in vivo is a complex task that requires various techniques ranging from genetics to biochemistry to computational biology to omics and beyond. Our research focuses on identifying and characterizing proteins that produce high-value plant lipids (or oils) which are essential to plant growth and development, human health and nutrition (e.g., omega-3 fatty acids), and industrial feedstocks (e.g., biofuels, lubricants). This work targets biochemical pathways ranging from model plants (e.g., Arabidopsis thaliana) to crops important to the Texas economy (e.g., cotton) to non-domesticated plant systems (e.g., Sterculia foetida). Students and personnel working on these structure-function projects will primarily learn and use genetic engineering, molecular biology, biochemical, and structural biology techniques.

2. Elucidating the Structural and Functional Role of Plant Thiols:

Cysteines (Cys) are chemically reactive amino acids containing sulfur that play diverse roles in plant biology. Recent proteomics investigations in the model plant Arabidopsis thaliana have revealed the presence of thiol post-translational modifications (PTMs) in several Cys residues. These PTMs are presumed to impact protein structure and function, yet mechanistic data regarding the specific Cys susceptible to modification and their biochemical relevance remain limited. To help address these limitations, we are characterizing the structure and functional roles of Cys in enzymes susceptible to thiol PTMs. Given the thiol proteome also changes in response to abiotic stress conditions (e.g., high temperature, drought, etc.) understanding these processes at the basic science level will enable translational applications that contribute to enhanced plant resilience. Students and personnel working on these projects primarily learn and use biochemistry, plant physiology, and genetics techniques.

3. Inclusive Research Training in STEM:

The Horn Lab prioritizes promoting and advancing an environment/culture of equal opportunity, equal access and inclusion in research training. Our lab strives to provide research opportunities at different experience levels from undergraduates to graduate students to professional scientists. We encourage all those interested in research, including underrepresented groups in STEM, to reach out to discuss research opportunities in our lab. We offer a range of research training experiences for students that just want to give research a try to more rigorous, targeted training plans that prepare students for competitive research- and/or medical-based careers.

Selected Publications:

The following are the most recent publications:

1. Cannon AE, Horn PJ (2023). The Molecular Frequency, Conservation and Role of Reactive Cysteines in Plant Lipid Metabolism. Plant and Cell Physiology- Special Issue in Plant and Algal Lipids. pcad163 doi.org/10.1093/pcp/pcad163
2. Horn PJ, Chapman KD (2023). Imaging plants in situ. Journal of Experimental Botany- Special Issue in Plant Metabolism. erad423 doi.org/10.1093/jxb/erad423
3. Borisjuk L, Horn P, Chapman, K, Jakob PM, Gündel A, Rolletschek H (2023). Seeing plants as never before. New Phytologist Tansley Review 238, 1775-1794. doi/10.1111/nph.18871
4. Hoh D, Horn P, Kanazawa A, Froehlich JE, Cruz J, Tessmer O, Hall D, Yin L, Benning C, Kramer, DM (2022). Genetically-determined variations in photosynthesis indicate roles for specific fatty acid species in chilling responses. Plant, Cell & Environment 45, 1682-1697. doi.org/10.1111/pce.14313
5. Armstrong NM, Spragley KJ, Chen WM, Hsu FC, Brewer MS, Horn PJ, Williams SR, Sale MM, Worrall BB, Keene KL (2021). Multi-omic analysis of stroke recurrence in African Americans from the Vitamin Intervention for Stroke Prevention (VISP) clinical trial. PLOS One. 16, e0247257. doi.org/10.1371/journal.pone.0247257
6. Horn PJ, Chapman KD, Ischebeck T (2021). Isolation of Lipid Droplets for Protein and Lipid Analysis. Plant Lipids: Methods and Protocols. Methods in Molec Biol 2295, 295-320. doi: 10.1007/978-1-0716-1362-7_16
7. Horn, PJ (2021). Where Do the Electrons Go? How numerous redox processes drive phytochemical diversity. Phytochemistry Reviews, 20, 367-407. doi.org/10.1007/s11101-020-09738-w

Other publications of interest:

1. Horn PJ, Smith DM, Clark RT, Froehlich JF, and Benning C. PEROXIREDOXIN Q stimulates the activity of the chloroplast 16:1Δ3trans FATTY ACID DESATURASE4 (2020). The Plant Journal 56, 2457-2464. doi:10.1111/tpj.14657.
2. Zienkiewicz A, Zienkiewicz K, Poliner E, Pulman JA, Du Z-Y, Stefano G, Tsai C-H, Horn PJ, Feussner I, Farre EM, Childs K, Brandizzi F, Benning C (2020). The Microalga Nannochloropsis during transition from quiescence to autotrophy in response to nitrogen availability. Plant Physiology 192, 1043-1055. doi.org/10.1104/pp.19.00854.
3. Horn PJ and Benning C (2016). The plant lipidome in human and environmental health. Science 353: 1228-1232. doi:10.1126/science.aaf6206
4. Horn PJ, Liu J, Cocuron JC, McGlew K, Thrower NA, Larson M, Lu C, Alonso AP, and Ohlrogge J (2016). Identification of multiple lipid genes with modifications in expression and sequence associated with the evolution of hydroxy fatty acid accumulation in Physaria fendleri. The Plant Journal 86, 322-348. doi:10.1111/tpj.13163
5. Horn PJ, James CN, Gidda SK, Kilaru A, Dyer JM, Mullen RT, Ohlrogge JB, and Chapman KD (2013). Identification of a new class of lipid droplet-associated proteins in plants. Plant Physiology 162, 1926-1936. doi:10.1104/pp.113.222455
6. Horn PJ, Korte AR, Neogi PB, Love E, Fuchs J, Strupat K, Borisjuk L, Shulaev V, Lee YJ, and Chapman KD (2012). Spatial mapping of lipids at cellular resolution in embryos of cotton. The Plant Cell 24, 622-636. doi:0.1105/tpc.111.094581 *Faculty of 1000 recommended *Featured In-Brief article by J.Mach in same issue.
7. James CN*, Horn PJ*, Case CR, Gidda SK, Zhang D, Mullen RT, Dyer JM, Anderson RG, and Chapman KD (2010). Disruption of the Arabidopsis CGI-58 homologue produces Chanarin-Dorfman-like lipid droplet accumulation in plants. Proceedings of the National Academy of Sciences 107, 17833-17838. doi:10.1073/pnas.0911359107 *Authors contributed equal to this work

CURRENT GRANT-FUNDED PROJECTS:

A Laser Microdissection System to Enhance Agricultural and Food Research in the North Texas and Southern Oklahoma Region. United States Department of Agriculture, National Institute for Food and Agriculture, Equipment Grants Program (USDA NIFA EGP). Brian G. Ayre (PI), Roisin C. McGarry, Vanessa M. Macias, Patrick J. Horn, and Jyoti Shah. $341,019 United Stated Department of Agriculture- National Institute of Food and Agriculture. Elucidating Cyclic Fatty Acid Biosynthesis and Compartmentalization to Improve Cottonseed Value (PI Patrick Horn, East Carolina; Kent Chapman, Co-PI). 3/15/2022- 3/14/2025 (#2022-67013-36897).

Teaching:

Biochemistry I (BIOC 4540/5540) Cell Biology (BIOL 3510)