Our lab has two main research projects. One that is an investigation into the beta-alanine synthetic pathway in Arabidopsis and another where we are researching the synthesis of specialized metabolites in tomatoes and tomato-related plants.
One of our projects involves the study of the enzymes and intermediates involved in the synthesis of beta-alanine (a key intermediate in the synthesis for vitamin B5) in the model organism Arabidopsis thaliana. Despite decades of work, it is not clear what the primary pathway(s) is for the synthesis of beta-alanine in plants. There is some evidence that spermine and propionate serve as precursors. However the evidence for spermine is light and propionate does not naturally occur in plants. Based on previous data working with mmsd Arabidopsis mutants, we hypothesize that beta-alanine is synthesized through BCAA degradation via the production of propionyl-CoA.
Our goal is to confirm that beta-alanine is in fact made from isoleucine (one of the three BCAAs). We are working on this project from two different, but related directions: (1) directly measuring the production of one of the pathway intermediates, 3-hydroxypropionate; and (2) directly measuring the production of beta-alanine. We have been using both NMR and GC-MS to follow the pathway from isoleucine and propionate (via propionyl-CoA). Recent data from our lab confirms this metabolic pathway in both Arabidopsis and wheat.
Many Solonaceae (Nightshade) plants have small hair-like tissues on the surface of the plant that are called glandular trichomes. These "chemical factories" produce a number of specialized metabolites that help protect the plant from a variety of pests. One type of specialized metabolite that we are interested in, are called acylsugars. The metabolic profile of acylsugars varies with plant species, with greatest variability coming from length and branching of the acyl-chains. Our current project is looking at the enzymes potentially responsible for acyl-chain elongation, with focus on substrate specificity in enzymes from trichome-enriched vs non-trichome-enriched tissues.
As part of a larger collaborative project with research groups at the University of Missouri and Williams College, our goal is to identify the process for how these acyl chains are synthesized. Understanding more about how these plants make acylsugars will help us identify opportunities to fine tune the biosynthetic pathway for increased production (or to diversify the types) to enhance crop defense in an agronomically important plant family. Data from this project will also provide insight for the commercial production of acylsugars, such as natural pesticides.
Goldfarb MH*‡; Boesel J*‡, Wilczewski-Shirai KC‡, Reinhart P‡, Scherger T‡, Webb C‡, Newlun M‡, Rouhier KA**. "Synthesis of β-alanine from isoleucine and propionate catabolism via aminotransferases" Plant Direct 2024 (Accepted) *Co-first authors, **Corresponding author, ‡Undergraduate students (Kenyon College)
Henkhaus, NA; Busch, W; Chen, A; Colón-Carmona, A; Cothran, M; Diaz, N; Dundore-Arias, JP; Gonzales, M; Hadziabdic, D; Hayes, RA; MacIntosh, GC; Na, A; Nyamasoka-Magonziwa, B; Pater, D; Peritore-Galve, FC; Phelps-Durr, T; Rouhier, K., Sickler, DB; Starnes, JH; … Stern, DB. “Removing systemic barriers to equity, diversity, and inclusion: Report of the 2019 Plant Science Research Network workshop “Inclusivity in the Plant Sciences”. Plant Direct 2022. 6(8), e432. https://doi.org/10.1002/pld3.432
Gipson, AB‡; Morton, KJ‡‡; Rhee, RJ‡; Simo, S‡; Clayton, JA‡; Perrett, ME‡; Binkley, CG‡; Jensen, EL‡; Oakes, DL‡; Rouhier, MF; Rouhier, KA*. “Disruptions in Valine Degradation Affect Seed Development and Germination in Arabidopsis” The Plant Journal 2017. 90(6):1029-1039 *Corresponding author. ‡Undergraduate students (Kenyon College), ‡‡Undergraduate student (Doane University)
Creamer, K‡; Ditmars, FS‡; Basting, PJ; Acero, S‡; Kunka, KS‡; Hamdallah, IN‡; Bush, SP‡; Scott, Z‡; He, A‡; Penix, SR‡; Gonzales, AS‡; Eder, EK‡; Camperchioli, D‡; Berndt, A‡; Clark, MW; Rouhier, KA; Slonczewski, JL. “Benzoate and Salicylate Tolerant Strains Lose Antibiotic Resistance during Laboratory Evolution of Escherichia coli K-12” Applied and Environmental Microbiology 2016. 83(2). ‡Undergraduate students (Kenyon College)
Lyon, M ‡; Wilson, M; Rouhier, K; Symonsbergen, D; Bastola, K; Thapa, I; Holmes, A; Sikich, S; Jackson, A. “Digital image analysis for DETECHIP® code determination” Signal & Imaging Processing: An International Journal 2012. 3(4) 51-63. ‡Undergraduate students (Doane University).
Lyon, M‡; Groathouse, J‡; Beaber, J‡; Turner, LM; Rouhier, KA; Wilson, MV; Symonsbergen, DJ; Sikich, SM; Holmes, AE. “DETECHIP®: An improved molecular sensing array” Journal Forensic Science 2011. 2(4) ‡Undergraduate students (Doane University).
Faraldos, JA; Giner, J-L*; Smith, DH; Wilson, M; Ronhovde, K ‡; Wilson, E; Clevette, D; Holmes, AE*; Rouhier, K.* “Enzymatic resolution of 1-Phenylethanol and formation of a diastereomer: an undergraduate 1H NMR experiment to introduce chiral chemistry” Journal Chemical Education 2011, 88(3), 334-336. *Corresponding authors. ‡Undergraduate student (Doane University).
Groathouse, J‡; Barcena, H; Gustafson, C‡; Wilson, MV; Symonsbergen, DJ; Lucas, KA; Holmes, AE. “Wild Plum: Novel particles of improved optical brightness and fluorescence” Journal Cosmetic Science 2010, 61, 279-288. ‡Undergraduate students (Doane University).
Burks, R; Pacquette, S‡; Guericke, M‡; Wilson, M; Symonsbergen, D; Lucas, K*; Holmes, A.* “DETECHIP®: A sensor for drugs of abuse” Journal of Forensic Science. 2010, 55(3), 723-727. *Corresponding authors. ‡Undergraduate students (Doane University).
Anderson, M; Wilcox, K‡; Guericke, M‡; Chu, H‡; Wilson, M; Wilson, E; Lucas, K*; Holmes, A.* “Enantio-discrimination of methamphetamine by circular dichroism using porphyrin tweezers” Chirality 2010, 22(4) 398-402. *Corresponding authors. ‡Undergraduate students (Doane University).
Lucas, K; Filley, J‡; Erb, J‡; Graybill, E; Hawes, J. “Peroxisomal metabolism of propionic acid and isobutyric acid in plants” Journal of Biological Chemistry 2007, 282, 24980-24989. ‡Undergraduate students (Miami University).
Furge, K*; Lucas, K*; Takahashi, M; Sugimura, J; Kort, E; Kanayama, H; Kagawa, S; Hoekstra, P; Curry, J; Ximing J. Teh, B. “Robust Classification of Renal Cell Carcinoma Based on Gene Expression Data and Predicted Cytogenetic Profiles.” Cancer Research 2004, 64, 4117-4121. *Co-first authors.