In Memorium

September 29, 1931 - October 7, 2007

A Tribute to Bud's Research
Download the ASPB Obituary

Ph.D. 1959 Montana State University

Research Interests

The major goals of this program are to investigate the regulation of synthesis of defensive proteins in plants that are induced by predator and pathogen attacks. Nearly 20 proteins have been identified whose systemic synthesis is regulated in response to herbivore and pathogen attacks. A lipid-based signal transduction pathway has been found to mediate the response. Signals from the plants have been identified and characterized, including a novel polypeptide signal, called systemin, analogous to polypeptide signals in animals, oligouronide fragments from the plant cell wall, and jasmonic acid, a prostagandin analog. Elucidating the biochemistry and cell biology of this pathway is the focus of our present research. The application of this knowledge to improve crop production and to understand ecological systems is a major goal of the program.

Selected Publicatons

Huffaker, A., and C.A. Ryan. 2007. Endogenous peptide defense signals in Arabidopsis differentially amplify signaling for the innate immune response. Proc. Natl. Acad. Sci. USA. In press.

Pearce, G., W.F. Siems, R. Bhattacharya, Y.-C. Chen, and C.A. Ryan. 2007. Three hydroxyproline-rich glycopeptides derived from a single petunia polyprotein precursor activate Defensin I, a pathogen defense response gene. J. Biol. Chem. In press (online).

Pearce, G., J. Narváez-Vásquez, and C.A. Ryan. 2006. Systemins, in Handbook of Bioactive Peptides, Abba Kastan ed., pp. 49-53.

Huffaker, A., Y. Yamaguchi, G. Pearce., and C.A. Ryan. 2006. AtPep1, in Handbook of Bioactive Peptides, Abba Kastan ed., pp. 5-8.

Moura, D.S., G. Pearce, and C.A. Ryan. 2006. RALF, in Handbook of Bioactive Peptides, Abba Kastan ed., pp. 33-36.

Srintanyarat, W., G. Pearce, W.F. Siems, C.A. Ryan, R. Wititsuwannakul, and G. Wititsuwannakul. 2006. Isolation and characterization of isoinhibitors of the potato inhibitor I family from the latex of rubber trees, Hevea brasiliensis. Phytochemistry 67:1644-1650.

Yamaguchi, Y., G. Pearce, W.F. Siems, and C. A. Ryan. 2006. The cell surface leucine-rich repeat receptor for AtPep1, an endogenous elicitor in Arabidopsis, is functional in transgenic tobacco cells. Proc. Natl. Acad. Sci. USA. 103:10104-10109.

Huffaker, A., G. Pearce, and C.A. Ryan. 2006. AtPep1, An endogeous pepide signal in Arabidopsis activates components of the innate immune response. Proc. Natl. Acad. Sci. USA 103:10098-10103.

Yamaguchi, Y., G. Pearce, and C.A. Ryan. 2006. The cell surface leucine-rich repeat receptor for AtPep1, an endogenous elicitor in Arabidopsis, is functional in transgenic tobacco cells. Proc. Natl. Acad. Sci. USA 103:10104-10109.

Ryan, C. A., G. Pearce, and J. Narváez-Vásquez. Cell Wall-Associated Peptides of the Systemin Family of Defense Signals. 2006. In The Science and Lore of the Plant Cell Wall, T. Hayashi, ed. Brown Walker Press. pp. 31-316.

Scheer, J., G. Pearce, and C.A. Ryan. 2005. LeRALF, a plant peptide that regulates root growth and development, specifically binds to 25 kD and 120 kD cell surface membrane proteins of Lycopersicon peruvianum. Planta. 221:667 674.

Narváez-Vásquez, J., G. Pearce, and C.A. Ryan. 2005. The plant cell wall matrix harbors a precursor of defense signaling peptides. Proc. Natl. Acad. Sci. USA. 102(36):12974-12977.

Narváez-Vásquez, J. and C.A. Ryan. 2004. The cellular localization of prosystemin: A functional role  for phloem parenchyma in systemin signaling. Planta 218:360-369.

Ryan, C. A. and G. Pearce. 2004. Peptide hormones/systemins. In Encyclopedia  of Biological Chemistry, W. Lennarz and M. D. Lane Eds. Elsevier. Volume 3, 381-384.

Diez-Diaz, M., V. Conejero, I. Rodrigo, G. Pearce, and C.A. Ryan. 2004. Isolation and characterization of wound-inducible carboxypeptidase inhibitor from tomato leaves. Phytochemistry 65:1919-1924.

Ryan, C. A. and G. Pearce. 2004. Peptide hormones for defense, growth, and development. In Plant Hormones, P. J. Davies ed. Elsevier,  pp. 654-670.

Orozco-Cardenas, M. and C.A. Ryan. 2002. Nitric oxide inhibits defense gene expression in leaves of wounded tomato plants. Plant Physiol. in press.

Ryan, C.A. and D.S. Moura. 2002. Systemic wound signaling in plants: A new perception. Proc. Natl. Acad. Sci. USA. 99:6519-6520.

Ryan, C.A. and G. Pearce. 2002. Polypeptide hormones in plants. In Encyclopedia of Plant Pathology.

Ryan, C.A., G. Pearce, D. Moura, and J.M. Scheer. 2002. Polypeptide hormones. Plant Cell 14:251-264.

Scheer, J.M. and C.A. Ryan. 2002. The systemin receptor SR160 from Lycopersicon peruvianum is a member of the LRR receptor kinase family. Proc. Natl. Acad. Sci. USA. 99:9585-9590.

Pearce, G., D.S. Moura, J. Stratmann, and C.A. Ryan. 2001. RALF, a 49 amino acid polypeptide signal arrests root growth and development. Proc. Natl. Acad. Sci. USA 98:12843-12847.

Scheer, J.M. and C.A. Ryan. 2001. A method for the quantitative recovery of proteins from polyacrylamide gels. Analytical Biochemistry 238:130-132.