Paul E. Staswick
Professor - Department of Agronomy and Horticulture
(402) 472-5624 | Email
- Ph.D. Purdue University
Current research in the Staswick laboratory addresses fundamental aspects of plant hormone biology. We have focused on jasmonic acid (JA) and related molecules that are particularly important in signaling resistance to disease and insects, and in protecting plants from other adverse environmental conditions. An Arabidopsis gene called JAR1 is essential for normal jasmonate response. We discovered that JAR1 encodes an enzyme that is structurally related to firefly luciferase and activates JA by conjugating it to the amino acid isoleucine, forming JA-Ile (see Staswick et al., 2004). Recent analysis of the molecular mechanism of jasmonate signal transduction has confirmed that JA-Ile is a key signaling molecule for the ubiquitin/proteasome pathway for jasmonate responses (see Staswick, 2008). We are currently studying the activities of other JA amino acid conjugates.
In addition to JAR1 there are 18 other closely related genes in Arabidopsis, collectively called the GH3 family in plants. In contrast with JAR1, seven of the Arabidopsis enzymes conjugate the auxin hormone indole 3-acetic acid (IAA) (see Staswick et al., 2005). Unlike the case for JA, conjugation of IAA is generally a mechanism to inactive this hormonal signal. We are continuing to characterize the activity of this his interesting enzyme family by determining the effect of over expressing and eliminating the expression of individual genes or combinations of these genes. Our discovery opens the way to a better understanding of how plant hormones work, and ultimately, may be used to improve plant growth, productivity and limit damage from insects and diseases.
Staswick P (2009) The tryptophan conjugates of jasmonic and indole-3-acetic acids are endogenous auxin inhibitors. Plant Physiol. 150:1310-1321.
Staswick P (2009) Plant hormone conjugation: A signal decision. Plant Signaling Behaviour 4:757-759.
Staswick P. (2008) JAZing up jasmonate signaling. Trends Plant Sci. 13:66-71.
Suza W, Staswick P. (2008) The role of JAR1 in jasmonoyl-L-isoleucine production in Arabidopsis wound response. Planta 227:1221-1232.
Katsir L, Schilmiller AL. Staswick PE. He SY. Howe GA. (2008) COI1 is a critical component of a receptor for jasmonate and the bacterial virulence factor coronatine. Proc. Natl. Acad. Sci. 105: 7100-7105.
Melotto M, Mecey C, Niu Y, Chung HS, Katsir L, Yao J, Zeng W, Thines B, Staswick P, Browse J, Howe G, He SY (2008) The bacterial toxin coronatine and the plant hormone jasmonoyl isoleucine target the physical interaction between the Arabidopsis COI1 F-box protein and the Jas domain of JAZ repressor proteins. Plant J. 55:979-988
Zhang Z, Li O, Li Z, Staswick PE, Wang M, Zhu Y, He Z (2007) Dual regulation role of GH3.5 in salicylic acid and auxin signaling during Arabidopsis-Pseudomonas syringae interaction. Plant Physiol. 145:450-464.
Park JE, Park JY, Kim YS, Staswick PE, Jeon J, Yun J, Kim SY, Kim J, Lee YH, Park CM. (2007) GH3-mediated auxin homeostasis links growth regulation with stress adaptation response in Arabidopsis. J Biol Chem. 282:10036-10046.
Guranowski A, Miersch O, Staswick PE, Suza W, Wasternack C. (2007) Substrate specificity and products of side-reactions catalyzed by jasmonate:amino acid synthetase (JAR1). FEBS Lett. 581:815-820.
Staswick PE, Serban B, Rowe M, Tiryaki I, Maldonado MT, Maldonado MC, Suza W. (2005) Characterization of an arabidopsis enzyme family that conjugates amino acids to indole-3-acetic acid. Plant Cell 17:616-627.
Staswick PE and Tiryaki I. (2004) The oxylipin signal jasmonic acid is activated by an enzyme that conjugates it to isoleucine in Arabidopsis. Plant Cell 16:2117-2127.
Leelapon O, Sarath G, Staswick PE. (2004) A single amino acid substitution in soybean VSPa increases its acid phosphatase activity nearly 20-fold . Planta 219:1071-1079.
Tiryaki I, Staswick PE (2002) An Arabidopsis thaliana mutant defective in jasmonate response is allelic to the auxin signaling mutant axr1 Plant Physiol. 130: 887-894.
Staswick PE, Tiryaki I, Rowe M. (2002) The jasmonate response locus JAR1 and several related arabidopsis genes encode enzymes of the firefly luciferase superfamily that show activity on jasmonic, salicylic, and indole-3-acetic acids in an assay for adenylation. Plant Cell, 14: 1405-1415.