The Experiments
Figure 3. Dr. Paul Staswick, Agronomy and Horticulture/School of Biological Sciences, University of Nebraska - Lincoln
Figure 4. Scott Dworak, Agronomy and Horticulture, Graduate Student, University of Nebraska - Lincoln
One biotic stress plants often encounter is herbivorous insects. Successful plants have mechanisms to cope with insect invasions. A series of discoveries identified jasmonic acid as a key to defense response1. This led to the following hypothesis: A plant that can chemically modify jasmonic acid can use this hormone as a signal molecule and mount a defense against feeding insects. The key was to conduct an experiment to test this hypothesis.
Scott Dworak (Fig. 4), a graduate student who was part of Dr. Staswick’s (Fig. 3) research team, describes one set of experiments he conducted through two short videos in this lesson. Watch the first video called Fragrant Signals (4 minutes, below) that describes the production of jasmonic acid in jar1 mutants and wild-type Arabidopsis thaliana, which led to the formation of a hypothesis and experiment.
1Staswick's publications:
- Staswick P.E. 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.
- 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
- 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.