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Sci. Signal., 16 February 2010
Vol. 3, Issue 109, p. cm4
CONNECTIONS MAP OVERVIEWS
Arabidopsis Jasmonate Signaling Pathway
Robin Liechti2, and
Edward E. Farmer1*
1 Current contributing authorities, Gene Expression Laboratory, Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, Biophore, CH-1015 Lausanne, Switzerland. 2 Former contributing authority, Swiss Institute of Bioinformatics, Vital-IT Group, Génopode, CH-1015 Lausanne, Switzerland.
Jasmonates control defense gene expression, growth, and fertility throughout the plant kingdom and have been studied extensively in Arabidopsis thaliana. The prohormone jasmonic acid (JA) is conjugated to amino acids such as isoleucine to form the active hormone jasmonoyl-isoleucine (JA-Ile). A series of breakthroughs has identified the SCF [SCF consists of four subunits: a cullin, SKP1 (S-phase kinase-associated protein 1), a RING finger protein (RBX1/HRT1/ROC1), and an F-box protein] CORONATINE INSENSITIVE1 (COI1) E3 ubiquitin ligase complex and the JASMONATE ZIM-DOMAIN (JAZ) proteins as central components in the perception of and transcriptional response to JA-Ile. JAZ proteins (most probably as dimers) bind transcription factors such as MYC2 before JA-Ile production. JA-Ile binds to COI1 to facilitate the formation of COI1-JAZ complexes, leading to ubiquitination and subsequent degradation of JAZ proteins. The degradation of JAZ proteins liberates transcription factors that function in the presence of the RNA polymerase II coregulatory complex Mediator to permit the expression of a number of jasmonate-regulated genes. Recent developments include the identification of COI1 as a receptor for jasmonates. Upstream of the signaling events, microRNA319 (miR319) negatively regulates the production of JA and JA-derived signals.