Connections Map Overview

The Canonical Jasmonate Signaling Pathway

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Science's STKE  07 Oct 2003:
Vol. 2003, Issue 203, pp. cm16
DOI: 10.1126/stke.2003.203.cm16


Jasmonates in plants are cyclic fatty acid-derived regulators structurally similar to prostaglandins in metazoans. These chemicals mediate many of plants' transcriptional responses to wounding and pathogenesis by acting as potent regulators for the expression of numerous frontline immune response genes, including defensins and antifungal proteins. Additionally, the pathway is critical for fertility. Ongoing genetic screens and protein-protein interaction assays are identifying components of the canonical jasmonate signaling pathway. A massive molecular machine, based on two multiprotein complexes [SCFCOI1 and the COP9 signalosome (CNS)], plays a central role in jasmonate signaling. This machine functions in vivo as a ubiquitin ligase complex, probably targeting regulatory proteins, some of which are expected to be transcriptional repressors. Some defense-related mediators, notably salicylic acid, antagonize jasmonates in controlling the expression of many genes. In Arabidopsis, NPR1 mediates part of this interaction, with another layer of control provided further downstream by the mitogen-activated protein kinase homolog MPK4. Numerous other interpathway connections influence the jasmonate pathway. Insights from Arabidopsis showed that an allele of the auxin signaling gene AXR1, for example, reduces the sensitivity of plants to jasmonate. AP2-domain transcription factors, such as ERF1, link the jasmonate pathway to the ethylene signaling pathway. As progress in characterizing several new mutants (some of which are hypersensitive to jasmonic acid) augments our understanding of jasmonate signaling, the Connections Map will be updated to include this new information.

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R. Liechti, E. E. Farmer, The jasmonate pathway. Science 296, 1649-1650 (2002). [Abstract] [Full Text]