The JAZ family of repressors is the missing link in jasmonate signalling

Abstract

Jasmonates are essential phytohormones for plant development and survival. However, the molecular details of their signalling pathway remain largely unknown. The identification more than a decade ago of COI1 as an F-box protein suggested the existence of a repressor of jasmonate responses that is targeted by the SCF(COI1) complex for proteasome degradation in response to jasmonate. Here we report the identification of JASMONATE-INSENSITIVE 3 (JAI3) and a family of related proteins named JAZ (jasmonate ZIM-domain), in Arabidopsis thaliana. Our results demonstrate that JAI3 and other JAZs are direct targets of the SCF(COI1) E3 ubiquitin ligase and jasmonate treatment induces their proteasome degradation. Moreover, JAI3 negatively regulates the key transcriptional activator of jasmonate responses, MYC2. The JAZ family therefore represents the molecular link between the two previously known steps in the jasmonate pathway. Furthermore, we demonstrate the existence of a regulatory feed-back loop involving MYC2 and JAZ proteins, which provides a mechanistic explanation for the pulsed response to jasmonate and the subsequent desensitization of the cell.

Tobacco Transcription Factors: Novel Insights into Transcriptional Regulation in the Solanaceae

“…Recently, it was shown that MYC2, a key transcriptional activator of jasmonate responses in Arabidopsis, interacts with the JAZ family of transcriptional repressors (Chini et al, 2007;Thines et al, 2007). The JAZ proteins are members of the ZIM family of TFs and interact with another central regulator of JA signaling, the F box protein COI1 (Chini et al, 2007;Thines et al, 2007). We have found at least 13 ZIMs in tobacco (Table I), and there are apparent homologs of the complete COI1/JAZ1/ Figure 3.…”

“…The phylogenetic tree identifies possible tobacco homologs of key regulators of light responses, such as the PIF/ PILs (subgroup E), and jasmonate responses, such as AtMYC2/jin1/jai1 (subgroup N). Recently, it was shown that MYC2, a key transcriptional activator of jasmonate responses in Arabidopsis, interacts with the JAZ family of transcriptional repressors (Chini et al, 2007;Thines et al, 2007). The JAZ proteins are members of the ZIM family of TFs and interact with another central regulator of JA signaling, the F box protein COI1 (Chini et al, 2007;Thines et al, 2007).…”

Jasmonic acid control of GLABRA3 links inducible defense and trichome patterning inArabidopsis

“…These data show that JA biosynthesis (catalyzed by AOS) is necessary and sufficient for trichome induction. COI1 encodes an F-box subunit of the SCF E3 ubiquitin ligase complex (SCF COI1 ) and is an essential component of the JA receptor (Xie et al, 1998;Chini et al, 2007;Thines et al, 2007;Katsir et al, 2008). Like aos, coi1-1 did not show increased trichomes in response to wounding (Fig.…”

“…Wounded tissue rapidly activates JA biosynthesis (Glauser et al, 2008), and increased JA triggers the SKP1/Cullin/F-box E3 ubiquitin ligase complex containing the F-box subunit CORONATINE INSENSITIVE1 (SCF COI1 ) to degrade the repressors of JA signaling -the JASMONATE-ZIM (JAZ) family proteins -by the ubiquitin/26S-proteasome pathway (Chini et al, 2007;Thines et al, 2007). In addition to their local synthesis and action, JAs also move systemically via vascular strands to transmit wound signals to distal tissues (Li et al, 2002;Thorpe et al, 2007).…”

Identification and characterization of the MYC2 gene in relation to leaf senescence response in hybrid poplar (Populus alba × P. glandulosa)

“…repressor와 결합한다 (Chini et al 2007;Thines et al 2007;Yan et al 2007;Pauwels et al 2010). 그 결과로 MYC2, MYC3, MYC4를 포함한 JA 반응에 필수적인 다양한 하부 전사인자들이 활성 화된다 (Cheng et al 2011;Fernández-Calvo et al 2011;Niu et al 2011).…”