OPDA-Ile – a new JA-Ile-independent signal?

Abstract

Expression takes place for most of the jasmonic acid (JA)-induced genes in a COI1-dependent manner via perception of its conjugate JA-Ile in the SCF COI1 -JAZ co-receptor complex. There are, however, numerous genes and processes, which are preferentially induced COI1-independently by the precursor of JA, 12-oxophytodienoic acid (OPDA). After recent identification of the Ile-conjugate of OPDA, OPDA-Ile, biological activity of this compound could be unequivocally proven in terms of gene expression. Any interference of OPDA, JA, or JAIle in OPDA-Ile-induced gene expression could be excluded by using different genetic background. The data suggest individual signaling properties of OPDA-Ile. Future studies for analysis of an SCF COI1 -JAZ co-receptorindependent route of signaling are proposed. Ten years ago, the new family of JASMONATE ZIM DOMAIN (JAZ) proteins with 12 members was occasionally identified in Arabidopsis in 3 different labs. [1][2][3] This was a breakthrough in JA research, since JAZ proteins were characterized as repressors of JA-Ile-induced gene expression. With identification of these proteins, it became clear that JA-Ile is perceived by the SCF COI1 -JAZ co-receptor complex. Components of this complex are the F-box protein called CORONATINE INSENSI-TIVE 1 (COI1), the Skp1/Cullin/complex with E3 ubiquitin ligase activity and the targets of the F-box protein, the JAZ proteins. JAZ proteins repress in the absence of JA-Ile positively acting transcription factors (TFs), such as MYC2, which bind to JA responsive elements (G-boxes) in the promoters of JAIle-regulated genes. Upon stress or developmentally regulated processes, an increase in JA-Ile level occurs leading to its binding in the SCF COI1 -JAZ co-receptor complex followed by proteasomal degradation of JAZ. Consequently, the free, positively acting MYC2 can switch on JA-Ile-responsive gene expression. 4 This basic scenario could be explained mechanistically upon crystallization of the complex, where an inositol-pentakisphosphate (IP 5 ) activates JA-Ile binding. 5 Interaction of the F-box protein COI1 and one of the JAZ proteins requires the C-terminal jas domain of JAZ. 6 This interaction is promoted by JA-Ile. Among the various stereo-isomeric forms of JA-Ile, the (+)-7-iso-JA-Ile has the highest activity. 7 JA-Ile perception via the SCF COI1 -JAZ-co-receptor complex was confirmed in the last couple of years including identification of new co-repressors and adaptors (for reviews, see refs. [8][9][10] ).There is, however, one open question due to the structural specificity in binding of the ligand JA-Ile. Among 40 different jasmonate compounds the stereoisomer (+)-7-iso-JA-Ile, carrying a ring conformation similar to coronatine, was most active. 7 Even coronatine was 10-fold more active then JA-Ile, although this bacterial toxin does not occur in plants. For the methyl ester of JA, for 12-oxo-phytodienoic acid (OPDA, the precursor of JA biosynthesis), and for OPDA-Ile (Fig. 1) no detectable promotion of JAZ3-COI1 interaction was recorded...

12-Oxo-Phytodienoic Acid Acts as a Regulator of Maize Defense against Corn Leaf Aphid

“…Besides acting as a precursor for JA biosynthesis, OPDA can activate downstream signaling mechanisms and promote enhanced callose accumulation (Taki et al, 2005;Böttcher and Pollmann, 2009;Scalschi et al, 2015;Wasternack and Hause, 2016;Wasternack and Strnad, 2016;Monte et al, 2018). Mp708 plants had constitutively elevated levels of both JA and OPDA (Shivaji et al, 2010).…”

Novel crosstalk between ethylene‐ and jasmonic acid‐pathway responses to a piercing–sucking insect in rice

“…However, the immediate downstream product catalyzed by AOC and also the precursor of JA, 12-oxo-phytodienoic acid (OPDA), has the potential to mediate other signaling pathways independent of JA. This may occur through OPDA-specific responses (Park et al, 2013;Guo et al, 2014), or the inactivity of OPDA in the promotion of JAZ3-COI1 interactions (Fonseca et al, 2009), even though JA and OPDA may share some initial synthesis steps (Wasternack & Hause, 2016;Wasternack & Strnad, 2016). Additionally, OsHPL3 regulates the synthesis of green leaf volatiles (GLVs) through a branch of JA biosynthesis that is quite divergent from JA (Tong et al, 2012;Ling & Weilin, 2016).…”

Genome-Wide Characterization of Jasmonates Signaling Components Reveals the Essential Role of ZmCOI1a-ZmJAZ15 Action Module in Regulating Maize Immunity to Gibberella Stalk Rot

“…Alfa-linolenic and linoleic acids also serve as the substrates to form 9-oxylipins, the diverse products of 9-LOXs-mediated oxidation of fatty acids at carbon position nine. JAs have been well documented for their vital roles in regulating plant growth and development, responses to mechanical trauma, and diverse abiotic and biotic stresses [ 3 , 7 , 9 , 10 , 11 ]. In particular, JAs display inhibitory effects on primary root growth [ 12 , 13 , 14 ].…”