Samenvatting Plant physiology H9: Jasmonic acid
Introduction:
Good jasmine odor
Jasmonic acid Biosynthesis:
JA is made from oxylipins = C18 poly-unsaturated fatty-acid (lipid) oxidation = oxidized
compounds derived from fatty acids
Start with -linolenic acid
o Stage 1 degradation of plastid membranes &
modification of C18 poly-unsaturated fatty acids (In
plastids/chloroplasts
Membrane degradation by lipase (DAD1) -
linolenic acid
-linolenic acid 13-hydroperoxylinolenic acid
by 13-lipoxygenase
13-hydroperoxylinolenic acid 12,13-
epoxylinolenic acid by allene oxide synthase (AOS)
12,13-epoxylinolenic acid OPDA by allene
oxidase cyclase (AOC)
o Stage 2 In the peroxisomes
Transport of OPDA to peroxisome
OPDA OPC (reduction) by OPDA reductase
Acetyl-CoA + OPC OPC-8:0 CoA by OPC-8:0 CoA
ligase
OPC-8:0 CoA oxidation by 3 rounds of -oxidation
(3 diff enzymes) 7-isojasmonic acid
JAR1 produces Jasmonyl-isoleucine active JA-
amino acid derivative
o Both membrane degradation (stage 1) as JA biosynthesis
can be stimulated by wounding or pathogens
o Bacterial coronatine of Pseudomonas syringae is a
structural analog of JA-Ile can activate JA responses by
binding on the receptor
, Jasmonic acid Signaling:
Receptor = COI1 = coronatine insensitive 1
o This is the F-box protein of the E3-ligase of an SCF-complex
o Ja-Ile binds to it
Protein complex to repress transcription factors for JA-response genes
o JAZ = Jasmonate zim domain protein
Repressor protein
Large gene family
Prevents expression by blocking JA specific transcription factors
JAZ is ubiquitinated by the SCF complex (with COI1) when JA-Ile is
present & degraded JA-responses bcs blocking stops
NOTE: MG132 can inhibit degradation of JAZ bcs it is an inhibitor of the
proteasome
o NINJA = novel interactor of JAZ
o TPL = Topless
Transcription factors are mostly from MYC2 which is a basic
o Basic helix-loop-helix-leucine zipper type transcription factor
Jasmonic acid Physiology:
• Inhibition of growth
• Regulation of anther and pollen development
• Tuber formation induction
• Seed germination inhibition (Look at slides bcs something strange!!!)
• Plant defense induction of plant defensing mechanisms against insects,
necrotrophic fungi … through producing defense proteins & metabolites/also after
wounding
o Local & systemic responses JA induces systemic acquired resistance (SAR)
o Me-JA is arborne & volatile so this happens next to the electric signal (faster)
• Promote curling of tendrils creeping on something
Introduction:
Good jasmine odor
Jasmonic acid Biosynthesis:
JA is made from oxylipins = C18 poly-unsaturated fatty-acid (lipid) oxidation = oxidized
compounds derived from fatty acids
Start with -linolenic acid
o Stage 1 degradation of plastid membranes &
modification of C18 poly-unsaturated fatty acids (In
plastids/chloroplasts
Membrane degradation by lipase (DAD1) -
linolenic acid
-linolenic acid 13-hydroperoxylinolenic acid
by 13-lipoxygenase
13-hydroperoxylinolenic acid 12,13-
epoxylinolenic acid by allene oxide synthase (AOS)
12,13-epoxylinolenic acid OPDA by allene
oxidase cyclase (AOC)
o Stage 2 In the peroxisomes
Transport of OPDA to peroxisome
OPDA OPC (reduction) by OPDA reductase
Acetyl-CoA + OPC OPC-8:0 CoA by OPC-8:0 CoA
ligase
OPC-8:0 CoA oxidation by 3 rounds of -oxidation
(3 diff enzymes) 7-isojasmonic acid
JAR1 produces Jasmonyl-isoleucine active JA-
amino acid derivative
o Both membrane degradation (stage 1) as JA biosynthesis
can be stimulated by wounding or pathogens
o Bacterial coronatine of Pseudomonas syringae is a
structural analog of JA-Ile can activate JA responses by
binding on the receptor
, Jasmonic acid Signaling:
Receptor = COI1 = coronatine insensitive 1
o This is the F-box protein of the E3-ligase of an SCF-complex
o Ja-Ile binds to it
Protein complex to repress transcription factors for JA-response genes
o JAZ = Jasmonate zim domain protein
Repressor protein
Large gene family
Prevents expression by blocking JA specific transcription factors
JAZ is ubiquitinated by the SCF complex (with COI1) when JA-Ile is
present & degraded JA-responses bcs blocking stops
NOTE: MG132 can inhibit degradation of JAZ bcs it is an inhibitor of the
proteasome
o NINJA = novel interactor of JAZ
o TPL = Topless
Transcription factors are mostly from MYC2 which is a basic
o Basic helix-loop-helix-leucine zipper type transcription factor
Jasmonic acid Physiology:
• Inhibition of growth
• Regulation of anther and pollen development
• Tuber formation induction
• Seed germination inhibition (Look at slides bcs something strange!!!)
• Plant defense induction of plant defensing mechanisms against insects,
necrotrophic fungi … through producing defense proteins & metabolites/also after
wounding
o Local & systemic responses JA induces systemic acquired resistance (SAR)
o Me-JA is arborne & volatile so this happens next to the electric signal (faster)
• Promote curling of tendrils creeping on something
