ETHYLENE BIOSYNTHESIS Jean-Claude PECH
Mar 26, 2015
ETHYLENE BIOSYNTHESIS
Jean-Claude PECH
ETHYLENE ORIGINATING FROM LIPIDS?
Until 1964, ethylene was though to derive fromthe enzymatic disruption of lipids involving free radicals formation
Arguments:-Oxygen is required for the biosynthesis ofethylene in plants;
-Free radical scavengers (antioxidants that prevent lipid oxidation, e.g. propyl gallate ...) inhibited ethylene production.
DISCOVERY OF METHIONINE AS A PRECURSOR OF ETHYLENE
Lieberman and Mapson, 1964* *Methionine
NH3+
CH3-S-CH2-CH2-CH-COO-
OTHER INHIBITORS OF ETHYLENE SYNTHESISLieberman and Owens, 1971
CH2-CH-CH2-O-C=C-CH-COOH
OH NH2 H NH2
H
Rhizobitoxine from Rhizobium japonicum
CH2-CH2-CH2-O-C=C-CH-COOH
NH2 H NH2
H
AVG= Amino ethoxy vinyl glycine from Streptomyces
Shang-Fa YANGDISCOVERY OF ACC AND METHIONINE CYCLE
« Knight of Roquetaillade », Ethylene Congress Agen, 1992
Radio-chromatograms of ethylene extracts of apple plugs
14C-Methionine
Plugs in air, 12h
Plugs in N2, 6h
Plugs in N2, 6hthen in air, 6h
* *Methionine
NH3+
CH3-S-CH2-CH2-CH-COO-
?
?CH2 CH2 * *
Ethylene
1-aminocyclopropane-1-carboxylic acid
CH2 CH2
CH
NH3+ COO-
* *S-Adenosyl Methionine
* *
NH3+
CH3-S-CH2-CH2-CH-COO-
Ade
+
L-methionine
S-adenosyl-methionine(AdoMet)
Yang CycleYang Cycle
HH22C NHC NH33
CCHH22C COOC COO--
ACCACC
EthyleneEthylene
5’-methylthioadenosine5’-methylthioadenosine(MTA)(MTA)
5’-methylthioribose (MTR)5’-methylthioribose (MTR)
5’-methylethioribose-1-phosphate 5’-methylethioribose-1-phosphate (MTR-1-P)(MTR-1-P)
2-keto-4-methylthiobutyric acid (KMBA)2-keto-4-methylthiobutyric acid (KMBA)
Ethylene biosynthesisEthylene biosynthesis
C=CC=CHHHH
HH HH
ATP+H2OATP+H2O
PPii+PP+PPii
11//22 O O22
HCN+HHCN+H22O+COO+CO22
HH22OOadenineadenine
ATPATPADPADP
OO22PPii+HOOCH+HOOCH transaminationtransamination
Abstract
« Knight of Roquetaillade », Ethylene Congress Agen, 1992
Don GRIERSON, DISCOVERY OF ACC OXIDASE
DISCOVERY OF A METHOD FOR MEASURING EFE IN A SOLUBLE FORM
Ververidis and John, 1991: Complete recovery in vitro ofethylene forming enzyme activity. Phytochemistry, 30:725-727
1: Highly impureextract
2: Highly pure extract
Silver staining Pre-immuneUnpurifiedserum
Purified serum
ACC SYNTHASE PURIFICATION FROM WOUNDED ZUCCHINI
L-methionine
S-adenosyl-methionine(AdoMet)
ACC synthaseACC synthase
Yang CycleYang Cycle
HH22C NHC NH33
CCHH22C COOC COO--
ACCACCACC oxidaseACC oxidase
EthyleneEthylene
5’-methylthioadenosine5’-methylthioadenosine(MTA)(MTA)
5’-methylthioribose (MTR)5’-methylthioribose (MTR)
5’-methylethioribose-1-phosphate 5’-methylethioribose-1-phosphate (MTR-1-P)(MTR-1-P)
2-keto-4-methylthiobutyric acid (KMBA)2-keto-4-methylthiobutyric acid (KMBA)
Ethylene biosynthesisEthylene biosynthesis
C=CC=CHHHH
HH HH
ATP+H2OATP+H2O
PPii+PP+PPii
11//22 O O22
HCN+HHCN+H22O+COO+CO22
HH22OOadenineadenine
ATPATPADPADP
OO22PPii+HOOCH+HOOCH transaminationtransamination
GACCGACCMACCMACC
Inhibitors of ACC synthase: Rhizobitoxine, AVG
Factors stimulating ACS gene expression:Auxins, chilling, wounding, drought, pathogens,ethylene
Inhibitors of ACC oxidase: Anoxia, uncouplers, free radical scavengers, Co++, Ni++, T°>35°C,
Factors stimulating ACO gene expression:Pathogens, ethylene, wounding
EFFECTORS OF ACC SYNTHASE AND ACC OXIDASE
At-ACS1 (induced by cycloheximide)
At-ACS5 [induced by Li, cycloheximide(CH) and low concentration of cytokinin(CK)] At-ACS4 (induced by CH, IAA and wounding)
At-ACS2 (induced by Li, CH, wounding)
At-ACS4 induced by CH, IAA, wounding)
At-ACS4 (induced by CH, IAA, anaerobisis and wounding)
Adult plant Etiolated seedling
At-ACS5 (basal level stimulated by Li and CK
At-ACS8 not yet characterized
At-ACS10 in response to light in plants overexpressing CONSTANS
At-ACS2 in young leaves and flowers
At-ACS7 (induced by CH)
At-ACS9 = eto1
At-ACS6 (induced by O3, Cu2+, IAA, CH, CN-, anaerobiosis, wounding, touching and ethylene)
At-ACS1
At-ACS2
Le-ACS2
Le-ACS4
At-ACS6
Le-ACS6
Le-ACS1A
Le-ACS1B
At-ACS7
At-ACS11
Le-ACS5
At-ACS4
At-ACS8
At-ACS5
At-ACS9
Le-ACS7
Le-ACS3
Le-ACS8
At-ACS10
At-ACS12
Branch I
Branch II
Branch III
*
****
ACC SYNTHASE GENE FAMILY IN ARABIDOPSIS
Le-ACO1, 3
Le-ACO1 in senescentor wounded leaves
Le-ACO2
Le-ACO1,2,3 and 4induced by O3
Le-ACO3 (breaker stage)
Le-ACO4
Le-ACO4
Le-ACS7 induced early by wounding
Le-ACS6 (in MG fruit) negativ. regul. by ethylene
Le-ACS4 induced by wounding
Le-ACS1A (breaker stage) negativ. regul. by ethylene
FLOWER
Le-ACS7 induced early by flooding
Le-ACS3 induced by flooding
Le-ACS2 and 4 positiv. regul. by ethylene
Le-ACS3 (not expressed in fruit, present in tomato cell suspension)
Le-ACS2 (stamens, mature and senescent anthers)
Le-ACS2 (senescent petals)
ACO AND ACS GENE EXPRESSION IN TOMATO
Regulation of ethylene biosynthetic genesRegulation of ethylene biosynthetic genes
ACC synthase Arabidopsis Rapidly induced by auxin (ACS4).
Induced by low levels of cytokinin (ACS5).Rumex Flood resistant species downregulates ACS,
flood sensitive does not. Rice Enzyme activity induced by hypoxia/flooding.Mung bean Induced by mechanical stress (AIM1).Tomato Induced by fruit ripening.
Induced by flooding (ACS3).Induced by ozone (ACS2).
Phaseolus Induced by auxin (ACS1).Synergistic induction with auxin (ACS2).
Winter squash Induced by auxin (accA).Induced by wounding (accW).
Phalaenopsis Induced by ethylene (ACS1)Induced in stigma after pollination or auxin treatment(ACS1, ACS2).Induced in ovary after pollination or auxin treatment(ACS3).
Carnation Late induction by ethylene, pollination induces expression after 12-24 hours in petals (CARACC3).
Stellaria Regulated by photoperiod.Potato Rapidly induced by ozone, infection and Cu2+ (ACS5).
Slowly induced by ozone, infection and Cu2+ (ACS4).Zucchini Induced by wounding and auxin only in fruit (ACC1A).
ACC oxidase
Arabidopsis Induced by ethylene (ACO2/E1305).Tomato ACO1 antisense transgenic plants have reduced
ethylene production and epinasty after flooding.Induced during flower development (ACO1-3).Induced by wounding (ACO1).Induced during senescence (ACO, ACO3).
Phalaenopsis Induced by ethylene.Unpollinated flowers cannot convert ACC toethylene.
Cantaloupe Induced by ethylene, wounding, NaCl, drought andripening (ACO1).Induced by NaCl and drought (ACO3).
Petunia Induced by ethylene (ACO3).Induced in senescing floral organs (ACO1, ACO3).Induced in developing pistils (ACO3, ACO4).
Winter SquashInduced by wounding, induction blocked by ethyleneinhibitor, endogenous ethylene accelerates induction.
Carnation Induced by pollination in styles and petals (SR120).Mung bean Induced by ethylene(ACO1, ACO2).Peach Induced by wounding and fruit ripening.Apple Induced during fruit ripening.Broccoli Induced after harvest (ACC Ox1).
Induced in reproductive organs postharvest (ACC Ox2).