1. ETHYLENE BIOSYNTHESIS
Jean-Claude PECH

2. Until 1964, ethylene was though to derive from
ETHYLENE ORIGINATING FROM LIPIDS?
Until 1964, ethylene was though to derive from
the enzymatic disruption of lipids involving
free radicals formation
Arguments:
-Oxygen is required for the biosynthesis of
ethylene in plants;
-Free radical scavengers (antioxidants that
prevent lipid oxidation, e.g. propyl gallate ...)
inhibited ethylene production.

3. DISCOVERY OF METHIONINE AS A PRECURSOR OF ETHYLENE
* *
Methionine
NH3+
CH3-S-CH2-CH2-CH-COO-
DISCOVERY OF METHIONINE
AS A PRECURSOR OF ETHYLENE
Lieberman and Mapson, 1964

4. OTHER INHIBITORS OF ETHYLENE SYNTHESIS
Lieberman and Owens, 1971
CH2-CH-CH2-O-C=C-CH-COOH
OH NH H NH2 H
Rhizobitoxine from Rhizobium japonicum
CH2-CH2-CH2-O-C=C-CH-COOH
NH H NH2 H
AVG= Amino ethoxy vinyl glycine from Streptomyces

5. Shang-Fa YANG
DISCOVERY OF ACC AND METHIONINE CYCLE
« Knight of Roquetaillade », Ethylene Congress Agen, 1992

6. Radio-chromatograms of ethylene extracts of apple plugs
14C-Methionine
Radio-chromatograms of
ethylene extracts of apple
plugs
Plugs in air, 12h
Plugs in N2, 6h
Plugs in N2, 6h
then in air, 6h

7. ? ? * * * * * * Methionine NH3+ CH3-S-CH2-CH2-CH-COO-
* *
Methionine
NH3+
CH3-S-CH2-CH2-CH-COO-
S-Adenosyl Methionine
* *
NH3+
CH3-S-CH2-CH2-CH-COO-
Ade +
1-aminocyclopropane-1
-carboxylic acid
CH CH2 CH
NH3+ COO- * ? ?
CH CH2 *
Ethylene

8. Ethylene biosynthesis
2-keto-4-methylthiobutyric acid (KMBA)
transamination
Pi+HOOCH O2
L-methionine
5’-methylethioribose-1-phosphate
(MTR-1-P)
Yang Cycle
ATP+H2O
Pi+PPi
ATP
ADP
S-adenosyl-methionine
(AdoMet)
5’-methylthioribose (MTR)
H2O
adenine
5’-methylthioadenosine
(MTA)
H2C NH3 C
H2C COO-
ACC
1/2 O2
HCN+H2O+CO2
C=C H
Ethylene

9. Abstract

13. « Knight of Roquetaillade », Ethylene Congress Agen, 1992
Don GRIERSON, DISCOVERY OF ACC OXIDASE
« Knight of Roquetaillade », Ethylene Congress Agen, 1992

17. DISCOVERY OF A METHOD FOR MEASURING EFE
IN A SOLUBLE FORM
Ververidis and John, 1991: Complete recovery in vitro of
ethylene forming enzyme activity. Phytochemistry, 30:

19. ACC SYNTHASE PURIFICATION FROM WOUNDED ZUCCHINI
Unpurified
serum
Purified serum
Silver staining
Pre-immune
1: Highly impure
extract
2: Highly pure extract

20. Ethylene biosynthesis
2-keto-4-methylthiobutyric acid (KMBA)
transamination
Pi+HOOCH O2
L-methionine
5’-methylethioribose-1-phosphate
(MTR-1-P)
Yang Cycle
ATP+H2O
Pi+PPi
ATP
ADP
S-adenosyl-methionine
(AdoMet)
5’-methylthioribose (MTR)
H2O
adenine
5’-methylthioadenosine
(MTA)
ACC synthase
H2C NH3 C
H2C COO-
ACC
GACC
MACC
1/2 O2
ACC oxidase
HCN+H2O+CO2
C=C H
Ethylene

21. Inhibitors of ACC synthase: Rhizobitoxine, AVG
EFFECTORS OF ACC SYNTHASE AND ACC OXIDASE
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

22. ACC SYNTHASE GENE FAMILY IN ARABIDOPSIS
At-ACS5 [induced by Li, cycloheximide(CH) and low
concentration of cytokinin(CK)]
At-ACS4 (induced by CH, IAA and wounding)
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 *
At-ACS1 (induced by cycloheximide)
At-ACS10 in response to light in plants over
expressing CONSTANS
At-ACS8 not yet
characterized
At-ACS2 in young leaves and flowers
At-ACS6 (induced by O3, Cu2+, IAA, CH, CN-, anaerobiosis, wounding, touching and ethylene)
At-ACS4 (induced by CH, IAA, anaerobisis
and wounding)
At-ACS7 (induced by CH)
At-ACS5 (basal
level stimulated
by Li and CK
At-ACS2 (induced by Li, CH, wounding)
At-ACS4 induced by CH, IAA, wounding)
At-ACS9 = eto1
Adult plant
Etiolated seedling

23. ACO AND ACS GENE EXPRESSION IN TOMATO
FLOWER
Le-ACS2 (stamens, mature and senescent anthers)
Le-ACO2
Le-ACS2 (senescent petals)
Le-ACO4
Le-ACO1, 3
Le-ACS3 (not expressed in fruit, present in tomato cell suspension)
Le-ACO3 (breaker stage)
Le-ACS4 induced by wounding
Le-ACO4
Le-ACS2 and 4 positiv. regul. by ethylene
Le-ACO1,2,3 and 4
induced by O3
Le-ACS1A (breaker stage) negativ. regul. by ethylene
Le-ACS6 (in MG fruit) negativ. regul. by ethylene
Le-ACS7 induced early by wounding
Le-ACO1 in senescent
or wounded leaves
Le-ACS3 induced by flooding
Le-ACS7 induced early by flooding

24. Regulation 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 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 to
ethylene.
Cantaloupe Induced by ethylene, wounding, NaCl, drought and
ripening (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 Squash Induced by wounding, induction blocked by ethylene
inhibitor, 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).