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Uv radiation-and-molecular-effects
1. The Effects of Ultraviolet
Radiation and Canopy
Shading on Grape Berry
Biochemistry & Molecular
Biology
Professor Brian Jordan
Professor of Plant Biotechnology
Agriculture and Life Sciences Faculty
Lincoln University
2. Responses of Plants to Light
Light
Photosynthesis Sugars
other organic
compounds
Information
leaf growth
stem growth
germination, etc.
flowering
dormancy
plant habit, etc.
direction of
growth
Small amounts
of light
Daily duration
of light
Direction of
light
9. Role of UV/Light in Grape Development
and Wine Quality
• Effect on “ageing” of white wines in New Zealand
• Changes to polyphenolic compounds
• Changes to amino acids/protein content
• Impact on aroma/flavour (methoxypyrazines)
• Lipoxygenase as an example of molecular approach
14. Amino Acid Metabolism and Implications for
Wine Industry
UV
(and PAR)
NITROGEN
(Uptake and assimilation)
AMINO ACIDS
Methoxypyrazines:
amino acids as
precursors to
flavour and aroma
compounds Phenolics: amino
acids as
precursors –
implicated in
ageing and
bitterness in white
wine
Amino acid
composition and
implications for
fermentation
bouquet and
yeast assimilable
nitrogen
Glutathione:
implicated in the
prevention of
browning
process
Valine, isoleucine,
leucine
Phenylalanine,
tyrosine, tryptophan
All amino acids
except proline
Cysteine,
glutamate, glycine
16. Light regulation of nitrogen
metabolism
• Light regulates the conversion of
glutamate into glutamine in the chloroplast
• This involves the GOGAT pathway and
requires ATP
• This assimilation of nitrogen then provides
amino acids/amines to the fruit
Glutamate Glutamine
19. Major aroma chemicals
• 3-mercaptohexanol/3-
mercaptohexanal
acetate
– Tropical fruit and
Citrus aromas
• Methoxypyrazines
– Green/green-pepper
or capsicum aromas
20. Present Understanding:
Synthesis of Thiol Precursors
Lipids and
Fatty Acids
in Cell
Membranes
5/6
Carbon
Backbone
eg, s-3-
(hexan-1-ol)-
Glutathione
LOX
HPL
etc
Non
Volatile
s-cysteine
Conjugate
Precursor
Grape Metabolism through Berry Development and in
Response to the Environment
Changes
during Must
Fermentation
Release
of Aroma
Volatiles
Primarily
by Yeast
VERAISON
Hard
Solid
Berry
Soft
Berry at
Harvest
‘Membrane Turnover’
GSTs
21. COOH
OOH
13(S)-HPOT
CHO
(3Z)-hexenal
COOHOHC
(9Z)-12-oxododec-9-enoic acid
CHO
OH
COOH
OHC
COOH
OH
COOH
HOOC
OH
CHO
O(O)H
Traumatin
(9Z)-12-hydroxy-9-dodecenoic acid
Traumatic acid
(3Z)-hexen-1-ol
(2E)-hexenal
(2E)-4-hydro(pero)xy-2-hexenal
(2E)-hexen-1-ol
HPL
IF
ADH
ADH
ADH
IF
LOX?
9(S)-HPOT
COOH
HOO
HPL
COOHOHC
9-oxononanoic acid
CHO
(3Z,6Z)-nonadienal
CHO
OH
(2E,6Z)-nonadienal
(3Z,6Z)-nonadien-1-ol
IF
ADH
HOOC CH3
a-linolenic acid
S t o r a g e lip id s
B io lo g ic a l m e m b r a n e s
F r e e fa tt y a c id s
13-LOX9-LOX
9(S)-HPOT - (10E, 12Z, 15Z)-9-hydro(pero)xy-10,12,15-octadecatrienoic acid;
13(S)-HPOT - (9Z,11E,15Z)-13-hydro(pero)xy-9,11,15-octadecatrienoic acid;
HPL - hydroperoxide lyase;
LOX - lypoxygenase;
ADH - alcohol dehydrogenase;
IF - isomerization factor;
LOX-HPL pathway
22. 13-LOXs
Type I
9-LOXs
Type I
Type II13-
LOXs
LO X1 Gm 1
LO X1 G m 2
LO X1 Ah 1
LO X1 Ps 2
LOX 1 G m 6
LOX1 Gm 7
L OX1 G m 3
LO X1
Ps 3
LO
X1
Lc
1
LO
X
1
G
m
4
LOX1Gm5
LOX1
Cs1
LOX1Cs2
LOX1St2
LOXLVv
LOX1At2
LOX1St1
LOX1Le1
LOX1Nt1
LOX1Prd
1
LO
X1
A
t1
L
O
X
1
C
a
1
LO
XM
Vv
LOX B Vv
LO XC Vv
L OX 1 Hv 1
LOX 1 Zm 3
LO X1 O s 1
LO X1 Zm 1
LOX 2 Zm 6
LO XD Vv
L OX 2 At 2
LOX 2 A t 3
L O X2 St 2
LOXO
VvLOXR
Vv
LO
X2
At 4
LO
XP
V
v
L
O
X
2
O
s
1
LO
X2
Zm
1
LOX2
Hv
1
LOX2Os2
LOX2At1
LOX2Bn2
LOX2St1
LOX2Pod1
LOX2Pod2
LOXJVv
LOXK
VvLOXA
Vv
L OX E
Vv
LOX F Vv
LO XG Vv
LOX H V v
LOXI Vv
Phylogenetic analysis of grape LOXs and characterised
LOXs from other plants
23. Proportional distribution of grape LOXs in
different berry fractions
Relative expression of four berry
expressed LOXs
SB berry expressed LOXs
0%
20%
40%
60%
80%
100%
VvLOXA VvLOXC VvLOXD VvLOXO
Proportionaltranscriptabundance
Skin
Pulp
Seed
26. I – berries with obvious signs of infection, NI – berries closely located to the
infected, Control – healthy berries distantly located from the infected.
Relative LOX gene expressions in SB berries infected with
Botrytis
27. Vmax 16.0546 0.6008
Km 2.1092 0.3049
Vmax 7.5836 0.1551
Km 0.8196 0.0981
Vmax 6.6200
Km 0.5582
30. Methoxypyrazines
• Little is known about their
biosynthesis
– Thought to derive from amino
acid biosynthesis
• Accumulate up until veraison
• Degrade after veraison and
with exposure of grape
bunches to light
• At low concentrations (ng.L-1
)
contribute to green/green-
pepper aromas
32. +UV No leaf No No No UV
removal frame UV-B
UV responses & wine quality
33. Effects of UV and Leaf Removal on Wine
Quality
• Methoxypyrazine levels low in juice at harvest, but high early in grape
development: control of gene expression from amino acid precursors
• Amino acid composition different in juice in response to light environment
• Regulation of proline biosynthesis important for fermentation
• Flavonoids accumulate with UV exposure: role of transcription factors
• Lipoxygenase pathway: complex gene family and expression pattern
34. Acknowledgements
Grape Biotechnology and UV Research
• Jason Wargent, Lancaster University, UK
• Scott Gregan
• Stephen Stilwell
• Andriy Podolyan (Ph.D.)
• Jim Shinkle, Trinity University, USA
• Dr Rainer Hofmann
• Dr Chris Winefield
• Professor Brian Jordan (Programme Leader)
Support From:
• Foundation for Research, Science & Technology
• NZ Royal Society/MoRST COST-ACTION 858
• Marlborough Wine Research Centre, Auckland University
& Plant & Food Research
• New Zealand Wine Industry
• Lincoln University
