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Uv radiation-and-molecular-effects

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  • 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
  • 3. 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 300 400 500 600 700 800 Wavelength (nm) Spectral irradiance (relative units) 900 1000 Plants Red & far red Blue UV-A UV-B
  • 4. Ultraviolet Penetration through the Stratospheric Ozone Layer UV-A 380-315nm UV-B 315-280nm UV-C <280nm O 3 layer 0% 100% Earth’s surface PAR 700nm – 380nm
  • 5. Photoperception to gene expression Photoperception Signal Transduction Gene Expression
  • 6. UV-B Photoreceptor UV-B Specific Photoreceptor Signal Transduction Non-Specific Via ROS Via DNA damage Changes to gene expression
  • 7. H 2 O 2 PR genes JA O 2 - PDF1.2 Ethylene SA Transcription factors Photosynthetic genes H 2 O 2 Chloroplast signal, electron transport/ photophosphorylation UV-B Peroxidase NADPH oxidase Receptor Signal Transduction Pathways ? NO Ca 2+ /CaM Phosphorylation NOS Chs
  • 8.  
  • 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
  • 10. Vineyard experiments
    • UVA+, UVB+ screen
    • UVA+, UVB- screen
    • UV- screen
    • No frame
    • No leaf removal, no frame
    UV+ UVA+ UV-
  • 11. UV-B Damage No UV-B Damage
  • 12. UV-absorbing compounds
  • 13.  
  • 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
  • 15. Amino Acid Composition Glutamine Proline Arginine Alanine Serine Glutamate Arginine Proline Glutamine Alanine Threonine Serine Increasing Amounts Chardonnay Sauvignon blanc
  • 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
  • 17. Amino acids
  • 18. Amino acids
  • 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. LOX-HPL pathway
  • 22. Phylogenetic analysis of grape LOXs and characterised LOXs from other plants 13-LOXs Type I 9-LOXs Type I Type II13-LOXs L O X 1 G m 1 L O X 1 G m 2 L O X 1 A h 1 L O X 1 P s 2 L O X 1 G m 6 L O X 1 G m 7 L O X 1 G m 3 L O X 1 P s 3 L O X 1 L c 1 L O X 1 G m 4 L O X 1 G m 5 L O X 1 C s 1 L O X 1 C s 2 L O X 1 S t 2 L O X L V v L O X 1 A t 2 L O X 1 S t 1 L O X 1 L e 1 L O X 1 N t 1 L O X 1 P r d 1 L O X 1 A t 1 L O X 1 C a 1 L O X M V v L O X B V v L O X C V v L O X 1 H v 1 L O X 1 Z m 3 L O X 1 O s 1 L O X 1 Z m 1 L O X 2 Z m 6 L O X D V v L O X 2 A t 2 L O X 2 A t 3 L O X 2 S t 2 L O X O V v L O X R V v L O X 2 A t 4 L O X P V v L O X 2 O s 1 L O X 2 Z m 1 L O X 2 H v 1 L O X 2 O s 2 L O X 2 A t 1 L O X 2 B n 2 L O X 2 S t 1 L O X 2 P o d 1 L O X 2 P o d 2 L O X J V v L O X K V v L O X A V v L O X E V v L O X F V v L O X G V v L O X H V v L O X I V v
  • 23. Proportional distribution of grape LOXs in different berry fractions Relative expression of four berry expressed LOXs SB berry expressed LOXs
  • 24. Relative gene expressions of berry expressed LOXs during development
  • 25. Relative gene expressions of berry expressed LOXs during upon wounding
  • 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.  
  • 28. pH effect on recombinant VvLOXA activity
  • 29. pH effect on recombinant VvLOXO activity
  • 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
  • 31. UV responses & wine quality
  • 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
  • 35.