Flower Power

1
Flower Power

• Multi-billion dollar international industry
• 12 billion per year in the United States
• 1.5 billion per year in the United Kingdom
• Premium on new and innovative varieties
• Cut flower prices have remained constant
• New varieties can receive 7 times the normal price

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Alterable Flower Traits
plus many more . . .
3
Limitations on Normal Breeding and Selection

• Process is slow
• Limited by gene pool of species

4
Alterable Flower Traits
plus many more . . .
5
Genetic Engineering Strategies to Produce New
Flower Varieties

• Change gene expression levels or location
• Reduce or increase transcription levels
• Introduce new genes
• Mutate existing ones to modify activity

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Moondust
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Major Flower Pigments

• Carotenoids (Yellows)
• Flavonoids (Reds and Blues)

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Other Uses of Pigments

• Anti-inflammatory
• Anti-ulcer
• Wound healing
• Antioxidant
• 200 million per year for anthocyanin production
  from grapes in the United States
• Read about astaxanthin in Glick and Pasternack
  pp. 566-569

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Anthocyanins

• Major flower pigment in higher plants
• Flavonoid
• Expressed in epidermal cells of petals, leaves,
  and stems
• Accumulates in vacuoles

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Anthocyanin Color

• Red, pink, violet, and blue
• Dependent on
• Pigment concentration
• pH of vacuole
• Hydroxylation of anthocyanins

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Anthocyanin Biosynthesis
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Anthocyanin Biosynthesis
Brick Red
Red
Blue
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Anthocyanin Biosynthesis
CHS
p-Coumaroyl-CoA
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Petunias
CHS
4,2,4,6-Tetrahydrocychalcone
p-Coumaroyl-CoA
Naringenin
Dihydrokaempferol
F3,5H
F3,5H
Dihydroquercetin
DFR
DFR
Cyanidin-3-glucoside
Delphinidin-3-glucoside
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Petunias Maize Dfr
CHS
4,2,4,6-Tetrahydrocychalcone
p-Coumaroyl-CoA
Naringenin
Dihydrokaempferol
F3,5H
F3,5H
Dihydroquercetin
Maize DFR
DFR
DFR
Cyanidin-3-glucoside
Delphinidin-3-glucoside
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Antisense Suppression
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Antisense Suppression
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Antisense Suppression
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White Chrysanthemums
CHS
SHC
p-Coumaroyl-CoA
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Sense Suppression

• Goal Make purple petunias more purple
• Strategy Overexpress CHS by introducing CHS
  transgene using Agrobacterium binary vector
• Construct

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Results of Transformation
Napoli et al. The Plant Cell. 1990.
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Results are Heritable with Transgene
Napoli et al. The Plant Cell. 1990.
Napoli et al. The Plant Cell. 1990.
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RNAi Initiation
Waterhouse et al. Nature. 2001
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RNAi Propagation
Vaucheret et al. J, of Cell Science. 2001
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RNAi Propagation
Waterhouse et al. Nature. 2001
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RNAi Maintenance
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Use of RNAi

• Very difficult to make knockouts of genes in
  plants
• Many gene copies
• Homologous recombination not possible
• RNAi silences all copies of gene