Transgenic Ornamental Crops - Transgenic Horticultural Crops: Challenges and Opportunities - page 63

of. low. molecular. weight,. volatile. organic. compounds. that. attracts. insect. and. ani-
mal.pollinators..Hundreds,.perhaps.thousands,.of.different.volatile.compounds.are.
emitted. from.lowers. in. varying.levels. and. mixtures. 41 . In.many. species,. including.
Antirrhinum ,. Petunia ,. and. Rosa ,. petals. are. the. primary. site. of. loral. scent. emis-
sion 42-44 .with.fragrance.compounds.emitted.from.both.the.adaxial.and.abaxial.petal.
epidermal.layers.of. Rosa .x. hybrida .'Anna'. 44 .Fragrance.is.a.dynamic.trait,.with.quan-
titative.and.qualitative.changes.occurring.during.lower.development,.in.response.to.
pollination,.through.day-night.cycles,.and.in.response.to.the.environment.(reviewed.
by.Clark.et.al. 45 ).
Petunia . x. hybrida . has. emerged. as. a. popular. model. system. for. characterizing.
loral.volatile.benzenoid/phenylpropanoid.synthesis.(Table.3.2).(reviewed.by.Clark.
et. al. 45 ).. The. loral. perfume. of. Petunia . cultivar. 'Mitchell'. is. dominated. by. ben-
zyl. alcohol,. benzaldehyde,. methylbenzoate,. benzylbenzoate,. phenylacetaldehyde,.
2-phenylethanol,. phenylethylacetate,. phenethylbenzoate,. isoeugenol,. and. eugenol,.

TABLE 3.2
Published Reports of Genetically Engineered Plants
with Modiied Floral Fragrance

Plant Genetic Modiication Effect on Floral Volatiles References

Petunia .x. hybrida 35S:: CbLIS Accumulation.of.nonvolatile.linalool.

conjugate

[153]

Petunia.CCD1.RNAi [33]

Reduced.β-ionone

35S:: SAAT No.effect [55]

Petunia. BSMT .RNAi Reduced.methylbenzoate [53]

Petunia. ODO1 .RNAi Reduced.volatile.benzenoids [47]

Petunia. PAAS .RNAi Reduced.phenylacetaldehyde [50]

Reduced.2-phenylethanol

Petunia. BPBT .RNAi Reduced.benzylbenzoate [51,52]

Reduced.phenethylbenzoate

35S:: RhAAT Higher.benzyl.acetate [154]

Higher.phenethyl.acetate

Petunia. CFAT .RNAi Reduced.isoeugenol [49]

35S:: LePAR Reduced.phenylacetaldehyde [54]

Higher.2-phenylethanol

35S:: AtPAP Higher.benzaldehyde [60]

Higher.phenylacetaldehyde
Higher.benzaldehyde.4-hydroxy
Higher.benzaldehyde.3,4-dimethoxy
Higher.vanillin

Dianthus caryophyllus 35S:: CbLIS Linalool.production [57]

35S::antisense F3H Higher.methyl.benzoate [58]

Eustoma grandilorum 35S:: CbBEAT No.effect [155]

Nicotiana tabacum 35S:: ClTER ,.

35S:: ClLIM ,.
35S:: ClPIN

Plants.with.all.three.genes.emit.
β-pinene,.limonene,.γ-terpinene,.
and.side.products

[153]