|
Plant Physiol, December 2001, Vol. 127, pp. 1383-1389
SCIENTIFIC CORRESPONDENCE
Floral Fragrance. New Inroads into an Old Commodity1
Alexander
Vainstein,*
Efraim
Lewinsohn,
Eran
Pichersky, and
David
Weiss
The Kennedy Leigh Centre for Horticultural Research and The Otto
Warburg Center for Biotechnology in Agriculture, Faculty of
Agricultural, Food and Environmental Quality Sciences, The Hebrew
University of Jerusalem, Rehovot 76100, Israel (A.V., D.W.); Newe
Ya'ar Research Center, ARO, Ramat Yishay 30095, Israel (E.L.); and
Department of Molecular, Cellular and Developmental Biology, University
of Michigan, Ann Arbor, Michigan 48109 (E.P.)
 |
INTRODUCTION |
The ability of flowering plants to
prosper throughout their long evolution has been strongly
dependent on the constant development of strategies to lure
pollinators. This has led to the creation of elaborate perianth forms,
splendid color patterns, and a broad spectrum of fragrances. Flower
morphogenesis and pigmentation have been intensively studied in the
last several decades, and today, the results of our deeper
understanding of the underlying pathways have already been harnessed
for crop improvement (Zuker et al., 1998 ). In contrast, knowledge of
the biochemistry of fragrance production and the mechanism regulating
its emission remains sketchy.
Flower scent is a composite character that is determined by a complex
mixture of low-molecular-weight volatile molecules. Due to the
invisibility of this character, to the shortcomings of humans' sense
of smell, and to the highly variable nature of the trait (in part
because of strong environmental influences), no simple, efficient, and
reliable methods to screen for genetic variation have been developed.
Moreover, to date, no convenient plant model systems that would enable
biochemical and forward and reverse genetic studies of flower scent are
available. For many years, the research into floral fragrance focused
on its chemical elucidation, coupled with chemical synthesis to produce the large quantities demanded by the perfume and food industries. Indeed, hundreds of structures are known (Knudsen et al., 1993) and
many are synthetically produced. Most fragrance compounds belong to
three major groups: phenylpropanoids (including benzenoids), fatty acid
derivatives, and terpenoids (Croteau et al., 2000). The
elucidation of their pathways with respect to the enzymes and genes
involved and the underlying molecular mechanisms controlling them has
just begun, with an Update on the topic having recently appeared in this journal (Dudareva and Pichersky, 2000).
Here, we review some of the methodological issues involved in the study
of floral scent and examine how the uniqueness and complexity of the
trait necessitate the integration of modern techniques with
non-conventional model systems. For example, several plant systems,
including flowers of Clarkia breweri, snapdragon (Antirrhinum majus), and rose (Rosa spp.), have
been chosen, not for their amenability to molecular studies, but mainly
for their fragrance characteristics and their amenability to chemical
and biochemical analyses (Fig. 1;
Pichersky et al., 1994; Dudareva et al., 2000). The use of diverse
plant systems in combination with modern metabolomic, genomic, and
proteomic approaches is expected to lead to a detailed understanding of
the underlying processes. Utilization of this knowledge to produce
fragrance compounds in transgenic plants and to improve the
often-lacking aroma characteristics of fruits, vegetables, and flowers
clearly has great biotechnological potential, and we review some
promising recent experimental attempts to engineer floral
scent.
View larger version (110K):
[in this window]
[in a new window]
|
Figure 1.
Headspace analysis of Arabidopsis (ecotype
Colombia) and rose (cv Fragrance Cloud) flowers. Headspace was
collected for 24 h (from a single rose flower and from
approximately 40 Arabidopsis flowers) into a Porapak Q cartridge
(Dudareva et al., 1998), and eluted with 1 mL of hexane containing 10 µg of ethyl myristate (EM) that served as an internal standard.
Samples were analyzed as described in Lewinsohn et al. (2001),
except that a Restek Rtx-5Sil MS (30 m × 0.25 mm) fused-silica
capillary column was used. The main components were identified by
comparing retention times and mass spectra with those of authentic
standards and complemented with computerized libraries. The major
volatiles identified in roses are 1: 3-hexen-1-ol acetate,
2: n-hexyl acetate, 3: 2-phenylethyl
alcohol, 4: citronellol, 5: 2-phenylethyl
acetate, 6: citronellyl acetate, 7: neryl
acetate, and 8: germacrene D. In Arabidopsis, only traces of
fatty acid degradation products and hydrocarbons were
identified.
|
|
| |
FLORAL SCENT AND POLLINATION |
Fragrance compounds play numerous important roles in the
interactions between plants and their surroundings, a major one being to attract pollinators, which are mostly, although by no means exclusively, insects (Dudareva and Pichersky, 2000). The unique combination of volatile molecules making the small and not-so-small differences in fragrance spectra among flowers of different species can
be distinguished by the olfactory receptors of insect antennae enabling
them to find and visit their flower(s) of choice (Pham-Delegue et al.,
1990; Raguso et al., 1996). However, little is currently known about
the innate ability of insects to detect specific volatiles or their
innate and learned responses (attraction, repulsion, or indifference)
to such compounds (Henning et al., 1992). This field of study should
see much more activity in coming years.
Although all floral organs can emit fragrance compounds, petals are the
main source of scent in most plants (Pichersky et al., 1994). Some
plants have developed highly specialized anatomical structures, termed
"scent glands," for fragrance production; in other plants, the
non-specialized floral epidermal cells are recruited for fragrance
production and emission (for review, see Dudareva and Pichersky, 2000).
In some cases, floral scent emission shows diurnal rhythms; flowers
that are pollinated at night often tend to have peak emissions at
night, whereas for day-pollinated flowers, the situation is reversed.
Whereas nocturnal emission of volatiles is controlled by an endogenous
circadian clock, daytime emission in most cases is controlled directly
by light (Jakobsen and Olsen, 1994). Nevertheless, circadian control of
fragrance production in day-emitting plants has been shown for rose
(Helsper et al., 1998) and snapdragon (Kolosova et al., 2001a).
Pollination by scent-guided insects is a critical step in the
successful production of food on the farm, and lack of efficient pollination can lead to low crop yields. For example, fruit orchards in
the United States are critically dependent on bee pollination, and the
major reduction in the number of bees that has occurred over the last
decade (due to disease) has caused a corresponding decrease in fruit
yield (Kraus and Page, 1995). Some plants that are introduced into a
new environment lacking suitable pollinators have very low pollination
rates from the start; for example, alfalfa plants grown for seed in the
southwestern United States have seed-set rates as low as 2% (Henning
et al., 1992).
Several commercial products have been developed based on bee pheromones
that are used to spray orchards to increase bee visitation rates, but
recent analysis has failed to demonstrate any significant increase in
fruit yield following their application (Ambrose et al., 1995). On the
other hand, it has been proposed, based on differences in floral
volatiles among alfalfa varieties and experiments with artificial
flowers, that selection for alfalfa plants emitting more linalool, a
monoterpene alcohol, will result in higher seed yield (Henning et al.,
1992).
| |
HEDONIC ATTRIBUTES OF FLORAL SCENT |
Although flower fragrance has evolved for the evolutionary success
of plants, mankind has long recognized its sensual pleasure. Man's
admiration of flower fragrance rapidly turned volatile substances into
a high-impact commercial commodity. Mainly synthetically produced, but
also natural, volatiles are heavily used in the perfume, cosmetics, air
freshener, laundry detergent, and the food and drink industries
(Burdock, 1995).
Humans, like insects, strongly associate scent with specific flowers,
e.g. rose, gardenia, and jasmine. Although the scent of certain flowers
can generally be described as pleasant or revolting the smell of roses
being a simile for pleasantness versus the smell of Hydrosme
rivieri flowers, which has been compared to rotten meat (Stransky
and Valterova, 1999)the pleasantness of other flowers to humans is
specific to the individual. All the same, the very same fragrance
compounds can be present in flowers that are perceived by humans as
having quite different scents. For example, the monoterpene geraniol, a
major volatile in rose flowers, is also emitted by the uniquely scented
jasmine flowers (Croteau and Karp, 1991); furthermore, this compound
contributes to the scents of more than 250 different plant species
(Knudsen et al., 1993). Not only the composition of the fragrance
pallette but also the overall level of the volatiles determine a
scent's appeal to humans (Burdock, 1995). When grown outdoors,
Narcissus tazetta is recognized by its pleasant scent,
whereas the smell emitted by a bouquet of narcissuses,
especially in a confined space where volatiles accumulate to
high levels, becomes highly unpleasant. The concentration of a
particular compound in a mixture of volatiles has dramatic effects; for
example, a high level of indole has a very unpleasant odor, reminiscent
of fecal matter, but at a high dilutions, it is perceived as floral and pleasant.
Since flower scent has almost never been a target trait in commercial
breeding programs, which have traditionally concentrated on color,
longevity, form, etc., it is lacking in most modern varieties (Zuker et
al., 1998). For example, carnation (Dianthus caryophyllus)
flowers traditionally possessed a spicy/clove odor, which is determined
by eugenol. In some old varieties, eugenol contributes up to 85% of
total headspace volatiles. Most modern varieties, however, produce low
levels of eugenol and lack the characteristic fragrance (Clery et al.,
1999). Furthermore, not only may fragrance not have been selected
for, it may actually have been unintentionally selected
against, for example, due to the negative correlation between longevity
and fragrance. One mechanistic explanation for such a correlation may
have to do with the observation that the common floral scent compounds
jasmonic acid and methyl jasmonate are known to promote flower
senescence (Porat et al., 1993).
| |
FRAGRANCE EVALUATION: OLFACTORY SENSING VERSUS ANALYTICAL
TOOLS |
For a molecule to impart an odor sensation in humans, it must have
at least a certain degree of volatility to reach the olfactory epithelium located in the upper nasal cavity (Thomson, 1987). The human
olfactory system can recognize and discriminate between a vast variety,
on the order of thousands, of odorous molecules, due to the expression
of an extremely large gene family of odorant receptors. A single
olfactory neuron is believed to express a single odor receptor gene.
These receptors, localized to the olfactory neuron cell surface,
activate G-proteins and initiate a cAMP-mediated signal transduction
cascade, leading ultimately to odor sensing (Zhao and Firestein, 1999).
The organoleptic perception threshold depends on the volatile molecule,
and for some it is extremely low. Several organic molecules can even be
detected at a concentration of less than 10 8
M (Thomson, 1987). Hence, a subject's assessment of the
influence of a specific fragrance compound in an aroma mixture on the
overall sensation imparted by the scent does not necessarily reflect
its absolute concentration in the scent, but depends on its perception threshold.
For some volatiles, the human nose, like the olfactory organs in
insects, can be more sensitive than analytical tools in the laboratory
(Hinterholzer and Schieberle, 1998). Nevertheless, attempts to
characterize floral scent using humans as the "sensory equipment"
face numerous difficulties, including the lack of specific words to
characterize specific scents. In contrast to the general acceptance of,
for example, words describing colors, scents are often described in the
literature as "woody," "fruity," "musty," etc. (Burdock,
1995); there is no clear agreement among scientists as to what physical
attributes such terms actually correspond to. Thus, for an objective
evaluation of floral scent, some type of instrumentation is clearly needed.
Mass spectroscopy (MS) detectors coupled to gas-chromatography
techniques have enabled chemical analyses of flower scent components with high levels of sensitivity (Van Beek, 1999). Sampling methods, however, have been somewhat more problematic. Since fragrance compounds
are often emitted to the atmosphere, several methodologies to trap
floral volatiles have been designed. They include headspace analysis
and solid-phase extraction (Van Beek, 1999). These methods, used to
collect and sample the volatiles emitted from flowers, are often
qualitative in nature. This is because the methods used to trap the
volatiles are often inefficient; thus, an indeterminate amount of
material is not captured and escapes into the atmosphere, and due to
the different physical properties of each compound in the scent, the
proportion that escapes is different for each (Van Beek, 1999). To
analyze volatiles accumulating in tissue, extraction using organic
solvents or supercritical fluid CO2, as well as
steam and hydrodistillation procedures, are often performed (Van Beek,
1999). It is easy to quantify the different volatiles utilizing these
latter methodologies, but they can also be problematic, since heat and
adverse pH conditions may modify the original volatile composition
present in the flowers. For example, phenethyl alcohol is largely lost
during the distillation of rose essential oil (Weiss, 1997). Lavender
flowers accumulate linalyl acetate, which is partially hydrolyzed
during distillation processes (Morin and Richard, 1985). Moreover,
these techniques are designed to analyze the volatiles that accumulate
in the flower tissues, and not necessarily those emitted by the
flowers, which constitute their scent.
It is thus apparent that the evaluation of fragrance is a highly
complex matter and the linkage between olfactory sensing and chemical
analyses is one of the main topics to be addressed. The first step in
this direction was made by the development of an electronic nose that
has three elements: an odor-sensor array, a data preprocessor, and a
pattern-recognition engine (Craven et al., 1996). The signals that form
the output of a sensor array do not provide a spectrum of scent
constituents but rather information relating to the quality of the
compounds, which are characterized by a particular sensor response
signature. Thus, whereas gas chromatography-MS can detect individual
volatiles quantitatively and qualitatively, the electronic nose can
only make a cumulative analysis. Recently, a promising simple
colorimetric sensor array for odor visualization was described (Rakow
and Suslick, 2000). This novel "smell-seeing" device utilizes the
color change induced in an array of metalloporphyrin dyes upon binding
of volatiles.
| |
IMPACT OF GENOMICS ON FLORAL SCENT RESEARCH |
The number of different flower volatiles is very large (Knudsen et
al., 1993) but, surprisingly, these compounds are biosynthesized by a
relatively small number of often overlapping metabolic pathways (Croteau and Karp, 1991; Croteau et al., 2000). In general, most plant
volatiles are derived from three main classes of compoundsterpenoids, phenylpropanoids/benzenoids, and fatty acid derivativeswhich are
often greatly modified (oxidized, esterified, methylated, etc.). Mono-
and sesquiterpenes belong to the terpenoids, the largest group (more
than 20,000) of natural products known (Croteau et al., 2000). These
terpenes are synthesized from isopentenyl diphosphate by different
mono- and sesquiterpene synthases (Trapp and Croteau, 2001).
Phenylpropanoids, including benzenoids, represent another biochemical
class of floral fragrance compounds, which derive from
L-Phe through the action of the pivotal enzyme
Phe ammonia lyase. The complete biosynthetic pathway to these
volatile compounds has not yet been characterized, but hydroxylation,
acetylation, and methylation reactions are involved (Croteau and
Karp, 1991). Other fragrance components, such as short-chain alcohols
and aldehydes, are formed by metabolic conversion or degradation of
phospholipids and fatty acids through the concerted action of
lipoxygenases, hydroperoxide lyases, isomerases, and dehydrogenases
(Croteau and Karp, 1991).
Clarkia breweri linalool synthase (LIS), which catalyzes the
formation of the acyclic alcohol monoterpene linalool, was the first
floral enzyme responsible for scent to be isolated and characterized (Pichersky et al., 1994), although several other enzymes responsible for the synthesis of volatiles from vegetative tissues had previously been (Alonso et al., 1992; Lewinsohn et al., 1992). The LIS protein was
purified to homogeneity from thousands of stigmata, and its cDNA was
cloned (Dudareva et al., 1996). Since that work, several other floral
genes involved in fragrance production have been isolated and
characterized in a similar way (Dudareva et al., 2000; Dudareva and
Pichersky, 2000). These include
S-adenosyl-L-Met:(iso) eugenol
O-methyltransferase (IEMT),
acetyl-CoA:benzylalcohol acetyltransferase (BEAT),
S-adenosyl-L-Met:salicylic acid carboxyl
methyltransferase (SAMT), and
S-adenosyl-L-Met:benzoic acid carboxyl
methyltransferase (BAMT). IEMT catalyzes the transfer of a
methyl group to eugenol and isoeugenol; BEAT catalyzes the production
of the ester benzylacetate from benzylalcohol and acetyl-CoA; SAMT
catalyzes the production of methylsalicylate from salicylic acid and
SAM; and BAMT catalyzes the production of methylbenzoate by
transferring the methyl group of SAM to benzoic acid. All of these
genes were isolated from C. breweri, except for
BAMT, which was cloned from flowers of snapdragon, in which
methylbenzoate is one of the major fragrance compounds (Dudareva et
al., 2000). In situ hybridization and immunolocalization studies
performed with LIS, IEMT, and BAMT
have revealed specific expression of these genes in the epidermal cells
of C. breweri and snapdragon flowers (Dudareva and
Pichersky, 2000; Kolosova et al., 2001b); providing evidence that at
least the volatile products of these enzymes are generated at the site
of emission, thus allowing their direct access to the surroundings.
All the aforementioned enzymes are members of gene families that are
found in the genomes of other species as well. For example, SAMT and
BAMT were found to define a new type of methyltransferase and the
Arabidopsis genome has close to 20 genes in this family (Dudareva and
Pichersky, 2000). The biochemical identification of the function of
SAMT in C. breweri has facilitated the characterization of
the Arabidopsis genes, and it was recently shown that one of them,
JMT, encodes the enzyme that catalyzes the formation
of methyljasmonate in vegetative tissues (Seo et al., 2001). The JMT
ortholog in Brassica campestris is expressed in floral
nectaries (Seo et al., 2000). Likewise, BEAT from C. breweri
is part of a new class of acyltransferases, the BAHD family
(St-Pierre and De Luca, 2000), which is widely distributed throughout
the plant kingdom, and some of the proteins in this family catalyze the formation of volatile esters (Dudareva et al., 1998; Aharoni et al.,
2000). The terpene synthase family, to which LIS belongs, is also a
rich source of enzymes for floral volatiles. Finally, IEMT is also part
of a large family, the O-methyl-transferases, and
several of these enzymes catalyze the formation of volatiles (Wang et
al., 1997). Overall, the data that have accumulated to date reveal that
mutations that create small changes in protein sequences can lead to
new enzymes that catalyze the formation of different fragrance
compounds. It should thus be emphasized that the examination of various
plant systems that contain such variant enzymes, which on superficial
examination (sequence comparisons but not enzymatic assays) seem to be
"the same" enzyme, can be extremely useful for gene discovery.
All the aforementioned floral scent genes, with the exception of
JMT, were isolated via classical biochemical approaches. To
date, no forward genetics approaches have been harnessed for the
characterization of fragrance genes, mainly due to the lack of an
efficient system for the identification of fragrance mutants. The novel
technologies of genomics, in contrast, allow quick access to plants
with poor genetic characterization, enabling the choice of a model
plant system based on the trait of interest (e.g. roses with copious
scent emission compared with the scent-poor Arabidopsis; Fig. 1) rather
than being limited to established model systems (Fiehn et al.,
2000). Indeed, several groups have recently used the high-throughput
technologies to identify new fragrance genes in fruits and vegetative
tissues (Aharoni et al., 2000; Lange et al., 2000; Gang et al., 2001).
Aharoni et al. (2000) were the first to combine expressed sequence tag
(EST) database mining with metabolic profiling and microarray
expression analyses to identify an aroma-related gene, alcohol
acyltransferase, responsible for the production of volatile esters in
strawberry fruit.
Research into floral scent genes using high-throughput tools has
recently been initiated in C. breweri
(https://sativa.biology.lsa.umich.edu/blast/blast.html), snapdragon (N. Dudareva, Purdue University, IN, personal communication), and rose
(http://agri3.huji.ac.il/~petals). These projects combine detailed
fragrance analyses with the creation of petal EST databases. Integration of rose microarray expression analyses with database mining, has led to the identification of several novel genes with putative functions in floral fragrance production
(http://agri3.huji.ac.il/~petals). The availability of an established
E. coli expression system, allowing rapid functional
analyses of fragrance genes (Dudareva et al., 1998), is expected to
lead to smooth advances in high-throughput identification of novel
scent genes. Indeed, several such genes from roses and C. breweri, including terpene synthases, acetyltransferases, and
methyltransferases have already been functionally characterized at the
protein level and shown to catalyze the formation of floral scent
components (http://agri3.huji.ac.il/~petals).
| |
MANIPULATION OF FLOWER FRAGRANCE |
The manipulation of fruit aroma and flower scent would obviously
have a great economic impact. Ornamental crops, a highly important
economic commodity (Jensen and Malter, 1995) with a world market value of over $30 billion, naturally represent the main
target for the genetic manipulation of flower fragrance level/spectrum. The lack of distinctive scent in many modern floricultural varieties, cut flowers in particular, further emphasizes the importance of ornamentals as a target (Zuker et al., 1998). Food crops can also be
considered an important target, in that the manipulation of floral
scent could improve seed set. Both crop types could also benefit from
metabolic engineering of fragrance for increased protection against
pathogens and pests (Dudareva and Pichersky, 2000).
However, the genetic engineering of ornamentals is currently lagging
far behind that of main food crops. The main reason is the lack of
efficient transformation systems for ornamental species; even when such
procedures are available, they are generally not suited to elite
varieties (Zuker et al., 1998). Although ornamentals are of high
economic importance, each crop represents only a small segment of a
market that consists of hundreds of varieties representing many
different species. Hence, the limited economic value of each ornamental
crop has prevented the massive investments, such as those spent on food
crops, needed to advance ornamentals into the molecular breeding era.
The high cost of registering transgenic crops is also a significant
constraint in ornamentals. Nevertheless, intensive research into the
micropropagation of ornamentals has led to the development of numerous
regeneration procedures that can be adapted to most gene-transfer
systems. As a result, the transformation of several major ornamentals,
e.g. rose, carnation, and chrysanthemum has been reported in the last
several years (Bajaj, 2001).
Two alternative approaches can be used to genetically engineer flower
fragrance. One is based on the introduction of foreign genes encoding
enzymes with activities that are missing in the target plant; these
allow new branching of existing pathways or the generation of a novel
one. The introduction of novel genes or the enhancement of existing
genes' activities may not, in itself, be sufficient to modulate flower
scent. A lack of substrate availability is one of the main limitations
in volatile production. For example, it was recently shown that the
level of methyl benzoate produced by snapdragon flowers is limited by
the level of its precursor, benzoic acid (Dudareva et al., 2000). It
may be possible to overcome the substrate shortage by enhancing the
activity/level of upstream enzymes (Sandmann, 2001).
The second approach is based on modulating (down- or up-regulating) the
expression of a native gene(s). Via this route, one can increase the
production of the volatile through up-regulation of a gene in the
pathway, or alternatively block the production of an undesirable
volatile. Inhibition of the native genes' activities can also enable
diversion of metabolic flow, leading to compositional modification of
the fragrance spectrum. This route was recently demonstrated in
carnation, in which blocking the anthocyanin biosynthetic pathway led
to increased methyl benzoate production and flower scent (Zuker et al.,
2001). Since both anthocyanins and methyl benzoate originate from the
same phenylpropanoid pathway, it was suggested that the flower's
enhanced scent production was due to diversion of metabolic flow toward
benzoic acid, which is the precursor of methyl benzoate. Note that the
redirection of metabolic flow may have a deleterious effect on the
plant as a result of depletion in available levels of the general
precursors necessary for normal plant development. The use of currently
available flower-specific promoters or of those yet to be isolated from
floral fragrance-related genes may be necessary to allow expression of
the transgene in an adequate spatial/temporal manner.
Whereas in the last decade several groups have reported the genetic
manipulation of plant volatile composition (Lewinsohn et al., 2001),
attempted metabolic engineering for fragrance production in flowers was
reported for the first time this year. These studies used the C. breweri LIS gene with the aim of generating the production of
linalool in plants lacking this monoterpene. However, introduction of
cauliflower mosaic virus 35S::LIS into petunia did
not result in linalool emission; instead, the non-volatile linalool
glycoside accumulated in the transgenic plants (Lucker et al., 2001),
which can happen naturally in other flowers (Watanabe et al., 1993). Introduction of a similar LIS construct into carnation, on
the other hand, led to the emission of linalool from petals as well as
from leaves (Lavy, 2001). Interestingly, transgenic carnation petals
also emitted the linalool derivatives cis- and trans-linalool oxide.
Although linalool and its derivatives represented almost 10% of the
total volatiles emitted by the petals, no olfactorily detectable change
in flower scent was observed by human subjects (Lavy, 2001). Note,
however, that no experiments with these transgenic plants and insect
pollinators have as yet been carried out. These two studies exemplify
additional problems that can be encountered in the genetic engineering
of flower fragrance: modification of the fragrance compound into a
non-volatile form, e.g. glycosylation; masking by other volatiles; or
the emitted amount being insufficient for olfactory detection by humans.
Metabolic engineering of odor in general and flower fragrance in
particular is still in its infancy. The rapid development of analytical
tools for metabolite profiling (e.g. http://www.phenomenome.com), allowing the simultaneous identification of thousands of compounds, together with ever-increasing genomic and EST databases, should be
highly instrumental in deciphering the molecular nature of pathways
leading to fragrance production. Using advanced metabolomics coupled
with microarray techniques, it should be possible to screen for the
genetic variation in fragrance production/emission with the aim of
finding not only genes coding for new fragrance biosynthetic enzymes
but also those regulating these pathways. Application of these
high-throughput analyses to an array of plant species, including
currently used model systems, should allow characterization of the
unique genetic variability created in nature. Furthermore, the
integration of proteomic tools into such studies, for example to design
enzymes/substrates, opens up almost unlimited possibilities for the
generation or manipulation of fragrance compounds.
| |
ACKNOWLEDGMENT |
We are grateful to Moshe Shalit for providing the data used in
Figure 1.
| |
FOOTNOTES |
Received August 9, 2001; accepted August 29, 2001.
1
This work was supported by the Ministry of
Science, Culture and Sports (Petal Genomics, grant no. 1410-2-00 to
A.V., E.L., and D.W.), by a BARD scholarship (to E.P.), and by the
National Science Foundation (grant no. MCB-99744636 to E.P.).
*
Corresponding author; e-mail vain{at}agri.huji.ac.il; fax
972-8-9468-263.
www.plantphysiol.org/cgi/doi/10.1104/pp.010706.
| |
LITERATURE CITED |
-
Aharoni A, Keizer LCP, Bouwmeester HJ, Sun ZK, Alvarez-Huerta M, Verhoeven HA, Blaas J, van Houwelingen AMML, De Vos RCH, van der Voet H
(2000)
Plant Cell
12: 647-661[Abstract/Free Full Text]
-
Alonso WR, Rajaoranivony JIM, Gershenzon J, Croteau R
(1992)
J Biol Chem
267: 7582-7587[Abstract/Free Full Text]
-
Ambrose JT, Schultheis JR, Bambara SB, Mangum W
(1995)
Am Bee J
135: 267-272
-
Bajaj YPS
(2001)
Biotechnology in Agriculture and Forestry, Vol. 48. Springer-Verlag, Berlin
-
Burdock GA
(1995)
Fenaroli's Handbook of Flavor Ingredients, Ed 3. CRC Press, Boca Raton, FL
-
Clery RA, Owen NE, Chambers SF
(1999)
J Essent Oil Res
11: 355-359
-
Craven MA, Gardner JW, Bartlett PN
(1996)
Trends Anal Chem
15: 486-493[CrossRef]
-
Croteau R, Karp F
(1991)
Perfume: Art, Science and Technology. Elsevier Applied Sciences, New York, pp 101-126
-
Croteau R, Kutchan TM, Lewis NG
(2000)
Biochemistry and Molecular Biology of Plants. American Society of Plant Physiologists, Rockville, MD, pp 1250-1318
-
Dudareva N, Cseke L, Blanc VM, Pichersky E
(1996)
Plant Cell
8: 1137-1148[Abstract]
-
Dudareva N, D'Auria JC, Nam KH, Raguso RA, Pichersky E
(1998)
Plant J
14: 297-304[CrossRef][ISI][Medline]
-
Dudareva N, Murfitt LM, Mann CJ, Gorenstein N, Kolosova N, Kish CM, Bonham C, Wood K
(2000)
Plant Cell
12: 949-961[Abstract/Free Full Text]
-
Dudareva N, Pichersky E
(2000)
Plant Physiol
122: 627-633[Free Full Text]
-
Fiehn O, Kopka J, Dormann P, Altmann T, Trethewey RN, Willmitzer L
(2000)
Nat Biotech
18: 1157-1161[CrossRef][ISI][Medline]
-
Gang D, Wang J, Dudareva N, Hee Nam K, Simon JE, Lewinsohn E, Pichersky E
(2001)
Plant Physiol
125: 539-555[Abstract/Free Full Text]
-
Helsper JPF, Davies JA, Bouwmeester HJ, Krol AF, van Kampen MH
(1998)
Planta
207: 88-95[CrossRef][ISI]
-
Henning JA, Peng YS, Montague MA, Teuber LR
(1992)
J Econ Entomol
85: 233-239[ISI]
-
Hinterholzer A, Schieberle P
(1998)
Flavour Fragr J
13: 49-55
-
Jakobsen HB, Olsen CE
(1994)
Planta
192: 365-371
-
Jensen MH, Malter AJ
(1995)
World Bank Tech Paper
253: 144-146
-
Knudsen JT, Tollesten L, Bergstrom GL
(1993)
Phytochemistry
33: 252-280[CrossRef]
-
Kolosova N, Gorenstein N, Kish CM, Dudareva N
(2001a)
Plant Cell
13: 2333-2347[Abstract/Free Full Text]
-
Kolosova N, Sherman D, Karlson D, Dudareva N
(2001b)
Plant Physiol
126: 956-964[Abstract/Free Full Text]
-
Kraus B, Page RE
(1995)
Environ Entomol
24: 1473-1480
-
Lange BM, Wildung MR, Stauber EJ, Sanchez C, Pouchnik D, Croteau R
(2000)
Proc Natl Acad Sci USA
97: 2934-2939[Abstract/Free Full Text]
-
Lavy M
(2001)
MSc Thesis. The Hebrew University of Jerusalem, Jerusalem, Israel
-
Lewinsohn E, Gijzen M, Croteau RB
(1992)
Regulation of Isopentenoid Metabolism. ACS Symposium Series 497, Washington, DC, pp 8-17
-
Lewinsohn E, Schalechet F, Wilkinson J, Matsui K, Tadmor K, Nam KH, Amar O, Lastochkin E, Larkov O, Ravid U
(2001)
Plant Physiol
127: 1256-1265[Abstract/Free Full Text]
-
Lucker J, Bowmeester J, Schwab W, Blaas J, van der Plas LHW, Verhoeven HA
(2001)
Plant J
27: 315-324[CrossRef][ISI][Medline]
-
Morin P, Richard H
(1985)
Dev Food Sci
10: 563-576
-
Pham-Delegue MH, Etievant P, Guichard E, Marilleau R, Douault P, Chauffaille J, Masson C
(1990)
J Chem Ecol
16: 3053-3065
-
Pichersky E, Raguso RA, Lewinsohn E, Croteau R
(1994)
Plant Physiol
106: 1533-1540[Abstract]
-
Porat R, Borochov A, Halevy AH
(1993)
Plant Growth Reg
13: 297-301
-
Raguso RA, Light DM, Pichersky E
(1996)
J Chem Ecol
22: 1735-1766[CrossRef][ISI]
-
Rakow NA, Suslick KS
(2000)
Nature
406: 710-713[CrossRef][Medline]
-
Sandmann G
(2001)
Trends Plant Sci
6: 14-17[CrossRef][ISI][Medline]
-
Seo HS, Song JT, Cheong JJ, Lee YH, Lee YW, Hwang I, Lee JS, Choi YD
(2001)
Proc Natl Acad Sci USA
98: 4788-4793[Abstract/Free Full Text]
-
Seo HS, Song SI, Lee JS, Do Choi Y
(2000)
Plant Mol Biol
42: 647-655[CrossRef][Medline]
-
St-Pierre B, De Luca V
(2000)
Evolution of Metabolic Pathways. Pergamon Press, Amsterdam, pp 249-284
-
Stransky K, Valterova I
(1999)
Phytochemistry
52: 1387-1390[CrossRef]
-
Thomson DMH
(1987)
Developments in Food Flavours. Elsevier, London, pp 1-216
-
Trapp SC, Croteau RB
(2001)
Genetics
158: 811-832[Abstract/Free Full Text]
-
Van Beek TA
(1999)
Chemicals from Plants. Perspectives on Plant Secondary Products. Imperial College Press, London, pp 91-186
-
Wang J, Dudareva N, Bhakta S, Raguso RA, Pichersky E
(1997)
Plant Physiol
114: 213-221[Abstract]
-
Watanabe N, Watanabe S, Nakajima R, Moon JH, Shimokihara K, Inagaki J, Etoh H, Asai T, Skata R, Ina K
(1993)
Biosci Biotech Biochem
57: 1101-1106
-
Weiss EA
(1997)
Essential Oil Crops. CAB International Wallingford, Oxon, UK
-
Zhao H, Firestein S
(1999)
Cell Mol Life Sci
56: 647-659[Medline]
-
Zuker A, Tzfira T, Ben-Meir H, Ovadis M, Shklarman E, Itzhaki
H, Forkmann G, Martens S, Neta-Sharir I, Weiss D, Vainstein A
(2001) Mol Breed (in press)
-
Zuker A, Tzfira T, Vainstein A
(1998)
Biotech Adv
16: 33-79
© 2001 American Society of Plant Physiologists
This article has been cited by other articles:
|
|
|
|
 
B. Spitzer, M. M. B. Zvi, M. Ovadis, E. Marhevka, O. Barkai, O. Edelbaum, I. Marton, T. Masci, M. Alon, S. Morin, et al.
Reverse Genetics of Floral Scent: Application of Tobacco Rattle Virus-Based Gene Silencing in Petunia
Plant Physiology,
December 1, 2007;
145(4):
1241 - 1250.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Wu, N. Watanabe, S. Mita, H. Dohra, Y. Ueda, M. Shibuya, and Y. Ebizuka
The Key Role of Phloroglucinol O-Methyltransferase in the Biosynthesis of Rosa chinensis Volatile 1,3,5-Trimethoxybenzene
Plant Physiology,
May 1, 2004;
135(1):
95 - 102.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Lucker, W. Schwab, B. van Hautum, J. Blaas, L. H. W. van der Plas, H. J. Bouwmeester, and H. A. Verhoeven
Increased and Altered Fragrance of Tobacco Plants after Metabolic Engineering Using Three Monoterpene Synthases from Lemon
Plant Physiology,
January 1, 2004;
134(1):
510 - 519.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Aharoni, A. P. Giri, S. Deuerlein, F. Griepink, W.-J. de Kogel, F. W. A. Verstappen, H. A. Verhoeven, M. A. Jongsma, W. Schwab, and H. J. Bouwmeester
Terpenoid Metabolism in Wild-Type and Transgenic Arabidopsis Plants
PLANT CELL,
December 1, 2003;
15(12):
2866 - 2884.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
I. Guterman, M. Shalit, N. Menda, D. Piestun, M. Dafny-Yelin, G. Shalev, E. Bar, O. Davydov, M. Ovadis, M. Emanuel, et al.
Rose Scent: Genomics Approach to Discovering Novel Floral Fragrance-Related Genes
PLANT CELL,
October 1, 2002;
14(10):
2325 - 2338.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
N. Lavid, J. Wang, M. Shalit, I. Guterman, E. Bar, T. Beuerle, N. Menda, S. Shafir, D. Zamir, Z. Adam, et al.
O-Methyltransferases Involved in the Biosynthesis of Volatile Phenolic Derivatives in Rose Petals
Plant Physiology,
August 1, 2002;
129(4):
1899 - 1907.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
TOP
INTRODUCTION
FLORAL SCENT AND POLLINATION