The publication in of suit one's taste

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					                                                                  melissa fiTzgeRald (right) and
                                                                  Teodie atienza analyze rice-grain                                             varieties. However, science has not         The following people generously           the key compounds that differentiate
                                                                  quality.                                                                      yet discovered what determines the          provided the rice that was used           the different types of aromatic rice,
                                                                                                                                                difference in taste between jasmine         in the meTa-PhoR project                  determine how many different types
                                                                                                                                                and basmati, let alone geographic                                                     of aromatic signatures there are, and
                                                                                                                                                                                            Supanee Jongee, Thailand
                                                                                                                                                and seasonal effects on the taste.                                                    develop a library of compounds to
                                                                                                                                                                                            Rauf Ahmed, Pakistan
                                                                                                                                                Presumably, jasmine and basmati rice        Sanjukta Das, India
                                                                                                                                                                                                                                      measure in the development of new
                                                                                                                                                have unique chemical signatures, and        Chanthakhone Boualaphan, Laos             aromatic varieties. This knowledge
                                                                                                                                                metabolomics should be the conduit          Asafaliza Ramil, Malaysia                 will put scientists in position to not
                                                                                                                                                to knowing and understanding those          Dewi Indrasari, Indonesia                 only understand the fundamental
                                                                                                                                                signatures. In this way, we hope to         Russell Reinke, Australia                 biochemical basis of aroma in rice but
                                                                                                                                                close the gap between the genes and         Fatemeh Habibi, Iran                      also to formulate targeted strategies
                                                                                                                                                the suite of compounds that interact        Nguyen Thi Lang, Vietnam                  for improving such traits of quality.
                                                                                                                                                to make what we detect as taste.                                                           The metabolomic profilers
                                                                                                                                                      Rice researchers have not                                                       plan to shine their torches at a joint
                                                                                                                                                yet succeeded in developing new           a database of soluble and volatile          META-PHOR–INQR meeting in
                                                                                                                                                varieties with higher yield while         plant metabolites (see www.meta-            Laos in May 2008. They will report
                                                                                                                                                still maintaining aromatic quality. for more information).              on their answers to the questions
                                                                                                                                                Examples of this can be found all              The International Network for          raised in this article and show
                                                                                                                                                over Asia. Take the highly prized,        Quality Rice (INQR) has provided a          their colleagues from national and
                                                                                                                                                traditional Thai jasmine variety,         platform for national rice research         international research organizations
                                                                                                                                                Khao Dawk Mali 105 (KDML105).             organizations interested in aroma to        some of the compounds and reactions
                                                                                                                                                The aroma of KDML105 is renowned          collaborate with the META-PHOR              that lie in that dark space between
                                                                                                                                                around the world, and many                project. Network members from               the genotype and phenotype of
                                                                                                                                                Southeast Asian rice breeders have        Thailand, Laos, Vietnam, Malaysia,          these aromatic rice varieties.

Illuminating the gap
                                                                                                                                                used the variety in breeding programs     the Philippines, Myanmar, Indonesia,
                                                                                                                       JoSe raYMond Panaligan
                                                                                                                                                that aim to obtain higher-yielding or     Australia, Pakistan, India, and             Dr. Fitzgerald is the head of IRRI’s Grain
                                                                                                                                                disease-resistant forms of the rice.      Iran have supplied a total of 32            Quality, Nutrition, and Postharvest Center
                                                                                                                                                      In one case, genes for resistance   of their highest-quality aromatic           and chair of the International Network for
                                                                                                                                                to the devastating blast fungus were      rice varieties to the META-PHOR             Quality Rice. Robert Hall is coordinator of
by Melissa Fitzgerald and Robert Hall                                                                                                           incorporated into KDML105 through         scientists. Of the 32 varieties, 21 are     the META-PHOR project and deputy business
                                                                                                                                                traditional breeding. In three studies,   traditional, five have fragrance from       unit manager, Bioscience, at Plant Research
                                                                                                                                                the blast-resistant form of KDML105       KDML105, and six carry fragrance            International, Wageningen, The Netherlands.
The new science of metabolomics is shining a light into the dark space between a rice plant’s                                                   had less than half of the key aromatic    from other traditional varieties.
                                                                                                                                                compound, 2-acetyl-1-pyrroline                 This initiative is giving scientists   META-PHOR is an international
genes and the resultant qualities we appreciate when we eat rice                                                                                (2AP), contained in KDML105 itself.       a real chance to do four key things:        project funded by the European Union
                                                                                                                                                      In another study at IRRI, a         determine the difference between            in its 6th framework programme

                                                                                                                                                number of varieties developed from        jasmine and basmati rice, identify          (FOOD-CT_2006-036220).
        he publication in 2005 of          protein, connect a glucose molecule                of rice quality, an obvious application           crosses with KDML105, and that had
        the rice genome—the sum            to a growing chain of starch, or join              for metabolomics is to try to solve               obtained the same fragrance gene, all
                                                                                                                                                                                                                                                             meTa-PhoR project
        total of genetic information       together to make the key aromatic                  some of the mysteries of aroma. Even              contained less 2AP than KDML105.                                                                             coordinator Robert hall.
        in the rice plant, encoded in      compound in fragrant rice. These                   Westerners who don’t grow up eating               Why is aroma best in KDML105?
its DNA—provided a huge boost to           processes, which are regulated or                  rice can discriminate between the                 This is the sort of question,
genetic research. But, as we try to find   carried out in families of reactions,              taste of Thai jasmine and Indian/                 lurking in the dark space between
genetic answers to questions such as       involve tens of thousands of small                 Pakistani basmati rice. Asians who                genes and taste, that perplexes
why one variety tastes delicious but       chemicals and compounds known as                   eat rice from the moment they can                 breeders and cereal chemists,
another tastes mediocre, we fall into      metabolites, many of which chemists                manage solid food, on the other hand,             and disappoints rice farmers, rice
that dark space between genotype           have never seen. The detection,                    can discriminate between basmati                  consumers, and rice traders.
and phenotype—that is, the unknown         identification, and quantification                 grown in the Punjab and basmati                         But are such questions still
processes at the subcellular level that    of these small compounds are the                   grown 50 km away, and between                     unanswerable? Metabolomics
are regulated by the genes, and that       elements of a new science called                   jasmine rice grown in different                   could be the torch that illuminates
lead to the end result that humans         metabolomics. Some of the small                    regions of Thailand. Besides jasmine              that darkness, thus enabling us to
can see, feel, and of course taste.        compounds dissolve in solutions and                and basmati, well-trained palates can             find some of the compounds that

                                                                                                                                                                                                                                                                                        PlanT reSearch inTernaTional
     That dark and seemingly               some are volatile. These features                  discriminate between the many, many               explain variability in taste. IRRI
impenetrable gap is buzzing with           determine the equipment that can be                more aromatic rice varieties grown in             is a collaborator in the META-
chemicals and reactions. It is the         used, or that needs to be developed,               Southeast, South, and Central Asia.               PHOR project, funded by the
place where a chemical compound            to identify and measure them.                           Scientists have found a gene                 European Union, to develop and
or compounds can switch on a gene,              For a person involved in                      for aroma, which is carried by both               standardize methods for metabolomic
link an amino acid onto a growing          unravelling the science of the traits              jasmine- and basmati-style rice                   profiling of plants, and to develop

38                                                 Rice Today April-June 2008                                                                                                                      Rice Today April-June 2008                                                     39

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