ACTA BIOLOGICA CRACOVIENSIA

BIOSYNTHESIS, GENETICS, AND METABOLISM OF CAROTENOIDS
studying carotenogenesis in cereals. Using the maize carotenoid
mutant collection, our laboratory discovered 15-cis zeta-carotene
isomerase (Z-ISO), a new carotenoid biosynthetic pathway
enzyme needed in all plants [1]. Z-ISO is especially needed in
absence of light, such as in roots and endosperm, the target tissue
for provitamin A biofortification. For other pathway enzymes,
we used bioinformatics and cloning to identify genes encoding
enzymes for biosynthesis and degradation of carotenoids in
maize and related grasses. We found extensive gene duplication
that is conserved in the grasses. We have been investigating the
role of gene family members in contributing to carotenogenesis.
To assess roles in endosperm, we took advantage of the extensive
maize germplasm collection. We compared endosperm transcript
profiles with carotenoid content and composition. Thus we elucidated
pathway control points and identified natural alleles for
breeding higher levels of endosperm provitamin A carotenoids.
Building on earlier collaborative studies, we discovered maize
HYD3 encoding a non heme di-iron beta-carotene hydroxylase, as
the partner locus needed for controlling endosperm provitamin A
content [2]. We also identified new targets for controlling pathway
flux that can be used in future efforts to enhance carotenoid levels
in endosperm [3,4]. Our ongoing research focuses on regulatory
and structural aspects of carotenoid biosynthesis to facilitate
predictive metabolic engineering for a sustainable solution to vitamin
A deficiency.
Funded by the US National Institutes of Health.
REFERENCES
CHEN et al. 2010. Isolation and characterization of the Z-ISO gene
encoding a missing component of carotenoid biosynthesis in
plants. Plant Physiol. 153: 66-79.
VALLABHANENI et al. 2009. Metabolite sorting of a germplasm collection
reveals the Hydroxylase3 locus as a new target for maize provitamin
A biofortification. Plant Physiol. 151: 1635-45.
VALLABHANENI et al. 2009. Timing and biosynthetic potential for
carotenoid accumulation in genetically diverse germplasm of
maize. Plant Physiol. 150: 562-72.
VALLABHANENI et al. 2010. The carotenoid dioxygenase gene family in
maize, sorghum, and rice. Arch. Biochem. Biophys. 504: 104-11.
Vol. 53, suppl. 1, 2011
ORAL PRESENTATIONS
An effective in vitro system for the functional
characterization of carotenogenic genes in rice
(Oryza sativa)
Chao Bai1 , Sol M. Rivera2 , Vicente Medina1 ,
Gerhard Sandmann3 , Ramon Canela2 , Changfu Zhu1 ,
Teresa Capell1 , Paul Christou1,4 1Departament de Producció Vegetal i Ciencia Forestal, Universitat
de Lleida, Av. Alcalde Rovira Roure, 191, Lleida, 25198, Spain,
chaobai37@pvcf.udl.cat, medinap@pvcf.udl.cat, zhu@pvcf.udl.cat,
teresa.capell@pvcf.udl.cat
2Departament de Química, Universitat de Lleida, Av. Alcalde
Rovira Roure, 191, Lleida, 25198, Spain, rivera@quimica.udl.cat,
canela@quimica.udl.cat
3Molecular Biosciences, J.W. Goethe Universitaet,
Siesmayerstrasse 70, Gebäude D Raum 217, 60323, Frankfurt am
Main, Germany, sandmann@bio.uni-frankfurt.de
4Institucio Catalana de Recerca i Estudis Avancats, Barcelona,
Spain, christou@pvcf.udl.cat
Carotenoids play fundamental roles in human nutrition. The
mechanisms that control carotenoid accumulation in plants are
complex and only partly understood. The amount of carotenoids
in plant tissues and organs do not appear to depend solely on
carotenogenic enzyme activities responsible for their synthesis.
The upstream precursor (MEP derived IPP and GGPP) pathways
may also positively influence their accumulation, while downstream
degradation pathways that metabolize carotenoids may
deplete the carotenoid pool. Recent studies in our laboratory and
elsewhere indicate that an effective strategy to enhance carotenoid
accumulation in staple crops requires the simultaneous introduction
and coordinated expression of multiple transgenes. A
rapid functional expression assay would be very advantageous in
assessing the nature and specific combinations of particular
transgenes to be used in any given experiment aiming towards
maximizing carotenoid accumulation reliable, inexpensive and
conclusive. We present and discuss recent results from experiments
utilizing combinations of transgenes involved in carotenogenesis
in stably engineered rice cell lines which exemplify the
utility of such in vitro cell assays to validate the function of multiple
carotenogenic genes.
Microarray analysis of gene expression
changes associated with the accumulation of
carotenoid pigments in the storage root of
carrot (Daucus carota)
Megan Bowman 1 , Philipp Simon 1,2,3
17–22 July 2011, Krakow, Poland
1 Plant Breeding and Plant Genetics Program, University of
Wisconsin-Madison, 1575 Linden Drive, Madison, WI USA 53706,
mbowman2@wisc.edu
2 Department of Horticulture, University of Wisconsin-Madison,
1575 Linden Drive, Madison, WI USA 53706
3 USDA-ARS Vegetable Crop Research Unit, 1575 Linden Drive,
Madison, WI USA 53706, psimon@wisc.edu
Carrot (Daucus carota var. sativus L.) provides more than 30%
of the pro-vitamin A carotenoid pigments the US alone, making
research into the accumulation of these pigments in carrot important.
The storage root of orange carrot contains α-and β-carotene,
but available carrot germplasm also accumulates high concentrations
of other carotenoid pigments such as lycopene and lutein,
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