ACTA BIOLOGICA CRACOVIENSIA

BIOSYNTHESIS, GENETICS, AND METABOLISM OF CAROTENOIDS
POSTERS
6.1.
β-carotene cleavage in Blakeslea trispora and
Phycomyces blakesleanus
Eugenio Alcalde1 , Silvia Polaino1 , M. Mar Herrador2 ,
Enrique Cerdá-Olmedo1 , Alejandro F. Barrero2 1 Departamento de Genética, Facultad de Biología, Universidad de
Sevilla, Reina Mercedes, s/n, 41071 Sevilla, Spain, eco@us.es
2 Departamento de Química Orgánica, Instituto de Biotecnología,
Universidad de Granada, Avda. Fuente Nueva, s/n, 18071
Granada, Spain, afbarre@ugr.es
Mixed cultures of strains of opposite sex ("mated cultures") of
Blakeslea trispora and Phycomyces blakesleeanus
(Mucoromycotina, Mucorales) may be used as industrial sources
of β-carotene. These cultures produce apocarotenoids that induce
an increased β-carotene content and the early morphogenetic
processes of the sexual cycle.
A new family of apocarotenoids with 7 carbons has been identified
in Phycomyces (2 compounds) (Polaino et al., 2010) and
Blakeslea (the same and three others). These new molecules represent
the missing link that proves that β-carotene is split into
fragments of 18, 15 and 7 carbons, heads of three separate families
of apocarotenoids.
The cocktail of apocarotenoids in Mucorales varies not only
between species, but between strains. Thus, the mated cultures of
Blakeslea, wild-type strains F921 and F986, contain eleven apocarotenoids:
two C 18 , two C 15 , a C 13 and five C7 compounds. Six
of them are new natural products and two are new for Blakeslea,
while 14 other apocarotenoids reported from other strains of
Blakeslea have not been found now.
REFERENCES
POLAINO S, HERRADOR MM, CERDÁ-OLMEDO E, BARRERO AF. 2010. Org.
Biomol. Chem. 8: 4229-4231.
6.2.
β-carotene enhancement in orange fruits
Elsa Pons1 , Ana Rodriguez1 , Berta Alquezar1 ,
Maria J. Rodrigo2 , Lorenzo Zacarias2 , Leandro Peńa1 1Instituto Valenciano de Investigaciones Agrarias (IVIA), Carretera
Moncada-Naquera Km. 5, 46113 Moncada, Valencia, Spain,
pons_els@gva.es, rodriguez_anabai@gva.es,
alquezar_ber@gva.es, lpenya@ivia.es
2Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC),
Avda. Catedrático Agustín Escardino 7, 46980 Paterna, Valencia,
Spain, lzacarias@iata.csic.es, mjrodrigo@iata.csic.es
Citrus is a very important fruit crop throughout the world not
only because of its economic significance but also for its great
value for human nutrition and well-being. Complex and heterogeneous
accumulation of carotenoids accounts for the typical
colouration of the peel and pulp of most citrus fruits, thus influencing
the commercial and visual quality of the fruits. Orange
fruit is an excellent natural dietary source providing health-promoting
compounds such as vitamin C, flavonoids and folic acid
in a combination and concentration unique among fruits and vegetables,
but it has low provitamin A content. The main carotenoid
with provitamin A activity is β-carotene, a compound hardly
detectable in the pulp of most oranges. The most
abundant/important provitamin-A compound in oranges is -cryp-
Vol. 53, suppl. 1, 2011
17–22 July 2011, Krakow, Poland
toxanthin, which has half provitamin A activity than β-carotene.
However, this carotenoid is usual in mandarins but relatively
scarce or absent in most orange cultivars.
With the aim of increasing orange fruit nutritional value, we
have attempted to enhance its content in β-carotene (provitamin
A) by metabolic engineering of carotenoid biosynthesis. Recent
advances in the identification and isolation of the genes responsible
for the carotenogenesis in citrus fruits combined with the
availability of genetic engineering tools have made feasible a metabolic
engineering approach to improve the content and composition
of certain carotenoids in oranges. In this work, we blocked
the expression of the endogenous β-carotene hydroxylase gene (β-
CHX), involved in the conversion of β-carotene into xanthophylls,
using RNA interference (RNAi) technology. Transgenic plants
were obtained that showed important changes in carotenoid content
and composition in both fruit peel and pulp, with β-carotene
increases accompanied by a general decrease in the accumulation
of downstream xanthophylls and enhanced production of flavorrelated
apocarotenals. The implications of these changes in nutritional
value and volatile composition of transgenic oranges will be
discussed.
6.3.
Studies on carotenoids and their volatile
apocarotenoid products in flowers of
Osmanthus fragrans
Susanne Baldermann 1 , Masaya Kato 2 , Peter Fleischmann 3 ,
Naoharu Watanabe 1
1Integrated Bioscience Section, Graduate School of Science and
Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka
422-8529, Japan, dsbalde@ipc.shizuoka.ac.jp,
acnwata@ipc.shizuoka.ac.jp
2Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku,
Shizuoka 422-8529, Japan, amkato@ipc.shizuoka.ac.jp
3Institute of Food Chemistry, Technische Universität
Braunschweig, Schleinitzstrasse 20, 38106 Braunschweig,
Germany, p.fleischmann@tu-braunschweig.de
The unique scent of flowers of Osmanthus fragrans is dominated
by carotenoid-derived constituents. In essential oil nearly 100 flavor
compounds originated from carotenoids have been identified
including β-ionone, α-ionone, dihydro-β-ionone, oxo-β-ionone,
and hydroxy-β-ionone (Kaiser, 2002). The essential oil contains
up to 19.5% of β-ionone and 11.7% β-ionone (Wang et al., 2009).
We report the contribution of Osmanthus carotenoid cleavage
enzymes in the bio-generation of β-ionone and α-ionone. cDNAs
encoding carotenoid cleavage dioxygenases (CCDs) were identified
based on conserved CCD sequences. To elucidate whether
the sequences encode functional CCDs cDNAs were transferred
into gluthathione fusion vectors for expression in E-coli and the
recombinant enzymes purified prior functional analysis. The relation
of carotenoids, volatile emission, and CCD transcripts was
investigated by determination of their changes over the floral
development and photo-rhythmic periods. Our results indicate
that OfCCD1 is likely involved in the C13-apocarotenoid biogenesis
in flowers of Osmanthus fragrans. The volatile reaction products,
β-ionone and α-ionone, have very low odor perception
thresholds for humans and exhibit a strong impact on floral
scents. By sensory evaluation we confirmed the impact of both
C13-apocarotenoids on the changes in scent perception of flowers
of Osmanthus fragrans in the course of the day (Baldermann et
al., 2010).
We thank Dr. A. Fujita (T. Hasegawa Co. Ltd., Japan) for support with
GC-MS measurements and sensory evaluations.
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