Planta (2008) 228:789–801
DOI 10.1007/s00425-008-0781-6
123
ORIGINAL ARTICLE
Cloning and characterisation of a maize carotenoid cleavage
dioxygenase (ZmCCD1) and its involvement in the biosynthesis
of apocarotenoids with various roles in mutualistic and parasitic
interactions
Zhongkui Sun · Joachim Hans · Michael H. Walter · Radoslava Matusova ·
Jules Beekwilder · Francel W. A. Verstappen · Zhao Ming · Esther van Echtelt ·
Dieter Strack · Ton Bisseling · Harro J. Bouwmeester
Received: 30 May 2008 / Accepted: 25 June 2008 / Published online: 21 August 2008
© The Author(s) 2008. This article is published with open access at Springerlink.com
Abstract Colonisation of maize roots by arbuscular
mycorrhizal (AM) fungi leads to the accumulation of apo-
carotenoids (cyclohexenone and mycorradicin derivatives).
Other root apocarotenoids (strigolactones) are involved in
signalling during early steps of the AM symbiosis but also
in stimulation of germination of parasitic plant seeds. Both
apocarotenoid classes are predicted to originate from cleav-
age of a carotenoid substrate by a carotenoid cleavage dioxy-
genase (CCD), but the precursors and cleavage enzymes
are unknown. A Zea mays CCD (ZmCCD1) was cloned by
RT-PCR and characterised by expression in carotenoid
accumulating E. coli strains and analysis of cleavage prod-
ucts using GC–MS. ZmCCD1 eYciently cleaves carote-
noids at the 9, 10 position and displays 78% amino acid
identity to Arabidopsis thaliana CCD1 having similar prop-
erties. ZmCCD1 transcript levels were shown to be elevated
upon root colonisation by AM fungi. Mycorrhization led to
a decrease in seed germination of the parasitic plant Striga
hermonthica as examined in a bioassay. ZmCCD1 is
proposed to be involved in cyclohexenone and mycorradi-
cin formation in mycorrhizal maize roots but not in strigo-
lactone formation.
Keywords Apocarotenoids · Arbuscular mycorrhizal
fungi · Carotenoid cleavage dioxygenase · Germination
stimulants · Maize · Striga spp.
Abbreviations
ABA Abscisic acid
AM fungi Arbuscular mycorrhizal fungi
DXR Deoxyxylulose-5-phosphate reductoisomerase
NCED 9-Cis-epoxycarotenoid dioxygenase
ZmCCD1 Zea mays carotenoid cleavage dioxygenase 1
Introduction
Carotenoid cleavage dioxygenases (CCDs) and 9-cis-epoxy-
carotenoid dioxygenases (NCEDs) constitute a family of
enzymes that catalyse the cleavage of carotenoids at spe-
ciWc double bonds. The cleavage products are collectively
called apocarotenoids (Schwartz et al. 2001; Auldridge
et al. 2006b). The Wrst carotenoid cleaving enzyme (Vp14)
was isolated from the abscisic acid (ABA) deWcient vivipa-
rous maize mutant. Vp14 is an NCED and catalyses the
rate-limiting step in ABA (also an apocarotenoid) biosyn-
thesis, the cleavage of the 9-cis-isomer of neoxanthin or
violaxanthin at the 11,12 position (Schwartz et al. 1997).
Based on the sequence homology to Vp14, nine CCDs have
been identiWed in the Arabidopsis thaliana genome. Among
them, Wve are Vp14-like (NCED2, NCED3, NCED5,
NCED6 and NCED9) and are supposed to be involved in
ABA biosynthesis (Tan et al. 2003). The other four have
been given the generic designation carotenoid cleavage
Z. Sun · R. Matusova · J. Beekwilder · F. W. A. Verstappen ·
Z. Ming · E. van Echtelt · H. J. Bouwmeester (&)
Plant Research International, P.O. Box 16,
6700 AA Wageningen, The Netherlands
e-mail: harro.bouwmeester@wur.nl
Z. Sun · T. Bisseling
Laboratory of Molecular Biology, WUR,
Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
J. Hans · M. H. Walter · D. Strack
Leibniz-Institut fuer PXanzenbiochemie,
Abteilung SekundaerstoVwechsel, 06120 Halle, Germany
R. Matusova · F. W. A. Verstappen · E. van Echtelt ·
H. J. Bouwmeester
Laboratory of Plant Physiology, Wageningen University,
Arboretumlaan 4, 6703 BD Wageningen, The Netherlands