Cloning and functional characterization of the maize carotenoid isomerase and β-carotene hydroxylase genes and their regulation during endosperm maturation

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2010
Author
Li, Qunrui
Farré Martinez, Gemma
Naqvi, Shaista
Breitenbach, Jürgen
Sanahuja Solsona, Georgina
Bai, Chao
Sandmann, Gerhard
Capell Capell, Teresa
Christou, Paul
Zhu, Changfu
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Li, Qunrui; Farré Martinez, Gemma; Naqvi, Shaista; Breitenbach, Jürgen; Sanahuja Solsona, Georgina; Bai, Chao; ... Zhu, Changfu. (2010) . Cloning and functional characterization of the maize carotenoid isomerase and β-carotene hydroxylase genes and their regulation during endosperm maturation. Transgenic Research, 2010, vol. 19, núm. 6, p. 1053-1068. https://doi.org/ 10.1007/s11248-010-9381-x.
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Abstract
In order to gain further insight into the partly-characterized carotenoid biosynthetic pathway in corn (Zea mays L.), we cloned cDNAs encoding the enzymes carotenoid isomerase (CRTISO) and β-carotene hydroxylase (BCH) using endosperm mRNA isolated from inbred line B73. For both enzymes, two distinct
cDNAs were identified mapping to different chromosomes. The two crtiso cDNAs (Zmcrtiso1 and Zmcrtiso2) mapped to unlinked genes each containing 12 introns, a feature conserved among all crtiso genes studied thus far. ZmCRTISO1 was able to convert tetra-cis prolycopene to all-trans lycopene but could not isomerize the 15-cis double bond of 9,15,9′-tri-cis-ζ-carotene. ZmCRTISO2 is inactivated by a premature termination codon in B73 corn, but importantly the mutation is absent in other corn cultivars and the active enzyme showed the same activity as ZmCRTISO1. The two bch cDNAs (Zmbch1 and Zmbch2) mapped to unlinked genes each coding sequences containing five introns. ZmBCH1 was able to convert β-carotene into β-cryptoxanthin and zeaxanthin, but ZmBCH2 was able to form β-cryptoxanthin alone and had a lower overall activity than ZmBCH1. All four genes were expressed during endosperm development, with mRNA levels rising in line with carotenoid accumulation (especially zeaxanthin and lutein) until 25 DAP. Thereafter, expression declined for three of the genes, with only Zmcrtiso2 mRNA levels maintained by 30 DAP. We discuss the impact of paralogs with different expression profiles and functions on the regulation of carotenoid synthesis in corn.
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http://hdl.handle.net/10459.1/58838
DOI
https://doi.org/ 10.1007/s11248-010-9381-x
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Transgenic Research, 2010, vol. 19, núm. 6, p. 1053-1068
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