CLONING OF CDNA ENCODING β-CAROTENE HYDROXYLASE FROM CITRUS (CITRUS UNSHIU MARC.)

-Cryptoxanthin, a monohydroxy carotene, is formed from -carotene by hydroxylation at position 3 in one side ring of this symmetrical precursor, whereas zeaxanthin is formed by hydroxylation of both rings.
Zeaxanthin is widely distributed in most plants and bacteria.
In contrast, the distribution of -cryptoxanthin is limited to several organisms.
The juice sacs of Satsuma mandarin (Citrus unshiu Marc.) are one of the tissues in which -cryptoxanthin mainly accumulates.

To understand the molecular mechanism of -cryptoxanthin biosynthesis in citrus, we isolated a partial cDNA encoding -carotene hydroxylase by 3′-RACE (rapid amplification of cDNA ends) reverse transcriptase-polymerase chain reaction (RT-PCR) using first-strand cDNA from juice sacs.
Full-length cDNA (CitBECH1) encoding -cryptoxanthin was then isolated from the fruit (juice sacs/segments epidermis) cDNA library of Satsuma mandarin using a partial cDNA clone of CitBECH1. The amino acid sequences deduced from the 1158-bp CitBECH1 clone showed marked similarity to -carotene hydroxylase from Arabidopsis (76.3% identity).

First International Citrus Biotechnology Symposium

A. Komatsu, Y. Ikoma, M. Omura, M. Yano

β-carotene hydroxylase, gene isolation, 3′-RACE RT-PCR, citrus

https://doi.org/10.17660/ActaHortic.2000.535.14