論文

査読有り
2016年6月

Expression and functional analysis of citrus carotene hydroxylases: unravelling the xanthophyll biosynthesis in citrus fruits

BMC PLANT BIOLOGY
  • Gang Ma
  • ,
  • Lancui Zhang
  • ,
  • Witchulada Yungyuen
  • ,
  • Issei Tsukamoto
  • ,
  • Natsumi Iijima
  • ,
  • Michiru Oikawa
  • ,
  • Kazuki Yamawaki
  • ,
  • Masaki Yahata
  • ,
  • Masaya Kato

16
1
開始ページ
148
終了ページ
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1186/s12870-016-0840-2
出版者・発行元
BIOMED CENTRAL LTD

Background: Xanthophylls are oxygenated carotenoids and fulfill critical roles in plant growth and development. In plants, two different types of carotene hydroxylases, non-heme di-iron and heme-containing cytochrome P450, were reported to be involved in the biosynthesis of xanthophyll. Citrus fruits accumulate a high amount of xanthophylls, especially beta,beta-xanthophylls. To date, however, the roles of carotene hydroxylases in regulating xanthophyll content and composition have not been elucidated.
Results: In the present study, the roles of four carotene hydroxylase genes (CitHYb, CitCYP97A, CitCYP97B, and CitCYP97C) in the biosynthesis of xanthophyll in citrus fruits were investigated. Phylogenetic analysis showed that the four citrus carotene hydroxylases presented in four distinct clusters which have been identified in higher plants. CitHYb was a non-heme di-iron carotene hydroxylase, while CitCYP97A, CitCYP97B, and CitCYP97C were heme-containing cytochrome P450-type carotene hydroxylases. Gene expression results showed that the expression of CitHYb increased in the flavedo and juice sacs during the ripening process, which was well consistent with the accumulation of beta,beta-xanthophyll in citrus fruits. The expression of CitCYP97A and CitCYP97C increased with a peak in November, which might lead to an increase of lutein in the juice sacs during the ripening process. The expression level of CitCYP97B was much lower than that of CitHYb, CitCYP97A, and CitCYP97C in the juice sacs during the ripening process. Functional analysis showed that the CitHYb was able to catalyze the hydroxylation of the beta-rings of beta-carotene and alpha-carotene in Escherichia coli BL21 (DE3) cells. Meanwhile, when CitHYb was co-expressed with CitCYP97C, alpha-carotene was hydroxylated on the beta-ring and epsilon-ring sequentially to produce lutein.
Conclusions: CitHYb was a key gene for beta,beta-xanthophyll biosynthesis in citrus fruits. CitCYP97C functioned as an epsilon-ring hydroxylase to produce lutein using zeinoxanthin as a substrate. The results will contribute to elucidating xanthophyll biosynthesis in citrus fruits, and provide new strategies to improve the nutritional and commercial qualities of citrus fruits.

Web of Science ® 被引用回数 : 11

リンク情報
DOI
https://doi.org/10.1186/s12870-016-0840-2
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/27358074
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000378874800002&DestApp=WOS_CPL

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