Distinct expression and function of carotenoid metabolic genes and homoeologs in developing wheat grains

BMC Plant Biology

Research Article

Xiaoqiong Qin¹  Shu Yu¹  Jorge Dubcovsky²  Kathryn Fischer³  Li Tian⁴ 

[1] Department of Plant Sciences, Mail Stop 3, University of California, 95616, Davis, CA, USA;Department of Plant Sciences, Mail Stop 3, University of California, 95616, Davis, CA, USA;Howard Hughes Medical Institute, 20815, Chevy Chase, MD, USA;Department of Plant Sciences, Mail Stop 3, University of California, 95616, Davis, CA, USA;Quantitative and Systems Biology Program, University of California, 95343, Merced, CA, USA;Department of Plant Sciences, Mail Stop 3, University of California, 95616, Davis, CA, USA;Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, 201602, Shanghai, China;Shanghai Chenshan Plant Science Research Center, Chinese Academy of Sciences, 201602, Shanghai, China;

关键词: β-carotene;    Carotenoid;    Carotenoid cleavage dioxygenase;    Endosperm;    Grain;    Provitamin A;    Spatial expression;    Wheat;   

DOI  :  10.1186/s12870-016-0848-7

 received in 2016-04-23, accepted in 2016-07-07,  发布年份 2016

来源: Springer

【 摘 要 】

Backgroundβ-carotene, the most active provitamin A molecule produced by plants, plays important roles in human nutrition and health. β-carotene does not usually accumulate in the endosperm (i.e. flour) of mature wheat grains, which is a major food source of calories for humans. Therefore, enriching β-carotene accumulation in wheat grain endosperm will enable a sustainable dietary supplementation of provitamin A. Several metabolic genes affecting β-carotene accumulation have already been isolated from wheat, including phytoene synthase 1 (PSY1), lycopene ε-cyclase (LCYe) and carotenoid β-ring hydroxylase1/2 (HYD1/2).ResultsIn this work, we cloned and biochemically characterized two carotenoid cleavage dioxygenases (CCDs), CCD1 and CCD4, from wheat. While CCD1 homoeologs cleaved β-apo-8′-carotenal, β-carotene, lutein and zeaxanthin into apocarotenoid products, CCD4 homoeologs were inactive towards these substrates in in vitro assays. When analyzed by real-time qPCR, PSY1, LCYe, HYD1/2 and CCD1/4 homoeologs showed distinct expression patterns in vegetative tissues and sections of developing tetraploid and hexaploid wheat grains, suggesting that carotenoid metabolic genes and homoeologs are differentially regulated at the transcriptional level in wheat.ConclusionsThe CCD1/4 enzyme activity and the spatial-temporal gene expression data provide critical insights into the specific carotenoid metabolic gene homoeologs that control β-carotene accumulation in wheat grain endosperm, thus establishing the knowledge base for generation of wheat varieties with enhanced β-carotene in the endosperm through breeding and genome editing approaches.

【 授权许可】

CC BY   
© The Author(s). 2016