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Zhu F, Luo T, Liu C, Wang Y, Yang H, Yang W, Zheng L, Xiao X, Zhang M, Xu R, Xu J, Zeng Y, Xu J, Xu Q, Guo W, Larkin RM, Deng X, Cheng Y. An R2R3-MYB transcription factor represses the transformation of α- and β-branch carotenoids by negatively regulating expression of CrBCH2 and CrNCED5 in flavedo of Citrus reticulate. THE NEW PHYTOLOGIST 2017; 216:178-192. [PMID: 28681945 DOI: 10.1111/nph.14684] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/30/2017] [Indexed: 05/23/2023]
Abstract
Although the functions of carotenogenic genes are well documented, little is known about the mechanisms that regulate their expression, especially those genes involved in α - and β-branch carotenoid metabolism. In this study, an R2R3-MYB transcriptional factor (CrMYB68) that directly regulates the transformation of α- and β-branch carotenoids was identified using Green Ougan (MT), a stay-green mutant of Citrus reticulata cv Suavissima. A comprehensive analysis of developing and harvested fruits indicated that reduced expression of β-carotene hydroxylases 2 (CrBCH2) and 9-cis-epoxycarotenoid dioxygenase 5 (CrNCED5) was responsible for the delay in the transformation of α- and β-carotene and the biosynthesis of ABA. Additionally, the expression of these genes was negatively correlated with the expression of CrMYB68 in MT. Further, electrophoretic mobility shift assays (EMSAs) and dual luciferase assays indicated that CrMYB68 can directly and negatively regulate CrBCH2 and CrNCED5. Moreover, transient overexpression experiments using leaves of Nicotiana benthamiana indicated that CrMYB68 can also negatively regulate NbBCH2 and NbNCED5. To overcome the difficulty of transgenic validation, we quantified the concentrations of carotenoids and ABA, and gene expression in a revertant of MT. The results of these experiments provide more evidence that CrMYB68 is an important regulator of carotenoid metabolism.
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Affiliation(s)
- Feng Zhu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Tao Luo
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Chaoyang Liu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yang Wang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Hongbin Yang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Wei Yang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Li Zheng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Xue Xiao
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Mingfei Zhang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Rangwei Xu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jianguo Xu
- Zhejiang Citrus Research Institute, Taizhou, Zhejiang, 318020, China
| | - Yunliu Zeng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Juan Xu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Qiang Xu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Wenwu Guo
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Robert M Larkin
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yunjiang Cheng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Key Laboratory of Horticultural Crop Biology and Genetic improvement (Central Region), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Institute of Citrus Science, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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