The light and hypoxia induced gene ZmPORB1 determines tocopherol content in the maize kernel  

作　　者：Nannan Liu Yuanhao Du Shijuan Yan Wei Chen Min Deng Shutu Xu Hong Wang Wei Zhan Wenjie Huang Yan Yin Xiaohong Yang Qiao Zhao Alisdair R.Fernie Jianbing Yan 

机构地区：[1]National Key Laboratory of Crop Genetic Improvement,Huazhong Agricultural University,Wuhan 430070,China [2]Hubei Hongshan Laboratory,Wuhan 430070,China [3]Agro-biological Gene Research Center,Guangdong Academy of Agricultural Sciences,Guangzhou 510640,China [4]College of Agronomy,Hunan Agricultural University,Changsha 410128,China [5]College of Agronomy,Northwest A&F University,Xi'an 710000,China [6]State Key Laboratory of North China Crop Improvement and Regulation,Hebei Sub-center of National Maize Improvement Center of China,College of Agronomy,Hebei Agricultural University,Baoding 071001,China [7]College of Life Sciences,South-Central Minzu University,Wuhan 430070,China [8]Plant Science Facility of the Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China [9]National Maize Improvement Center of China,Beijing Key Laboratory of Crop Genetic Improvement,China Agricultural University,Beijing 100093,China [10]Shenzhen Key Laboratory of Synthetic Genomics,Guangdong Provincial Key Laboratory of Synthetic Genomics,Shenzhen Institute of Synthetic Biology,Shenzhen Institute of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055,China [11]Max Planck Institute of Molecular Plant Physiology,Potsdam-Golm 14476,Germany

出　　处：《Science China(Life Sciences)》2024年第3期435-448,共14页中国科学（生命科学英文版）

基　　金：supported by the National Natural Science Foundation of China(32200221,U1901201);the National Key Research and Development Program of China(2022YFD1201502);the Key Area Research and Development Program of Guangdong Province,China(2022B0202060003);Huazhong Agricultural University Scientific&Technological Self-Innovation Foundation。

摘　　要：Tocopherol is an important lipid-soluble antioxidant beneficial for both human health and plant growth. Here, we fine mapped a major QTLqVE1 affecting γ-tocopherol content in maize kernel, positionally cloned and confirmed the underlying gene ZmPORB1(por1), as a protochlorophyllide oxidoreductase. A 13.7 kb insertion reduced the tocopherol and chlorophyll content, and the photosynthetic activity by repressing ZmPORB1 expression in embryos of NIL-K22, but did not affect the levels of the tocopherol precursors HGA(homogentisic acid)and PMP(phytyl monophosphate). Furthermore, ZmPORB1 is inducible by low oxygen and light, thereby involved in the hypoxia response in developing embryos. Concurrent with natural hypoxia in embryos, the redox state has been changed with NO increasing and H_(2)O_(2) decreasing, which lowered γ-tocopherol content via scavenging reactive nitrogen species. In conclusion, we proposed that the lower lightharvesting chlorophyll content weakened embryo photosynthesis, leading to fewer oxygen supplies and consequently diverse hypoxic responses including an elevated γ-tocopherol consumption. Our findings shed light on the mechanism for fine-tuning endogenous oxygen concentration in the maize embryo through a novel feedback pathway involving the light and low oxygen regulation of ZmPORB1 expression and chlorophyll content.

关 键 词：MAIZE TOCOPHEROL HYPOXIA PHOTOSYNTHESIS ZmPORB1 

分 类 号：S513[农业科学—作物学]