The Or Gene Enhances Carotenoid Accumulation and Stability During Post-Harvest Storage of Potato Tubers  

作　　者：Li Li Yong Yang Qiang Xu Katherine Owsiany Ralf Welsch Chureeporn Chitchumroonchokchai Shan Lu Joyce Van Eck Xiu-Xin Deng Mark Failla Theodore W. Thannhauser 

机构地区：[1]Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY 14853, USA [2]Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA [3]Key Laboratory of Horticultural Plant Biology （Ministry of Education）, Huazhong Agricultural University, Wuhan, Hubei, China [4]Faculty of Biology, University of Freiburg, Freiburg, Germany [5]Department of Human Nutrition, Ohio State University, Columbus, OH 43210, USA [6]State Kay Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, China [7]Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY 14853, USA

出　　处：《Molecular Plant》2012年第2期339-352,共14页分子植物（英文版）

摘　　要：Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we investigated transgenic potato tubers that expressed the cauliflower Orange （Or） gene. We found that the Or transgene not only promoted retention of 13-carotene level, but also continuously stimulated its accumulation during 5 months of cold storage. In contrast, no increased levels of carotenoids were observed in the tubers of vector-only controls or a yellow- flesh variety during the same period of storage. The increased carotenoid accumulation was found to be associated with the formation of lipoprotein-carotenoid sequestering structures, as well as with the enhanced abundance of phytoene synthase, a key enzyme in the carotenoid biosynthetic pathway. Furthermore, the provitamin A carotenoids stored were shown to be stable during simulated digestion and accessible for uptake by human intestinal absorptive cells. Proteomic analysis identified three major functional groups of proteins （i.e. heat shock proteins, glutathione-S-transferases, and carbohydrate metabolic proteins） that are potentially important in the Or-regulated carotenoid accumulation. Our results show that regulation of carotenoid sequestration capacity is an important mechanism by which carotenoid stability is regulated. Our findings suggest that induction of a proper sink structure formation in staple crops may provide the crops with a unique ability to promote and/or stabilize provitamin A accumulation during plant growth and post-harvest storage.Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we investigated transgenic potato tubers that expressed the cauliflower Orange （Or） gene. We found that the Or transgene not only promoted retention of 13-carotene level, but also continuously stimulated its accumulation during 5 months of cold storage. In contrast, no increased levels of carotenoids were observed in the tubers of vector-only controls or a yellow- flesh variety during the same period of storage. The increased carotenoid accumulation was found to be associated with the formation of lipoprotein-carotenoid sequestering structures, as well as with the enhanced abundance of phytoene synthase, a key enzyme in the carotenoid biosynthetic pathway. Furthermore, the provitamin A carotenoids stored were shown to be stable during simulated digestion and accessible for uptake by human intestinal absorptive cells. Proteomic analysis identified three major functional groups of proteins （i.e. heat shock proteins, glutathione-S-transferases, and carbohydrate metabolic proteins） that are potentially important in the Or-regulated carotenoid accumulation. Our results show that regulation of carotenoid sequestration capacity is an important mechanism by which carotenoid stability is regulated. Our findings suggest that induction of a proper sink structure formation in staple crops may provide the crops with a unique ability to promote and/or stabilize provitamin A accumulation during plant growth and post-harvest storage.

关 键 词：Carotenoids CHROMOPLASTS Or gene potato provitamin A loss staple crops post-harvest storage. 

分 类 号：Q562[生物学—生物化学] S435.32[农业科学—农业昆虫与害虫防治]