title: Enhancement of Thiamin Content in Arabidopsis thaliana by Metabolic Engineering.
abstract: Thiamin is an essential nutrient in the human diet. Severe thiamin deficiency leads to beriberi, a lethal disease which is common in developing countries. Thiamin biofortification of staple food crops is a possible strategy to alleviate thiamin deficiency-related diseases. In plants, thiamin plays a role in the response to abiotic and biotic stresses, and data from the literature suggest that boosting thiamin content could increase resistance to stresses. Here, we tested an engineering strategy to increase thiamin content in Arabidopsis. Thiamin is composed of a thiazole ring linked to a pyrimidine ring by a methylene bridge. THI1 and THIC are the first committed steps in the synthesis of the thiazole and pyrimidine moieties, respectively. Arabidopsis plants were transformed with a vector containing the THI1-coding sequence under the control of a constitutive promoter. Total thiamin leaf content in THI1 plants was up approximately 2-fold compared with the wild type. THI1-overexpressing lines were then crossed with pre-existing THIC-overexpressing lines. Resulting THI1 × THIC plants accumulated up to 3.4- and 2.6-fold more total thiamin than wild-type plants in leaf and seeds, respectively. After inoculation with Pseudomonas syringae, THI1 × THIC plants had lower populations than the wild-type control. However, THI1 × THIC plants subjected to various abiotic stresses did not show any visible or biochemical changes compared with the wild type. We discuss the impact of engineering thiamin biosynthesis on the nutritional value of plants and their resistance to biotic and abiotic stresses.
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97330, USA Hermiston Agricultural Research and Extension Center, Oregon State University, 2121 S First Street, Hermiston, OR 97838, USA Present address: Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Dong
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97330, USA.
authors.forename: Virginia O
authors.initials: VO
authors.lastname: Stockwell
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97330, USA Hermiston Agricultural Research and Extension Center, Oregon State University, 2121 S First Street, Hermiston, OR 97838, USA aymeric.goyer@oregonstate.edu.
authors.forename: Aymeric
authors.initials: A
authors.lastname: Goyer
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003433:Crosses, Genetic; D060847:Metabolic Engineering / Q000379:methods*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000254:growth & development; D013312:Stress, Physiological; D013831:Thiamine / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D029681:Arabidopsis Proteins; D017382:Reactive Oxygen Species; C437085:THI1 protein, Arabidopsis; D013831:Thiamine
keywords: Arabidopsis; Engineering; Plants; Thiamin; Vitamin B1