title: The Reaumuria trigyna leucoanthocyanidin dioxygenase (RtLDOX) gene complements anthocyanidin synthesis and increases the salt tolerance potential of a transgenic Arabidopsis LDOX mutant.
abstract: Reaumuria trigyna is a typical, native desert halophyte that grows under extreme conditions in Inner Mongolia. In a previous transcriptomic profiling analysis, flavonoid pathway-related genes in R. trigyna showed significant differences in transcript abundance under salt stress. Leucoanthocyanidin dioxygenase (LDOX, EC 1.14.11.19) is one of three dioxygenases in the flavonoid pathway that catalyzes the formation of anthocyanidins from leucoanthocyanidins. In this study, we cloned the full-length cDNA of R. trigyna LDOX (RtLDOX), and found RtLDOX recombinant protein was able to replace flavanone-3-hydroxylase (F3H, EC 1.14.11.9), another dioxygenase in the flavonoid pathway, to convert naringenin to dihydrokaempferol in vitro. R. trigyna LDOX can complement the Arabidopsis LDOX mutant transparent testa11 (tt11-11), which has reduced proanthocyanin (PA) and anthocyanin levels in seeds, to accumulate these two compounds. Thus, RtLDOX acts as a multifunctional dioxygenase to effect the synthesis of PA and anthocyanins and can perform F3H dioxygenase activities in the flavonoid biosynthesis pathway. The RtLDOX promoter harbored many cis-acting elements that might be recognized and bound by transcription factors related to stress response. RtLDOX expression was strongly increased under salt stress, and RtLDOX transgenic Arabidopsis mutant under NaCl stress accumulated the content of flavonoids leading to an increased antioxidant activities and plant biomass. These results suggest that RtLDOX as a multifunctional dioxygenase in flavonoid biosynthesis involves in enhancing plant response to NaCl stress.
authors.affiliation: Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010020, People's Republic of China. Electronic address: 523537961@qq.com.
authors.forename: Huirong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010020, People's Republic of China. Electronic address: 358275900@qq.com.
authors.forename: Chao
authors.initials: C
authors.lastname: Du
authors.affiliation: Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010020, People's Republic of China. Electronic address: 184612362@qq.com.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010020, People's Republic of China. Electronic address: 6469479575@qq.com.
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010020, People's Republic of China. Electronic address: 13856265@qq.com.
authors.forename: Linlin
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010020, People's Republic of China. Electronic address: ycwang@imu.edu.cn.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000096:biosynthesis*; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D055162:Biocatalysis / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D044950:Flavanones / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005816:Genetic Complementation Test; D009154:Mutation / Q000235:genetics*; D010105:Oxygenases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D030821:Plants, Genetically Modified; D044945:Proanthocyanidins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance / Q000187:drug effects / Q000235:genetics*; D012639:Seeds / Q000187:drug effects / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D032363:Tamaricaceae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*
chemical_list: D000872:Anthocyanins; D044950:Flavanones; D005419:Flavonoids; D044945:Proanthocyanidins; D012333:RNA, Messenger; D012965:Sodium Chloride; C080220:aromadedrin; D010105:Oxygenases; C105763:leucoanthocyanidin dioxygenase; C005273:naringenin
keywords: Enzyme activity; Leucoanthocyanidin dioxygenase; Reaumuria trigyna; Stress tolerance