The Reaumuria trigyna leucoanthocyanidin dioxygenase (RtLDOX) gene complements anthocyanidin synthesis and increases the salt tolerance potential of a transgenic Arabidopsis LDOX mutant.
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.
['Zhang|Huirong|H|', 'Du|Chao|C|', 'Wang|Yan|Y|', 'Wang|Jia|J|', 'Zheng|Linlin|L|', 'Wang|Yingchun|Y|']
D000595:Amino Acid Sequence D000872:Anthocyanins D017360:Arabidopsis D055162:Biocatalysis D004591:Electrophoresis, Polyacrylamide Gel D044950:Flavanones D005419:Flavonoids D018506:Gene Expression Regulation, Plant D017343:Genes, Plant D005816:Genetic Complementation Test D009154:Mutation D010105:Oxygenases D010802:Phylogeny D030821:Plants, Genetically Modified D044945:Proanthocyanidins D011401:Promoter Regions, Genetic D012333:RNA, Messenger D055049:Salt Tolerance D012639:Seeds D016415:Sequence Alignment D017386:Sequence Homology, Amino Acid D012965:Sodium Chloride D013312:Stress, Physiological D032363:Tamaricaceae
Reaumuria trigyna Leucoanthocyanidin dioxygenase Enzyme activity Stress tolerance