title: Regulation of flavanone 3-hydroxylase gene involved in the flavonoid biosynthesis pathway in response to UV-B radiation and drought stress in the desert plant, Reaumuria soongorica.
abstract: Flavonoid are known to have various functions in growth, development, reproduction, and also involved in diverse stress responses in plants. However, little is known about the roles of the key enzymes in the flavonoid biosynthetic pathway in response to environmental stress, such as UV-B radiation and drought. To understand this problem, we investigated the participation of flavanone 3-hydroxylase gene (F3H), a key enzyme in flavonoid biosynthetic pathway under UV-B radiation and drought stress in the desert plant Reaumuria soongorica. A novel cDNA sequence, named as RsF3H, was isolated from R. soongorica. The deduced amino acids showed high identities to other F3Hs. A phylogenetic analysis indicated that RsF3H appeared to be most homologous to F3H from Malus domestica (MdF3H). RsF3H protein structure contained all five conserved motifs for 2-oxoglutarate-dependent dioxygenases (2-ODDs) and an Arg-X-Ser motif, all of which were also found in other F3Hs. Quantitative real-time RT-PCR analysis showed that there was a rapid increase in gene expression of RsF3H under stress. Both UV-B radiation and drought stress induced an increase in RsF3H enzyme activity and the accumulation of the products in the flavonoid biosynthetic pathway (total flavonoid and anthocyanin). The antioxidant ability (inhibition of lipid oxidation) of total flavonoid was enhanced during this study. The results suggested that one explanation of the stress tolerance of R. soongorica may be a combination of an increase in RsF3H gene expression, RsF3H enzyme activity and the anti-oxidative ability of the metabolic end products in the flavonoid biosynthetic pathway in response to UV-B radiation and drought.
authors.affiliation: Shapotou Desert Research & Experiment Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Donggang West Road 320, Lanzhou 730000, PR China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Meiling
authors.initials: M
authors.lastname: Liu
authors.forename: Xinrong
authors.initials: X
authors.lastname: Li
authors.forename: Yubing
authors.initials: Y
authors.lastname: Liu
authors.forename: Bo
authors.initials: B
authors.lastname: Cao
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000595:Amino Acid Sequence; D003889:Desert Climate; D055864:Droughts; D044950:Flavanones / Q000235:genetics / Q000378:metabolism; D005419:Flavonoids / Q000096:biosynthesis / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics; D032363:Tamaricaceae / Q000201:enzymology / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D044950:Flavanones; D005419:Flavonoids; D010940:Plant Proteins; D006899:Mixed Function Oxygenases; C048797:flavanone 3-dioxygenase
keywords: 2-ODDs; 2-oxoglutarate-dependent dioxygenases; Drought; F3H; Flavonoid biosynthetic pathway; HPLC; MDA; ORF; RACE; ROS; Reaumuria soongorica; RsF3H; TBA; TDR; UV-B; flavanone 3-hydroxylase; high performance liquid chromatography; malonaldehyde; open reading frame; qRT-PCR; quantitative real-time RT-PCR; rapid amplification of cDNA ends; reactive oxygen species; thiobarbituric acid; time domain reflectometry