Cloning of a 9-cis-epoxycarotenoid dioxygenase gene and the responses of Caragana korshinskii to a variety of abiotic stresses.
Abscisic acid (ABA) regulates plant adaptive responses to various environmental stresses. Oxidative cleavage of cis-epoxycarotenoids catalyzed by 9-cis-epoxycarotenoid dioxygenase (NCED) is the main regulatory step in the biosynthesis of ABA in higher plants. Using RACE technology, a full-length cDNA-encoding NCED gene was isolated and characterized from the leaves of Caragana korshinskii (Peashrub). The 2442-bp full-length CkNCED1 had a 1818-bp ORF, which encodes a peptide of 605 amino acids. The deduced amino acid sequence of CkNCED1 protein shared high identity with other NCEDs. Southern blot analysis revealed that the gene CkNCED1 was a single copy in the genome of C. korshinskii. When C. korshinskii plants were exposed to a water deficit, ABA accumulation was followed by large increases in CkNCED1 mRNA in leaves and stems, but only a moderate increase in the roots. Conversely, rehydration of stressed leaves caused a rapid decrease in CkNCED1 mRNA and ABA levels. RT-PCR and Quantitative real-time PCR analysis showed that salt stress rapidly induced the strong expression of CkNCED1 in leaves and roots of C. korshinskii, as well as ABA accumulation. The expression of CkNCED1 and ABA accumulation was also induced by cold stress and the application of exogenous ABA. Taken together, these results suggest that CkNCED1 likely plays a primary role in the biosynthesis of ABA in C. korshinskii.
Institute of Animal Science, Chinese Academy of Agricultural Science, 2-Yuan-Ming-Yuan West Rd., Haidian district, Beijing 100193, P R China.
Xuemin
X
Wang
Zan
Z
Wang
Jie
J
Dong
Meizhen
M
Wang
Hongwen
H
Gao
D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology; D000595:Amino Acid Sequence; D032602:Caragana / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D003080:Cold Temperature; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D049308:Dioxygenases; D018628:Gene Dosage; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010105:Oxygenases / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology; D014867:Water / Q000494:pharmacology
D018076:DNA, Complementary; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014867:Water; D012965:Sodium Chloride; D000040:Abscisic Acid; D010105:Oxygenases; D049308:Dioxygenases; C109043:9-cis-epoxy-carotenoid dioxygenase