Abstract: In order to investigate the correlation between the expression level of PsGA20ox gene and endogenous GA₃ contents during dormancy release in tree peony, using tree peony Lu hehong as plant materials, RACE PCR amplification was carried out based on the obtained partial cDNA sequence by 454 sequencing.The results of fragment assembly indicated that full-length cDNA sequence of the PsGA20ox gene was 1 391 bp including a 1 146 bp open reading frame(ORF), 16 bp 5'terminal UTR and 212 bp 3'terminal UTR followed by 17 bp polyA tail.Analysis of the ORF sequence showed that the ORF of PsGA20ox encoded a protein of 381 amino acids.The result of sequence homology indicated that PsGA20ox protein had relatively highly identity with that of poplar, and there was an identity of 77.6%.The results of RT-PCR indicated that the expression of PsGA20ox continuously increased in the tree peony flower buds during the early stage of dormancy release(from 0 to 14 d chilling treatment), followed by gradually decrease until 28 d, and the expression level of all treatment points were more than that of 0 d.The change trend of the endogenous GA₃ content by enzyme-linked immunoassay was similar to that of PsGA20ox expression.Significant positive correlation between the expression level of PsGA20ox and the contents of endogenous GA₃ was obtained.These results indicated that PsGA20ox played an important role to accelerate dormancy release by regulating the synthesis of endogenous GA₃.

Key words: Tree peony Paeonia suffroticosa, PsGA20ox, Endogenous gibberellin, Chilling, Endo-dormancy release

CLC Number: 

• S685.03