Abstract:Aimed to study the characteristics and functions of ACS gene, in the present study, we cloned a 1aminocyclopropane1carboxylate synthetase gene named NtACS1 (GeneBank KX082936) based on the RNASeq database from the flower of Narcissus tazetta var.‘Yunxiang’ using RTPCR method. The length of the open reading frame (ORF) of ACS is 552 bp, encoding 183 amino acids coupled with a molecular weight of 20.6 kDa and theoretical isoelectric point of 6.30. qRTPCR analysis showed that the relative expression level of NtACS1 both in petals and coronas are decreased gradually along with the aging of flower. Moreover,the expression data of NtACS1 gene were consistent with those obtained by RNASeq,implied that the NtACS1 protein as an ACC synthetase might play a role in the catalytic system 1 of ethylene biosynthesis. Furthermore, sense plant expression vectors of NtACS1 were successfully constructed with agrobacterium mediated transformation, and 6 positive transgenic tobacco plants were ultimately obtained. Our current study will lay an experimental foundation for the future application of the genetic transformation to prolong florescence of ‘Yunxiang’.