Abstract: 【Objective】An 1-Aminocyclopropane-1-Carboxylic acid Oxidase gene (BnACO1) was cloned from ramie and analyzed by bioinformatics method. The expression pattern was revealed in different organs and under stresses.【Method】The full-length sequence of ACO gene cDNA was cloned from Xiangzhu 3 ramie by RT-PCR and RACE methods. Then the sequence of BnACO1 gene and protein sequences were analyzed through bioinformatics means. The relative expression level of BnACO1gene in various organs of ramie and under ABA, drought, NaCl stresses was examined by real-time fluorescence PCR.【Result】The full length sequence and the ORF of the BnACO1 gene were 1 476 bp and 981 bp, respectively, which encoded 326 amino acids. The molecular weight is 36.81 kD and the pI is 4.95. The similarity comparison revealed that the gene nucleotide sequence shared 83%, 81%, 79%, 79%, and 79% of homology with the Ficus carica (AB307720), Pelargonium (U19856), Diospyros kaki (AB073009), Pyrus pyrifolia (JN807390), Actinidia chinensis (HQ293208) ACO gene, and the similarity of the amino acid sequences with that of these species was 87%, 80%, 80%, 78%, and 83%, respectively. The results of semi-quantitative RT-PCR showed that the BnACO1 expressed in root, stem, shoot tip and blade, female flowers and male flowers, with the higher expression level in male flowers, while the lowest expression level in root and stem. The results of real-time PCR showed that the BnACO1 was induced by ABA, dehydration and NaCl.【Conclusion】BnACO1 belongs to ACO gene family, which involved in abiotic stress responses to ABA, drought and NaCl. It may play a role in gender differences of ramie and have distinctive expression pattern in the regulation of development and stress responses.

Key words: Boehmeria nivea (L.)Gaud , ethylene , ACC oxidase , expression