Paulownia witches’-broom disease which was caused by the paulownia witches’-broom phytoplasma(PaWB) is one of the severest diseases in paulownia production.Antigenic membrane protein(Amp) gene was cloned from Paulownia plants infected with Paulownia witches’-broom phytoplasma in Shaanxi Province.The gene was 696 bp in length,encoding a predicted protein of 231 amino acids.Homology analysis of sequence from PaWB and other 8 phytoplasmas of GenBank available showed that amp gene of PaWB was 100% identical to PaWB-Japan,and closely related to those of onion yellow(AY) and aster yellow(OY) in the same 16Sr Ⅰgroup with nucleotide acids sequences homology rate of 97%;However it had a lower nucleotide acids sequences homology rate of 37% with western X disease in 16Sr Ⅲ group.Prediction of protein structure showed that molecular weight of Amp was 24.7 ku and isoelectric point was 9.935.The Amp protein possessed acentral hydrophilic region and two hydrophobic transmembrane regions.There were several potential cleavage sites of signal peptide,the strongest cleavage site was at the end of Amp and there was no potential cleavage sites in the middle Amp.The information suggested that the protein should be of good antigenicity.
