苦楝丛枝病植原体海南株系SecY基因序列分析及亚组分类

利用植原体16SrⅠ组通用引物对secYF1／secYR1，应用PCR技术从采白海南省儋州地区的表现典型丛枝症状的苦楝植株总DNA中扩增到约1．4kb的特异片段，将此片段克隆后进行序列测定，序列分析及系统关系树构建的结果表明，该片段长1358bp，苦楝丛枝病海南株系（Chinaberry witches＇-broom phytoplasma strain Hainan，CWB-Hn）与玉米丛矮（Maize bushy sttmt，MBS）植原体聚类在同一条进化枝上；AluⅠ，MseⅠ和Tsp509Ⅰ这3种酶的电子酶切图谱表明，CWB-Hn与MBS的酶切图谱一致，故初步判定苦楝丛枝病植原体海南株系属于secY-L亚组，在亚组水平上进一步明确了苦楝丛枝病植原体海南株系的分类地位。

Sequence Analysis of SecY of Phytoplasma from Chinaberrywitches'-broom phytoplasma in Hainan and Is Sub-section Identification

The samples of witches'-broom from Chinaberry tree were collected in Danzhou, Hainan Province. By using universal primers (secYF1/secYR1) for phytoplasma secY, a fragment of about 1.4 kb was amplified in DNA samples extracted from diseased Chinaberry tree. Phylogenetic analysis based on amino acid sequences of the secY gene from the Chinaberry witches'-broom strain Hainan and representative phytoplasma strains in the 16SrI group showed that Chinaberry witches'-broom phytoplasma strain Hainan (CWB-Hn) and maize bushy stunt (MBS) was in the same clade. The PCR-amplified secY fragments were digested in silico with 3 distinct restriction enzymes (AluI, MseI and Tsp509I ) for RFLP analysis. The resultant deduced restriction map suggested that restriction enzyme mapping of CWB-Hn was consistent with that of MBS. The results indicated that CWB-Hn belongs to secY-L subgroup.