桃黄化病病原植原体的鉴定及16S rDNA序列分析

 对四川省成都市龙泉驿区桃植原体黄化病病原进行了研究。经DAP I荧光染色, 在荧光显微镜下观察到病叶叶脉韧皮部存在荧光点; 在透射电镜下病叶韧皮部存在植原体菌体, 其大小为40～650 nm, 平均大小350 nm, 单位膜厚度10～16 nm。利用植原体16S rDNA通用引物对桃植原体黄化病患病植株提取的DNA进行nested2PCR扩增, 获得115 kb的特异片段, 同时构建了16S rDNA系统进化树。桃黄化病植原体序列与油桃黄化NecY2In1 (nectarine yellows) 病原同源性最高。从而探明了桃黄化病病原为植原体及其分类地位。

The Identification and Sequence Analysis of 16S Ribosomal DNA of the Phytoplasma sp. Associated with Peach Yellow Disease

The phytop lasma associated with peach yellow disease occurred in Longquanyi District in Sichuan Province was studied. The specific fluorescence dots for the pathogen were observed in phloem cells of leaf veins under a fluorescence microscope by staining with 4, 62diamidino222phenylindole diacetate. Phytoplasma-like particles were also found in the same tissues under a transmission electronic microscope. Its diameter was 40-650 nm, 350 nm on average and the thickness of the unitmembrane of the pathogen was 10 - 16 nm. The 16S rDNA about 115 kb was amplified by nested-PCR with universal p rimers for Phytoplasm a using the total DNA extracted from diseased peach as the temp lates. A phylogenetic tree was constructed based on the sequences of 16S rDNA. The result showed that Phytoplasm a associated with peach yellow disease was closely related to nectarine yellows (NecY2In1).