柳树丛枝病病原分子鉴定

Molecular identification of the pathogen of willow witches’-broom

柳树(Willow)是杨柳科(Salicaceae)柳属(Salix)乔木植物,大多数品种具有耐旱耐盐碱的特性,对环境具有良好的适应能力[1]。柳树在甘肃省内广泛种植,是风景林、防护林和水土保持林的重要组成树种。柳树丛枝病是一种典型的植原体病害,当寄主植株被病原物侵染时,顶芽生长受到抑制而侧芽提前萌发,导致受害枝条无法正常抽条或木质化,严重时甚至引起整株枯死[2],对林业的生态、经济和社会效益造成了极大损失。近年来,柳树丛枝病在甘肃省各市州发生严重,已经引起省内各界的普遍关注。

To clarify the taxonomic status of the phytoplasma causing willow witches’-broom in Gansu Pro-vince,this study used nested PCR technique to clone the 16S rDNA gene using total DNA collected from differ-ent regions and species of willow witches’-broom samples as templates,and nine 1250 bp target fragments were obtained using P1/P7 and R16F2n/R16R2;the sequences of the above genes were compared by homolo-gy,The results showed that the 16S rDNA gene of willow witches’-broom phytoplasma strain had the highest homology with Willow proliferation phytoplasma(Willow proliferation)in Inner Mongolia,both above 99.1%;the phylogenetic tree was constructed and found that the 16S rDNA gene of willow witches’-broom clustered with members of 16SrVI-A subgroup.The phylogenetic tree was constructed,and the 16S rDNA gene of willow witches’-broom clustered with members of the 16SrVI-A subgroup;and the virtual RFLP analysis reported that the highest sequence similarity with the one obtained in this study was the reference pattern of the 16SrVI-A subgroup,with a similarity coefficient around 0.98,so the willow witches’-broom phytoplasma in Gansu Province could be classified into the 16SrVI-A subgroup.Meanwhile,the phytoplasma resources were preserved by grafting and identified as vector insects based on amplification of the 16S rDNA gene in the willow shoulder reticulata.