菊花绿变病植原体在中国的发生及分子鉴定

对内蒙古农业大学校园内表现花器绿变症状的菊花样品进行采集和DNA提取,应用植原体16S rRNA基因和rp基因的引物进行巢式PCR扩增,从感病样品中分别扩增得到了长度均约为1.2 kb的片段。序列一致性分析表明,菊花绿变植原体16S rRNA基因与翠菊黄化植原体匈牙利风信子株系(GenBank登录号MN080271)、印度玉米株系(KY565571)、印度繁缕株系(KC623537)和印度马铃薯株系(KC312703)的核酸一致性最高,为99.9%,rp基因序列与翠菊黄化植原体立陶宛洋葱株系(GU228514)的核酸一致性最高,为99.8%。基于16S rRNA基因和rp基因构建系统进化树时发现,菊花绿变植原体均与16SrI-B亚组成员聚为一起。16S rRNA基因相似性系数分析表明,菊花绿变植原体与洋葱黄化植原体(AP006628)的相似性系数最高为1.00,洋葱黄化植原体(AP006628)在分类上属于16SrI-B亚组。因此,我们可以确定该菊花绿变植原体属于16SrI-B亚组。这是我国首次报道菊花绿变病的发生。

The occurrence and molecular identification of Chrysanthemum virescence phytoplasma in China

Fresh samples of flowers of Chrysanthemum morifolium with a main symptom of virescence were collected on the campus of Inner Mongolia Agricultural University,and total DNA of the samples was extracted.Using primers for amplifying phytoplasmal 16S rRNA gene and rp gene in nested PCRs,respectively,fragments of around 1.2 kb were generated from the symptomatic samples.Nucleotide sequence identity analysis indicated that the 16S rRNA gene of Chrysanthemum virescence phytoplasma has the highest identity of 99.9%with those of aster yellows phytoplasma clone AJ15(GenBank accession no.MN080271),aster yellows phytoplasma isolate 1(Jammu)(KY565571),Stellaria media phytoplasma clone ChickY2(KC623537),and Solanum tuberosum phytoplasma isolate AKT2(KC312703),respectively;the rp gene showed the highest identity of 99.8% with that of onion proliferation phytoplasma strain OnP2(GU228514).Phylogenetic trees reconstructed from 16S rRNA and rp genes,respectively,indicated that Chrysanthemum virescence phytoplasma is closely related to members of subgroup 16SrI-B.Further,a similarity coefficient of 1.00 was observed between Chrysanthemum virescence phytoplasma and onion yellows phytoplasma OY-M(AP006628)which is a representative strain of subgroup 16SrI-B,suggesting that Chrysanthemum virescence phytoplasma belongs to subgroup 16SrI-B.This was the first record of Chrysanthemum virescence disease in China.