西瓜花叶病毒中国分离株全基因组核苷酸序列测定

Watermelon and melon mosaic disease is the important disease in agricultural production,mostly caused by watermelon mosaic virus.In this paper,the complete nucleotide sequence of watermelon mosaic virus Chinese isolate(WMV-Ch)was firstly determined.Excluding the 3’-terminal poly(A)tail,the genome was 10037 nt long,containing 5’-and 3’-terminal untranslated regions and a large open reading frame.The genome encoded a polyprotein of 3217 amino acids with a predicted Mr of 365.8 kD.Based on comparison with the proposed location of cleavage sites of other potyvirus polyproteins,10 mature proteins were predicted.There were 92.5% nucleotide and 96.4% amino acid identities over entire genome between WMV-Ch and France isolate(WMV-Fr),respectively.The nucleotide identity of the coat protein genes among WMV-Ch and WMV from different countries was all less than 95%,and phylogenetic tree revealed that WMV-Ch was most close to Japanese isolate.

柳树黄化病植原体的分子分类

【目的】柳树黄化病是一种重要的植原体病害,本研究旨在明确柳树黄化病植原体(Willow Yellow phytoplasma,WY)的分类地位,为进一步开展致病性和防治研究奠定基础。【方法】采用植原体特异引物通过PCR方法从患病植株DNA中扩增植原体16S rDNA基因和核糖体蛋白基因(ribosomal proteins gene,rp),对所得的序列进行分析,构建同源进化树,并用限制性片段长度多态性(RFLP)对巢式PCR产物进行分析。【结果】首次从柳树黄化病植原体中分离出了16S rDNA基因和rp基因,大小分别为1246bp和1212bp。通过对植原体16S rDNA和rp基因的核苷酸同源性比较和RFLP分析,发现该分离物与16SrI组的核苷酸同源性均在99%以上,与16SrI-C亚组中的小麦蓝矮病植原体同源性高达99.8%(16SrDNA)和99.6%(rp),且RFLP分析与16SrI-C亚组的植原体有相同的酶切条带。【结论】柳树黄化植原体应划分于16SrI-C亚组。