苹果球壳孢腐烂病菌在中国的适生性及其入侵风险

为明确我国禁止进境的植物检疫性真菌有害生物——苹果球壳孢腐烂病菌Sphaeropsis pyriputrescens在中国的适生性以及入侵风险,采用专家评判的生物学建模方法确立了其适生性评判标准,运用ArcGIS软件分析其在我国的适生范围和适生程度;同时采用多指标综合评判法量化分析该病菌入侵我国的风险等级。结果表明,苹果球壳孢腐烂病菌在我国具有很广阔的适生范围,中、高度适生区随季节变化明显。1—4月,中、高度适生区从南到北逐渐扩大;6月,高度适生区扩展到东北和新疆北部;9—10月,在苹果采摘前期和采摘期,苹果球壳孢腐烂病菌处于侵染活跃期,其高度适生区域面积最大,包含了陕西、河北、山东、甘肃、辽宁、河南、山西等我国苹果和梨主产区。按照有害生物多指标综合评判法,对15项评估指标进行赋值,计算所得风险综合评价值R为2.54,该病菌入侵我国的风险等级属特别危险。     

BTV-16四结构蛋白的共表达与病毒样颗粒的制备

目前疫苗免疫是预防蓝舌病的主要有效手段,蓝舌病病毒样颗粒(VLPs)疫苗是蓝舌病疫苗研究的热点之一。为了制备蓝舌病病毒血清16型(BTV-16)病毒样颗粒,研究对载体pFastBac-Dual进行了改造,使其具有4个独立启动子的多克隆位点。依次将BTV-16 VP2、VP5、VP3和VP7基因插入到改造后载体(pF4)的4个多克隆位点中,成功构建了四表达重组质粒pF4-VP2-VP5-VP3-VP7,经转座获得重组杆粒Bacmid-VP2-VP5-VP3-VP7。通过转染Sf9细胞,获得可表达4种蛋白的重组杆状病毒rBac-VP2-VP5-VP3-VP7。经重组杆状病毒感染Sf9细胞,可共表达蛋白VP2、VP5、VP3和VP7,并通过蔗糖梯度离心制备出具有典型特征的BTV-16病毒样颗粒。     

Study on burrowing nematode,Radopholus similis,pathogenicity test system in tobacco as host

Radopholus similis (Cobb 1893) Thorne (1949) is a destructive migratory endoparasitic plant nematode. In this study, the pathogenic process of R. similis infection in Nicotiana benthamiana (tobacco) was studied using quartz sand culture in laboratory. The results showed that R. similis mainly parasitised the root cortex, leading to cortical cell decomposition and tissue decay. We optimised the inoculation conditions to establish a method for determining the pathogenicity of R. similis as follows: (1) a glass culture tube was filled with quartz sand (about 1/3 of the height) and sterilised twice; (2) 20-day-old N. benthamiana seedlings were transplanted into test tubes and cultivated for 10 days at (25±1)°C; (3) R. similis female nematodes were inoculated in the root rhizosphere at a rate of 150 nematodes per plant; (4) the number of nematodes, disease severity, and growth of the plant at 30 days post-inoculation (dpi) were determined. The pathogenicity of eight R. similis populations from different hosts was determined, which proved the feasibility of this method.