Bt-Cry5Aa 基因转化棉花及其抗虫性鉴定

我国棉花抗虫基因大都为Cry1Ab/c,抗性风险日趋增加。本研究依据棉花密码子偏好,人工合成Bt-Cry5Aa抗虫基因,通过花粉管通道法转入棉花,并通过卡那霉素法及PCR方法对不同世代转化株进行鉴定,同时进行了抗虫性测试。结果表明,通过花粉管通道法成功获得转Bt-Cry5Aa基因植株,通过田间卡那霉素鉴定,阳性株率T1为7.76%,T2为73.1%,T3为95.5%;PCR检测显示,T1阳性率为2.35%,T2为55.8%,T3为94.5%;田间抗性试验分析,转Bt-Cry5Aa株系对第2、3、4代棉铃虫校正死亡率分别达到85.42%、75.35%和62.79%,其抗虫性与GK19相比差异不显著;Bt-Cry5Aa能够部分替代目前主流鳞翅目抗虫基因,是棉铃虫的新抗源。     

Simultaneous Estimation of Actual Litter Enzymatic Catalysis and Respiration Rates with a Simple Model of C Dynamics in Sphagnum-Dominated Peatlands

C dynamics in soils plays an important role in the interactions between climate and terrestrial ecosystems. Given the importance of the soil C pool in future climate scenarios, accurate models that can then be integrated into global models are required. On the one hand, models of soil C dynamics can be very simplistic in that only solid organic matter (OM) is taken into account with constant rates. Such models can miss important features of soil C dynamics such as enzymatic activity and CO₂ production. On the other hand, some models are too complicated to be experimentally calibrated, tested, and widely used. We propose a model of soil C dynamics that (i) integrates all C fluxes from the solid to the gaseous form, and (ii) can be easily implemented experimentally. Because peatlands are important C stores that are experiencing vegetation changes, the model was tested on experimental results obtained with peatland litter: Sphagnum cuspidatum (autochtonous vegetation), Molinia caerulea, and Betula spp. (both invasive species). Our model was able to accurately describe the early stages of C dynamics in litter especially when only one pool of OM was used and when catalysis and respiration rates were allowed to decrease with time. Our model is efficient in assessing the entire actual catalysis rate. This is a notable achievement as usually, enzyme activity is measured on specific enzymes in conditions often far from actual ones. Our model appeared to be sufficiently robust and worthy of development, keeping in mind that it should remain experimentally testable.     

降香黄檀的DNA条形码鉴定研究

DNA条形码技术是利用基因组中一段短的标准序列进行物种的鉴定并探索其亲缘进化关系。本研究对采自海南不同地区降香黄檀五个居群24份样品的psbA-trnH,rbcL,核ITS及ITS2序列进行PCR扩增和测序,比较各序列扩增和测序效率。种间和种内变异,采用BLAST1和邻接 (NJ) 法构建系统聚类树方法评价不同序列的鉴定能力。结果表明ITS2在所研究的材料中具有最高的扩增和测序效率,而ITS扩增效率较低。ITS2完整序列在区分黄檀属不同种间差异具有较大优势。因此可利用ITS2从分子水平区分降香黄檀与其他混伪种。