炭疽菌附着胞的研究进展

摘 要：炭疽菌属Colletotrichum Corda 是一类重要的植物病原菌，寄主范围广，对农林生产危害很大。炭疽菌能产生特殊的侵染结构附着胞穿透寄主组织，附着胞的形成对炭疽菌确立侵染非常关键。综述了炭疽菌分生孢子在寄主表面的附着、附着胞的形成、附着胞对环境影响因素的应答和附着胞的穿透。影响炭疽菌附着胞形态发育的因素很多，其中硬质疏水表面在短时间内通常是有利于附着胞的形成。并简要概述了炭疽菌附着胞的基因克隆研究情况。     

大豆铁蛋白cDNA的克隆及植物表达载体的构建

以大豆为材料,利用RT-PCR法扩增得到大小约750bp的片段,将这个片段连接到克隆载体pBlueskript SK＋上进行测序,结果证明,此片段就是大豆的铁蛋白基因。将此片段再正向插入到植物表达载体pBI121的CaMV35s启动子和NOS终止子之间,构建了植物表达载体pBIFe,并成功地将该载体导入根癌农杆菌EHA105。此项工作为获得表达铁蛋白的转基因植物奠定了基础。     

Cloning,Expression and Bioinformatics Analysis of Enterococcus faecalis from Northeast Black Bear

In order to detect Enterococcus faecalis endocarditis antigen (EfaA) of bear that was used to disclose the infected Northeast Black bear immediately, a pair of PCR primers was synthesized by EfaA gene of Enterococcus faecalis that was recorded in GenBank (accession number:U03756.1) and the target fragment was 689 bp. The PCR product was cloned by pMD19-T vector, then was transferred to Escherichia coli DH5α competent cells and the positive clones were filtered. Recombinant plasmid (pMD19-T-EfaA) was extracted. Identification of PCR and digestion, sequencing, the structure prediction of proteins were operated. The results showed that EfaA gene was cloned successfully, and the gene homology with ATCC 29212 was 100.0%. pMD19-T-EfaA was constructed successfully, structure of proteins was predicted. This study provided theoretical basis for diagnostic methods of Enterococcus faecalis and laid basis for prevention and control of Northeast Black bear disease.     

猪乙脑病毒HW株的全基因组克隆及分析

流行性乙型脑炎(Japanese encephalitis virus,JEV)是一种中枢系统人畜共患急性传染病,由蚊为媒介传播,以高热和狂暴或沉郁等神经症状为特征[1],猪患乙型脑炎的主要症状表现为怀孕母猪流产,产死胎或弱仔,公猪则患睾丸炎,仔猪呈神经症状,使养猪业遭受巨大损失。1988年我国学者方     

Embryo-mediated genome editing for accelerated genetic improvement of livestock

Selecting beneficial DNA variants is the main goal of animal breeding. However, this process is inherently inefficient because each animal only carries a fraction of all desirable variants. Genome editing technology with its ability to directly introduce beneficial sequence variants offers new opportunities to modernize animal breeding by overcoming this biological limitation and accelerating genetic gains. To realize rapid genetic gain, precise edits need to be introduced into genomically-selected embryos, which minimizes the genetic lag. However, embryo-mediated precision editing by homology-directed repair (HDR) mechanisms is currently an inefficient process that often produces mosaic embryos and greatly limits the numbers of available edited embryos. This review provides a summary of genome editing in bovine embryos and proposes an embryo-mediated accelerated breeding scheme that overcomes the present efficiency limitations of HDR editing in bovine embryos. It integrates embryo-based genomic selection with precise multi-editing and uses embryonic cloning with elite edited blastomeres or embryonic pluripotent stem cells to resolve mosaicism, enable multiplex editing and multiply rare elite genotypes. Such a breeding strategy would enable a more targeted, accelerated approach for livestock improvement that allows stacking of beneficial variants, even including novel traits from outside the breeding population, in the most recent elite genetic background, essentially within a single generation.     

胡椒4-香豆酸：辅酶A连接酶Pn4CL基因的克隆及表达分析

根据胡椒4-香豆酸：辅酶A连接酶（4-coumarate:coenzyme A ligase, 4CL）基因的部分序列设计引物,运用RACE方法获得其家族成员的1个全长cDNA,命名为Pn4cl,长度2130 bp,开放阅读框1638 bp,编码545个氨基酸。预测Pn4CL分子量为59.57 kDa,理论等电点为5.70。该基因含有AMP-binding（AMP-binding enzyme）、CaiC[Acyl-CoA synthetase (AMP-forming) /AMP-acid ligaseⅡ]、PLN02246、AFD-class I等结合域,具有植物4CL所共有的保守结构域。系统进化分析表明,Pn4CL与北细辛的同源性最高,同时与木兰分支类植物的4CL聚类在一起,与菊分支的进化距离较近,与蔷薇分支的进化距离较远。亚细胞定位表明,该蛋白定位在细胞膜上。Real-time RT-PCR结果表明,该基因受外援激素SA和MeJA诱导表达,同时接种辣椒疫霉菌后,Pn4CL基因的表达量在抗/感2种胡椒中均出现先增加后减少的现象,并且在抗病种质中表达量较高。研究结果为Pn4CL的功能研究提供了理论依据。     

芒果中性/碱性转化酶MiNI基因的克隆与表达分析

采用RT-PCR技术克隆了1个编码NI基因的cDNA序列,命名为MiNI基因,并对不同来源的中性/碱性转化酶的分子特征及系统进化进行比较分析。结果表明：MiNI基因开放阅读框为2034 bp,编码677个氨基酸,相对分子量为76.6 kDa,理论等电点为6.24;生物信息学分析结果显示,NI二级结构α螺旋占38.85%,无规则卷曲占35.45%,伸展链占18.91%,β折叠占6.79%;MiNI具有glycoside hydrolase family 100结构保守域,与克里曼丁桔、龙眼、巴西橡胶树和番木瓜都具有一致的motif位点;MiNI基因编码的氨基酸序列与克里曼丁桔、龙眼氨基酸序列同源性最高;构建NI系统进化树分析表明,与芒果遗传距离最近的是克里曼丁桔,最远的是玉米和枸杞。qRT-PCR分析显示,果皮MiNI基因表达量远高于果肉;花后10~40 d,果皮MiNI基因表达量显著下降;花后40~100 d,果皮MiNI基因表达量维持在一个相对稳定水平;花后100~130 d,随着果实成熟,果皮MiNI基因表达量又显著上升;而花后10~40 d,果肉MiNI基因表达量显著下降,至果实发育后期果肉MiNI基因表达量始终处于极低水平。该研究为进一步了解MiNI基因在芒果果实蔗糖代谢过程中的作用以及从分子角度阐明芒果糖代谢机理奠定理论和技术基础。     

小麦耐冷相关基因TaCTR的克隆及其表达特性分析

低温冷害是小麦生长发育过程中面临的重要非生物逆境因素。为了挖掘小麦耐冷功能基因,本研究采用同源克隆的方法从普通小麦品种小偃22中分离到一个耐冷相关基因TaCTR,该基因序列全长2 192 bp,含有12个外显子、11个内含子,编码区全长为1 407 bp,编码468个氨基酸,分子量约为53.43 kDa;系统进化树分析表明,该基因在进化关系上与山羊草最近;亚细胞定位结果显示,该基因编码的蛋白为膜蛋白;实时荧光定量PCR（RT-PCR）结果表明,TaCTR在不同品种、不同组织和不同发育阶段低温特异表达;在干旱、高盐及GA处理下,TaCTR的表达量显著上升,说明该基因可能参与调控小麦的抗逆反应。     

芜菁Br14-3-3的克隆及其在非生物胁迫下的表达分析

克隆了‘津田芜菁’（Brassica rapa subsp. rapifera‘Tsuda’）通用调节因子14-3-3基因cDNA序列,命名为Br14-3-3（GenBank登录号为MK896872）。该基因全长1 113 bp,开放阅读框全长774 bp,编码含有257个氨基酸的多肽。荧光定量PCR分析Br14-3-3在‘津田芜菁’不同组织中及其在温度、脱水、渗透、ABA和无机盐等非生物胁迫下幼苗中的表达,结果表明该基因在‘津田芜菁’的花中表达量最高,幼苗中次之;低温抑制了Br14-3-3的表达,其他非生物胁迫可诱导该基因表达,暗示Br14-3-3在非生物胁迫应答中发挥功能。