北京口岸进境苗木线虫检出分析

近年来,北京口岸多次从进境苗木中检出植物病原线虫。本文对北京口岸线虫检出情况进行分析,总结了线虫疫情的特点,并提出加强进境苗木检疫监管的工作建议。旨在为提高口岸对进境苗木的检疫监管、降低检疫性线虫传入风险提供参考。     

船检截获的检疫性线虫及传入我国的危险性

马铃薯金线虫、马铃薯白线虫是我国一类危险性有害生物,2000年3月江苏南京、江阴和常州3口岸在进境的国际航行船舶上短时间内连续3次截获该类线虫,其中马铃薯金线虫是我国进境运输工具检疫中首次发现,马铃薯白线虫更是我国检验检疫部门对外检疫中的首次发现,说明进境船舶也是危险性线虫传播的重要途径之一。目前口岸检验检疫局对进境国际航行船舶检验检疫时,对蔬菜上存在的线虫疫情检测力度尚需加强,存在检疫性植物寄生线虫由此途径传入我国的隐患,进境船检时加强线虫检验检疫工作刻不容缓。1　马铃薯金、白线虫的截获和鉴定过程2000年3月15…     

全国口岸进境邮寄物中截获线虫的疫情分析

本文对全国口岸2003~2016年4月从邮寄物中截获的线虫进行了汇总与分析,归纳了邮寄物中截获寄生线虫的种类、来源等,结果表明,全国口岸从邮寄物中共计截获线虫42属、4 448批次,其中包括检疫性线虫11种、49批次,随着邮寄物品数量和种类的增加,邮检中线虫的截获率逐年增加。目前进境邮寄物中线虫的疫情十分复杂,应对进境苗木、植物产品、蔬菜水果等加强检疫监管,以防止线虫疫情进一步扩展。     

深圳口岸从进境旅客携带红掌苗上截获香蕉穿孔线虫

深圳口岸从进境旅客随身携带红掌苗中分离出穿孔线虫,经形态观察和测量,结果表明该线虫为香蕉穿孔线虫。加强进境旅客随身携带花卉苗木及对来自疫区花卉种苗检疫工作,是严防香蕉穿孔线虫及其他危险性有害生物传入的重要措施之一。     

大连口岸进境苜蓿检疫监管及对策

近年来,随着畜牧业的发展,我国对高蛋白含量的美国苜蓿需求日益增大。作为北方重要的港口,大连口岸于2010年4月首次进口美国苜蓿草,截止到10月份,已有6471.43 t,货值达181.77万美元的美国苜蓿从大连口岸进境,其疫情监管形势日益严峻。本文简述了大连口岸进境苜蓿草的检疫流程及检验监管现状,并对存在的问题提出了建议。     

从进境美国苜蓿草中检出4种漆斑菌

本文作者从广东口岸进境的美国苜蓿(Medicago sativa)干草中检出露湿漆斑菌(Myrothecium roridum)、疣孢漆斑菌(Myrothecium verrucaria)、查氏漆斑菌(Myrothecium lachastrae)、禾谷漆斑菌(Myrothecium gramineum)。在我国,至今尚未有上述4种漆斑菌在苜蓿草的发生危害的记录。本文对上述4种漆斑菌的培养性状和形态特征进行描述,以期为口岸对进境苜蓿草漆斑菌的检疫鉴定提供参考。     

亟待加强进境种球花卉上鳞球茎茎线虫的检疫工作

１９９７年元月,南京动植物检疫局检疫邮自荷兰的一批种球花卉时,截获中国禁止进境的二类检疫危险性线虫——鳞球茎茎线虫（Ｄｉｔｙｌｅｎｃｈｕｓｄｉｐｓａｃｉ）在国际邮件中发现该线虫,在口岸检疫尚属首次。今后,随着我国从疫区引进种球类花卉不断增多,该线虫势...     

伞滑刃属线虫专家鉴定系统

近年来,口岸检验检疫机构多次在进境木质包装中截获活体线虫,其中多次截获到伞滑刃属的松材线虫和与其形态相似的拟松材线虫.由于线虫形体细小,种的形态差别不大,一般非专业的工作人员难以进行鉴定.     

南海口岸进境林木种苗线虫检疫情况分析

本文汇总了2008～2010年南海口岸进境林木种苗的线虫截获情况,共截获15科26属超过40种植物寄生线虫,其中检疫性线虫有7种,分别为短体线虫(非中国种)Pratylenchus Filipjev(non-Chinese species)、毛刺线虫属(传毒种类)Trichodorus Cobb(The species transmit viruses)、根结线虫(非中国种)Meloidogyne Goeldi(non-Chinese species)等;根据携带线虫状况分析了检疫性线虫的截获情况,提出了防止危险性线虫入境、扩散措施,为口岸防止线虫入境提供借鉴。     

增城口岸频频截获松材线虫

20 0 0年 1 0月 1 2日 ,我局检验检疫人员在口岸码头作业区进行检疫查验过程中 ,发现增城某公司装载由美国进口、出具无木质包装声明染色牛皮纸的集装箱底板上用于固定货物的钉板为针叶材 ,蓝变症状明显 ,且伴有发霉现象。取样回实验室浸泡检验 ,2天后分离到 3种线虫活体 ,经鉴定为松材线虫、滑刃线虫及小杆线虫。经广州局食品与动植物检疫技术中心复核无误。这是自 2 0 0 0年第 2 3号公告及 1 4号局令生效以来我局第 3次从美、日进境木质包装中截获松材线虫。这之前我们已先后于 2 0 0 0年 6月从日本进境、出具非针叶树声明及 2 0 0 0年 9…     

土壤表面积水深度对入渗的影响

采用HYDRUS-1D模型,对积水入渗问题进行了数值模拟,并分析了积水深度变化对入渗的影响.采用土柱降雨入渗的观测数据进行模型参数率确定及验证,结果表明HYDRUS-1D模型具有良好的模拟效果.进而,使用HYDRUS-1D模型模拟不同积水深度下的土壤含水量变化情况,分析发现,在不同的积水深度情况下,土柱表面入渗通量有较明显的差异,积水深每降低0.5 cm,同一时间相同观测点位置处土壤含水量减少1.2%～2.8%,当上表面水头逐渐增大时这种现象更加明显.     

马铃薯腐烂茎线虫28S rDNA-D2/D3区序列分析

 我国危害甘薯的马铃薯腐烂茎线虫rDNA-ITS基因片段长度存在A型(900bp)和B型(1100bp)2个类型,A型腐烂茎线虫群体的ITS片段比B型群体少200bp。为了进一步研究这2种类型群体的发育关系,本文用线虫通用引物D2A和D3B对来自国内的21个马铃薯腐烂茎线虫群体和1个韩国的马铃薯腐烂茎线虫28SrDNA-D2/D3区进行了PCR扩增,均产生大小一致的片段,长度约为780bp,克隆、测序后用DNAMAN5.2软件和MEGA4软件进行分析比对,结果表明我国21个马铃薯腐烂茎线虫群体28SrDNA-D2/D3区只有20余个碱基的差异,相似率达97.2%。基于UPGMA构建的系统发育树很好地区分了马铃薯腐烂茎线虫A型和B型群体,展现出了群体的来源及发育关系。     

利用28S rDNA D1/D2区和ITS rDNA序列鉴定甜瓜白粉病病原菌

为了明确宁夏干旱带压砂甜瓜白粉病病原菌,从病原菌分生孢子中提取DNA,PCR扩增ITSrDNA和28S rDNA D1/D2区段,测序后进行BLAST比对.结果表明,病原菌的ITS rDNA和28SrDNA D1/D2序列与菜豆叉丝单囊壳白粉菌Podosphaera phaseoli、凤仙花又丝单囊壳白粉菌P.bal-saminae、菊科叉丝单囊壳白粉菌P.fwca、苍耳单囊壳白粉菌P.xanthii、瓜类单囊壳白粉菌P.fuligi-nea等叉丝单囊壳属Podosphaera的多个种的ITS rDNA和28S rDNA D1/D2序列之间相似度均大于99%,鉴定甜瓜白粉病病原菌为叉丝单囊壳属Podosphaera.     

从子囊菌炭球菌中分离的活性成分L-696,474和cytochalasin D对植物病原真菌的活性

在我国云南省高等真菌中寻找新的天然农用抗真菌活性物质时,发现炭球菌子实体甲醇提取物具有较强的离体抗真菌活性。采用生物活性追踪和化学分离相结合的方法,从中分离得到2个具有较强农用抗真菌活性化合物,经红外、质谱、氢谱和碳谱确定其为L-696,474和cytochalasin D。在离体和活体条件下分别测定了L-696,474和cytochalasin D对10种植物病原菌的菌丝抑制率和2种植物病原菌的孢子萌发率,并评价了其对小麦白粉病的治疗和保护作用。结果表明:小麦纹枯病菌、油菜菌核病菌对L-696,474最为敏感,浓度为10μg/mL时菌丝抑制率分别为83.5%和82.9%;小麦赤霉病菌、小麦全蚀病菌、油菜菌核病菌、小麦叶枯病菌和苹果炭疽病菌对cytochalasin D最为敏感,浓度为10μg/mL时菌丝抑制率分别为83.6%、82.4%、81.9%、80.5%和79.7%。L-696,474和cytochalasin D在200μg/mL时完全抑制苹果炭疽病的孢子萌发;在500μg/mL时对小麦白粉病10天后的治疗作用分别为74.3%和85.7%,保护作用为67.1%和79.5%。     

The carboxyterminal processing protease of D1 protein: Herbicidal activity of novel inhibitors of the recombinant and native spinach enzymes

The carboxyterminal processing protease of D1 protein (CtpA) is predicted to be an excellent target for the discovery of a general broad-spectrum herbicide. Directed and random screening of compounds against recombinant spinach CtpA (rCtpA) has led to the discovery of five different chemical classes of inhibitors. Lead compounds from each inhibitor class were investigated for their in vitro effects on the activities of both recombinant and native spinach CtpA. All of the lead compounds have K_i values of less than 50 μM when tested against rCtpA, and all except one showed competitive inhibition. Results from partially purified native CtpA from spinach were similar to those from the recombinant form of the enzyme, thus validating the use of rCtpA in the inhibitor screen. Compounds from three of the classes of CtpA inhibitors show in vivo herbicidal activity against Arabidopsis thaliana when applied either by addition to growth media or by spraying the leaves. Transgenic Arabidopsis plants which over-express CtpA showed greater resistance to the compounds than wild-type plants providing evidence that these inhibitors are directly acting against CtpA.     

甘肃小麦禾谷孢囊线虫rDNA-ITS和28S rDNA-D2/D3区序列特征及ITS-RFLP分析

禾谷孢囊线虫是危害禾谷类作物的重要病原,严重威胁我国小麦主产区的小麦产量和品质。利用通用引物对甘肃、河南、安徽禾谷孢囊线虫群体28SrDNA-D2/D3区和rDNA-ITS区进行PCR扩增和序列测定,利用UPG-MA方法分析了甘肃省7个种群、河南1个种群、安徽1个种群的禾谷孢囊线虫群体D2/D3区和ITS区的系统发育关系;用9种限制性内切酶对7个甘肃禾谷孢囊线虫群体的rDNA-ITS区进行了RFLP分析。结果表明:中国甘肃的禾谷孢囊线虫rDNA-D2/D3区片段长度约为780bp,rDNA-ITS片段长度约为1040bp。7个甘肃禾谷孢囊线虫群体、1个河南安阳群体、1个安徽蚌埠群体的D2/D3区和新西兰的H.aucklandica群体亲缘关系很近;其ITS区同澳大利亚的H.australis、北京通州的H.avenae(AY148382)的亲缘关系很接近。RFLP分析表明,9种限制性内切酶酶切禾谷孢囊线虫群体的rDNA-ITS共产生了22个酶切片段,不同酶切的RFLP分布型在7个种群间没有差异。甘肃省禾谷孢囊线虫群体的rDNA-ITS区具有高度的保守性,与中国的C型群体相近,但不同于欧洲的A型群体和印度的B型群体。这是首次报道甘肃CCN种群分子特征。     

The carboxyterminal processing protease of D1 protein: expression, purification and enzymology of the recombinant and native spinach proteins

The carboxyterminal processing protease of D1 protein (CtpA) is predicted to be an excellent target for a general broad-spectrum herbicide. The gene for spinach CtpA has been expressed in Escherichia coli. The expressed protein that was found mainly in inclusion bodies has been purified and refolded on a nickel-chelate column. Active recombinant CtpA was recovered. Two assays for CtpA activity were developed, a medium-throughput HPLC assay using a fluorescent substrate and a high-throughput assay based on fluorescence polarization capable of application in a high-throughput 96-well plate format. This high-throughput assay was developed to screen chemistry for CtpA inhibitors. Native spinach CtpA was partially purified and the native and recombinant enzymes were compared kinetically for their K(m) and V(max) values using different peptide substrates. Native CtpA partially purified from spinach was shown to have similar kinetic properties to recombinant CtpA. Antibodies developed against the recombinant protein were used to estimate the in planta abundance of the native enzyme in spinach. Since only a small proportion of the recombinant protein is refolded during isolation and it appears that only a small proportion of this enzyme is active, size-exclusion chromatography and light scattering experiments were performed on rCtpA in order to gain insight into its structure and the reasons why most of the protein is not active. The use of rCtpA to screen for herbicidal compounds and the more general question of how good a herbicide target the enzyme is are discussed.     

Hydrus-3D模型模拟田间点源入渗与水分再分布准确性评价

滴灌条件下水分入渗与再分布是评价滴灌灌溉效率的重要内容,通过Hydrus3D模型模拟单点源和点源交汇情况下水分入渗及其再分布过程,并利用田间试验实测资料进行验证。结果表明:采用Hydrus3D软件建立的模型可较好地模拟单点源水分入渗、水平湿润锋扩散过程及土壤剖面水分的分布情况,水平湿润锋距离的模拟值和实测值的误差在灌水结束时达到最大,且滴头流量越大,误差亦越明显,其中最大绝对误差为4.6 cm,最大相对误差达0.167,R2在0.95以上,F检验P值大于0.05,且RMSE在2.1以内;模型模拟的土壤体积含水量分布和实测值基本一致,模拟值和实测值的R2在0.90以上,F检验P值大于0.05,RMSE均小于0.07;湿润范围模拟结果和实测结果的吻合度较高。灌水结束后20 h,模拟土壤剖面含水量的分布情况与实测值基本一致,模拟值和实测值R2在0.575~0.652之间,F检验P值大于0.05,RMSE在0.013左右,双点源交汇区整个剖面模拟值和实测值R2为0.526以上,F检验P值大于0.05,RMSE均小于0.01,模拟结果较好,说明Hydrus3D模型可模拟土壤水分再分布情况。     

Biological control mechanisms of D-pinitol against powdery mildew in cucumber

D-pinitol is an effective agent for controlling powdery mildew (Podosphaera xanthii) in cucumber. In this study, we determined the mechanisms of D-pinitol in controlling powdery mildew in cucumber plants. We compared P. xanthii development on cucumber leaf surface treated with D-pinitol or water (2 mg ml⁻¹) at different time points after inoculation. The germinating conidia, hyphae, and conidiophores of the pathogen were severely damaged by D-pinitol at any time of application tested. The highest level of suppression of fungal development was obtained at 3 days after inoculation. The contents of chlorophyll, total phenolics, flavonoid, and gallic acid and its derivatives (GAD); the activities of phenylalanine ammonialyase (PAL), polyphenoloxidase (PPO), peroxidase (POX), and superoxide dismutase (SOD); and the expression of the genes encoding for PR-1, peroxidase (POX), lipoxygenase (LOX1), chitinase (Chit1) were higher in the cucumber leaves treated with D-pinitol and inoculated than in the leaves either treated with D-pinitol or inoculated with the pathogen. These results suggest that D-pinitol triggers several plant defense responses in cucumber leading to pathogen suppression and resistance to powdery mildew.