小麦与条锈菌互作中过氧化物酶的细胞化学研究

采用细胞化学方法对小麦与条锈菌互作过程中过氧化物酶的分布及其活性大小进行了研究,结果表明：过氧化物酶主要分布于细胞壁和细胞间隙中;在未行接种的小麦叶片中,抗病品种和感病品种的过氧化物酶活性均比较低;条锈菌侵染后,诱导抗、感病品种叶片中的过氧化物酶活性升高,且抗病品种升高的幅度明显大于感病品种;感病品种中过氧化物酶活性在侵染位点附近细胞壁上表现升高,而抗病品种中该酶的活性在侵染点细胞以及远离侵染点的叶肉细胞的细胞壁和细胞间隙中均显著升高。高活性的过氧化物酶是小麦抗条锈性的生化标记和重要机制之一。     

水稻与白叶枯病菌互作机制研究进展

水稻白叶枯病由Xanthomonas oryzae pv.Oryzae(Xoo)致病菌引起,为水稻三大病害之一,对世界水稻生产造成了严重危害.水稻与Xoo互作符合“基因对基因”假说,是研究植物与细菌互作的典型模式系统.水稻基因组以及Xoo基因组测序的完成,极大地推动了水稻-Xoo互作分子机理的研究.就有关水稻与Xoo互作机制的最新研究进展作一概述.     

烟草受精前后胚囊中钙调素的免疫细胞化学定位

应用辣根过氧化物酶标记抗体的光镜免疫细胞化学技术和胶体金标记抗体的电镜免疫细胞化学技术定位烟草（Ｎｉｃｏｔｉａｎａｔａｂａｃｕｍｖａｒ．ｍａｃｒｏｐｈｙｌａ）胚囊成员细胞中的钙调素,比较了不同类型细胞之间钙调素的分布特点,并探讨了受精前后钙调素在胚囊中分布的变化规律。     

蚕豆保卫细胞中钙调素的免疫电镜定位

以蚕豆横切和平切气孔为材料,对钙调素进行了免疫胶体金电镜定位的结果表明:在蚕豆保卫细胞的细胞核、细胞质、细胞膜、叶绿体、液泡、高尔基体、细胞壁中都有金颗粒分布,在线粒体上的分布较少.     

玉米根尖细胞内钙调素的胶体金免疫电镜定位

钙调素(Calmodulin,简称CaM)抗体是研究CaM的特异性生物探针,常被用来研究CaM的定量和分布.CaM分布的研究不仅对揭示细胞内CaM的作用位点有重要意义,而且还可深入探讨CaM的功能.     

R-Avr基因互作介导的植物抗病性

Ｒ－Ａｖｒ基因互作介导的植物抗病性李汝刚范云六伍宁丰李茂林（中国农业科学院生物技术研究中心,北京１０００８１）植物在整个生长发育周期中面临着种类繁多的病原微生物袭击,但真正能引起植物病害的病原并不多,这表明植物能抵抗大多数病原微生物袭击,表现非亲合性...     

Avr／Cf互作诱发番茄Pto互作因子Pti编码基因的表达

植物抗病基因Pto和Cf产物具完全不同的结构域,其细胞定位也不同。二决定的抗病性产生机制的异同令人关注。采用两种过敏性反应（hypersensitive response,HR）产生系统研究了Pro互作蛋白Pti4,Pti5和Pti6编码基因在Avr/Cf互作中的时序表达：（1）通过杂交方法获取同含互补基因对Avr4/Cf-4和Avr9/Cf-9的番茄（Lycoper-sicon esculentum Mill.）种子,常温下这些种子发芽后形成的苗产生HR坏死斑。（2）先将Avr/Cf苗置于33℃下培养,此时番茄苗生长正常,不形成HR坏死斑。然后将温度降至25℃,数小时内这些苗即形成HR坏死斑。不同方法研究结果均表明,随Avr/Cf苗中HR坏死斑的形成,Pti4、Pti5和Pti6均受显诱导表达。但它们的表达水平和动态不同,这些结果表明,这些Pti在功能上互补,可能同时涉及Pto和Cf决定性抗性的调节作用。     

白芷培养细胞外钙调素结合蛋白的胶体金电镜定位研究

利用胶体金标记技术制备了具有生物活性的植物CaM-BSA-gold探针,并用此探针建立了白芷愈伤组织培养细胞胞外钙调素结合蛋白(CaMBPs)的透射电镜标记方法。标记结果显示,在1mmol/L Ca~(2 )存在下,用EGTA洗涤过的白芷愈伤组织培养细胞壁表面有金颗粒分布,而分别在含有EGTA、TFP、过量未标记的CaM、CaM抗体存在的情况下,用金标CaM探针进行标记.以及用金标羊抗兔抗体替代金标CaM探针进行标记的各对照组,细胞壁表面金颗粒则消失,说明白芷愈伤组织培养细胞壁表面存在着CaM结合位点或CaMBPs。     

互作基因定位方法的研究和计算机软件的开发

质量性状中存在6种可能的基因互作类型, 即互补、重叠、累加、显性上位、隐性上位和抑制。在遗传研究中, 有时会遇到互作基因定位的问题, 但至今未见有关互作基因定位方法和计算机软件的系统的研究报道。文章给出了基于极大似然估计的互作基因定位方法及相应的计算机软件(IGMapping 1.0)。计算机模拟表明, 此方法可以无偏地估计一个共显性标记与一个互作基因之间的重组率或连锁距离。     

白芷培养细胞外钙调素结合蛋白的胶体金电镜定位研究

利用胶体金标主民技术制备了具有生物活性的植物Ｃａｍ－ＢＡＳ－ｇｏｌｄ探针,并用此探针建立了白芷愈伤组织培养细胞下调素结合蛋白的透射电镜标 记方法。标记结果显示,在１ｍｍｏｌ／ＬＣａ＾２＋存在下,用ＥＧＴＡ洗涤过的白芷愈伤组织培养细胞壁表面有金颗粒分布,而分别在含有ＥＧＴＡ、ＴＦＰ、过量未标记的ＣａＭ、ＣａＭ抗体存在的民政部下,用金示ＣａＭ探针进行标记,以及用的各对照组,细胞壁表面金颗粒则消失,说明     

CAPS and DHPLC Analysis of a Single Nucleotide Polymorphism in the Cytochrome b Gene Conferring Resistance to Strobilurins in Field Isolates of Blumeria graminis f. sp. hordei

A single nucleotide polymorphism in the wheat powdery mildew (Blumeria graminis f. sp. tritici) cytochrome b gene is responsible for resistance to inhibitors of the quinol outer binding site of the cytochrome bc₁ complex (QoI) fungicides. Analysis of a partial sequence of the cytochrome b gene from field isolates resistant and sensitive to QoI fungicides revealed the same point mutation in barley powdery mildew (B. graminis f. sp. hordei). Analysis of 118 and 40 barley powdery mildew isolates using a cleaved amplified polymorphic sequence assay and denaturing high performance liquid chromatography, respectively, confirmed that this single nucleotide polymorphism also confers resistance to QoI fungicides in barley powdery mildew.     

Genetics of Powdery Mildew Resistance in Barley

A comprehensive, critical review on the present knowledge regarding the genetics of resistance of barley to the powdery mildew fungus is presented. The review deals with six kinds of resistance: Race-specific resistance; Mlo resistance; partial resistance; induced resistance; passive resistance; and non-host resistance. Most of the sections are subdivided into: phenotype of the interaction; resistance mechanisms; and genetics. A distinction is made between three groups of genes involved in the defense of plants to diseases: those that serve exclusively to mediate resistance; those that are mobilized to strengthen the plants' defense; and those that serve exclusively functions other than disease defense, but may bring about resistance. The more than 200 gene symbols assigned to race-specific mildew resistance genes over time are summarized and revised to 85 symbols that may be considered valid.     

Interaction of a Blumeria graminis f. sp. hordei effector candidate with a barley ARF‐GAP suggests that host vesicle trafficking is a fungal pathogenicity target

Filamentous phytopathogens, such as fungi and oomycetes, secrete effector proteins to establish successful interactions with their plant hosts. In contrast with oomycetes, little is known about effector functions in true fungi. We used a bioinformatics pipeline to identify Blumeria effector candidates (BECs) from the obligate biotrophic barley powdery mildew pathogen, Blumeria graminis f. sp. hordei (Bgh). BEC1–BEC5 are expressed at different time points during barley infection. BEC1, BEC2 and BEC4 have orthologues in the Arabidopsis thaliana‐infecting powdery mildew fungus Golovinomyces orontii. Arabidopsis lines stably expressing the G. orontii BEC2 orthologue, GoEC2, are more susceptible to infection with the non‐adapted fungus Erysiphe pisi, suggesting that GoEC2 contributes to powdery mildew virulence. For BEC3 and BEC4, we identified thiopurine methyltransferase, a ubiquitin‐conjugating enzyme, and an ADP ribosylation factor‐GTPase‐activating protein (ARF‐GAP) as potential host targets. Arabidopsis knockout lines of the respective HvARF‐GAP orthologue (AtAGD5) allowed higher entry levels of E. pisi, but exhibited elevated resistance to the oomycete Hyaloperonospora arabidopsidis. We hypothesize that ARF‐GAP proteins are conserved targets of powdery and downy mildew effectors, and we speculate that BEC4 might interfere with defence‐associated host vesicle trafficking.     

Pathotypes of Blumeria graminis f. sp. tritici,the causal agent of wheat powdery mildew from some regions of Iran

Wheat powdery mildew is controlled mainly by race-specific resistance. To be effective, breeding wheat for resistance to powdery mildew requires knowledge of virulence diversity in local populations of the pathogen. Isolates of Blumeria graminis, collected in 2009 and 2010 from three areas of Iranian production, were analysed for virulence using a host differential series comprised of 16 known genes conferring resistance to powdery mildew. The results showed that high-virulence frequencies to genes Pm1, Pm2, Pm4a, Pm5, Pm6, Pm7, Pm8 and Pm9 were found over both years and across all three areas. Virulence frequencies for Pm3a and Pm3b were intermediate, while virulence frequencies for Pm3a, Pm3c, Pm4a and Pm2, 6 were low. Genes Pm1, 2, 9 and Pm2, 4b, 8 were highly resistant in all regions. Virulence to Pm8 increased to high levels, while virulence to Pm4a decreased across the area surveyed from 2009 to 2010.     

Fusarium oxysporum f. sp. radicis-lycopersici can Induce Systemic Resistance in Barley Against Powdery Mildew

Drench inoculation of the undisturbed roots of barley seedlings with Fusarium oxysporum f. sp. radicis‐lycopersici (FORL) significantly reduced the primary infection frequency of Blumeria graminis f. sp. hordei (BGH) on the first leaves. The length of secondary hyphae and subsequent conidial production of BGH were also found to be significantly reduced by preinoculation with FORL. The reduction in infection frequency was observed as early as 48 h after inducer treatment, namely when plants were challenge‐inoculated immediately following inoculation with FORL. The induced resistance continued up to 16 days after treatment as indicated by the reduction in infection frequency, up to 22 days after treatment when evaluated as a reduction in the length of secondary hyphae, and up to 35 days after treatment when evaluated as a reduction in conidial production. Characteristics of FORL that may explain its success as an inducer of resistance against barley powdery mildew are discussed.     

受白粉菌诱导大麦抗感等基因系蛋白质变化的双向电泳分析

分别对接种与否的大麦抗—感白粉病等基因系—叶期幼苗取材进行蛋白质双向电泳分析。结果表明,病原的侵入使抗—感两系在30Kd以下的低分子量区域的蛋白质发生了明显变化。接种48小时之后,抗病系在pH5.5、6.0、6.8及8.8附近出现了对照中所没有的蛋白质,而在pH6.0和8.8附近的蛋白质则较对照有减小的趋势;感病系在pH6.0附近蛋白质明显增多,在pH8.8处不仅在量上有大幅度提高,而且种类也有增加。结果还表明,抗—感系间在未接种的情况下双向电泳图谱也有差异,接种之后由于感病系在pH8.8处蛋白质的特异性合成,使抗—感两系间的差异缩小。     

Cloning and Expression Analysis of a Putative ABC Transporter Gene BgABC1 from the Biotrophic Pathogenic Fungus Blumeria graminis f. sp. tritici

A putative ATP‐binding cassette (ABC) transporter gene (BgABC1) was isolated from the biotrophic pathogenic fungus Blumeria graminis f. sp. tritici (Bgt). Analysis of the deduced amino acid sequence of BgABC1 showed that the BgABC1 protein had a conserved nucleotide‐binding fold in the N‐terminus, and six transmembrane domains (TMDs) in the C‐terminus. Analysis of the BgABC1 expression using real‐time polymerase chain reaction showed that expression of the gene was increased significantly when the fungus was growing in wheat seedlings treated with 14α‐demethylase‐inhibiting fungicide, triadimefon. The results indicated that the BgABC1 was involved in the protection of the fungus against fungicide toxicity.     

小麦秆锈菌生理小种21C3CPH和Ug99 SSR标记的筛选

小麦秆锈病是一种专化性很强的大区远距气传病害,曾造成多个小麦种植国家和地区的毁灭性损失,新的强毒力小种Ug99含有对Sr31等多个重要抗秆锈基因的联合毒性,对我国的小麦生产有巨大潜在威胁,因此,加强小麦秆锈菌生理小种的监测和鉴定是有效防治该病害的基础性研究工作和关键环节。现代分子生物学的迅猛发展,为许多研究提供了新的方法和手段,分子标记技术在区分小麦秆锈菌生理小种方面显示了充分的可行性。本研究利用25对SSR引物对7个小麦秆锈菌主要生理小种进行DNA多态性分析,结果显示,所有特异引物对秆锈菌的扩增结果均呈现出丰富的多态性,秆锈菌的不同生理小种之间存在遗传差异。其中引物SSR180在21C3CPH中扩增出205bp的特异性条带;引物SSR6在Ug99中扩增出170bp的特异性条带,经过多次的重复试验,这些特异性条带均能够比较稳定地重复出现,说明引物SSR180和SSR6可用于小种21C3CPH和Ug99的特异性检测。