共查询到18条相似文献，搜索用时 500 毫秒
1.
小麦穗组织中脱氧镰刀菌烯醇毒素的免疫细胞化学定位 总被引：5，自引：0，他引：5
采用免疫细胞化学技术对禾谷镰刀菌(Fusarium graminearum)在侵染小麦穗部过程中产生的脱氧镰刀菌烯醇毒素(deoxynivalenol,DON)进行了定位分析。在接种后24h,当菌丝在外稃、内稃的内侧表面扩展而尚未侵入寄主细胞前,病菌已分泌DON,并且DON已扩散到寄主组织内。在菌丝细胞内,DON主要被定位于细胞质、线粒体及细胞壁上;在寄主细胞中DON主要分布于细胞壁、叶绿体、细胞质和内质网上。在侵染初期(接种后2 d),菌丝仅能在寄主细胞间隙扩展,随寄主组织中DON浓度的升高,寄主细胞相应发生了一系列病理变化。随寄主细胞坏死(接种后3~4d),病菌进入坏死的寄主细胞。上述结果表明,DON在禾谷镰刀菌的侵染、致病和定殖过程中起着重要的作用。毒素标记结果表明病菌产生的毒素可通过穗轴微管束组织从侵染部位向上、向下转输,毒素向上的转输量明显高于向下转输 相似文献
2.
戊唑醇抑制苹果树腐烂病菌的形态毒理学研究 总被引：1，自引：0，他引：1
为揭示苹果树腐烂病防控常用药剂戊唑醇的杀菌机理,本研究通过显微技术观察了戊唑醇对苹果树腐烂病致病菌苹果黑腐皮壳菌Valsa mali 孢子萌发、菌丝形态及细胞结构的影响。结果发现:戊唑醇能够抑制病原菌孢子萌发,但不影响孢子的膨大,主要是抑制其芽管的伸长,使芽管畸形、增粗、分枝增多等,从而不能正常侵入寄主。经戊唑醇处理后,病原菌菌丝形态和细胞结构均发生了明显变化,主要表现为:菌丝顶端膨大、分枝增多,菌丝增粗等;细胞隔膜增多且不规则增厚,细胞壁不规则增厚,线粒体增多、膜增厚或不规则缢缩,细胞核增多、核仁弥散,细胞液泡化严重,形成空腔,原生质外渗,细胞最终坏死等。同时,在已坏死的菌丝内可发现子菌丝,且子菌丝也表现出异常现象,如细胞壁不规则增厚、线粒体数量增多及细胞质坏死等。研究表明,戊唑醇不仅对苹果树腐烂病菌孢子萌发具有一定影响,并可导致芽管和菌丝细胞畸形,从而显著抑制病菌的成功侵染。该结果可为采用戊唑醇淋刷树干进行病害预防提供理论依据。 相似文献
3.
禾谷镰刀菌在小麦穗部侵染过程的细胞学研究 总被引：8，自引：0，他引：8
采用扫描和透射电镜技术系统地观察了禾谷镰刀菌(Fusarium graminearum)在小麦穗部的侵染过程。接种后6~12 h,分生孢子在小麦穗部的任何部位均可萌发,每个孢子可产生1至多个芽管,新产生的芽管并不立即入侵寄主组织,而是在寄主体表生长扩展;接种后36~48 h观察,小穗颖片、外稃、内稃的内侧和子房的表面形成了密集的菌丝网,然而在小麦穗轴表面、颖片和内稃的外表面,菌丝生长缓慢、分布稀疏,但颖片外表边缘的菌丝可跨越边缘扩展到颖片的内表皮上;接种后36 h,寄主体表菌丝产生入侵菌丝,以直接入侵方式由颖片、外稃、内稃的内侧及子房的顶部侵入寄主组织体内,随后,菌丝以胞间和胞内生长的方式向下扩展;接种后4~5 d,菌丝由上述组织扩展到达穗轴后,在穗轴内沿微管束组织和皮层组织向上和向下扩展,延伸到相邻小花,随菌丝在小麦穗部组织内不断地生长扩展,使得寄主细胞坏死、解体,并最终导致整个麦穗的枯死。 相似文献
4.
多堆柄锈菌侵染玉米的细胞学及超微结构特征 总被引：2，自引：1，他引：1
为明确玉米对多堆柄锈菌Puccinia polysora侵染后病理反应的细胞学特征,利用扫描和透射电镜技术分析了玉米自交系与多堆柄锈菌互作中二者的细胞变化过程。多堆柄锈菌对玉米的侵染主要以直接穿透叶片表皮侵入为主,少量可从气孔和细胞间隙侵入。接种后,病菌夏孢子在感病自交系叶片上快速并大量萌发,在叶表生长蔓延并侵入表皮组织细胞,7 d后形成夏孢子堆;在抗病自交系上,病菌萌发、菌丝生长均受到明显抑制,少量入侵的病菌也由于寄主细胞死亡而导致菌丝和夏孢子干瘪死亡。侵染早期在感病寄主细胞间隙出现菌丝并穿透细胞壁,在胞内产生分枝菌丝,此时寄主细胞结构正常;随着菌丝进一步扩展,叶绿体等结构发生紊乱,被侵染细胞逐渐死亡。在抗病自交系上,接菌24 h后寄主即出现过敏性坏死反应,侵入位点与周围细胞快速坏死,抑制菌丝生长蔓延;叶绿体中清晰可见深色颗粒状物质;72 h后细胞壁外侧产生大量致密的深色结晶体,应为与抗病反应相关的酚类物质。表明抗多堆柄锈菌的玉米材料可能存在2种抗病途径,即寄主与病菌互作中由分子识别引起的免疫反应和病菌侵入后的系统防卫反应。 相似文献
5.
为了筛选出防治苹果炭疽叶枯病的有效杀菌剂, 采用室外先接种后施药和先施药后接种的方法, 测试了6种药剂的内吸治疗效果和8种药剂的保护效果。在病菌侵染后的72 h内使用吡唑醚菌酯, 或在病菌侵染后的24 h内使用咪鲜胺对病斑的显症有一定的治疗效果。波尔多液在喷施后18 d, 对炭疽叶枯病菌侵染的抑制效果仍达50%, 肟菌?戊唑醇、烯酰?吡唑酯和唑醚?代森联3种药剂在施药后的第11天, 其保护效果与对照仍有显著差异, 持效期达11 d, 代森锰锌、甲基硫菌灵、氢氧化铜和咪鲜胺4种保护剂的持效期只能维持6 d。炭疽叶枯病的防治应以波尔多液为主, 并与吡唑醚菌酯等有机杀菌剂交替使用, 有机铜制剂不能替代波尔多液。 相似文献
6.
大豆疫霉菌对大豆下胚轴侵染过程的细胞学研究 总被引：3，自引：0，他引：3
接种后1.5~24h,用光镜和电镜研究了2个大豆品种与大豆疫霉菌Ps411的亲和性和非亲和性互作。观察结果表明,大豆疫霉菌对大豆下胚轴的侵染过程可分为侵入前、侵入、皮层组织中的扩展和进入维管束组织4个连续阶段。大豆下胚轴接种后在25℃保湿培养,1.5h后游动孢子即形成休止孢并萌发产生附着孢,3h后侵入表皮细胞,6h后进入皮层组织,24h后进入维管束组织。病原菌主要以侵染菌丝直接侵入表皮,表皮细胞间隙是主要侵入部位。皮层细胞是病原菌定殖和发展的主要场所,胞间菌丝侵入皮层细胞并形成吸器。在菌丝与寄主细胞接触部位的寄主细胞壁与质膜之间常有胞壁沉积物的形成。在抗病品种上病菌的侵染事件与感病品种基本一致,但不能形成正常的吸器,胞壁沉积物明显多于感病品种,菌丝在寄主组织内的扩展明显受到抑制。利用β-1,3-葡聚糖免疫金标记单克隆抗体进行的免疫细胞化学的研究表明,胞壁沉积物内含有大量的β-1,3-葡聚糖,在大豆疫霉菌菌丝壁中也存在β-1,3-葡聚糖。以上结果表明,病原菌的侵染可诱导抗病寄主细胞内β-1,3-葡聚糖迅速的合成与积累、并形成胞壁沉积物,以抵御病菌的侵染与扩展。 相似文献
7.
玉米叶片受新月弯孢菌侵染后的细胞病理学变化 总被引：6，自引：0，他引：6
本文利用透射电子显微镜技术与细胞化学技术研究了玉米叶片受弯孢菌侵染后的超微结构和细胞壁的组成成份变化。透射电镜观察发现,病菌侵入后,菌丝先在寄主细胞间扩展,随着寄主细胞病变、坏死,菌丝可进入寄主细胞形成胞内菌丝。随病菌侵入和在寄主体内扩展,寄主细胞先后发生了一系列的超微结构变化,叶绿体、液泡等细胞器解体,出现质壁分离现象,并最终解体、坏死、变形。细胞化学标记定位发现,受侵寄主细胞壁中纤维素、木聚糖和果胶质的标记密度明显低于未接种的健康组织,表明细胞壁降解酶(如纤维素酶、木聚糖酶和果胶酶)的产生与病菌侵染和致病过程密切相关。 相似文献
8.
腔孢叶斑病是牡丹生产上出现的一种新病害,近几年在洛阳及菏泽牡丹种植园危害越来越重。为了筛选防治该病的化学药剂,本文采用菌丝生长速率法测定了3类8种杀菌剂对病菌菌丝生长的抑制活性,采用涂布平板法测定了多菌灵、戊唑醇及嘧菌酯对病菌孢子萌发和芽管伸长的影响,并在含药平板上测定了3种药剂对病菌产孢量的作用。结果表明:三唑类药剂对病菌菌丝生长的毒力最强,EC50为0.020~0.096μg/mL,且戊唑醇对孢子萌发和产孢也有很强的抑制活性,在0.1μg/mL时孢子即不能萌发;甲氧基丙烯酸酯类药剂对菌丝生长的毒力较强,EC50为0.408~0.939μg/mL,嘧菌酯对芽管伸长和产孢量均表现出很强的抑制活性,10μg/mL时,芽管几乎不再伸长,对产孢的抑制率可达到99%以上;而苯并咪唑类药剂对菌丝生长的毒力较弱,EC50为12.167~30.104μg/mL,多菌灵对孢子萌发的抑制作用弱,100μg/mL时孢子萌发率仍达到90%以上,对产孢的抑制作用也较弱,为63.02%。根据药剂对病菌生长和发育各阶段的影响,生产中应采用适宜的施用方法:戊唑醇和嘧菌酯可作为保护剂在病害发生前期喷施,也可作为治疗剂在病害发生流行期应用,但为防止抗药性菌株的出现,两者应当轮换或复配使用。 相似文献
9.
利用小麦种子根接种小麦全蚀病菌Gaeumannomyces graminis var．tritici，研究了不同致病力菌株的致病特点。结果表明，弱致病菌株可侵染小麦，但罹病过程缓慢，接种第5天仅在皮层观察到少量菌丝体，13天有少量菌丝进入中柱，中柱组织在菌丝侵入前褐变，未出现导管堵塞现象，也不能导致典型的黑根症状。强致病菌株接种第2天可侵入皮层，8天即进入中柱，并在寄主组织内产生大量菌丝体，致使寄主皮层组织和中柱细胞大量褐变和坏死，以及导管堵塞。 相似文献
10.
采用菌丝生长速率法和孢子萌发抑制法, 测定了14种杀菌剂单剂及基于单剂筛选结果的二元复配剂对红枣黑斑病菌Alternaria tenuissima菌丝生长和孢子萌发的抑制作用, 以此评价防治红枣黑斑病的杀菌剂和复配药剂的效果。结果表明, 咯菌腈和嘧菌环胺对靶标病菌菌丝生长的抑制效果最佳, 其EC50分别为0.091 3和0.099 8 μg/mL; 吡唑醚菌酯和啶酰菌胺对病菌孢子萌发抑制效果最佳, 其EC50分别为0.015 3和0.293 4 μg/mL。吡唑醚菌酯与戊唑醇按照8∶2和3∶7(w/w)的比例进行复配, 对病菌菌丝生长的抑制表现出相加作用, 其SR值分别为1.124 5和0.916 9; 两者以5∶5和3∶7(w/w)的比例进行复配, 对孢子萌发的抑制表现出相加作用, 其SR值分别为1.164 6和0.901 0。吡唑醚菌酯、啶酰菌胺、咯菌腈、嘧菌环胺和异菌脲等对病菌菌丝生长和孢子萌发均有抑制效果; 吡唑醚菌酯与戊唑醇3∶7(w/w)复配对病菌菌丝生长及孢子萌发的抑制效果均表现出相加作用。上述结果为红枣黑斑病防治药剂的开发和后续田间应用提供了理论支持。 相似文献
11.
The infection process of Fusarium avenaceum on wheat spikes and the alteration of cell wall components in the infected host tissue were examined by means of electron microscopy and cytochemical labelling techniques following spray inoculation at growth stage (GS) 65 (mid-flowering). Macroconidia of the pathogen germinated with one to several germ-tubes 6–12 h after inoculation (hai) on host surfaces. The germ-tubes did not penetrate host tissues immediately, but extended and branched on the host surfaces. Hyphal growth on abaxial surfaces of the glume, lemma and palea was scanty 3–4 days after inoculation (dai) and no direct penetration of the outer surfaces of the spikelet was observed. Dense mycelial networks formed on the inner surfaces of the glume, lemma, palea and ovary 36–48 hai. Penetration of the host tissue occurred 36 hai by infection hyphae only on the adaxial surfaces of the glume, lemma, palea and upper part of ovary. The fungus penetrated the cuticle and hyphae extended subcuticularly or between the epidermal wall layers. The subcuticular growth phase was followed by penetration of the epidermal wall, and hyphae spread rapidly inter- and intracellularly in the glume, lemma, palea and ovary. During this necrotrophic colonization phase of the wheat spike, a series of alterations occurred in the host tissues, such as degeneration of cytoplasm and cell organelles, collapse of host cells and disintegration of host cell walls. Immunogold labelling techniques showed that cell walls of spike tissues contained reduced amounts of cellulose, xylan and pectin near intercellular hyphae or infection pegs compared to walls of healthy host tissues. These studies suggest that cell wall degrading enzymes produced by F. avenaceum facilitated rapid colonization of wheat spikes. The different penetration properties of abaxial and adaxial surfaces of the spikelet tissues as well as the two distinct colonization strategies of host tissues by F. avenaceum are discussed. The penetration and colonization behaviour of F. avenaceum in wheat spikelets resembled that of F. culmorum and F. graminearum, although mycotoxins produced by F. avenaceum differed from those of the latter two Fusarium species. 相似文献
12.
Wanyoike Mary Wanjiru Kang Zhensheng Heinrich Buchenauer 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(8):803-810
Cytological studies were carried out to elucidate the importance of cell wall degrading enzymes (CWDE) during infection of wheat spikes by Fusarium graminearum. Scanning electron micrographs revealed that at 6–24 hours after inoculation (hai) of single spikelets with macroconidia of F. graminearum, the fungus germinated by forming several germ tubes and developed a dense hyphal network in the cavity of the spikelet. At 24–36hai, the fungus formed infection hyphae which invaded the ovary and inner surface of the lemma and palea. Transmission electron microscopical studies revealed that the fungus extended inter- and intracellularly in the ovary, lemma and rachis and caused considerable damage and alterations to the host cell walls. In different tissues of healthy and F. graminearum-infected wheat spikes the cell wall components cellulose, xylan and pectin were localized by means of enzyme-gold and immuno-gold labelling techniques. Localization of cellulose, xylan and pectin showed that host cell walls which were in direct contact with the pathogen surface had reduced gold labelling compared to considerable higher labelling densities of walls distant from the pathogen–host interface or in non-colonized tissues. The reduced gold labelling densities in the infected host cell walls indicate that these polysaccharide degrading enzymes might be important pathogenicity factors of F. graminearum during infection of wheat spikes. The results revealed that, infection and colonization of wheat spikes by F. graminearum and reactions of infected host tissue were similar to those reported for F. culmorum. 相似文献
13.
Z. Kang H. Buchenauer 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(7):653-660
After single spikelet inoculation, the infection process of Fusarium culmorum and spread of fungal hyphae in the spike tissues were studied by scanning and transmission electron microscopy. While hyphal growth on outer surfaces of the spike was scanty and no successful penetration was observed, the fungus developed a dense mycelium on the inner surfaces and effectively invaded the lemma, glume, palea and ovary by penetration pegs. During the inter- and intracellular spreading of the fungus, marked alterations in the host tissues were observed, including degeneration of cytoplasm, cell organelles, and depositions of electron dense material between cell wall and plasmalemma. Ultrastructural studies revealed that host cell walls in proximity of the penetration peg and in contact with hyphae were less dense or transparent which suggested that cell wall degrading enzymes were involved in colonisation of host tissues by fungal hyphae. Enzyme- and immunogold-labelling investigations confirmed involvement of extracellular enzymes, that is cellulases, xylanases and pectinases, in degradation of cell wall components. Localization studies of trichothecenes indicated that toxins could be detected in host tissues at an early stage of infection. 相似文献
14.
《Physiological and Molecular Plant Pathology》2002,60(3):141-153
Two antisera raised against acidic β-1,3-glucanase and acidic chitinase from tobacco were used to investigate the subcellular localization of the two enzymes in Fusarium culmorum -infected wheat spike by means of the immunogold labelling technique. The studies demonstrated that the distribution of β-1, 3-glucanase and chitinase were very similar in the uninoculated healthy and infected wheat spikes. The enzymes were localized mainly in the cell walls of different tissues including the lemma, ovary and rachis of the wheat spike, while the cytoplasm and organelles of cells in these tissues showed almost no labelling. However, the accumulation of β-1,3-glucanase and chitinase in the infected wheat spikes differed distinctly between resistant and susceptible wheat cultivars. The labelling densities for the two enzymes in the infected lemma, ovary and rachis of the susceptible cultivar Agent increased only slightly as compared to the corresponding uninoculated healthy tissues, whereas higher labelling densities of β-1,3-glucanase and chitinase were found in the infected tissues of wheat spikes from the resistant cultivar Arina compared to the corresponding uninoculated healthy tissues. Furthermore, the labelling of β-1,3-glucanase and chitinase also occurred over the cell walls of the hyphae in the infected wheat spike, but not over the hyphal cytoplasm. In addition, labelling for the two enzymes was often detected over the cell wall appositions and the electron-dense material located between the host cell and the hyphal cell in the infected tissues of the resistant wheat cultivar. The findings reported in the present study indicate that β-1,3-glucanase and chitinase accumulation in the F. culmorum -infected wheat spike may be involved in resistance to pathogen spread in the host tissue. 相似文献
15.
Zhensheng Kang Lili Huang Ulrich Krieg Astrid Mauler‐Machnik Heinrich Buchenauer 《Pest management science》2001,57(6):491-500
The effects of tebuconazole, a systemic fungicide, on the morphology, structure, cell wall components and toxin production of Fusarium culmorum were investigated in vitro. Treatment was by application of four filter paper strips (0.75 cm × 5.0 cm) soaked in 20 µg ml ?1 fungicide placed around a point inoculum in Petri dishes. Mycelial growth was strongly inhibited by fungicide treatment. Scanning electron microscopic observations showed that the fungicide caused irregular swelling and excessive branching of hyphae. The morphological changes induced by the fungicide at the ultrastructural level included considerable thickening of the hyphal cell walls, excessive septation, the formation of the incomplete septa, extensive vacuolisation, accumulation of lipid bodies and progressing necrosis or degeneration of the hyphal cytoplasm. Non‐membrane inclusion bodies were often detected in the hyphal cytoplasm. Furthermore, the formation of new hyphae (daughter hyphae) inside collapsed hyphal cells was common following treatment. The daughter hyphae also displayed severe alterations such as irregular thickening of the cell walls and necrosis of the cytoplasm. Using cytochemical techniques, the labelling densities of chitin and β‐1,3‐glucan in the cell walls of the fungicide‐treated hyphae were more pronounced than in those of the control hyphae. Moreover, immunogold labelling with antiserum against deoxynivalenol (DON) revealed that Fusarium toxin DON was localized in the cell walls, cytoplasm, mitochondria and vacuoles of the hyphae from the control and the fungicide treatment, but the labelling density in the fungicide‐treated hyphae decreased dramatically compared with the control hyphae, indicating that tebuconazole reduced Fusarium toxin production of the fungus. © 2001 Society of Chemical Industry 相似文献
16.
禾谷镰刀菌侵染引致小麦穗组织细胞壁成分变化的细胞化学研究 总被引：1，自引：0，他引：1
本文采用细胞化学方法, 对健康和禾谷镰刀菌(Fusarium graminearum)侵染的小麦穗组织中细胞壁主要成分进行了比较分析。电镜观察发现, 被侵穗部组织细胞壁中的主要成分如纤维素、木聚糖和果胶质的标记密度下降, 显著低于未接种的健康对照组织。结果表明病菌侵染和扩展过程中分泌产生了纤维素酶、木聚糖酶和果胶酶等细胞壁降解酶类, 造成寄主细胞壁成分的分解及细胞壁松弛, 从而有利于病菌在寄主穗部组织中的侵染和扩展。 相似文献
17.
《Physiological and Molecular Plant Pathology》2004,64(1):45-53
The fungal pathogen Fusarium graminearum attacks the seed spikes of barley and wheat, causing sterility, reduced seed weight and accumulation of mycotoxins. To explore infection patterns in barley and in the Arabidopsis model system, the green fluorescent protein gene (gfp) was used to transform F. graminearum. Inoculation of intact barley spikes resulted in rapid colonization of the brush hairs (ovary epithelial hairs) at the extruded seed tip within 7 h. Colonization followed a pattern of rapid basipetal growth along the pericarp epithelium (interior to the lemma and palea), accompanied by slower growth inward through the pericarp and testa. However, at 16 days after infection the aleurone and starchy endosperm remained uninfected, despite heavy colonization of the pericarp. Colonization of the outer lemma also occurred but was much slower. No increase in amylase enzyme activities was found, discounting the possibility that F. graminearum utilizes gibberellin-induced host enzymes to tap the endosperm for nutrients. The transformed Fusarium strain readily infected Arabidopsis thaliana leaves and produced copious spores within distant leaves. Results show the utility of gfp in tracing the growth of this pathogen, without misinterpretation due to contaminating fungi, and for resistance studies utilizing the Arabidopsis model system. 相似文献
18.
Pathogen development and host responses in wheat spikes of resistant and susceptible cultivars infected by Fusarium culmorum causing Fusarium head blight (FHB), were investigated by means of electron microscopy as well as immunogold labelling techniques. The studies revealed similarities in the infection process and the initial spreading of the pathogen in wheat spikes between resistant and susceptible cultivars. However, the pathogen’s development was obviously more slow in the resistant cultivars as in comparison to a susceptible one. The structural defence reactions such as the formation of thick layered appositions and large papillae were essentially more pronounced in the infected host tissues of the resistant cultivars, than in the susceptible one. β -1,3-glucan was detected in the appositions and papillae. Furthermore, immunogold labelling of lignin demonstrated that there were no differences in the lignin contents of the wheat spikes between susceptible and resistant cultivars regarding the uninoculated healthy tissue, but densities of lignin in host cell walls of the infected wheat spikes differed distinctly between resistant and susceptible cultivars. The lignin content in the cell walls of the infected tissues of the susceptible wheat cultivar increased slightly, while the lignin accumulated intensely in the host cell walls of the infected wheat spikes of the resistant cultivars. These findings indicate that lignin accumulation in the infected wheat spikes may play an important role in resistance to the spreading of the pathogen in the host tissues. Immunogold labelling of the Fusarium toxin DON in the infected lemma showed the same labelling patterns in the host tissues of resistant and susceptible cultivars. However, there were distinct differences in the toxin concentration between the tissues of the susceptible and resistant cultivars. At the early stage of infection, the labelling densities for DON in resistant cultivars were significantly lower than those in the susceptible one. The present study indicates that the FHB resistant cultivars are able to develop active defence reactions during infection and spreading of the pathogen in the host tissues. The lower accumulation of the toxin DON in the tissues of the infected spikes of resistant cultivars which results from the host’s defence mechanisms may allow more intensive defence responses to the pathogen by the host. 相似文献