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黄瓜黑星病菌致病机理的研究Ⅲ细胞壁降解酶和毒素对寄主超微结构的影响及其协同作用 总被引：5，自引：1，他引：5
本文通过透射电镜和扫描电镜观察,初步明确了果胶酶、纤维素酶及毒素对黄瓜叶组织超微结构的影响。在致病过程中,3种致病因子起着各自独立又相互联系的作用。3种致病因子对寄主超微结构的影响中,纤维素酶分解细胞壁能力最强,毒素对细胞质膜的作用最大,3种致病因子均可造成质壁分离,液泡、内质网受损。而叶绿体的被膜、片层结构主要被纤维素酶降解,线粒体的被膜主要被果胶酶降解,3种致病因子均能使叶绿体、线粒体内部空泡化。在分解叶表皮的过程中,所研究的3种致病因子首先是果胶酶降解果胶层,然后是纤维素酶、果胶酶、毒素对栅栏组织的分解,最后是纤维素酶、毒素作用于薄壁细胞壁,毒素、纤维素酶、果胶酶协同作用于细胞内部组织。 相似文献
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在电镜下观察发现,菜豆锈病菌侵染菜豆后,逐步对其超微结构产生影响:寄主细胞发生质壁分离;叶绿体变形;叶绿体的片层结构排列零乱;线粒体脊模糊不清,直至叶绿体解体;线粒体空泡化;少数细胞的细胞壁分解;不同细胞的细胞器堆积在一起。同时,病原菌的侵染激发了寄主抗病性的细胞学表现:供试的抗感菜豆品种都表现为在病原菌侵入位点的寄主细胞壁内侧有高电子致密物质沉积;与吸器母细胞接触的寄主细胞壁加厚以及在吸器颈周围有电子不透明物质形成。只是这3种反应在抗病品种中表现得更加强烈。此外,抗病品种中还有一些特有的抗性特征,如被侵染细胞及其相邻细胞的快速坏死,吸器母细胞侵入位点的寄主细胞壁外侧也有一种高电子致密物质沉积,抗病品种中真菌吸器周围聚集含大量线粒体的寄主细胞的细胞质,且吸器外基质比感病品种中的宽。 相似文献
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小麦赤霉病菌毒素对小麦抗病突变体及其亲本细胞超微结构的影响 总被引：7，自引：1，他引：6
在小麦赤霉病菌毒素的作用下,小麦抗赤霉病突变体92k809及其亲本新克旱九内颖细胞超微结构发生了变化。随着处理时间的增长,细胞器和膜系统破坏程度加剧,但在相同处理时间内,突变体细胞的超微结构破坏程度比其亲本要轻。对赤霉病菌毒素最敏感的是线粒体,其次是叶绿体、细胞质膜和细胞核膜。本文还探讨了赤霉病菌毒素在致病过程中的作用及其致病机理。 相似文献
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杉苗叶片受炭疽病菌侵染后超显微结构变化的研究 总被引：1，自引：0，他引：1
杉苗叶片受炭疽病菌(Colletotrichum gloeosporioides(Penz) Sace)侵染后,在受害程度不同的寄主细胞中,叶绿体、线粒体、细胞壁、细胞质.高尔基小泡和质膜的结构、大小及内含物有不同程度的变化。在相对没有损害的细胞中,观察到细胞壁膨胀、细胞质变浓、凝聚和出现质膜体。这一现象是细胞对病原侵入的反应,其细胞壁成份,厚度和胞质中化学成分的改变.与抵抗病原侵入有关. 相似文献
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水稻基腐病菌毒素对烟草活性氧代谢及细胞超微结构的影响 总被引：2，自引：0，他引：2
用水稻基腐病菌毒素注射烟草叶片后,烟草细胞中O2-·和NO大量增加,H2O2含量明显降低,SOD、CAT和POD等酶的活性发生变化。毒素引起烟草细胞死亡,但没有细胞程序性死亡(PCD)的DNA梯特征。病菌毒素处理烟草叶片后,电导率增大,细胞膜透性增加。电镜观察烟草细胞的超微结构表明,毒素处理8h后,叶绿体变形,叶绿体基质片层大部分消解,基粒结构消失,叶绿体外膜和内膜剥离,质壁分离和细胞膜内陷,细胞器消解;处理48h后,细胞内含物完全消解,细胞膜消失,细胞壁皱缩变形。本研究表明,毒素引起烟草细胞死亡与植物抗病反应HR中细胞坏死的生理生化机制不同,但可能存在相似的信号传导途径。 相似文献
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水稻条纹叶枯病细胞病理变化的观察 总被引：20，自引：1，他引：19
利用透射电子显微镜和免疫胶体金标记技术,观察水稻条纹叶枯病病叶细胞病理变化,病毒粒体、病毒外壳蛋白和病害特异蛋白在寄主细胞中的分布。结果表明,病叶叶肉细胞中线粒体增多,细胞核变大,几乎每个细胞中都有蛋白体,叶绿体基粒片层变稀疏和变粗,或被挤压和变细,或叶绿体解体,基粒片层残留于细胞质中。在叶肉细胞和维管束筛管细胞中发现一些内含体和电子密度较高的物体,在高放大倍数下,可以清楚的看出为点状和丝状结构,其直径约为8nm。免疫胶体金标记显示,病毒外壳蛋白和病害特异蛋白存在于叶绿体、细胞质和细胞核以及细胞壁上,但线粒体中没有发现。 相似文献
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宿根矮化病菌对甘蔗品质及茎、叶超微结构的影响 总被引：2，自引：0，他引：2
甘蔗宿根矮化病(Ratoon Stunting Disease, RSD)是由Leifsonia xyli subsp.xyli (Lxx)引起的,是目前世界所有植蔗地区危害性极大的病害之一。本实验以甘蔗品种新台糖22号(ROC22)健康植株为对照,感染RSD植株为处理,观察和测定RSD侵染甘蔗引起的蔗株农艺性状、蔗糖分以及茎、叶超微结构的变化。结果表明:(1)感染RSD种茎的出苗率比对照减少2.94个百分点;株高比对照下降28.85 cm;茎径比对照减少0.28 cm;节间长度比对照减短3.50 cm;单茎重比对照低0.36 kg。(2)感染RSD植株的蔗糖分低于对照0.9个百分点(绝对值)。(3)利用透射电镜技术对感染RSD植株茎、叶细胞超微结构进行观察表明,叶片叶肉细胞、维管束鞘细胞及茎细胞内的细胞器及细胞核都发生了明显的病理变化。与健康叶片相比,叶绿体变形,叶绿体基质片层大部分消解,基粒结构消失,叶绿体外膜和内膜剥离。线粒体形态异常,有的肿大、内嵴模糊,严重者内嵴消失并空泡化,仅剩未被消解的残骸;细胞核形态变为不规则,核膜破裂,染色质分布不均匀,呈降解状态。在感染RSD甘蔗茎维管束导管细胞内积累有大量的电子致密物质,细胞壁有不同程度的溶解和断裂,这可能和RSD病原细菌侵染有关。以上结果表明:RSD侵染甘蔗后,可能导致光合效率下降,对水分和营养物质的运输能力降低,从而导致甘蔗品质和产量的降低。 相似文献
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HMC毒素对雄性不育玉米线粒体结构和功能的影响 总被引：4，自引：0，他引：4
用HMC毒素处理C型不育系玉米和同核保持系(N)玉米的线粒体,透射电镜观察发现:HMC毒素可使C细胞质玉米线粒体内膜受到严重破坏,嵴消失,线粒体变为由外膜围成的空泡状;N细胞质大多数线粒体没有受到损伤,有的只受到轻微的破坏,但内膜仍可见。用氧电极测定线粒体的呼吸控制值(RCR)和氧化磷酸化效率(P/O),结果表明:HMC毒素的加入可使C细胞质玉米叶片的线粒体的RCR下降等于或大于20%,加毒素后再加ADP,耗氧曲线不能进入状态Ⅲ呼吸,线粒体的呼吸保持在Ⅳ态,表明毒素处理后ADP几乎没有被消耗,出现类似氧化磷酸化解偶联现象,P/O由于ADP没有被消耗而趋于零;N细胞质玉米叶片的线粒体的RCR下降等于或小于5%,P/O变化很小。可见,HMC毒素对C型不育玉米线粒体的内膜结构和氧化磷酸化功能均表现专化毒害作用。 相似文献
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ABSTRACT Pyrenophora tritici-repentis race 2 produces Ptr ToxA, a host-selective toxin previously described as a pathogenicity factor for tan spot on wheat. The objective of this research was to evaluate the role of host sensitivity to toxin, conditioned by a single dominant gene on chromosome 5BL, in the disease development by race 2. An F(2)-derived F(6) recombinant inbred population of 108 wheat lines, produced from crosses of toxin-sensitive, disease-susceptible cv. Kulm with the toxin-insensitive, disease-resistant cv. Erik segregated 1:1 for toxin reaction. However, the population was skewed toward resistance to race 2 of the fungus. Toxin reaction accounted for 24.4% of the genetic variance for disease. Heritability estimates suggested the presence of four to five genes that influence disease reaction in the population. Toxin-insensitive mutants, previously derived Kulm, were susceptible to race 2, although disease developed more slowly on the mutants than it did on the wild-type Kulm. The data indicate that sensitivity to Ptr ToxA influences disease severity in some host genotypes without defining susceptibility. 相似文献
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细胞骨架解聚药物对小麦与叶锈菌互作诱发的细胞过敏性反应的影响 总被引：5，自引：0，他引：5
小麦(Triticum aestivum)品种洛夫林10和叶锈菌小种366组成不亲和组合,小麦叶片发生过敏性坏死反应(HR)是小麦抵抗叶锈菌侵染的重要因素。在接种前给小麦叶片分别预注射微管解聚药物磺草硝(oryzalin)和微丝解聚药物细胞松弛素D (cytochalasin D,CD),结果表明2种药物注射使得寄主因叶锈菌侵染诱导的细胞过敏性坏死数目明显减少,并且注射药物的浓度越大,寄主细胞发生HR的数量越少。说明肌动蛋白和微管蛋白的聚合状态是诱发小麦叶片发生HR防卫反应所必需的,细胞骨架在小麦抵抗叶锈菌侵染过程中可能起着重要作用。 相似文献
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ABSTRACT A toxin, designated SnTox1, was partially purified from culture filtrates of isolate Sn2000 of Stagonospora nodorum, the causal agent of wheat leaf and glume blotch. The toxin showed selective action on several different wheat genotypes, indicating that it is a host-selective toxin (HST). The toxic activity was reduced when incubated at 50 degrees C and activity was eliminated when treated with proteinase K, suggesting that the HST is a protein. The synthetic hexaploid wheat W-7984 and hard red spring wheat Opata 85, the parents of the International Triticeae Mapping Initiative (ITMI) mapping population, were found to be sensitive and insensitive, respectively, to SnTox1. The ITMI mapping population was evaluated for toxin reaction and used to map the gene conditioning sensitivity. This gene, designated Snn1, mapped to the distal end of the short arm of chromosome 1B. The wheat cv. Chinese Spring (CS) and all CS nullisomic-tetrasomic lines were sensitive to the toxin, with the exception of N1BT1D. Insensitivity also was observed when the 1B chromosome of CS was substituted with the 1B chromosome of an insensitive accession of Triticum dicoccoides. In addition, a series of 1BS chromosome deletion lines were used to physically localize the sensitivity gene. Physical mapping indicated that Snn1 lies within a major gene-rich region on 1BS. This is the first report identifying a putative proteinaceous HST from S. nodorum and the chromosomal location of a host gene conferring sensitivity. 相似文献
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ABSTRACT The host-selective toxin Ptr ToxA is produced by races 1 and 2 of Pyrenophora tritici-repentis, causal agent of tan spot of wheat. Ptr ToxA has been causally associated with pathogenicity by the race 2 phenotype in this system. However, the role of toxin in disease caused by race 1, the most prevalent form of the fungus in the central and northern Great Plains of North America, has not been rigorously investigated. Three independent wheat lines harboring mutations for insensitivity to Ptr ToxA were derived from ethylmethane sulfonate treatment of the hard red spring wheat cv. Kulm, possessing the single dominant gene for toxin sensitivity. Each of the three mutants was insensitive to Ptr ToxA in bioassays based on necrosis development and electrolyte leakage. Each mutant was crossed to each of the other mutants and to the wild-type Kulm. Segregation data indicate that each mutant line harbors a single recessive mutation for toxin insensitivity that maps to or near the same locus, possibly the toxin-sensitivity gene. Each toxin-insensitive mutant line was susceptible to two isolates of race 1 of P. tritici-repentis. F(2) and F(3) generations derived from crosses between Kulm and each mutant segregated for toxin reaction. However, segregation for fungal reaction was not evident, and all F(3) families were tan spot susceptible regardless of toxin reaction. Host insensitivity to Ptr ToxA is not necessarily equivalent to resistance to race 1. Ptr ToxA should not be used alone as a proxy for fungal inoculations by breeding programs aimed at developing tan spot-resistant wheat. 相似文献
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N. F. CREIGHTON 《Plant pathology》1989,38(4):484-493
W-type isolates of Pseudocercosporella herpotrichoides grown on a maize-based agar and exposed to near- ultra-violet radiation at c . 13°C produced a greenish black colour, whilst R-type isolates produced a pink or pale brown colour in the agar medium. More colonies from directly plated lesions or from spore suspensions could be recognized as P. herpotrichoides and could be more easily differentiated as W-type or R-type or as mixtures of both by colour production on maize agar (MA) than by colony morphology on potato dextrose agar (PDA), despite the presence of other fungi. Isolates with intermediate morphology on PDA were positively identified as W-type or R-type on MA; their pathogenicities to wheat and rye seedlings were usually similar to those of W-type or R-type isolates with typical colony morphology, confirming their identification on MA. Drops of mixed suspensions of W-type and R-type spores on PDA formed fast-growing colonies with smooth margins which sometimes had slow-growing sectors with feathery margins. Drops of the same mixtures on MA formed greenish black colonies which sometimes had pink or pale brown sectors. However, when these mixtures were spread onto MA, W-type and R-type colonies could easily be differentiated by colour. 相似文献
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几种除草剂对不同麦类品种的效应 总被引：1，自引：0，他引：1
1991～1993年对50个麦类品种和4个除草剂效应进行了研究。一种除草剂对不同的麦类品种在出苗数、百株苗分蘖数、百株苗鲜重的抑制率有差异,不同的除草剂对一个麦类品种也产生不同的抑制率。从中选出14个品种用甲黄隆超微WP ai 0.5g/666.7m~2进行喷雾处理作产量测定,增产率最高的是浙麦4号,为24.18％,增产率最低的是扬87—158,为0.67％。浙麦1号上几种除草剂的比较试验,增产率最高的是绿黄隆超微WP ai 0.75g/666.7m~2,为33.3％,增产率最低的是丁草胺60％EC75ml/666.7m~2,为16.8％。试验结果表明,甲黄隆在浙麦1号上的最佳施用期是播后芽前至一叶一心期,最佳施用量是ai 0.3～0.4g/666.7m~2。 相似文献
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Biochemical differences between the wheat, rye and couch-grass pathotypes of the eyespot pathogen, Pseudocercosporella herpotrichoides, have been identified by comparing isoenzyme profiles and DNA markers from several isolates. The wheat (W) and rye (R) pathotypes were clearly differentiated by both techniques, with isoenzyme profiling also separating the couch-grass isolates from the W- and R-type isolates. The isoenzyme profiles separated the P. herpotrichoides pathotypes from the two related species, P. anguioides and P. aestiva. The isoenzyme profiles of P. anguioides were closer to those of the R-type isolates of P. herpotrichoides than the W-type isolates, whereas the banding pattern of P. aestiva was very different. The isoenzyme profiles of the two German isolates, originally obtained from Nirenberg's laboratory, P. herpotrichoides var. herpotrichoides and var. acuformis, were similar to those of the wheat and rye pathotypes, respectively, isolated from UK-infected material. 相似文献
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Survey of benomyl resistance in Pseudocercosporella herpotrichoides on winter wheat and barley in England and Wales in 1983 总被引：18，自引：18，他引：0
Surveys of 528 randomly selected commercial fields in England and Wales in 1983 showed that isolates of Pseudocercosporella herpotrichoides resistant to benomyl were common and widespread on winter wheat and winter barley. During June and July resistant strains were recovered from 16 to 66% of fields and the proportion of resistant isolates was 37–52%. The frequency of occurrence of resistant isolates was positively correlated with the number of applications of carbendazimgenerating (MBC) fungicides during the previous 8 years. Benomyl resistance was found in 21–48% of fields where it was claimed that MBC had never been used, and 7–28% of isolates from those fields, were resistant. Resistance was more frequent in R-type than in W-type isolates of the pathogen. The proportion of R-type isolates decreased as the number of previous winter wheat crops rose and increased with the number of winter barley crops grown and with the number of MBC sprays applied to crops in previous years. The implications of these findings for the control of eyespot in England and Wales are discussed. 相似文献
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