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江苏省几种作物丝核菌交互致病性的聚类分析 总被引：1，自引：0，他引：1
本文在鉴定江苏省几种作物病原丝核菌所属种及菌丝融合群的基础上,进行六种作物病原丝核菌菌株与其寄主的人工交互接种试验,结果表明六种作物病原丝核菌对各自的原分离作物均表现强致病性。将该六种病菌在六种作物上的病情指数经聚类分析可划分为三类,第一类为水稻纹枯病菌,在人工接种条件下可侵染六种作物,综合致病力最强,平均病指为42、38;第二类为玉米、大豆纹枯病菌及棉花立枯病菌,其致病特性及症状与水稻纹枯病菌相似,但致病力较弱,平均病指分别为31、0,25、80和18、95:第三类为大、小麦纹枯病菌,其致病特性与前两者截然不同,不侵染大豆和棉花,平均病指为28、1和26、53。据致病力划分的类群与菌株所属的分类地位基本吻合。另外,本文还讨论了病原丝核菌在自然界中相互侵染的可能性,以及各种作物丝核菌种群的多样性等问题。 相似文献
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《植物病理学报》2017,(1)
水稻纹枯病是严重影响水稻生产的真菌病害,水稻相对病斑高度法作为评估立枯丝核菌AG-1 IA致病力的传统方法,需要将水稻培养至分蘖末期或抽穗期,再进行活体接种,耗时耗力,且试验条件不易控制。本研究以水稻相对病斑高度法(活体接种)为对照,利用水稻离体叶鞘法和离体叶片法测定了水稻纹枯病菌致病力和粗毒素活性,比较活体接种法与离体接种法的相关性。结果表明水稻离体叶片法、水稻离体叶鞘法和水稻相对病斑法测定致病力和粗毒素活性结果均呈显著正相关,水稻离体叶片法和离体叶鞘法测定结果能够准确反映立枯丝核菌AG-1 IA的致病力和粗毒素活性,离体评估方法操作方便,试验条件易于控制。因此,水稻离体叶片法、叶鞘法可以替代活体接种法作为测定立枯丝核菌AG-1 IA致病力和粗毒素活性的方法。水稻离体叶片法、叶鞘法与活体接种法结合起来可作为测定立枯丝核菌AG-1 IA毒素活性测定的新方法。本研究的结果还表明,水稻不同组织对水稻纹枯病菌毒素敏感性不同,水稻的叶鞘组织比叶片组织对纹枯病菌敏感。由于粗毒素的致病力与活体菌株接种的致病力存在显著差异,因此纹枯病菌毒素以外的致病因子,也是不容忽视的。在定量分析立枯丝核菌AG-1 IA与水稻的互作中,需要将不同水稻的组织进行区分,才能更加精准地了解互作机制。 相似文献
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水稻纹枯病是水稻世界三大病害之一,严重影响水稻的产量与质量,揭示水稻纹枯病菌的致病机理对于防治水稻纹枯病具有重要意义。为此,本研究对立枯丝核菌AG1 IA的自然突变不致病菌株Rs3的形态和组织病理学研究以及基因组重测序分析其关键致病基因的突变,探寻其致病力丧失的原因。研究结果显示,与野生型AG1 IA相比,不致病菌株Rs3具有生长慢、接种水稻叶片不产生侵染附着结构,以及不导致水稻产生坏死病斑等生物学特点。而重测序结果分析显示,与野生型AG1 IA相比,不致病菌株Rs3的基因组范围内存在大量的突变,包括SNP和Indel,其中涉及与菌丝生长相关的actin基因,致病相关的cAMP通路、MAPK通路和钙离子信号等通路基因,以及效应因子相关基因。本研究通过对水稻纹枯病菌不致病菌株的组织病理学差异以及基因组层面上的基因突变分析,从菌株对寄主的识别、侵染生长和致病信号通路方面揭示了Rs3致病力丧失的可能原因,为后续纹枯病菌关键致病因子的发病机理研究奠定基础。 相似文献
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从类似纹枯病的水稻病株上分离到一种在菌核形态上与纹枯病菌(Rhizoctonia solani)有明显差异的真菌,致病性测定结果表明该菌能侵染水稻、玉米和大豆。对该菌的显微形态、生物学特性以及核糖体DNA-ITS序列进行研究,结果表明该菌为嗜水小核菌(Sclerotium hydrophilum Sacc.)。病菌在30℃、pH为6~9条件下生长表现最佳,属硫胺素自养型菌;营养菌丝与立枯丝核菌相似,菌核球形或椭圆形,数量极多,其平均大小仅为386.4μm×420.7μm;该菌的核糖体DNA-ITS序列与GenBank中唯一一个嗜水小核菌(登录号为DQ875597)的同源性为99.5%,并且与大多数丝核菌(Rhizoctonia spp.)也有一定的同源性,病菌的28S rDNA-RFLP分析结果进一步说明了该菌在系统发育上与丝核菌类真菌具有较高的同源性。通过比较该菌和几种与水稻纹枯病相关丝核菌核糖体DNA-ITS序列的差异,设计了一对特异性引物PS-1和PS-2,能专一地从被该菌侵染的水稻感病组织中扩增出一段约550bp的DNA。 相似文献
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采用人工接种方法,将烟草立枯病病菌菌株TRs-5接种于烟草云烟87的不同部位,观察其发病效果。研究了菌株接种体在不同接种温度和培养时间对发病效果的影响,并比较了其与稻纹枯病病菌菌株RRs08-22-2接种于水稻品种中优679的致病效果。结果表明,菌株TRs-5既能侵染烟草幼苗近地表的茎基部,导致其发病,也能侵染烟草成株苗叶面形成坏死病斑。在温度28℃环境下接种比在20℃的导致发病更严重。用培养2 d的菌丝体接种比培养4 d的导致更大的病斑。在寄主烟草上,菌株TRs-5比菌株RRs08-22-2的致病力强,但在寄主水稻上,菌株TRs-5比菌株RRs08-22-2的致病力弱。初步发现这2个病菌与2个寄主之间存在致病专化现象。 相似文献
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新疆北疆棉田立枯丝核菌不同菌丝融合群致病力的研究 总被引：1，自引：0，他引：1
从新疆北疆棉区采集了典型的棉花立枯病病苗及棉田土标样686份,按常规分离方法分离得到399个分离物,从中鉴定出272个纯化的立枯丝核菌(Rhizoctonia solani Kühn)菌株。用标准菌株,通过载玻片菌丝融合试验测定,将纯化的272个菌株划归为3个菌丝融合群:即AG-2、AG-4和AG-5,分别占总菌株的6.24%、84.2%和1.1%。另有23个菌株不与任何标准菌株融合,占8.46%,说明新疆北疆棉田立枯丝核菌的优势菌系是多核丝核菌的AG-4融合群。通过从10种不同配方培养基中筛选效果好的麦芽蛋白胨(MPDA)配方培养基(Ⅱ)进行对峙培养,将纯化获得的272个丝核菌菌株,划分为6个不同的营养亲和群。将多核的不同菌丝融合群及其各营养亲和群代表菌株在3种不同主栽棉花品种上(每品种都加不接菌的对照)进行温室盆栽致病力测定,结果以AG-4对棉花的致病力最强,其次是非融合类,AG-2和AG-5虽致病,但并不致死苗,其平均病指数分别为94.9、81.4、53.1、43.5。 相似文献
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棉花黄萎病菌致病力测定及评价方法研究 总被引：1，自引：0，他引：1
棉花黄萎病菌致病力测定及评价是抗病育种及病害综合防治的基础。本文以我国三大棉区的167个黄萎菌菌株为对象,研究致病力测定及评价中不同批次之间病情指数的校准及致病力类型划分标准等关键技术环节。结果表明,以中等致病力类型菌株Vd076为校正菌株,以感病性稳定的冀棉11为校正鉴别寄主,以校正菌株在校正鉴别寄主上病情指数达到50.0±5.0时的调查结果进行各菌株的致病力评价,可获得较好的校正效果,使不同批次试验数据具有可比性;依据聚类分析结果,制定了致病力类型划分标准,强、中、弱3种致病力类型的平均校正病指分别为﹥40.0、20.1~40.0和20.0;通过对不同鉴别寄主组合的分析,推荐陆地棉中棉所41号、豫棉21、鲁棉研28、中棉所35号、中棉所8号、冀棉11作为鉴别寄主。该研究为棉花黄萎病菌致病力变异等相关研究工作提供了技术支撑。 相似文献
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黄淮区大豆花叶病毒株系组成与分布 总被引：10，自引：0，他引：10
用8个大豆品种作为一组株系鉴别寄主,将黄淮豆区8省市202个毒株划分为7个株系(y1~y7)。y1及y2为弱毒株系,仅侵染感病品种(1138-2、文丰5号);y3、y4、y5为中毒株系,分别侵染感病和中抗品种(齐黄10号、徐豆1号、诱变30、鲁豆4号);y6及y7为强毒株系,除侵染以上品种外,还侵染高抗品种(齐黄22、密荚1号)。全区弱毒株系占55.9%,中毒株系占28.7%,强毒株系占15.3%。江苏、山东、河南、河北、安徽和北京市以弱毒株系为主(43.5%~88.9%),山西省以中毒株系为主(50.0%),陕西省弱毒株系、中毒株系各占50.0%,山东、河南、河北3省强毒株系所占比例较高(22.4%~33.3%)。株系分布具有一定的稳定性。 相似文献
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The aim of this study was to isolate, identify and characterize ascochyta blight pathogens from Cicer judaicum , a wild annual Cicer species which grows in Israel and other Mediterranean countries in sympatric distribution with legume crops, and determine their virulence and aggressiveness to other wild and domesticated legumes. Native C. judaicum plants exhibited symptoms resembling ascochyta diseases of grain legume crops. Two distinct pathogens were isolated and identified as Phoma pinodella and Didymella rabiei using morphological and molecular tools; their infectivity was verified using Koch's postulates. The virulence of these pathogens was examined on 13 legume species, of which P. pinodella was virulent to Pisum sativum , P. fulvum , C. judaicum , C. arietinum , C. reticulatum , C. pinnatifidum and C. bijugum . Didymella rabiei infected all these Cicer species, but not the other legume species tested. Aggressiveness of the pathogens was tested on wild and domesticated chickpea and pea. Didymella rabiei isolated from C. judaicum had significantly higher ( P < 0·001) aggressiveness than P. pinodella from C. judaicum on both wild and domesticated chickpea. Disease severity on the former species ranged from 62·5% to 70% and on the latter from 41% to 56%. Phoma pinodella isolates from C. judaicum were more aggressive on C. arietinum and P. sativum than on C. judaicum and P. fulvum . Results of the current study suggest that C. judaicum may serve as an alternative host to ascochyta pathogens that endanger chickpea and possibly other crops and wild species growing in close proximity. 相似文献
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Fifty strains of Fusarium oxysporum, recovered from rhizosphere soil around native Gossypium species and found to be mildly virulent on cotton (Gossypium hirsutum), were used to assay the propensity for evolution of virulence using serial passage assays through cotton. Only one lineage A strain, 2613, successfully completed 10 successive passages, while all others lost the ability to cause foliar disease symptoms at various stages during this process. Based on 46 amplified fragment length polymorphism (AFLP) markers generated with four EcoRI x MseI primer combinations, mutants were identified in offspring isolates from strain 2613 regardless of whether serial passages occurred in cotton or on water agar, suggesting the occurrence of spontaneous mutations. Significantly increased virulence was observed in the offspring isolates generated on cotton, while no increasing virulence was found in those obtained on water agar, suggesting that the evolution of virulence in F. oxysporum f. sp. vasinfectum is associated with the presence of cotton. No clear correlation was observed between the AFLP mutations and increased virulence in this study. 相似文献
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ABSTRACT The abundance and diversity of phlD(+) Pseudomonas spp. colonizing the rhizospheres of young, field-grown corn and soybean plants were assayed over a 3-year period. Populations of these bacteria were detected on the large majority of plants sampled in the state of Ohio, but colonization was greater on corn. Although significant variation in the incidence of rhizosphere colonization was observed from site to site and year to year on both crops, the magnitude of the variation was greatest for soybean. The D genotype was detected on plants collected from all 15 counties examined, and it represented the most abundant subpopulation on both crops. Additionally, six other genotypes (A, C, F, I, R, and S) were found to predominate in the rhizosphere of some plants. The most frequently observed of these were the A genotype and a newly discovered S genotype, both of which were found on corn and soybean roots obtained from multiple locations. Multiple isolates of the most abundant genotypes were recovered and characterized. The S genotype was found to be phylogenetically and phenotypically similar to the D genotype. In addition, the novel R genotype was found to be most similar to the A genotype. All of the isolates displayed significant capacities to inhibit the growth of an oomycete pathogen in vitro, but such phenotypes were highly dependent on media used. When tested against multiple oomycete pathogens isolated from soybean, the A genotype was significantly more inhibitory than the D genotype when incubated on 1/10x tryptic soy agar and 1/5x corn meal agar. Seed inoculation with different isolates of the A, D, and S genotypes indicated that significant root colonization, generally in excess of log 5 cells per gram of root, could be attained on both crops. Field trials of the A genotype isolate Wayne1R indicated the capacity of inoculant populations to supplement the activities of native populations so as to increase soybean stands and yields. The relevance of these findings to natural and augmentative biocontrol of root pathogens by these bacteria is discussed. 相似文献
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防治棉花黄萎病的生防细菌NCD-2的田间效果评价及其鉴定 总被引：39，自引：0，他引：39
生防细菌NCD-2是自棉花根围土壤分离到的一株细菌菌株,田间小区试验表明:NCD-2菌株对棉花黄萎病的防治效果2年平均为85.4%,3年大区示范防病效果为51.2%~60.6%,并且该生防细菌对棉花产量和产量构成因子(单铃重、衣分、衣指、籽指等)及纤维品质(绒长)有所提高和改善。同时,本文测定了NCD-2对主要大田作物的安全性,证明其对小麦、玉米、棉花、马铃薯、黄瓜、茄子和大豆7种作物没有致病性,并且对这些作物的出苗、生长和发育没有不良影响。应用API50CH和API20 E细菌鉴定试剂盒,将NCD-2鉴定为枯草芽孢杆菌(Bacillus subtilis Cohn.)。 相似文献
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Economic and herbicide use impacts of glyphosate-resistant crops 总被引：4，自引：0，他引：4
Gianessi LP 《Pest management science》2005,61(3):241-245
More than 95% of United States maize, cotton, soybean and sugarbeet acres are treated with herbicides for weed control. These products are used to improve the economic profitability of crop production for farmers. Since their introduction in 1996, over 75 million acres of genetically engineered glyphosate-resistant crops have been planted, making up 80% of soybean acres and 70% of cotton acres in the USA. These genetically engineered crops have been adopted by farmers because they are perceived to offer greater economic benefits than conventional crop and herbicide programs. The adoption of glyphosate-resistant crops has saved US farmers 1.2 billion dollars associated with the costs of conventional herbicide purchases, application, tillage and hand weeding. With the adoption of glyphosate-resistant sugarbeets on currently planted sugarbeet acres, US growers could potentially save an additional 93 million dollars. The adoption of glyphosate-resistant crops by US agriculture has reduced herbicide use by 37.5 million lbs, although the adoption of glyphosate-resistant sugarbeets would dampen this reduction by 1 million lbs. 相似文献