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1.
为了解橡胶树2种炭疽病菌的侵染结构发育分化过程,采用平板菌落生长速率法测定了3株胶孢炭疽菌Colletotrichum gloeosporioides和3株尖孢炭疽菌C.acutatum的菌丝生长速率,测量其分生孢子大小,显微观察2种炭疽菌在疏水表面诱导下侵染结构的发育分化过程。结果表明,胶孢炭疽菌菌丝生长速率为0.96~1.36 cm/d,显著高于尖孢炭疽菌的菌丝生长速率0.72~0.89 cm/d,但二者分生孢子大小无显著差异。在疏水表面诱导下,2种炭疽菌分生孢子在接种2~6 h后开始萌发,12 h孢子萌发率为71.70%~88.05%,13~16 h开始分化附着胞,24 h附着胞形成率为48.99%~70.74%,36 h菌丝诱发形成大量附着枝,48 h后分生孢子产生的次生菌丝也可诱发形成附着枝,附着枝呈圆形、姜瓣形、梨形或不规则形。分生孢子极易产生,可在菌丝顶端成簇或菌丝侧面排列产生,也可由分生孢子形成的芽管产生,或在芽管分化附着胞过程分枝形成分生孢子;附着胞多着生于芽管顶端,少数附着胞顶端可继续萌发类似短芽管结构,再次分化形成可黑色化的次级附着胞。表明橡胶树2种炭疽菌不同菌株间分生孢子萌发时间、孢子萌发率、附着胞形成时间和形成率有一定差异,但种间无明显差异;橡胶树炭疽菌分生孢子极易形成,在疏水表面容易分化形成附着胞和附着枝,说明具有极强的适生性。 相似文献
2.
栗疫病菌的培养性状、毒力与dsRNA的关系 总被引：10，自引：1，他引：10
根据菌落的培养性状将中国东部12个省(市)的429个栗疫病菌(Cryphonectria parasitica)菌株划分为5种培养类型。其中Ⅰ型为桔黄色菌落的野生型正常菌株,占总菌株数的89.3%;Ⅱ~Ⅳ型为培养性状不正常菌株,共有46株,菌落有黄褐色、白色和深褐色等类型。供试菌株间存在明显的毒力分化,可分为强中弱三种类型。培养性状正常的菌株毒力普遍较强,极少菌株检测到dsRNA;培养性状不正常的菌株毒力一般较低,在菌落白色的菌株中都检测到dsRNA。在所测试的70个菌株中含dsRNA的菌株有38个,其中32个属于弱毒力类型,其他6个属中毒力类型;分布于除河南、湖南和广东以外的其他9个省(市)。 相似文献
3.
氰烯菌酯(2-氰基-3-氨基-3-苯基丙烯酸乙酯,JS399-19) 是一种对禾谷镰孢菌Fusarium graminearum具有专化活性的新型杀菌剂。离体条件下,采用菌丝生长速率法测定了该药剂对禾谷镰孢菌抗性菌株和敏感菌株的生长抑制活性;同时采用孢子萌发法测定了其对禾谷镰孢菌分生孢子萌发的影响。结果表明,氰烯菌酯能够强烈地抑制禾谷镰孢菌敏感菌株菌丝的生长,EC50值分布在0.092~0.141 μg/mL之间;并可降低敏感菌株分生孢子的萌发速率,以及影响其萌发的方式,使芽管从分生孢子基部和中间细胞萌发的比率增加;同时氰烯菌酯使敏感菌株分生孢子膨大、畸形,并使其芽管肿胀、扭曲,明显抑制其芽管的伸长生长;但对抗性菌株的抑制作用和致畸作用不明显。 相似文献
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由辣椒尖孢炭疽菌(Colletotrichum acutatum)侵染引起的炭疽病是辣椒生产中最具有破坏性的真菌病害,严重影响辣椒的品质和产量。本研究以辣椒尖孢炭疽病菌HHDL02为对象,采用1 mol·L-1 NH4Cl 2%的酶裂解液裂解分生孢子萌发2 h的芽管,裂解2～3 h可以高效制备原生质体,结合PEG介导转化法成功将GFP基因导入,其转化菌株菌落形态、菌丝生长速率、分生孢子形态、孢子萌发、附着胞形成、产孢量和致病性与野生型菌株无明显差异,且后代荧光信号遗传稳定。PEG介导的原生质体转化适合辣椒尖孢炭疽菌遗传操作,有助于其致病机理的研究。 相似文献
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球孢白僵菌生物学特性与其对不同昆虫侵染差异相关性分析 总被引：1，自引：0，他引：1
球孢白僵菌对不同目标昆虫的侵染能力存在很大差异。应用4株不同寄主来源的球孢白僵菌对2龄小菜蛾和棉铃虫幼虫进行毒力测定,扫描电镜观察分生孢子在试虫体表的萌发及侵染过程,同时测定了4菌株的生长速率、产孢量和孢外酶水平等生物学特性。结果表明,供试菌株中HFW-05的生长速率及酶活性均高于其余3菌株;菌株HFW-05对小菜蛾致病力较高,处理6d后校正死亡率为87．1％,其余3株为30％左右;4菌株对棉铃虫6d后校正死亡率均低于20％。扫描电镜观察结果表明,菌株HFW-05附着在小菜蛾表皮12h后,孢子萌发后直接或产生较短芽管穿透表皮,36h后,未穿透小菜蛾表皮的菌丝体断裂为芽生孢子;其余处理分生孢子在试虫表皮均能萌发,但芽管多呈蔓延生长直至断裂为芽生孢子,未能有效穿透寄主表皮,且孢子生长周期均长于菌株HFW-05。单纯依据孢子萌发率、产孢量或酶活评价筛选高毒力菌株是不够的。 相似文献
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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
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采用菌丝生长速率法和显微镜观察,研究了咪鲜胺对水稻恶苗病菌Fusarium fujikuroi生长发育及菌丝形态的影响。结果表明:咪鲜胺对水稻恶苗病菌敏感菌株及其抗药性突变体的菌丝生长、孢子萌发、芽管伸长均有明显的抑制作用,而对产孢量无影响。当咪鲜胺浓度为0.5 μg/mL时,能够完全抑制敏感菌株菌丝的生长,而不能抑制不同抗性水平抗性菌株的菌丝生长。随抗性倍数从24倍增加到112倍,药剂对抗药突变体菌落扩展的影响逐渐减小。咪鲜胺对敏感菌株菌丝生长的EC50 值为0.047 μg/mL,最小抑制浓度(MIC) 为 0.5 μg/mL。 20.00 μg/mL咪鲜胺可完全抑制亲本敏感菌株的孢子萌发,而对不同抗药突变体孢子萌发和芽管伸长的抑制率分别为84.1% ~89.0%和58.5％ ~65.8%,表明抗药突变体在菌丝生长、孢子萌发、芽管伸长等阶段对药剂的敏感性与亲本菌株相比都有了不同程度的降低。10 μg/mL咪鲜胺处理菌丝12 h后,亲本菌株菌丝顶端膨大畸形,抗药突变体的菌丝顶端膨大,并在菌丝上长有许多细小分枝,表明药剂对抗药突变体次生菌丝生长的抑制作用不明显。 相似文献
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为了明确不同白僵菌菌株的生物学特征,对15株白僵菌菌株的ITS片段进行测序分析,并对这些菌株的菌落生长速率、产孢量、孢子萌发率、单芽管孢子萌发比例、单芽管平均长度和长芽管平均长度等多项生物学指标进行测定。结果表明,单芽管孢子萌发比例变化范围在11．91％～96．03％;单芽管平均长度和双芽管平均长度分别为6．28-21．43μm和10．338～19．902μm;各菌株间孢子萌发率差异很大,变化范围22．09％-86．32％。对菌株的培养特性（孢子萌发率、产孢量和菌落生长速率）与孢子萌发特性（单芽管孢子萌发比例、芽管总平均长度和芽管整齐度）这两个主因子进行典型相关分析,两性状集团总体相关不显著（P=0．341）,而孢子萌发率与单芽管孢子萌发比例相关显著,菌落生长速率与芽管总平均长度呈显著相关。 相似文献
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为研究球孢白僵菌对不同昆虫的致病力及其在昆虫体表侵染的差异,探讨球孢白僵菌对不同寄主昆虫侵染的毒力差异,本研究选择了不同分离来源的9株球孢白僵菌,以半翅目的烟粉虱和鳞翅目的小菜蛾为试验材料,详细比较了球孢白僵菌对烟粉虱2龄若虫和小菜蛾2龄幼虫的毒力差异,以及在侵染过程中孢子吸附、孢子萌发及芽管伸长速度差异。结果表明,9株球孢白僵菌有6株对2种昆虫毒力差异显著,3个菌株差异不显著。对2种昆虫毒力差异不显著的菌株Bb271在2种昆虫体表单位面积的孢子吸附数量、孢子萌发率和芽管伸长速度均无显著差异;对2种昆虫毒力差异显著的2个菌株Bb104和Bb120在2种昆虫体表单位面积的孢子吸附数量和孢子萌发率无显著差异,但在2种昆虫体表的芽管伸长速度差异显著（P<0.05）。因此,从本研究结果来看,球孢白僵菌对不同昆虫的致病力强弱与昆虫体表单位面积的孢子吸附数量和孢子萌发率无关,与球孢白僵菌在昆虫体表的芽管伸长速度有关。芽管伸长速度可以作为球孢白僵菌菌株对寄主昆虫致病力强弱的形态学依据。 相似文献
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本文通过孢子萌发检测、平板生长抑制法和果实病害防治试验,测定了淡紫紫孢菌Purpureocillium lilacinus PL36-1防治储藏期番茄果实灰霉病的效果。结果表明,菌株PL36-1发酵滤液不仅能够抑制灰葡萄孢分生孢子萌发和芽管伸长,而且可以抑制灰葡萄孢菌丝生长。对峙培养的菌株PL36-1显著抑制灰葡萄孢的菌丝生长,菌丝生长抑制率可达到74.45%,菌株PL36-1产生的挥发性物质也对灰葡萄孢菌丝生长有一定的抑制作用。菌株PL36-1发酵液处理樱桃番茄果实后,能有效控制番茄果实灰霉病的发生,含有2×10~8孢子/m L的发酵液10 d的防治效果达70.64%。 相似文献
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ABSTRACT The Cryphonectria parasitica populations in two 6-year-old European chestnut (Castanea sativa) coppices were investigated in southern Switzerland over a period of 4 years. Occurrence of white isolates indicating an infection with Cryphonectria hypovirus, vegetative compatibility groups (VCGs), hypovirulence conversion capacity, and mating types were used to characterize the populations. Sampling of randomly chosen cankers in the first year yielded 59% white isolates in one and 40% in the other population. The distribution of the VCGs and mating types was similar among white and orange isolates, indicating a homogeneous infection of the two populations by the hypovirus. Fourteen VCGs were found in the first population, 16 VCGs in the second. Altogether, 21 VCGs were determined. The same three VCGs dominated in both populations, comprising more than 60% of all isolates. Several VCGs were represented only by white isolates. Five of the six most common VCGs were clustered in two hypovirulence conversion groups, with almost 100% hypovirus transmission within each cluster. Repeated sampling of the same cankers in 1990, 1992, and 1994 did not reveal an increase of white isolates. The portion of blighted stems rose from 37% to about 60% in both plots within 4 years. In this time, chestnut blight killed 15% and competition an additional 21% of the sprouts. Predominantly, sprouts with low diameters at breast height were killed. The growth rate of new cankers was high in their first year and decreased gradually in the following years. A role of hypovirulence in the decline of disease severity was evident since (i) cankers yielding white isolates grew slower and killed considerably fewer sprouts than cankers with orange isolates; and (ii) the majority of the cankers yielded white isolates at least once during the 4-year observation period. 相似文献
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Laboratory assays demonstrated that two isolates of Trichoderma viride and one isolate of Trichoderma pseudokoningii degraded up to 80% of sclerotia of four isolates of Sclerotium cepivorum in a silty clay soil, and also degraded up to 60% of sclerotia in three other soil types. Relationships were defined between the degree of sclerotial degradation by the two T. viride isolates in the silty clay soil and both temperature and soil water potential. Sclerotia were degraded between 10 and 25°C at −0·00012 MPa, but there was little activity of T. viride at 5°C or at −4 MPa. Degradation of S. cepivorum sclerotia also occurred in the absence of Trichoderma at soil water potentials approaching saturation . Experiments using onion seedling bioassays showed that the efficacy of Trichoderma isolates for the control of white rot using the same selection of soils and S. cepivorum isolates was variable, but that there was significant disease control overall. The importance of environmental factors and pathogen isolate in relation to effective biological control of white rot is discussed. 相似文献
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采用RT-PCR方法扩增并克隆了2013年湖南省水稻上发生的南方水稻黑条矮缩病毒(Southern rice blackstreaked dwarf virus,SRBSDV)S10片段的近全长序列,采用生物信息学软件Mega、RDP和DnaSP分析其编码的开放阅读框(open reading fragment,ORF)遗传多样性。结果表明:2013年湖南省15个SRBSDV分离物S10编码的ORF序列同源性在99.5%以上,不同分离物中存在3~30个突变位点,绝大部分的核酸突变为无义突变,没有发现可能的重组。在系统发育树上,15个分离物聚类为2个分支,其中湖南汉寿的10个分离物和永州的2个分离物(HuNyz12和HuNyz29)与我国浙江分离物聚为1个亚组、湖南永州的其他3个分离物与我国南部的云南、海南等及越南的分离物聚为1个亚组。系统发育结果表明,SRBSDV随传毒介体白背飞虱迁飞从我国南部向北部扩散。 相似文献
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ABSTRACT In France, chestnut blight, caused by Cryphonectria parasitica, has been controlled since 1974 in orchards, but never in coppice forests, by releasing hypovirulent strains infected with CHV1 hypovirus. We tested the hypothesis that this biological control (BC) has lead to a decrease in blight severity, spread of hypovirulence, and change in C. parasitica populations. The low severity of chestnut blight was confirmed in the six regions studied (subdivided into zones). The remission of cankers was associated with the presence of white isolates presumed to be hypovirulent. These two parameters were also correlated, at the zonal level, to the frequency of sites where BC was used. However, the estimates of the natural background level of hypovirulence, independent of BC, ranged from 4% in forests in Dordogne to 60% in orchards in Lozère. Differences in the rate of hypovirulent isolates among regions were consistent with the diversity of vegetative compatibility (VC) types in populations of C. parasitica. The highest VC-type diversity and mean allelic diversity for known vegetative incompatibility (vic) genes were observed in Dordogne. We showed that the current diversity of VC types in populations of C. parasitica was lower than in 1981. We found 30 VC types among 1,113 isolates of C. parasitica. Ten VC types were incompatible with known EU testers, suggesting that one additional vic gene or allele at one of the six vic loci known should be present in Europe. 相似文献
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Four fungi ( Chaetomium globosum, Trichoderma viride, T. harzianum, Trichoderma sp.) were capable of reducing the incidence of onion white rot relative to the untreated control in two soil-box trials. When applied as a soil additive (sand: bran: fungal homogenate, 1:1:2) at the rate of 0-1% wheat bran/g dry soil, all fungal isolates provided levels of disease control equivalent to the fungicide (procymidone 0-5 g a.i./100g seed) treatment. The best results were achieved with the Chaetomium globosum and Trichoderma (C62) isolates which gave 78% and 73% control of white rot. respectively, in trial 1 and 67% and 73% control, respectively, in trial 2. Reduced control was observed when the test fungi were applied as seed coatings or incorporated into alginate pellets. 相似文献
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Richardson BA Klopfenstein NB Zambino PJ McDonald GI Geils BW Carris LM 《Phytopathology》2008,98(4):413-420
Cronartium ribicola, the causal agent of white pine blister rust, has been devastating to five-needled white pines in North America since its introduction nearly a century ago. However, dynamic and complex interactions occur among C. ribicola, five-needled white pines, and the environment. To examine potential evolutionary influences on genetic structure and diversity of C. ribicola in western United States, population genetic analyses of C. ribicola were conducted using amplified fragment length polymorphism (AFLP) molecular markers. The fungus was sampled at six sites. Collections for two of the six sites were from separate plantings of resistant-selected western white pine and sugar pine. Heterozygosity based on polymorphic loci among populations ranged from 0.28 to 0.40, with resistant-selected plantations at the extremes. Genetic differentiation was also highest between these two populations. Principal coordinates analysis and Bayesian assignment placed most isolates that are putative carriers of virulence to major-gene resistance into a discernable cluster, while other isolates showed no clustering by site or host species. These results indicate that C. ribicola in western North America is not genetically uniform, despite its presumed single site of introduction and relatively brief residence. Moreover, major-gene resistance appears to have imposed strong selection on the rust, resulting in reduced genetic diversity. In contrast, no evidence of selection was observed in C. ribicola from hosts that exhibit only multigenic resistance. 相似文献
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ABSTRACT Ninety isolates of grape powdery mildew (Uncinula necator) from Europe (sixty-two) and India (twenty-eight) were collected. Ten of the sixty-two European isolates originated from mycelium overwintering in dormant buds ("flagshoots"). Mating types were determined, and genetic variation was assessed by random amplified polymorphic DNA (RAPD). Forty-one European isolates, including all "flagshoot" isolates, were mating type +, and twenty-one were mating type -. All Indian isolates were mating type -. Phenetic analysis based on 414 amplicons revealed three main groups. Most European isolates (53) clustered together. Nine flagshoot isolates clustered in a second distinct group. These isolates, which coexisted with other isolates in the field, may represent a genetically isolated biotype of U. necator. Indian isolates clustered into two groups. The first group (15 isolates) was a subgroup of the group containing European nonflagshoot isolates. The second group (12 isolates) was distinct from the other groups. These two groups of Indian isolates may represent genetically isolated populations with different climatic tolerances. A polymerase chain reaction primer pair, derived from a RAPD fragment specific to the Indian isolates, proved to be suitable for field studies. 相似文献