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1.
山东省小麦赤霉病菌种群组成及其致病力分化 总被引：2，自引：2，他引：0
由禾谷镰孢菌群Fusarium graminearum clade引起的赤霉病是小麦的重要病害。为明确山东省小麦赤霉病菌的种群组成及其致病力,于2011年和2012年从山东省15地市分离了95株小麦赤霉病菌,在形态和分子生物学鉴定种的基础上,采用鉴定B型毒素化学型的特异性引物进行毒素化学型分析。在95个菌株中,93株分离物为禾谷镰孢菌F.graminearum,2株为燕麦镰孢菌F.avenaceum。94株分离物为脱氧雪腐镰孢菌烯醇(deoxynivalenol,DON)化学型,1株为雪腐镰孢菌烯醇(nivalenol,NIV)化学型。在94株DON毒素化学型菌株中,90株为15-乙酰脱氧雪腐镰孢菌烯醇(15-acetyldeoxynivalenol,15-AcDON)化学型,4株为3-乙酰脱氧雪腐镰孢菌烯醇(3-acetyldeoxynivalenol,3-AcDON)化学型。在小麦扬花期,采用单花滴注接种法对29个菌株进行了致病力测定,供试菌株的致病力分化明显。表明在山东省冬小麦产区,产15-AcDON毒素的F.gra-minearum是小麦赤霉病菌的优势种群。 相似文献
2.
为确定引起呼和浩特市苜蓿根腐病的病原菌种类,采用常规组织分离法对采集的疑似苜蓿根腐病病样进行病原菌分离与培养,利用形态学观察结合分子生物学方法对分离物代表菌株进行鉴定,并采用土壤接种法对代表菌株的致病性进行测定。结果表明,共分离获得6类形态学特征不同的分离物,各随机选择1株代表菌株进行鉴定,结合分子生物学鉴定结果确定呼和浩特市苜蓿根腐病病原菌有6种,分别是麦根腐平脐蠕孢菌Bipolaris sorokiniana、立枯丝核菌Rhizoctonia solani、木贼镰刀菌Fusarium equiseti、变红镰刀菌F. incarnatum、锐顶镰刀菌F. acuminatum和织球壳枯萎菌Plectosphaerella cucumerina,分别分离到1、7、14、26、7和14株菌株,占总分离菌株数的1.45%、10.14%、20.29%、37.68%、10.14%和20.29%。其中,立枯丝核菌的致病力最强,接种苜蓿幼苗发病的病情指数达82.67,其次为木贼镰刀菌、变红镰刀菌、锐顶镰刀菌、麦根腐平脐蠕孢菌和织球壳枯萎菌,病情指数分别为72.67、62.67、58.67、52.... 相似文献
3.
为明确洛阳市牡丹灰霉病的病原菌种类,于2015年从该地区的4个牡丹Paeonia suffruticosa Andr.种植区采集灰霉病样品,采用组织分离法对病原菌进行分离和纯化,结合形态学和基因序列分析对分离物进行鉴定,采用针刺接种法测定不同分离物对牡丹离体叶片的致病性。结果表明,从灰霉病样品中分离获得40株分离物,这些分离物分别属于Ⅰ、Ⅱ、Ⅲ型菌,I型菌不易产孢但产菌核;Ⅱ型菌易产孢,后期产生少量菌核;Ⅲ型菌易产孢,且产生大量菌核。产孢分离物均形成直立状分生孢子梗,孢子梗分枝顶端聚生葡萄穗状分生孢子,分生孢子卵圆形或长卵圆形。供试菌株的ITS序列和G3PDH基因序列与灰葡萄孢Botrytis cinerea Pers.的同源性达到99%;致病性测定结果表明,各菌群代表菌株对牡丹均有致病性,但不同菌群间致病力有差异。研究表明,引起洛阳市牡丹灰霉病的病原菌为灰葡萄孢,且菌群类型多样。 相似文献
4.
山东省小麦根腐病病原菌的分离鉴定 总被引：8，自引：3，他引：5
为明确山东省小麦根腐病的病原菌种类,于2012—2014年从山东省10个地市采集小麦病株,通过组织分离法获得了185株分离物,利用形态学鉴定方法,结合基于5.8S r DNA-ITS序列或TEF-1α基因序列分析的分子鉴定方法对分离物进行了鉴定。结果表明:分离物中共得到135株麦根腐平脐蠕孢Bipolaris sorokiniana,占分离病原菌总数的72.97%,属优势种群;50株镰孢属Fusarium菌株,其中14株尖孢镰孢菌Fusarium oxysporum、19株层出镰孢菌Fusarium proliferatum和17株黄色镰孢菌Fusarium culmorum;按照柯赫氏法则进行致病性测定,证实了4种病原菌对鲁麦21号具有致病性,麦根腐平脐蠕孢的致病力较强,病情指数显著高于镰孢菌属真菌。研究表明,山东小麦根腐病主要是由麦根腐平脐蠕孢和镰孢属真菌侵染引起的,麦根腐平脐蠕孢为优势菌群。 相似文献
5.
拟康宁木霉Hailin菌株对马尾松幼苗的促生和防病作用 总被引：1，自引：0，他引：1
《中国植保导刊》2020,(2)
采用菌株形态学和r DNA-ITS序列比对分析的方法进行了Hailin菌株的鉴定,采用平皿对峙法研究了Hailin菌株对尖孢镰孢菌(Fusarium oxysporum)的抑菌效果,测定了接种尖孢镰孢菌和Hailin菌株后对马尾松(Pinus massoniana Lamb)幼苗的发病率和生长指标的影响。经形态学、分子鉴定和进化树分析,菌株Hailin为拟康宁木霉(Trichoderma koningiopsis)。Hailin菌株与尖孢镰刀菌平皿对峙培养5d后,对其抑制率为77.78%;蘸根针刺微伤处理接种Hailin菌株30 d后,对马尾松幼苗立枯病的防治率为58.3%;接种Hailin菌株与不接种的马尾松幼苗相比,其株高、湿重、根长分别提高了3.86%、78.74%和13.2%。Hailin菌株抑制尖孢镰孢菌的作用机制包括竞争作用、重寄生作用以及通过产生代谢产物抑制病原菌的生长。其中,Hailin菌株通过非挥发性代谢产物和挥发性代谢产物对尖孢镰孢菌菌丝生长的抑制率分别为97.80%和77.80%。 相似文献
6.
7.
为监测小麦茎基腐病病原菌的变化,2019—2020年自河南省安阳、濮阳和鹤壁等17个市129个采样点采集小麦茎基腐病病株样品并分离病原菌,对所有分离物进行形态学鉴定,利用特异性引物、ITS和EF-1α基因序列进行分子生物学鉴定,并于室内对优势病原菌菌株进行致病力测定。结果表明,共分离得到892株镰孢菌Fusarium分离物,所得分离物中假禾谷镰孢F. pseudograminearum共851株,所占比例为95.41%,为优势种;禾谷镰孢F. graminearum共16株,所占比例为1.79%。除信阳市外,其他16个市优势病原菌均为假禾谷镰孢。不同假禾谷镰孢菌株存在明显的致病力分化,但多数为强致病力菌株。 相似文献
8.
为明确在福建省南平市的橘柚和三明市的温州蜜橘上发现的疑似柑橘褐斑病的病原菌种类,采用组织分离法获得纯化菌株,通过回接法验证菌株的致病性,利用形态学特征对病原菌进行初步鉴定,并采用最大似然法以多聚半乳糖醛酸酶基因endoPG为靶标对本研究以及国内外已报道的链格孢菌株构建系统发育树,分析其遗传多样性。结果表明,从病组织中共分离获得26株纯培养菌株,经形态学鉴定均为链格孢菌Alternaria spp.。利用分生孢子液接种橘柚离体嫩叶发现,有22株菌株能侵染橘柚叶片并产生与田间相似的褐斑病症状,确认该病害为链格孢引起的柑橘褐斑病。系统发育树分析结果显示,分离所得的26株菌株均聚在已报道的4个柑橘链格孢进化分支Clade1～Clade4中,其中21株菌株聚在国内特有的分支Clade4中,有3株菌株和1株菌株分别聚在国内外兼有的分支Clade3和Clade1中,1株菌株聚在国外特有的分支Clade2中,表明在福建省采集的这些柑橘褐斑病菌均为链格孢菌,且遗传多样性较丰富。 相似文献
9.
水稻新病害叶鞘黑斑病的病原鉴定 总被引：2，自引：0，他引：2
2011年7月,在湖南省花垣县水稻上发现一种新的病害,症状表现为叶鞘上出现长椭圆形黑斑,病健交界模糊。分离到的4隔孢弯孢霉(HNHY001)经离体和活体人工接种均可产生黑斑;另一种黑孢霉菌株(HNHY002)不引致叶鞘黑斑。从湖南省栽培水稻150份种子样本中共分离到弯孢霉菌株27个,其中4个菌株具有4隔孢子。这4个菌株中1个菌株不产生子座,其余3个均产生分枝子座。经人工接种除不产生子座的外,其余3个菌株均能产生典型的叶鞘黑斑。HNHY001的rDNA-ITS序列(GenBank登录号JQ360963)经BLAST搜索,与之最接近的几个序列为膝曲旋孢腔菌(Cochliobolus geniculatus)及其有丝分裂产孢种—4隔孢弯孢霉。鉴于单独以及与其它4隔孢弯孢霉菌株进行对峙培养均未产生有性阶段,建议根据此菌无性阶段特征即分生孢子较直、4横隔、子座分枝等特征,鉴定为膝曲旋孢腔菌有丝分裂产孢种之一的假弯孢(C.fallax)。水稻叶鞘黑斑病系国内外首次报道。 相似文献
10.
真菌病毒在真菌中广泛存在,一些真菌病毒可以影响病原真菌营养生长、产孢和色素形成等性状。本文研究了真菌病毒在水稻稻瘟菌中的多样性以及其对寄主生物学性状的影响。采用单孢分离的方法从发病水稻叶片上分离获得了120个稻瘟菌菌株,其中约52%携带dsRNA片段。菌株QSP5被2个基因组为dsRNA的病毒即产黄青霉病毒1-C(Magnaporthe oryzae chrysovirus 1-C, MoCV1-C)和稻瘟菌病毒3(M. oryzae virus 3, MoV3)所侵染。对菌株QSP5进行单个的分生孢子纯化,获得了仅携带MoV3的菌株QSP5-9。菌株QSP5与QSP5-9的产孢量、菌丝形态以及菌落形态存在明显差异,经研究推测MoCV1-C与菌株QSP5 的产孢能力衰退、菌丝生长和产色素异常相关。同时对MoV3的稳定性进行了初步的研究。从稻瘟菌菌株QSP5获得了100个单孢分离物,通过对随机挑选的40个单孢分离物进行检测,结果表明这些分离物100%携带MoV3,只有部分单孢分离物携带MoCV1-C。另外,从稻瘟菌菌株QSP5-9获得了94个单孢分离物,对随机挑选的45个单孢分离物进行检测,结果表明这些分离物中均含有与菌株QSP5-9大小相同的dsRNA片段。根据以上结果推定MoV3在稻瘟菌菌株QSP5和QSP5-9及其无性后代中具有一定的稳定性。 相似文献
11.
Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They
represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing
slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more
stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively).
Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were
significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr
s
,P=0.007 and 0.039, respectively) and perennials (Spearmanr
s
,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles. 相似文献
12.
Epidemiology of Toxigenic Fungi and their Associated Mycotoxins for Some Mediterranean Crops 总被引：9，自引：0，他引：9
Antonio Logrieco Antonio Bottalico Giuseppina Mulé Antonio Moretti Giancarlo Perrone 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(7):645-667
Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams. 相似文献
13.
The genera ofMicrogaster Latreille 1804 andHygroplitis Thomson 1895 from China are presented systematically in this paper. Thirty-two species ofMicrogaster and three species ofHygroplitis are known in China. Diagnosis, character variation, distribution and host of each species among the two genera are presented,
including its host and distribution. Keys to the species ofMicrogaster andHygroplitis are given.
http://www.phytoparasitica.org posting Dec. 19, 2006. 相似文献
14.
Plant Viruses Transmitted by Whiteflies 总被引：18，自引：0，他引：18
David R. Jones 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(3):195-219
One-hundred and fourteen virus species are transmitted by whiteflies (family Aleyrodidae). Bemisia tabaci transmits 111 of these species while Trialeurodes vaporariorum and T. abutilonia transmit three species each. B. tabaci and T. vaporariorum are present in the European–Mediterranean region, though the former is restricted in its distribution. Of the whitefly-transmitted virus species, 90% belong to the Begomovirus genus, 6% to the Crinivirus genus and the remaining 4% are in the Closterovirus, Ipomovirus or Carlavirus genera. Other named, whitefly-transmitted viruses that have not yet been ranked as species are also documented. The names, abbreviations and synonyms of the whitefly-transmitted viruses are presented in tabulated form together with details of their whitefly vectors, natural hosts and distribution. Entries are also annotated with references. Whitefly-transmitted viruses affecting plants in the European–Mediterranean region have been highlighted in the text. 相似文献
15.
M. Fortass S. Diallo 《European journal of plant pathology / European Foundation for Plant Pathology》1993,99(4):219-226
Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes. 相似文献
16.
B. Blanco-Urgoiti M. Tribodet S. Leclere F. Ponz C. Pérez de san román F.J. Legorburu C. Kerlan 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(8):811-819
A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVYN strain and six to the PVYO strain. No PVYC was found. Two other isolates reacted serologically like PVYO, but were unable to elicit a hypersensitive response from the Nytbr gene and probably represent the PVYZ group. At the molecular level, these two isolates showed a combination of both PVYO and PVYN and could be recombinants of these strains. Another isolate reacted serologically like PVYO, but induced vein necrosis in tobacco, like PVYN-Wilga. Some PVYN isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVYNTN group. The PVYNTN, PVYN-Wilga and PVYZ groups probably represent pathotypes within strains PVYN and PVYO, respectively. The present study also confirms previous reports showing a high genetic variation at the 5
end within the PVYN strain. 相似文献
17.
L. Blommers H. Helsen F. Vaal 《European journal of plant pathology / European Foundation for Plant Pathology》1988,94(2):95-103
The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed. 相似文献
18.
Paul W. J. Taylor Rebecca Ford 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):127-133
Molecular diagnostic techniques have been developed to differentiate the Ascochyta pathogens that infect cool season food and feed legumes, as well as to improve the sensitivity of detecting latent infection
in plant tissues. A seed sampling technique was developed to detect a 1% level of infection by Ascochyta rabiei in commercial chickpea seed. The Ascochyta pathogens were shown to be genetically diverse in countries where the pathogen and host have coexisted for a long time. However,
where the pathogen was recently introduced, such as A. rabiei to Australia, the level of diversity remained relatively low, even as the pathogen spread to all chickpea-growing areas.
Pathogenic variability of A. rabiei and Ascochyta pinodes pathogens in chickpea and field pea respectively, appears to be quantitative, where measures of disease severity were based
on aggressiveness (quantitative level of infection) rather than on true qualitative virulence. In contrast, qualitative differences
in pathogenicity in lentil and faba bean genotypes indicated the existence of pathotypes of Ascochyta lentis and Ascochyta fabae. Therefore, reports of pathotype discrimination based on quantitative differences in pathogenicity in a set of specific genotypes
is questionable for several of the ascochyta-legume pathosystems such as A. rabiei and A. pinodes. This is not surprising since host resistance to these pathogens has been reported to be mainly quantitative, making it difficult
for the pathogen to overcome specific resistance genes and form pathotypes. For robust pathogenicity assessment, there needs
to be consistency in selection of differential host genotypes, screening conditions and disease evaluation techniques for
each of the Ascochyta sp. in legume-growing countries throughout the world. Nevertheless, knowledge of pathotype diversity and aggressiveness within
populations is important in the selection of resistant genotypes. 相似文献
19.
F. K. Crutcher M. A. Henry‐Gregory H. H. Wilkinson S. E. Duke T. Wheeler C. M. Kenerley 《Plant pathology》2018,67(4):839-847
In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population. 相似文献
20.
H. A. Van Hoof H. Huttinga A. Knaap H. P. Maas Geesteranus W. H. M. Mosch D. G. J. De Raay-Wieringa 《European journal of plant pathology / European Foundation for Plant Pathology》1979,85(3):87-98
In 1975 many tumours were observed in plants ofBegonia Schwabenland grown in Aalsmeer. Submersion of the roots ofNicotiana megalosiphon seedlings in a homogenate of tumorous tissue, induced tumours after two weeks. Short periods of submergence yielded results similar to those obtained after longer periods. Tumour homogenates lost their infectivity after ten min at 50°C. Aphids transmitted the infectious agent.Treatment with propylene oxide did not inhibit infectivity completely. Filtration through a 450 nm filter removed the infectious agent.Tobacco tumor virus or a viroid could not be isolated. Cultures ofCorynebacterium fascians, isolated from tumours ofN. megalosiphon were highly infectious and induced tumours in healthyN. megalosiphon andBegonia. Tumorous tissue homogenates ofPelargonium zonale, Dahlia sp.,Gladiolus sp., andLilium sp. also caused tumours inN. megalosiphon, from whichC. fascians was isolated. It was not possible to produce tumours inN. megalosiphon with homogenates from roses with symptoms of bud proliferation.Samenvatting In 1975 werden vele tumoren waargenomen inBegonia Schwabenland op Aalsmeerse bedrijven (Fig. 1). De infectiositeit van tumorweefsel kon goed en snel worden vastgesteld door de wortels van zaailingen vanNicotiana megalosiphon in een homogenaat van tumorweefsel te dompelen. Tumoren ontstonden na twee weken, de eindbeoordeling geschiedde na een maand (Fig. 2). Ook verschillende andereNicotiana spp.,Melilotus officinalis (Fig. 3) enPisum odoratum (Fig. 4) werden aangetast.Bij de infectiositeitstoets gaven zeer korte dompeltijden even goede resultaten als langere (Tabel 1). Infectieus sap verloor zijn infectievermogen na 10 min verhitting bij 50°C. Bladluizen brachten de smetstof over. Propyleenoxide verminderde de infectiositeit wel, doch onderdrukte deze niet totaal. Bij filtratie door een 450 nm filter bleef het infectieuse agens op het filter achter. Het tumor-inducerende agens was ook aanwezig in die delen van planten met tumoren welke gezond leken en het ging voor een gering deel over met zaad (Tabel 2).Uit tumoren konden wij geen tabakstumorvirus of een viroïde isoleren. Culturen vanCorynebacterium fascians, geïsoleerd uit tumoren vanN. megalosiphon bleken zeer infectieus en veroorzaakten tumoren inN. megalosiphon enBegonia. Homogenaten van tumorweefsel vanPelargonium zonale, dahlia (Fig. 5), gladiool (Fig. 6) enLilium Mid Century Hybrid Enchantment (Fig. 7) veroorzaakten ook tumoren opN. megalosiphon, waaruitC. fascians werd geïsoleerd. Met sap van kroeskopzieke rozen konden wijN. megalosiphon niet besmetten. 相似文献