Characteristics for Practical Use of Attenuated Isolate UA-Fukushima of <Emphasis Type="Italic">Tomato mosaic virus</Emphasis>     

Tsutomu MATSUMOTO  Yuichiro NARA  Hiromitsu FURUYA  Harumi TAKAHASHI  Kiichi TAIRAKO  Hideki YAMAMOTO 《Journal of General Plant Pathology》2002,68(4):382-384

L₁₁A-Fukushima (L₁₁A-F) derived from attenuated isolate LuA of Tomato mosaic virus (ToMV) has the highest ability to cross protect against virulent ToMV among LuA and its derivatives and is stably inherited. Growth, yield, fruit quality and symptom attenuation of inoculated tomato plants did not differ significantly between L₁₁A-F and L₁₁A. The infectivity of progeny viruses in tomato infected with LuA-F was less than 4% of that with virulent ToMV. From these results, L₁₁A-F appears to possess the properties necessary for practical use. To manage L₁₁A-F strictly, a PCR-based assay to detect trace contamination of virulent ToMV in L₁₁A-F preparations was established. Received 10 June 2002/ Accepted in revised form 30 October 2002  相似文献   

Effects of Latent Infection of Stock Plants and Abundance of Thrips on the Occurrence of <Emphasis Type="Italic">Tomato spotted wilt virus </Emphasis>in Chrysanthemum Fields     

Shohei MATSUURA  Shigeru HOSHINO  Hideaki HAYASHI  Tetsuyuki KOHGUCHI  Kyoji HAGIWARA  Toshihiro OMURA 《Journal of General Plant Pathology》2002,68(1):99-102

DAS-ELISA proved to be reliable enough to detect a latent infection by Tomato spotted wilt virus (TSWV) in asymptomatic stock plants of chrysanthemum. A high density of Frankliniella occidentalis, the predominant vector, in the presence of latently infected stock plants resulted in a high incidence of disease in the chrysanthemum production field. The incidence of disease was low when the vector thrips were not abundant in spite of the presence of latently infected stock plants. These results suggest that an infestation of the vector thrips causes severe secondary spread of TSWV originating from latently infected stock plants in chrysanthemum production fields. Received 27 July 2001/ Accepted in revised form 27 November 2001  相似文献   

Gene Flow Analysis of Phytophthora porri Reveals a New Species: Phytophthora brassicae Sp. Nov.     

Willem A. Man in 't Veld  Arthur W.A.M. de Cock  Elena Ilieva  C. André Lévesque 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(1):51-62

Isozyme analysis and sequence analysis of the internal transcribed spacer regions (ITS-1 and ITS-2) and the 5.8S subunit of the ribosomal DNA gene repeat were used to examine whether isolates of Phytophthora porri from Allium and Brassica represent a single homogeneous species. Twenty-six strains of P. porri, 16 strains isolated from the genus Allium, and 10 strains isolated from the genus Brassica, were analyzed using malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH) and lactate dehydrogenase (LDH), represented altogether by four putative loci (Mdh-2, Idh-1, Idh-2, and Ldh-2). Isozyme analysis revealed that strains isolated from Allium contained five private alleles at three isozyme loci (Ldh-2 ⁸³, Ldh-2 ¹⁰⁴, Idh-1 ¹⁰⁸, Idh-1 ¹¹², and Idh-2 ⁹⁸), whereas six different alleles were observed at four isozyme loci (Ldh-2 ⁸⁵, Ldh-2 ¹⁰⁰, Ldh-2 ¹¹⁴, Idh-1 ¹⁰⁰, Idh-2 ¹⁰⁰, and Mdh-2 ¹¹¹) in strains obtained from Brassica. The heterozygosity at the Ldh-2 locus, differing in allele composition, however, between strains from Allium and Brassica, was present in all strains, indicating that it is probably fixed. Sequence analysis of the ITS regions and the 5.8S subunit showed consistent differences between isolates from Allium and isolates from Brassica. Based on isozyme data, ITS sequence analysis and formerly published differences in restriction enzyme patterns of mitochondrial DNA, morphology and pathogenicity, it was concluded that the isolates of P. porri Foister did not represent a homogeneous species. Isolates from Brassica constitute a distinct species which is described here as P. brassicae sp. nov. It was inferred from isozyme patterns, which were in no case intermediate between the two species, that P. porri and P. brassicae do not hybridize and are reproductively isolated by barriers to gene flow.  相似文献   

Distribution of citrus viroids and <Emphasis Type="Italic">Apple stem grooving virus</Emphasis> on citrus trees in Japan using multiplex reverse transcription polymerase chain reaction     

Takao Ito  Nobuyuki Namba  Tsutae Ito 《Journal of General Plant Pathology》2003,69(3):205-207

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Indole-3-acetic acid biosynthesis in <Emphasis Type="Italic">Aciculosporium take</Emphasis>, a causal agent of witches' broom of bamboo     

Eiji Tanaka  Chihiro Tanaka  Atsushi Ishihara  Yasumasa Kuwahara  Mitsuya Tsuda 《Journal of General Plant Pathology》2003,69(1):1-6

 Aciculosporium take (Ascomycota; Clavicipitaceae) is a causal agent of witches' broom of bamboo plants. The symptoms of this disease are believed to be induced by plant hormones, particularly auxins. Indole-3-acetic acid (IAA) was identified in cultures of this fungus in an l-tryptophan-supplemented liquid medium. IAA production was confirmed on 30 isolates of A. take from various hosts and locations at levels up to 1 mg/l. The biosynthetic pathway of IAA in A. take culture was examined by analyzing intermediate products and by feeding experiments. The results showed that the indole-3-pyruvic acid pathway (l-tryptophan → indole-3-pyruvic acid → indole acetaldehyde → IAA) was the dominant pathway in A. take. Received: June 3, 2002 / Accepted: July 25, 2002  相似文献   

Inconspicuous restraint of rice seedling growth by root-infecting fungi in soil of a rice paddy field     

Hiromitsu Furuya  Tsutomu Matsumoto  Shin-ichi Fuji  Hideki Naito 《Journal of General Plant Pathology》2003,69(2):115-119

 Rice seedling growth, estimated by plant height and root development and discoloration, was better in pasteurized soil than in unpasteurized soil obtained from a flooded rice field. Rice seedlings also grew better in sterilized soil modified by adding roots harvested from the pasteurized soil than in soil modified by adding roots harvested from the unpasteurized soil. The results demonstrate that seedling growth in the rice field soil was inhibited by soil microorganisms, even though no typical symptoms such as seedling blight or damping-off appeared. Pythium aristosporum is suggested to be involved in the inhibition. Thus, it appears that inconspicuous restraint of rice seedling growth could occur in soils of rice paddy fields. Received: May 20, 2002 / Accepted: October 16, 2002 Acknowledgments The authors thank Dr. T. Ichitani, former professor at Osaka Prefectural University, for providing an isolate of Pythium aristosporum for comparison, and Mr. Mitsuaki Sato of Akita Prefectural College of Agriculture for technical assistance.  相似文献   

Functional heterogeneity in resources within landscapes and herbivore population dynamics     

Norman Owen-Smith 《Landscape Ecology》2004,19(7):761-771

Large mammalian herbivores are notorious for their propensity towards population irruptions and crashes, yet many herbivore populations remain relatively stable. I explore how resource heterogeneity within landscapes dampens population instability, using a metaphysiological modelling approach considering patch state distributions. Resource heterogeneity is functionally stabilizing through spreading consumption away from preferred resources before these become critically depleted. Lower-quality resources act as a buffer against starvation during critical periods of the seasonal cycle. Enriching resource quality is destabilizing, even if patch diversity is maintained, because food quantity then becomes the limitation. The potential consequences of landscape fragmentation are explored using the Serengeti ecosystem, characterised by broadscale resource gradients, as a hypothetical example. Further insights provided by the model are illustrated with specific examples concerning the effects of patch scales and waterpoint distribution. A metaphysiological modelling approach enables the basic consequences of landscape heterogeneity to be distinguished from further effects that may arise from specific patch scales and configurations, without the distracting detail of spatially explicit models.  相似文献   

Validation of the specificity and sensitivity of species-specific primers that provide a reliable molecular diagnostic for <Emphasis Type="Italic">Xiphinema diversicaudatum</Emphasis>, <Emphasis Type="Italic">X. index</Emphasis> and <Emphasis Type="Italic">X. vuittenezi</Emphasis>     

Judith Hübschen  Lilo Kling  Ulrike Ipach  Volker Zinkernagel  Nathalie Bosselut  Daniel Esmenjaud  Derek J.F. Brown  Roy Neilson 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):779-788

Xiphinema diversicaudatum and X. index are vector nematode species of economic importance in viticulture regions as they can transmit Arabis Mosaic, Grapevine Fanleaf and Strawberry Latent Ringspot viruses to grapevine. Wang et al. (2003) designed species-specific diagnostic primers from ribosomal genes for both these vector species as well as a vector and a non-vector species X. italiae and X. vuittenezi, respectively. Our study aimed to confirm the specificity and determine the sensitivity and reliability of the primers for the two vector species, X. diversicaudatumand X. indexwhen challenged with closely related longidorid species and general nematode communities typical of vineyard soil. With one exception, no PCR product was observed when the primers were tested against six Longidorus, one Paralongidorus and one Xiphinema non-target species. Occasionally (three out of eight replicate PCR reactions) a weak PCR product was noted when primers for X. index were tested with L. elongatus. Furthermore, when challenged with a range of non-target nematode species comprising the nematode community typical of viticulture soil, no PCR product was amplified. An experimental dilution series of extracted DNA rigorously demonstrated that DNA from an equivalent single specimen of the target virus-vector species, X. diversicaudatum and/or X. index, could be detected amongst 1000 equivalent non-targetX. vuittenezi. Also, extracted DNA from an equivalent single target specimen was detected when added to DNA extracted from the overall soil nematode community. The primers were assessed further by using serial mixtures of actual nematodes rather than extracted DNA to simulate field soil. Using this method, a single target nematode could be detected amongst 200 non-target specimens. Given their specificity, sensitivity and reliability, it appears that these diagnostic primers will be of great benefit to phytosanitary/quarantine services related to the viticulture industry.  相似文献   

Identification of Chlamydophila pneumoniae in an emerald tree boa, Corallus caninus.     

Elliott R Jacobson  Darryl Heard  Arthur Andersen 《Journal of veterinary diagnostic investigation》2004,16(2):153-154

Tissues were evaluated from emerald tree boas, Corallus caninus, from a collection in which chlamydiosis was diagnosed. To determine the strain of chlamydia infecting these snakes, tissue samples from 5 frozen snakes were tested by a quantitative TaqMan polymerase chain reaction (PCR) test and a PCR sequence analysis test. Of the 22 samples tested, 9 were categorized as either positive or weakly positive with the TaqMan test, and 6 yielded an amplicon using a serial PCR test that amplified a portion of the 23S ribosomal RNA gene. A PCR product suitable for sequencing was obtained from the heart of one of the snakes. Sequence analysis showed that the snake had been infected with Chlamydophila pneumoniae. These findings show that C. pneumoniae can infect emerald tree boas, broadening the range of reptiles known to be infected by this primarily human pathogen.  相似文献   

Morphofunctional description of mucous cells in the gills of the Arapaimidae Arapaima gigas (Cuvier) during its development          下载免费PDF全文

C. A. Ramos  O. T. F. da Costa  W. L. P. Duncan  M. N. Fernandes 《Anatomia, histologia, embryologia》2018,47(4):330-337

The gill structure of the Amazonian fish Arapaima gigas (Cuvier 1829) shows ontogenetic changes during development, particularly due the transition from the aquatic to the obligatory air breathing mode of respiration. However, three main cell types can be found in the gills: mitochondrial rich cells, pavement cells and mucous cells (MCs). The MCs are involved in the secretory pathway. The functions of the secreted molecules include mechanical protection of epithelia, protection against parasites and bacterial infection, and role on ion regulation. In this study, we analysed mucous cell location and mucous cell type, based on pH, during the development of A. gigas. Using samples obtained from the environment, gills were collected and fixed in buffered solution. Histological techniques for the identification of MCs were performed Alcian Blue (AB) and periodic acid‐Schiff (PAS). The results showed the presence of PAS+ and AB+ cells in the whole filament in all examined fish. In animals less than 50 g, few MCs were present, and no differences were observed in AB+ and PAS+ cells. In animals weighing close to 500 g, more PAS+ cells than AB+ cells were observed, and in animals that weighed more than 1,000 g, more AB+ cells than PAS+ cells were observed. These observations may be a result of the ontogenetic changes in the gill epithelia, which can change the osmorespiratory compromise in ion regulation functions as well the glycosaminoglycans secreted by PAS cells, which in large animals can play a role in the protection against parasites and bacterial infection.  相似文献