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    Identification and pathogenicity of three species of Pythium newly isolated from diseased wheat and barley just after thawing in Japan.
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    Abstract:
    Three species of Pythium (P. okanoganense, P. vanterpoolii, P. volutum) were newly identified as pathogens of Pythium snow rot of wheat and barley in Japan. From the results on frequency of isolation and pathogenicity, it can be concluded that P. okanoganense is an important pathogen, like P. iwayamai and P. paddicum reported previously by other authors, but both P. vanterpoolii and P. volutum are minor.
    Keywords:
    Pythium
    Fungal pathogen
    Take-all
    Isolation
    Pathogenicity tests of various species of <i>Pythium, Fusarium</i> and <i>Rhizoctonia sotani</i> were made on five plants namely cotton, pea, tomato, maize and wheat. <i>Pythium ultimum proved to be the most destructive species to tomato and cotton seedlings. The four species of <i>Fusarium</i> tested showed considerably different pathogenic abilities. Isolate of <i>Rhizoctonia soleni</i> (A — from soil) showed slight pathogenicity to all test plants and isolate (B — from cotton seedlings) was highly destructive to cotton and pea.
    Rhizoctonia
    Pythium
    Pythium ultimum
    Root rot
    Citations (2)
    Using different over-wintering pathogen sources of watermelon bacterial fruit blotch and different inoculated-pathogen methods to test the pathogenicity of Xinong No.9.The results showed that the over-wintering pathogen sources of diseased fruit extract,dry diseased leaf,fresh diseased leaf and bacteria carrying soil all had pathogenicity,in which the over-wintering pathogen sources of bacteria carrying soil and dry diseased leaf had stronger pathogenicity;four different inoculated-pathogen methods(seed soaking,root drenching,needle inoculation and spraying) had a certain impact on pathogenicity of different over-wintering pathogen sources,in which the needle inoculation method had the strongest pathogenicity.Therefore,the results provide a scientific base for popularizing control measures,such as deep tillage,weed out diseased residues in filed,soil disinfection,reducing wounds caused by filed operation,etc..
    Citations (0)
    The lethal dose for 50%(LD50) of Vibrio anguillarum W-1 in seaperch fry and the pathogenicity of strain W-1 stored in different conditions were investigated in this paper.The results showed that the LD50 for seaperch fry with immersion infection was 2.5×107.5cell/mL while the LD50 for the seaperch fry challenged with immersion after abdominal puncture was 2.5×107cell/mL.The pathogen W-1 was an opportunistic pathogen and injury was the main infection factor.In addition,the strain W-1 reproduced many times as well as the strain W-1 stored at 15℃,-20℃ and-80℃ had a strong pathogenicity to the seaperch fry.
    Vibrio anguillarum
    Strain (injury)
    Opportunistic pathogen
    Median lethal dose
    Citations (0)
    Variation in the infection capacity of a pathogen may be due to different relationships: the actual stage in the life-cycle of the pathogen, the variability in terms of biotype or race and the virulence of the pathogen in terms of the amount of inoculum needed to establish infection. These factors will be discussed in the following sections: (1) pathogenicity as related to the life-cycle or ontogenesis of the pathogen, (2) pathogenicity as related to physiologic or pathogenic races or strains of the pathogen (pathotypes), (3) pathogenicity as related to infection potential of the pathogen, (4) pathogenicity as related to the actual condition of the pathogen. These aspects are all important with regard to seed transmission of the pathogen and to their bearing on further secondary spread of disease.
    Fungal pathogen
    Scolecobasidium humicola, a previously undescribed fungal pathogen of fish was isolated from coho salmon (Oncorhynchus kisutch). In natural infections the kidney was the organ most affected. The disease was difficult to transmit experimentally and appeared to be only weakly contagious.
    Fungal pathogen
    Fungal disease
    Citations (42)
    Ten isolates of Pythium arrhenomanes and a single isolate of P. spinosum caused root rot and significant reductions in growth of sugarcane cultivar CP 70-321 in pathogenicity tests. Isolates of six other Pythium spp. were tested, and none consistently affected plant growth. Disease severity was greatest in experiments conducted under moderate temperature conditions. In tests conducted at high temperatures, the predominant symptoms were root discoloration and feeder root necrosis, and a range in virulence was apparent among isolates of P. arrhenomanes
    Pythium
    Citations (23)
    Three species of Pythium (P. okanoganense, P. vanterpoolii, P. volutum) were newly identified as pathogens of Pythium snow rot of wheat and barley in Japan. From the results on frequency of isolation and pathogenicity, it can be concluded that P. okanoganense is an important pathogen, like P. iwayamai and P. paddicum reported previously by other authors, but both P. vanterpoolii and P. volutum are minor.
    Pythium
    Fungal pathogen
    Take-all
    Isolation
    Laboratory investigations of the pathogenesis of Pseudogymnoascus destructans, the fungal causal agent of bat White Nose Syndrome (WNS), presents unique challenges due to its growth requirements (4°-15°C) and a lack of infectivity in the current disease models. Pseudogymnoascus pannorum is the nearest fungal relative of P. destructans with wider psychrophilic – physiological growth range, and ability to cause rare skin infections in humans. Our broad objectives are to create the molecular toolkit for comparative study of P. destructans and P. pannorum pathogenesis. Towards these goals, we report the successful development of an invertebrate model in the greater wax moth Galleria mellonella. Both P. destructans and P. pannorum caused fatal disease in G. mellonella and elicited immune responses and histopathological changes consistent with the experimental disease.
    Galleria mellonella
    Fungal pathogen
    Human pathogen
    Opportunistic pathogen