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Shinichi Kusakari - One of the best experts on this subject based on the ideXlab platform.
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Digital microscopic analysis of conidiogenesis of powdery mildew pathogens isolated from melon leaves
Phytoparasitica, 2015Co-Authors: Yoshihiro Takikawa, Shinichi Kusakari, Teruo Nonomura, Yoshinori Matsuda, Koji Kakutani, Shouta Miyamoto, Naoki Okamoto, Tomoe Murakami, Hideyoshi ToyodaAbstract:Melons (Cucumis melo L.) grown hydroponically in a greenhouse were heavily infested with powdery mildew. We isolated powdery mildew pathogens from the melon leaves and identified the isolate as Podosphaera xanthii KMP-6N, based on morphological characteristics and sequences of ribosomal DNA internal transcribed spacer (rDNA-ITS) regions. Host ranges of KMP-6N were determined by estimating the infectivity or pathogenicity after inoculating the conidia onto multiple plant species. The fungi caused severe powdery mildew symptoms on Cucurbitaceae plants, producing scattered conidia on Conidiophores. The goal of this study was to observe KMP-6N conidiogenesis on melon leaves. The pathogen formed completely catenated Conidiophores approximately 24 h from Conidiophore erection to release of mature conidia. Six conidia were produced on the Conidiophores and only the conidia at the apex reached maturity. The cycles of conidial release were repeated on melon leaves 14 to 18 times, at approximately 6-h intervals. In the final stage, conidia were released without causing growth and septation of generative cells. Conidiophores produced an average of 36 conidia during a 90-h period. In our study, the modes of conidiogenesis, lifetime of Conidiophores and productivity of conidia on a Conidiophore were described for powdery mildew fungi.
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formation of conidial pseudochains by tomato powdery mildew oidium neolycopersici
Plant Disease, 2006Co-Authors: Wataru Oichi, Teruo Nonomura, Yoshinori Matsuda, Hideyoshi Toyoda, Ling Xu, Shinichi KusakariAbstract:ABSTRACT The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living Conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the Conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the Conidiophores once four conidial cells were connected. The Conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when Conidiophores were exposed to stronger winds (1.0 m/s). The present st...
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Consecutive monitoring of lifelong production of conidia by individual Conidiophores of Blumeria graminis f. sp. hordei on barley leaves by digital microscopic techniques with electrostatic micromanipulation.
Mycological Research, 2006Co-Authors: Nobuyuki Moriura, Wataru Oichi, Shinichi Kusakari, Teruo Nonomura, Yoshinori Matsuda, Koji Kakutani, Shinya Nakashima, Tatsuo Hirai, Takeshi Sameshima, Katsuhide HigashiAbstract:Conidial formation and secession by living Conidiophores of Blumeria graminis f. sp. hordei on barley leaves were consecutively monitored using a high-fidelity digital microscopic technique combined with electrostatic micromanipulation to trap the released conidia. Conidial chains formed on Conidiophores through a series of septum-mediated division and growth of generative cells. Apical conidial cells on the Conidiophores were abstricted after the conidial chains developed ten conidial cells. The conidia were electrically conductive, and a positive charge was induced in the cells by a negatively polarized insulator probe (ebonite). The electrostatic force between the conidia and the insulator was used to attract the abstricted conidia from the Conidiophores on leaves. This conidium movement from the targeted Conidiophore to the rod was directly viewed under the digital microscope, and the length of the interval between conidial septation and secession, the total number of the conidia produced by a single Conidiophore, and the modes of conidiogenesis were clarified. During the stage of conidial secession, the generative cells pushed new conidial cells upwards by repeated division and growth. The successive release of two apical conidia was synchronized with the successive septation and growth of a generative cell. The release ceased after 4-5 conidia were released without division and growth of the generative cell. Thus, the life of an individual Conidiophore (from the erection of the Conidiophore to the release of the final conidium) was shown to be 107 h and to produce an average of 33 conidia. To our knowledge, this is the first report on the direct estimation of life-long conidial production by a powdery mildew on host leaves.
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Formation of Conidial Pseudochains by Tomato Powdery Mildew Oidium neolycopersici
Plant Disease, 2006Co-Authors: Wataru Oichi, Teruo Nonomura, Yoshinori Matsuda, Hideyoshi Toyoda, Shinichi KusakariAbstract:The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living Conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the Conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the Conidiophores once four conidial cells were connected. The Conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when Conidiophores were exposed to stronger winds (1.0 m/s). The present study successfully demonstrated that the pathogen required wind to disperse progeny conidia from the Conidiophores and produced conidial pseudochains when the wind was below a critical level, independent of high relative humidity as reported previously.
Wataru Oichi - One of the best experts on this subject based on the ideXlab platform.
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formation of conidial pseudochains by tomato powdery mildew oidium neolycopersici
Plant Disease, 2006Co-Authors: Wataru Oichi, Teruo Nonomura, Yoshinori Matsuda, Hideyoshi Toyoda, Ling Xu, Shinichi KusakariAbstract:ABSTRACT The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living Conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the Conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the Conidiophores once four conidial cells were connected. The Conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when Conidiophores were exposed to stronger winds (1.0 m/s). The present st...
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Consecutive monitoring of lifelong production of conidia by individual Conidiophores of Blumeria graminis f. sp. hordei on barley leaves by digital microscopic techniques with electrostatic micromanipulation.
Mycological Research, 2006Co-Authors: Nobuyuki Moriura, Wataru Oichi, Shinichi Kusakari, Teruo Nonomura, Yoshinori Matsuda, Koji Kakutani, Shinya Nakashima, Tatsuo Hirai, Takeshi Sameshima, Katsuhide HigashiAbstract:Conidial formation and secession by living Conidiophores of Blumeria graminis f. sp. hordei on barley leaves were consecutively monitored using a high-fidelity digital microscopic technique combined with electrostatic micromanipulation to trap the released conidia. Conidial chains formed on Conidiophores through a series of septum-mediated division and growth of generative cells. Apical conidial cells on the Conidiophores were abstricted after the conidial chains developed ten conidial cells. The conidia were electrically conductive, and a positive charge was induced in the cells by a negatively polarized insulator probe (ebonite). The electrostatic force between the conidia and the insulator was used to attract the abstricted conidia from the Conidiophores on leaves. This conidium movement from the targeted Conidiophore to the rod was directly viewed under the digital microscope, and the length of the interval between conidial septation and secession, the total number of the conidia produced by a single Conidiophore, and the modes of conidiogenesis were clarified. During the stage of conidial secession, the generative cells pushed new conidial cells upwards by repeated division and growth. The successive release of two apical conidia was synchronized with the successive septation and growth of a generative cell. The release ceased after 4-5 conidia were released without division and growth of the generative cell. Thus, the life of an individual Conidiophore (from the erection of the Conidiophore to the release of the final conidium) was shown to be 107 h and to produce an average of 33 conidia. To our knowledge, this is the first report on the direct estimation of life-long conidial production by a powdery mildew on host leaves.
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Formation of Conidial Pseudochains by Tomato Powdery Mildew Oidium neolycopersici
Plant Disease, 2006Co-Authors: Wataru Oichi, Teruo Nonomura, Yoshinori Matsuda, Hideyoshi Toyoda, Shinichi KusakariAbstract:The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living Conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the Conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the Conidiophores once four conidial cells were connected. The Conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when Conidiophores were exposed to stronger winds (1.0 m/s). The present study successfully demonstrated that the pathogen required wind to disperse progeny conidia from the Conidiophores and produced conidial pseudochains when the wind was below a critical level, independent of high relative humidity as reported previously.
Yoshinori Matsuda - One of the best experts on this subject based on the ideXlab platform.
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Effects of light quality on Conidiophore formation of the melon powdery mildew pathogen Podosphaera xanthii
Phytoparasitica, 2018Co-Authors: Tomoko Suzuki, Yoshinori Matsuda, Shougo Nishimura, Kazuhiro Yagi, Ryousuke Nakamura, Yoshihiro Takikawa, Koji Kakutani, Teruo NonomuraAbstract:The lengths of Conidiophores in fungal colonies of the melon powdery mildew pathogen Podosphaera xanthii Pollacci KMP-6 N cultured under greenhouse (natural) conditions differed markedly from those cultured in a growth chamber. We hypothesized that light wavelength was responsible for the differences in Conidiophore length. In this study, we examined the effects of light-emitting diode (LED) irradiation (purple, blue, green, orange, and red light) and white light on colony development and Conidiophore formation in KMP-6 N using a stereomicroscope and a high-fidelity digital microscope. Colonies on leaves were flat under greenhouse conditions and under red LED light irradiation but were stacked under growth chamber conditions and under purple, blue, green, and orange LED light irradiation. In addition, KMP-6 N formed catenated conidia comprising six conidia per Conidiophore under greenhouse conditions and red light but more than seven conidia per Conidiophore under growth chamber conditions and purple, blue, green, and orange light. Furthermore, almost none of the conidia on top of the Conidiophores grown under blue light were fully constricted. Therefore, these fungi could not scatter their conidia and spread infection. This is the first report of the effects of LED lights on Conidiophore formation in the melon powdery mildew fungus P . xanthii . The results provide insight into the mechanisms underlying the responses of Conidiophores to light of specific wavelengths and conidial scatter from Conidiophores of melon powdery mildew fungi.
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Digital microscopic analysis of conidiogenesis of powdery mildew pathogens isolated from melon leaves
Phytoparasitica, 2015Co-Authors: Yoshihiro Takikawa, Shinichi Kusakari, Teruo Nonomura, Yoshinori Matsuda, Koji Kakutani, Shouta Miyamoto, Naoki Okamoto, Tomoe Murakami, Hideyoshi ToyodaAbstract:Melons (Cucumis melo L.) grown hydroponically in a greenhouse were heavily infested with powdery mildew. We isolated powdery mildew pathogens from the melon leaves and identified the isolate as Podosphaera xanthii KMP-6N, based on morphological characteristics and sequences of ribosomal DNA internal transcribed spacer (rDNA-ITS) regions. Host ranges of KMP-6N were determined by estimating the infectivity or pathogenicity after inoculating the conidia onto multiple plant species. The fungi caused severe powdery mildew symptoms on Cucurbitaceae plants, producing scattered conidia on Conidiophores. The goal of this study was to observe KMP-6N conidiogenesis on melon leaves. The pathogen formed completely catenated Conidiophores approximately 24 h from Conidiophore erection to release of mature conidia. Six conidia were produced on the Conidiophores and only the conidia at the apex reached maturity. The cycles of conidial release were repeated on melon leaves 14 to 18 times, at approximately 6-h intervals. In the final stage, conidia were released without causing growth and septation of generative cells. Conidiophores produced an average of 36 conidia during a 90-h period. In our study, the modes of conidiogenesis, lifetime of Conidiophores and productivity of conidia on a Conidiophore were described for powdery mildew fungi.
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formation of conidial pseudochains by tomato powdery mildew oidium neolycopersici
Plant Disease, 2006Co-Authors: Wataru Oichi, Teruo Nonomura, Yoshinori Matsuda, Hideyoshi Toyoda, Ling Xu, Shinichi KusakariAbstract:ABSTRACT The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living Conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the Conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the Conidiophores once four conidial cells were connected. The Conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when Conidiophores were exposed to stronger winds (1.0 m/s). The present st...
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Consecutive monitoring of lifelong production of conidia by individual Conidiophores of Blumeria graminis f. sp. hordei on barley leaves by digital microscopic techniques with electrostatic micromanipulation.
Mycological Research, 2006Co-Authors: Nobuyuki Moriura, Wataru Oichi, Shinichi Kusakari, Teruo Nonomura, Yoshinori Matsuda, Koji Kakutani, Shinya Nakashima, Tatsuo Hirai, Takeshi Sameshima, Katsuhide HigashiAbstract:Conidial formation and secession by living Conidiophores of Blumeria graminis f. sp. hordei on barley leaves were consecutively monitored using a high-fidelity digital microscopic technique combined with electrostatic micromanipulation to trap the released conidia. Conidial chains formed on Conidiophores through a series of septum-mediated division and growth of generative cells. Apical conidial cells on the Conidiophores were abstricted after the conidial chains developed ten conidial cells. The conidia were electrically conductive, and a positive charge was induced in the cells by a negatively polarized insulator probe (ebonite). The electrostatic force between the conidia and the insulator was used to attract the abstricted conidia from the Conidiophores on leaves. This conidium movement from the targeted Conidiophore to the rod was directly viewed under the digital microscope, and the length of the interval between conidial septation and secession, the total number of the conidia produced by a single Conidiophore, and the modes of conidiogenesis were clarified. During the stage of conidial secession, the generative cells pushed new conidial cells upwards by repeated division and growth. The successive release of two apical conidia was synchronized with the successive septation and growth of a generative cell. The release ceased after 4-5 conidia were released without division and growth of the generative cell. Thus, the life of an individual Conidiophore (from the erection of the Conidiophore to the release of the final conidium) was shown to be 107 h and to produce an average of 33 conidia. To our knowledge, this is the first report on the direct estimation of life-long conidial production by a powdery mildew on host leaves.
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Formation of Conidial Pseudochains by Tomato Powdery Mildew Oidium neolycopersici
Plant Disease, 2006Co-Authors: Wataru Oichi, Teruo Nonomura, Yoshinori Matsuda, Hideyoshi Toyoda, Shinichi KusakariAbstract:The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living Conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the Conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the Conidiophores once four conidial cells were connected. The Conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when Conidiophores were exposed to stronger winds (1.0 m/s). The present study successfully demonstrated that the pathogen required wind to disperse progeny conidia from the Conidiophores and produced conidial pseudochains when the wind was below a critical level, independent of high relative humidity as reported previously.
Teruo Nonomura - One of the best experts on this subject based on the ideXlab platform.
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Effects of light quality on Conidiophore formation of the melon powdery mildew pathogen Podosphaera xanthii
Phytoparasitica, 2018Co-Authors: Tomoko Suzuki, Yoshinori Matsuda, Shougo Nishimura, Kazuhiro Yagi, Ryousuke Nakamura, Yoshihiro Takikawa, Koji Kakutani, Teruo NonomuraAbstract:The lengths of Conidiophores in fungal colonies of the melon powdery mildew pathogen Podosphaera xanthii Pollacci KMP-6 N cultured under greenhouse (natural) conditions differed markedly from those cultured in a growth chamber. We hypothesized that light wavelength was responsible for the differences in Conidiophore length. In this study, we examined the effects of light-emitting diode (LED) irradiation (purple, blue, green, orange, and red light) and white light on colony development and Conidiophore formation in KMP-6 N using a stereomicroscope and a high-fidelity digital microscope. Colonies on leaves were flat under greenhouse conditions and under red LED light irradiation but were stacked under growth chamber conditions and under purple, blue, green, and orange LED light irradiation. In addition, KMP-6 N formed catenated conidia comprising six conidia per Conidiophore under greenhouse conditions and red light but more than seven conidia per Conidiophore under growth chamber conditions and purple, blue, green, and orange light. Furthermore, almost none of the conidia on top of the Conidiophores grown under blue light were fully constricted. Therefore, these fungi could not scatter their conidia and spread infection. This is the first report of the effects of LED lights on Conidiophore formation in the melon powdery mildew fungus P . xanthii . The results provide insight into the mechanisms underlying the responses of Conidiophores to light of specific wavelengths and conidial scatter from Conidiophores of melon powdery mildew fungi.
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Digital microscopic analysis of conidiogenesis of powdery mildew pathogens isolated from melon leaves
Phytoparasitica, 2015Co-Authors: Yoshihiro Takikawa, Shinichi Kusakari, Teruo Nonomura, Yoshinori Matsuda, Koji Kakutani, Shouta Miyamoto, Naoki Okamoto, Tomoe Murakami, Hideyoshi ToyodaAbstract:Melons (Cucumis melo L.) grown hydroponically in a greenhouse were heavily infested with powdery mildew. We isolated powdery mildew pathogens from the melon leaves and identified the isolate as Podosphaera xanthii KMP-6N, based on morphological characteristics and sequences of ribosomal DNA internal transcribed spacer (rDNA-ITS) regions. Host ranges of KMP-6N were determined by estimating the infectivity or pathogenicity after inoculating the conidia onto multiple plant species. The fungi caused severe powdery mildew symptoms on Cucurbitaceae plants, producing scattered conidia on Conidiophores. The goal of this study was to observe KMP-6N conidiogenesis on melon leaves. The pathogen formed completely catenated Conidiophores approximately 24 h from Conidiophore erection to release of mature conidia. Six conidia were produced on the Conidiophores and only the conidia at the apex reached maturity. The cycles of conidial release were repeated on melon leaves 14 to 18 times, at approximately 6-h intervals. In the final stage, conidia were released without causing growth and septation of generative cells. Conidiophores produced an average of 36 conidia during a 90-h period. In our study, the modes of conidiogenesis, lifetime of Conidiophores and productivity of conidia on a Conidiophore were described for powdery mildew fungi.
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formation of conidial pseudochains by tomato powdery mildew oidium neolycopersici
Plant Disease, 2006Co-Authors: Wataru Oichi, Teruo Nonomura, Yoshinori Matsuda, Hideyoshi Toyoda, Ling Xu, Shinichi KusakariAbstract:ABSTRACT The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living Conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the Conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the Conidiophores once four conidial cells were connected. The Conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when Conidiophores were exposed to stronger winds (1.0 m/s). The present st...
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Consecutive monitoring of lifelong production of conidia by individual Conidiophores of Blumeria graminis f. sp. hordei on barley leaves by digital microscopic techniques with electrostatic micromanipulation.
Mycological Research, 2006Co-Authors: Nobuyuki Moriura, Wataru Oichi, Shinichi Kusakari, Teruo Nonomura, Yoshinori Matsuda, Koji Kakutani, Shinya Nakashima, Tatsuo Hirai, Takeshi Sameshima, Katsuhide HigashiAbstract:Conidial formation and secession by living Conidiophores of Blumeria graminis f. sp. hordei on barley leaves were consecutively monitored using a high-fidelity digital microscopic technique combined with electrostatic micromanipulation to trap the released conidia. Conidial chains formed on Conidiophores through a series of septum-mediated division and growth of generative cells. Apical conidial cells on the Conidiophores were abstricted after the conidial chains developed ten conidial cells. The conidia were electrically conductive, and a positive charge was induced in the cells by a negatively polarized insulator probe (ebonite). The electrostatic force between the conidia and the insulator was used to attract the abstricted conidia from the Conidiophores on leaves. This conidium movement from the targeted Conidiophore to the rod was directly viewed under the digital microscope, and the length of the interval between conidial septation and secession, the total number of the conidia produced by a single Conidiophore, and the modes of conidiogenesis were clarified. During the stage of conidial secession, the generative cells pushed new conidial cells upwards by repeated division and growth. The successive release of two apical conidia was synchronized with the successive septation and growth of a generative cell. The release ceased after 4-5 conidia were released without division and growth of the generative cell. Thus, the life of an individual Conidiophore (from the erection of the Conidiophore to the release of the final conidium) was shown to be 107 h and to produce an average of 33 conidia. To our knowledge, this is the first report on the direct estimation of life-long conidial production by a powdery mildew on host leaves.
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Formation of Conidial Pseudochains by Tomato Powdery Mildew Oidium neolycopersici
Plant Disease, 2006Co-Authors: Wataru Oichi, Teruo Nonomura, Yoshinori Matsuda, Hideyoshi Toyoda, Shinichi KusakariAbstract:The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living Conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the Conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the Conidiophores once four conidial cells were connected. The Conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when Conidiophores were exposed to stronger winds (1.0 m/s). The present study successfully demonstrated that the pathogen required wind to disperse progeny conidia from the Conidiophores and produced conidial pseudochains when the wind was below a critical level, independent of high relative humidity as reported previously.
Hiroyuki Horiuchi - One of the best experts on this subject based on the ideXlab platform.
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Expression of asexual developmental regulator gene abaA is affected in the double mutants of classes I and II chitin synthase genes, chsC and chsA, of Aspergillus nidulans
Current Genetics, 2005Co-Authors: Masayuki Ichinomiya, Akinori Ohta, Hiroyuki HoriuchiAbstract:The chsA and chsC encode classes II and I chitin synthases, respectively, of the filamentous fungus Aspergillus nidulans . The ΔchsA Δ chsC double mutants (ΔAC mutants) show defects in asexual development: a striking reduction in the number of Conidiophores and aberrant Conidiophore morphology. Here, we examined the involvement of regulatory genes for asexual development ( brlA , abaA , and medA ) in the conidiation defects of the ΔAC mutants. Spatial expression patterns of brlA , abaA , and medA in Conidiophores of the wild-type strains and ΔAC mutants were examined by in-situ staining using a reporter gene; expression of either gene was detected at abnormal sterigmata in the ΔAC mutants as well as at normal ones in the wild-type strain. However, abaA expression was not prominent at a subset of Conidiophores developing long chains of aberrant sterigmata, suggesting that induction of the abaA expression was retarded in the ΔAC mutants. Based on these results and those previously presented, possible mechanisms involved in the conidiation defects are discussed.
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Evidence that the Aspergillus nidulans class I and class II chitin synthase genes, chsC and chsA, share critical roles in hyphal wall integrity and Conidiophore development.
Journal of Biochemistry, 2000Co-Authors: Makoto Fujiwara, Masayuki Ichinomiya, Akinori Ohta, Hiroyuki Horiuchi, Takayuki Motoyama, Masamichi TakagiAbstract:Although many chitin synthase genes have been identified in a broad range of fungal species, there have been only a few reports about their role in fungal morphogenesis. In most cases, single gene disruption or replacement did not reveal their function, possibly because of functional redundancy among them. We obtained null mutants of Aspergillus nidulans chsA and chsC genes encoding non-essential class II and class I chitin synthases, respectively. The DeltachsA DeltachsC mutant exhibited growth defects on media supplemented with sodium dodecyl sulfate (SDS), high concentration of salts, chitin-binding dyes, or chitin synthase competitive inhibitors, suggesting loss of integrity of hyphal wall. Moreover, remarkable abnormalities of the double mutant were observed microscopically during its asexual development. The Conidiophore population was drastically reduced. Interestingly, secondary Conidiophores were occasionally produced from vesicles of the primary ones. The morphology of these Conidiophores was similar to those of the A. nidulans developmental mutants, medusa (medA), abacus (abaA), and some kinds of bristle (brlA). In situ staining patterns suggested that chsA was mainly expressed in the metulae, phialides, and conidia, whereas chsC was expressed in hyphae as well as Conidiophores. These results suggest that ChsA and ChsC share critical functions in hyphal wall integrity and differentiation.