Tomato seedlings damping-off is a limiting factor in commercial greenhouse production. To determine the causal agents of disease, sampling and fungal isolation were performed during 2012. Samples were collected from i...Tomato seedlings damping-off is a limiting factor in commercial greenhouse production. To determine the causal agents of disease, sampling and fungal isolation were performed during 2012. Samples were collected from infected seedlings growing in greenhouses in the Syrian coastal region. Isolation of fungi was done in the laboratories of the Agronomical Reaserch Center, in Lattakia and the molecular analyses were done in the Biotechnology Center at Tishreen University, Lattakia, Syria, during the years 2012, 2013. Eight isolates ofPythium sp. obtained were purified using hyphal tip method （named P1, P2, P3, P4, P5, P6, P7 and P8）. Isolates were morphologically identified by optical microscope, then molecularly Characterized using genus specific ITS primers. The results of morphological characterization of pathogenic species suggested the detection of Pythium aphanidermatum, P. ultimum. The analysis of DNAs from the different isolates with ITS primers, recognizing the inter transcript spacer of nuclear ribosomal DNA proved that the eight, isolates were belonging to the species P. ultimum. The complete sequences of ribosomal DNA internal transcribed spacers regions of selected isolates were determined and submitted to GenBank. The GenBank-BLAST homology search revealed P. ultimum as the most similar sequence （〉 96% identity） with GenBank entry AB355596.展开更多
Restriction fragment length polymorphism （RFLP） profiles of the amplified products of Internal Transcribed Spacer （ITS） region of rDNA using four restriction enzymes （Alul, Rsal, HinfI and HhaI） revealed distinc...Restriction fragment length polymorphism （RFLP） profiles of the amplified products of Internal Transcribed Spacer （ITS） region of rDNA using four restriction enzymes （Alul, Rsal, HinfI and HhaI） revealed distinctness of six Indian isolates of Steinernema one each from Maharashtra （IARI-EPN-mh）, Himachal Pradesh （IARI-EPN-hp）, Dehradun （IARI-EPN-dhdl）, Jharkhand （IARI-EPN-jhl） and two from Madhya Pradesh （IARI-EPN-bpll ＆ IARI-EPN-gwll）, when compared with the only native species Steinernema thermophilum. One of the restriction enzyme, Rsal could differentiate all the six species/strains from one another. The three restriction enzymes yielded patterns which were of diagnostic value but Rsal appeared to be the best diagnostic marker for differentiating these isolates. A tree constructed based upon the band sharing amongst the isolates, produced trichotomy which placed strains from Madhya Pradesh and Jharkhand in one group showing 94% homology, one strain from Bhopal （M.P） formed separate clade along with S. thermophilum with 72% similarity. These isolates, from Maharashtra, Himachal Pradesh and Dehradun, showed only 51% similarity with the S. thermophilum by forming separate clade.展开更多
目的：建立乌头霜霉病病原菌快速分子检测方法,为乌头种苗检疫及栽培环境土壤安全性评价提供依据。方法：使用真菌DNA提取试剂盒提取病原菌DNA,采用真菌核糖体内转录间隔区（ITS）通用引物ITS1/ITS4,对病原菌的r DNA-ITS区间序列进行扩...目的：建立乌头霜霉病病原菌快速分子检测方法,为乌头种苗检疫及栽培环境土壤安全性评价提供依据。方法：使用真菌DNA提取试剂盒提取病原菌DNA,采用真菌核糖体内转录间隔区（ITS）通用引物ITS1/ITS4,对病原菌的r DNA-ITS区间序列进行扩增,将聚合酶链式反应（PCR）产物回收纯化并进行序列测定,并将测得的ITS序列同Gene Bank中搜索到的相关ITS序列进行比较,运用DNAMAN比对出特异序列片段,利用特异序列片段通过Primer Premier 5.0设计并筛选特异性引物,建立乌头霜霉病病原菌快速PCR检测方法。结果：从Primer Premier 5.0设计的8对引物中筛选出了灵敏度高、特异性强的引物对L1A/L1B,该引物能够从乌头霜霉病病原菌DNA扩增出670 bp的具有检测价值的明亮条带,利用该引物也能够检测出乌头种苗、成株以及栽培土壤是否存在乌头霜霉病原菌。结论：筛选出的引物对L1A/L1B能够快速、简便、有效地检测出乌头霜霉病病原菌,建立的方法能用于对乌头种苗霜霉病的提前检测或检疫。展开更多
Four new species of Hymenoscyphus (H. brevicellulus, H. hyaloexcipulus, H. microcaudatus, and H. subsymmetricus) and a new Chinese record (H. subpallescens) are described. These five species share common characteristi...Four new species of Hymenoscyphus (H. brevicellulus, H. hyaloexcipulus, H. microcaudatus, and H. subsymmetricus) and a new Chinese record (H. subpallescens) are described. These five species share common characteristics: small apothecia (<3mm in diameter); hymenium whitish, pale yellow, to yellow in color; ectal excipulum of textura prismatica; asci arising from simple septa; ascospores scutuloid and guttulate; saprophytic nutrition; and leaf habitats, except for H. subsymmetricus, which grows on herbaceous stems. Phylogenetic analyses of internal transcribed spacer nuclear ribosomal DNA sequences, the universal DNA barcode for fungi, for 16 species in the genus indicated that these taxa were closely related to H. microserotinus, in accordance with their morphological features, but represented independent species. The distinguishing features of each new species from its relatives are discussed, and their phylogenetic relationships explored.展开更多
文摘Tomato seedlings damping-off is a limiting factor in commercial greenhouse production. To determine the causal agents of disease, sampling and fungal isolation were performed during 2012. Samples were collected from infected seedlings growing in greenhouses in the Syrian coastal region. Isolation of fungi was done in the laboratories of the Agronomical Reaserch Center, in Lattakia and the molecular analyses were done in the Biotechnology Center at Tishreen University, Lattakia, Syria, during the years 2012, 2013. Eight isolates ofPythium sp. obtained were purified using hyphal tip method （named P1, P2, P3, P4, P5, P6, P7 and P8）. Isolates were morphologically identified by optical microscope, then molecularly Characterized using genus specific ITS primers. The results of morphological characterization of pathogenic species suggested the detection of Pythium aphanidermatum, P. ultimum. The analysis of DNAs from the different isolates with ITS primers, recognizing the inter transcript spacer of nuclear ribosomal DNA proved that the eight, isolates were belonging to the species P. ultimum. The complete sequences of ribosomal DNA internal transcribed spacers regions of selected isolates were determined and submitted to GenBank. The GenBank-BLAST homology search revealed P. ultimum as the most similar sequence （〉 96% identity） with GenBank entry AB355596.
文摘Restriction fragment length polymorphism （RFLP） profiles of the amplified products of Internal Transcribed Spacer （ITS） region of rDNA using four restriction enzymes （Alul, Rsal, HinfI and HhaI） revealed distinctness of six Indian isolates of Steinernema one each from Maharashtra （IARI-EPN-mh）, Himachal Pradesh （IARI-EPN-hp）, Dehradun （IARI-EPN-dhdl）, Jharkhand （IARI-EPN-jhl） and two from Madhya Pradesh （IARI-EPN-bpll ＆ IARI-EPN-gwll）, when compared with the only native species Steinernema thermophilum. One of the restriction enzyme, Rsal could differentiate all the six species/strains from one another. The three restriction enzymes yielded patterns which were of diagnostic value but Rsal appeared to be the best diagnostic marker for differentiating these isolates. A tree constructed based upon the band sharing amongst the isolates, produced trichotomy which placed strains from Madhya Pradesh and Jharkhand in one group showing 94% homology, one strain from Bhopal （M.P） formed separate clade along with S. thermophilum with 72% similarity. These isolates, from Maharashtra, Himachal Pradesh and Dehradun, showed only 51% similarity with the S. thermophilum by forming separate clade.
文摘目的：建立乌头霜霉病病原菌快速分子检测方法,为乌头种苗检疫及栽培环境土壤安全性评价提供依据。方法：使用真菌DNA提取试剂盒提取病原菌DNA,采用真菌核糖体内转录间隔区（ITS）通用引物ITS1/ITS4,对病原菌的r DNA-ITS区间序列进行扩增,将聚合酶链式反应（PCR）产物回收纯化并进行序列测定,并将测得的ITS序列同Gene Bank中搜索到的相关ITS序列进行比较,运用DNAMAN比对出特异序列片段,利用特异序列片段通过Primer Premier 5.0设计并筛选特异性引物,建立乌头霜霉病病原菌快速PCR检测方法。结果：从Primer Premier 5.0设计的8对引物中筛选出了灵敏度高、特异性强的引物对L1A/L1B,该引物能够从乌头霜霉病病原菌DNA扩增出670 bp的具有检测价值的明亮条带,利用该引物也能够检测出乌头种苗、成株以及栽培土壤是否存在乌头霜霉病原菌。结论：筛选出的引物对L1A/L1B能够快速、简便、有效地检测出乌头霜霉病病原菌,建立的方法能用于对乌头种苗霜霉病的提前检测或检疫。
基金supported by the National Natural Science Foundation of China (31070015,31093440)the Knowledge Innovation Project of the Chinese Academy of Sciences (KSCX2-EW-J-6)
文摘Four new species of Hymenoscyphus (H. brevicellulus, H. hyaloexcipulus, H. microcaudatus, and H. subsymmetricus) and a new Chinese record (H. subpallescens) are described. These five species share common characteristics: small apothecia (<3mm in diameter); hymenium whitish, pale yellow, to yellow in color; ectal excipulum of textura prismatica; asci arising from simple septa; ascospores scutuloid and guttulate; saprophytic nutrition; and leaf habitats, except for H. subsymmetricus, which grows on herbaceous stems. Phylogenetic analyses of internal transcribed spacer nuclear ribosomal DNA sequences, the universal DNA barcode for fungi, for 16 species in the genus indicated that these taxa were closely related to H. microserotinus, in accordance with their morphological features, but represented independent species. The distinguishing features of each new species from its relatives are discussed, and their phylogenetic relationships explored.
