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Chilli anthracnose disease caused by Colletotrichum species
Po Po THAN, Haryudian PRIHASTUTI, Sitthisack PHOULIVONG, Paul W.J. TAYLOR, Kevin D. HYDE
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2008, 9(10): 764-778.
https://doi.org/10.1631/jzus.B0860007
Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum species have been reported as causal agents of chilli anthracnose disease worldwide. The ambiguous taxonomic status of Colletotrichum species has resulted in inaccurate identification which may cause practical problems in plant breeding and disease management. Although the management and control of anthracnose disease are still being extensively researched, commercial cultivars of Capsicum annuum that are resistant to the pathogens that cause chilli anthracnose have not yet been developed. This paper reviews the causal agents of chilli anthracnose, the disease cycle, conventional methods in identification of the pathogen and molecular approaches that have been used for the identification of Colletotrichum species. Pathogenetic variation and population structure of the causal agents of chilli anthracnose along with the current taxonomic status of Colletotrichum species are discussed. Future developments leading to the disease management strategies are suggested.
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Biological control of aflatoxin contamination of crops
Yan-ni YIN, Lei-yan YAN, Jin-hua JIANG, Zhong-hua MA
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2008, 9(10): 787-792.
https://doi.org/10.1631/jzus.B0860003
Aflatoxins produced primarily by two closely related fungi, Aspergillus flavus and Aspergillus parasiticus, are mutagenic and carcinogenic in animals and humans. Of many approaches investigated to manage aflatoxin contamination, biological control method has shown great promise. Numerous organisms, including bacteria, yeasts and nontoxigenic fungal strains of A. flavus and A. parasiticus, have been tested for their ability in controlling aflatoxin contamination. Great successes in reducing aflatoxin contamination have been achieved by application of nontoxigenic strains of A. flavus and A. parasiticus in fields of cotton, peanut, maize and pistachio. The nontoxigenic strains applied to soil occupy the same niches as the natural occurring toxigenic strains. They, therefore, are capable of competing and displacing toxigenic strains. In this paper, we review recent development in biological control of aflatoxin contamination.
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New and rare lignicolous hyphomycetes from Zhejiang Province, China
Mongkol WONGSAWAS, Hong-kai WANG, Kevin D. HYDE, Fu-cheng LIN
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2008, 9(10): 797-801.
https://doi.org/10.1631/jzus.B0860008
Sporidesmiopsis zhejiangensis sp. nov. and Spadicoides americana were found on submerged wood from streams in Zhejiang Province, China. Sporidesmiopsis zhejiangensis is characterized by obclavate to fusiform, 5-6-distoseptate, versicolorous, verruculose conidia with an apical mucilaginous sheath. Spadicoides americana is a new record to China. These taxa are described and illustrated, and morphological differences between these species and their similar species were summarized.
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Fluorescent co-localization of PTS1 and PTS2 and its application in analysis of the gene function and the peroxisomal dynamic in Magnaporthe oryzae
Jiao-yu WANG, Xiao-yan WU, Zhen ZHANG, Xin-fa DU, Rong-yao CHAI, Xiao-hong LIU, Xue-qin MAO, Hai-ping QIU, Yan-li WANG, Fu-cheng LIN, Guo-chang SUN
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2008, 9(10): 802-810.
https://doi.org/10.1631/jzus.B0860001
The peroxisomal matrix proteins involved in many important biological metabolism pathways in eukaryotic cells are encoded by nucleal genes, synthesized in the cytoplasm and then transported into the organelles. Targeting and import of these proteins depend on their two peroxisomal targeting signals (PTS1 and PTS2) in sequence as we have known so far. The vectors of the fluorescent fusions with PTS, i.e., green fluorescence protein (GFP)-PTS1, GFP-PTS2 and red fluorescence protein (RFP)-PTS1, were constructed and introduced into Magnaporthe oryzae Guy11 cells. Transformants containing these fusions emitted fluorescence in a punctate pattern, and the locations of the red and green fluorescence overlapped exactly in RFP-PTS1 and GFP-PTS2 co-transformed strains. These data indicated that both PTS1 and PTS2 fusions were imported into peroxisomes. A probable higher efficiency of PTS1 machinery was revealed by comparing the fluorescence backgrounds in GFP-PTS1 and GFP-PTS2 transformants. By introducing both RFP-PTS1 and GFP-PTS2 into Δmgpex6 mutants, the involvement of MGPEX6 gene in both PTS1 and PTS2 pathways was proved. In addition, using these transformants, the inducement of peroxisomes and the dynamic of peroxisomal number during the pre-penetration processes were investigated as well. In summary, by the localization and co-localization of PTS1 and PTS2, we provided a useful tool to evaluate the biological roles of the peroxisomes and the related genes.
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A simple and effective method for total RNA isolation of appressoria in Magnaporthe oryzae
Tong-bao LIU, Jian-ping LU, Xiao-hong LIU, Hang MIN, Fu-cheng LIN
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2008, 9(10): 811-817.
https://doi.org/10.1631/jzus.B0860011
Appressorium formation is an important event in establishing a successful interaction between the rice blast fungus, Magnaporthe oryzae, and its host plant, rice. An understanding of molecular events occurring in appressorium differentiation will give new strategies to control rice blast. A quick and reliable method to extract total RNA from appressorium is essential for studying gene expression during appressorium formation and its mechanism. We found that duplicate film is an efficient substratum for appressorium formation, even when inoculated with high density conidia. When inoculated with conidia at 1×106 ml−1, the percentages of conidium germination and appressorium formation were (97.98±0.67)% and (97.88±0.45)%, respectively. We applied Trizol before appressorium collection for total RNA isolation, and as much as 113.6 μg total RNA was isolated from the mature appressoria at 24 h after inoculation. Functional analysis of two genes, MNH6 and MgATG1, isolated from the cDNA subtractive library, revealed that the quantity of RNA was good enough to construct a cDNA (complementary DNA) library or a cDNA subtractive library. This method may be also applicable for the appressorium RNA isolation of other pathogenic fungi in which conidia differentiate into appressoria in the early stages of host infection.
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Isolation and identification of Sclerotinia stem rot causal pathogen in Arabidopsis thaliana
Ai-rong WANG, Wen-wei LIN, Xiao-ting CHEN, Guo-dong LU, Jie ZHOU, Zong-hua WANG
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2008, 9(10): 818-822.
https://doi.org/10.1631/jzus.B0860010
A new stem rot disease is found to occur naturally on Arabidopsis plants in greenhouses of Fuzhou, China. In order to identify its pathogen, we conducted a series of fungal isolation and purification, plant reinoculation, and ascus and ascospore induction from the sclerotia. The isolate caused typical water-soaked lesions after reinoculation and produced sclerotia both on Arabidopsis plants and culture medium plates, and the sclerotia could be induced to produce discal apothecia and 8 binucleate ascospores per ascus. These disease symptom and fungal morphology data revealed that the fungus Sclerotinia sclerotiorum (Lib.) de Bary was the pathogen for Arabidopsis stem rot. To confirm this, we further amplified its large subunit ribosomal DNA (LSU rDNA) by polymerase chain reaction (PCR), and compared the sequence with the known LSU rDNA sequences in GenBank. The results show that the sequence shares the highest identities with the LSU rDNAs of different S. sclerotiorum strains. Taking all these data together, we concluded that the fungus that caused the Arabidopsis stem rot is S. sclerotiorum (Lib.) de Bary. This is the first report that Arabidopsis is naturally infected by S. sclerotiorum.
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Diversity analysis of soil dematiaceous hyphomycetes from the Yellow River source area: I
Hao-qin PAN, Jin-feng YU, Yue-ming WU, Tian-yu ZHANG, Hong-feng WANG
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2008, 9(10): 829-834.
https://doi.org/10.1631/jzus.B0860002
Twenty-four soil samples of eight ecosystem-types around the Yellow River source area were investigated for the number and specific composition of soil dematiaceous hyphomycetes by dilution plate technique. And then the co-relationship between genus species of soil dematiaceous hyphomycetes and ecosystem-types was analyzed. The results show that the amount and species distribution of soil dematiaceous hyphomycetes had an obvious variability in different ecosystem-types, and that the dominant genus species varied in the eight ecosystem-types studied, with Cladosporium being the dominant genus in seven of the eight ecosystem-types except wetland. The index of species diversity varied in different ecosystem-types. The niche breadth analysis showed that Cladosporium had the highest niche breadth and distributed in all ecosystem-types, while the genera with a narrow niche breadth distributed only in a few ecosystem-types. The results of niche overlap index analysis indicated that Stachybotrys and Torula, Doratomyces and Scolecobasidium, Cladosporium and Chrysosporium had a higher niche overlap, whereas Arthrinium and Gliomastix, Phialophora and Doratomyces, Oidiodendron and Ulocladium had no niche overlap.
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Fungal diversity on fallen leaves of Ficus in northern Thailand
Hong-kai WANG, Kevin D. HYDE, Kasem SOYTONG, Fu-cheng LIN
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2008, 9(10): 835-841.
https://doi.org/10.1631/jzus.B0860005
Fallen leaves of Ficus altissima, F. virens, F. benjamina, F. fistulosa and F. semicordata, were collected in Chiang Mai Province in northern Thailand and examined for fungi. Eighty taxa were identified, comprising 56 anamorphic taxa, 23 ascomycetes and 1 basidiomycete. Common fungal species occurring on five host species with high frequency of occurrence were Beltraniella nilgirica, Lasiodiplodia theobromae, Ophioceras leptosporum, Periconia byssoides and Septonema harknessi. Colletotrichum and Stachybotrys were also common genera. The leaves of different Ficus species supported diverse fungal taxa, and the fungal assemblages on the different hosts showed varying overlap. The fungal diversity of saprobes at the host species level is discussed.
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14 articles
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