Displaying publications 61 - 80 of 87 in total

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  1. Multilocus resistance evolution to azole fungicides in fungal plant pathogen populations
    Mohd-Assaad N, McDonald BA, Croll D
    Mol Ecol, 2016 Dec;25(24):6124-6142.
    PMID: 27859799 DOI: 10.1111/mec.13916
    Evolution of fungicide resistance is a major threat to food production in agricultural ecosystems. Fungal pathogens rapidly evolved resistance to all classes of fungicides applied to the field. Resistance to the commonly used azole fungicides is thought to be driven mainly by mutations in a gene (CYP51) encoding a protein of the ergosterol biosynthesis pathway. However, some fungi gained azole resistance independently of CYP51 mutations and the mechanisms leading to CYP51-independent resistance are poorly understood. We used whole-genome sequencing and genome-wide association studies (GWAS) to perform an unbiased screen of azole resistance loci in Rhynchosporium commune, the causal agent of the barley scald disease. We assayed cyproconazole resistance in 120 isolates collected from nine populations worldwide. We found that mutations in highly conserved genes encoding the vacuolar cation channel YVC1, a transcription activator, and a saccharopine dehydrogenase made significant contributions to fungicide resistance. These three genes were not previously known to confer resistance in plant pathogens. However, YVC1 is involved in a conserved stress response pathway known to respond to azoles in human pathogenic fungi. We also performed GWAS to identify genetic polymorphism linked to fungal growth rates. We found that loci conferring increased fungicide resistance were negatively impacting growth rates, suggesting that fungicide resistance evolution imposed costs. Analyses of population structure showed that resistance mutations were likely introduced into local populations through gene flow. Multilocus resistance evolution to fungicides shows how pathogen populations can evolve a complex genetic architecture for an important phenotypic trait within a short time span.
    Matched MeSH terms: Ascomycota/genetics*
  2. Fulltext Analysis of the leaf transcriptome of Musa acuminata during interaction with Mycosphaerella musicola: gene assembly, annotation and marker development
    Passos MA, de Cruz VO, Emediato FL, de Teixeira CC, Azevedo VC, Brasileiro AC, et al.
    BMC Genomics, 2013 Feb 05;14:78.
    PMID: 23379821 DOI: 10.1186/1471-2164-14-78
    BACKGROUND: Although banana (Musa sp.) is an important edible crop, contributing towards poverty alleviation and food security, limited transcriptome datasets are available for use in accelerated molecular-based breeding in this genus. 454 GS-FLX Titanium technology was employed to determine the sequence of gene transcripts in genotypes of Musa acuminata ssp. burmannicoides Calcutta 4 and M. acuminata subgroup Cavendish cv. Grande Naine, contrasting in resistance to the fungal pathogen Mycosphaerella musicola, causal organism of Sigatoka leaf spot disease. To enrich for transcripts under biotic stress responses, full length-enriched cDNA libraries were prepared from whole plant leaf materials, both uninfected and artificially challenged with pathogen conidiospores.

    RESULTS: The study generated 846,762 high quality sequence reads, with an average length of 334 bp and totalling 283 Mbp. De novo assembly generated 36,384 and 35,269 unigene sequences for M. acuminata Calcutta 4 and Cavendish Grande Naine, respectively. A total of 64.4% of the unigenes were annotated through Basic Local Alignment Search Tool (BLAST) similarity analyses against public databases.Assembled sequences were functionally mapped to Gene Ontology (GO) terms, with unigene functions covering a diverse range of molecular functions, biological processes and cellular components. Genes from a number of defense-related pathways were observed in transcripts from each cDNA library. Over 99% of contig unigenes mapped to exon regions in the reference M. acuminata DH Pahang whole genome sequence. A total of 4068 genic-SSR loci were identified in Calcutta 4 and 4095 in Cavendish Grande Naine. A subset of 95 potential defense-related gene-derived simple sequence repeat (SSR) loci were validated for specific amplification and polymorphism across M. acuminata accessions. Fourteen loci were polymorphic, with alleles per polymorphic locus ranging from 3 to 8 and polymorphism information content ranging from 0.34 to 0.82.

    CONCLUSIONS: A large set of unigenes were characterized in this study for both M. acuminata Calcutta 4 and Cavendish Grande Naine, increasing the number of public domain Musa ESTs. This transcriptome is an invaluable resource for furthering our understanding of biological processes elicited during biotic stresses in Musa. Gene-based markers will facilitate molecular breeding strategies, forming the basis of genetic linkage mapping and analysis of quantitative trait loci.

    Matched MeSH terms: Ascomycota/genetics
  3. Induction of apoptosis against cancer cell lines by four ascomycetes (endophytes) from Malaysian rainforest
    Hazalin NA, Ramasamy K, Lim SM, Cole AL, Majeed AB
    Phytomedicine, 2012 May 15;19(7):609-17.
    PMID: 22397996 DOI: 10.1016/j.phymed.2012.01.007
    Endophytic fungi have been shown to be a promising source of biologically active natural products. In the present study, extracts of four endophytic fungi isolated from plants of the National Park, Pahang were evaluated for their cytotoxic activity and the nature of their active compounds determined. Those extracts exhibiting activity with IC(50) values less than 17 μg/ml against HCT116, MCF-7 and K562 cell lines were shown to induce apoptosis in these cell lines. Molecular analysis, based on sequences of the rDNA internal transcribed spacers ITS1 and ITS4, revealed all four endophytic fungi to be ascomycetes: three sordariomycetes and a dothideomycete. Six known compounds, cytochalasin J, dechlorogriseofulvin, demethylharzianic-acid, griseofulvin, harzianic acid and 2-hexylidene-3-methyl-succinic acid were identified from a rapid dereplication technique for fungal metabolites using an in-house UV library. The results from the present study suggest the potential of endophytic fungi as cytotoxic agents, and there is an indication that the isolates contain bioactive compounds that mainly kill cancer cells by apoptosis.
    Matched MeSH terms: Ascomycota/genetics; Ascomycota/chemistry*
  4. Fulltext Nematophagous fungi as a biological control agent for nematode parasites of small ruminants in Malaysia: a special emphasis on Duddingtonia flagrans
    Chandrawathani P, Jamnah O, Waller PJ, Höglund J, Larsen M, Zahari WM
    Vet Res, 2002 Nov-Dec;33(6):685-96.
    PMID: 12498569
    Approximately 2,800 fresh dung samples from animals, mainly ruminant livestock, were screened for the presence of nematophagous fungi in Malaysia. Arthrobotrys spp. was noted on numerous occasions, but only one isolate of Duddingtonia flagrans was made. For the purposes of producing sufficient quantities of this fungus for feeding trials in sheep, various, commonly available, cheap plant materials were tested as possible growth substrates. This showed that cereal grains (wheat, millet and rice) were the best media for fungal growth. Pen feeding trials were carried out using sheep, both naturally and experimentally infected with nematode parasites (predominantely Haemonchus contortus), to test the efficiency of D. flagrans when administered either in a grain supplement, or incorporated into a feed block. These showed that the fungus survived gut passage in sheep and that dose rates of approximately 1 x 10(6) D. flagrans spores / animal / day, reduced the percentage of infective larvae developing in faecal cultures by more than 90%. These results indicate that using D. flagrans as a biological control agent of nematode parasites, is a promising alternative to nematode parasite control of small ruminants in Malaysia, where anthelmintic resistance is now a major problem.
    Matched MeSH terms: Ascomycota/growth & development; Ascomycota/physiology*
  5. Fulltext Metabolic Profile of Scytalidium parasiticum-Ganoderma boninense Co-Cultures Revealed the Alkaloids, Flavonoids and Fatty Acids that Contribute to Anti-Ganoderma Activity
    Ahmad R, Lim CK, Marzuki NF, Goh YK, Azizan KA, Goh YK, et al.
    Molecules, 2020 Dec 16;25(24).
    PMID: 33339375 DOI: 10.3390/molecules25245965
    In solving the issue of basal stem rot diseases caused by Ganoderma, an investigation of Scytalidium parasiticum as a biological control agent that suppresses Ganoderma infection has gained our interest, as it is more environmentally friendly. Recently, the fungal co-cultivation has emerged as a promising method to discover novel antimicrobial metabolites. In this study, an established technique of co-culturing Scytalidium parasiticum and Ganoderma boninense was applied to produce and induce metabolites that have antifungal activity against G. boninense. The crude extract from the co-culture media was applied to a High Performance Liquid Chromatography (HPLC) preparative column to isolate the bioactive compounds, which were tested against G. boninense. The fractions that showed inhibition against G. boninense were sent for a Liquid Chromatography-Time of Flight-Mass Spectrometry (LC-TOF-MS) analysis to further identify the compounds that were responsible for the microbicidal activity. Interestingly, we found that eudistomin I, naringenin 7-O-beta-D-glucoside and penipanoid A, which were present in different abundances in all the active fractions, except in the control, could be the antimicrobial metabolites. In addition, the abundance of fatty acids, such as oleic acid and stearamide in the active fraction, also enhanced the antimicrobial activity. This comprehensive metabolomics study could be used as the basis for isolating biocontrol compounds to be applied in oil palm fields to combat a Ganoderma infection.
    Matched MeSH terms: Ascomycota/metabolism; Ascomycota/chemistry*
  6. Fulltext Endophytic Diaporthe sp. ED2 Produces a Novel Anti-Candidal Ketone Derivative
    Tong WY, Leong CR, Tan WN, Khairuddean M, Zakaria L, Ibrahim D
    J Microbiol Biotechnol, 2017 Jun 28;27(6):1065-1070.
    PMID: 28297749 DOI: 10.4014/jmb.1612.12009
    This study aimed to examine the anti-candidal efficacy of a novel ketone derivative isolated from Diaporthe sp. ED2, an endophytic fungus residing in medicinal herb Orthosiphon stamieus Benth. The ethyl acetate extract of the fungal culture was separated by open column and reverse phase high-performance liquid chromatography (HPLC). The eluent at retention time 5.64 min in the HPLC system was the only compound that exhibited anti-candidal activity on Kirby-Bauer assay. The structure of the compound was also elucidated by nuclear magnetic resonance and spectroscopy techniques. The purified anti-candidal compound was obtainedas a colorless solid and characterized as 3-hydroxy-5-methoxyhex-5-ene-2,4-dione. On broth microdilution assay, the compound also exhibited fungicidal activity on a clinical strain of Candida albicans at a minimal inhibitory concentration of 3.1 μg/ml. The killing kinetic analysis also revealed that the compound was fungicidal against C. albicans in a concentration- and time-dependent manner. The compound was heat-stable up to 70°C, but its anti-candidal activity was affected at pH 2.
    Matched MeSH terms: Ascomycota/metabolism; Ascomycota/chemistry*
  7. Emergence of Aureobasidium pullulans as human fungal pathogen and molecular assay for future medical diagnosis
    Chan GF, Puad MS, Chin CF, Rashid NA
    Folia Microbiol (Praha), 2011 Sep;56(5):459-67.
    PMID: 21909832 DOI: 10.1007/s12223-011-0070-9
    Despite the great importance of Aureobasidium pullulans in biotechnology, the fungus had emerged as an opportunistic human pathogen, especially among immunocompromised patients. Clinical detection of this rare human fungal pathogen presently relies on morphology diagnosis which may be misleading. Thus, a sensitive and accurate quantitative molecular assay for A. pullulans remains lacking. In this study, we presented the microscopy observations of A. pullulans that reveals the phenotypic plasticity of the fungus. A. pullulans-specific primers and molecular beacon probes were designed based on the fungal 18S ribosomal RNA (rRNA) gene. Comparison of two probes with varied quencher chemistry, namely BHQ-1 and Tamra, revealed high amplification efficiency of 104% and 108%, respectively. The optimized quantitative real-time PCR (qPCR) assays could detect and quantify up to 1 pg concentration of A. pullulans DNA. Both assays displayed satisfactory performance parameters at fast thermal cycling mode. The molecular assay has great potential as a molecular diagnosis tool for early detection of fungal infection caused by A. pullulans, which merits future study in clinical diagnosis.
    Matched MeSH terms: Ascomycota/genetics; Ascomycota/isolation & purification*
  8. Fulltext First report on a novel Nigrospora sphaerica isolated from Catharanthus roseus plant with anticarcinogenic properties
    Ayob FW, Simarani K, Zainal Abidin N, Mohamad J
    Microb Biotechnol, 2017 Jul;10(4):926-932.
    PMID: 28612376 DOI: 10.1111/1751-7915.12603
    This paper reports on the vinca alkaloid produced by a novel Nigrospora sphaerica isolated from Catharanthus roseus. Through liquid chromatography-mass spectrometry (LCMS), only the crude mycelia extract of this fungus was positive for determination of vinblastine. This vinca alkaloid was then purified by using high-performance liquid chromatography (HPLC) and tested for cytotoxicity activity using MTT assays. The breast cell line cancer (MDA-MB 231) was treated with a purified vinblastine which was intracellulary produced by N. sphaerica. The purified vinblastine from extracted leaf of C. roseus was used as a standard comparison. A positive result with a value of half maximal inhibitory concentration (IC50 ) of > 32 μg ml-1 was observed compared with standard (IC50 ) of 350 μg ml-1 only. It showed that a vinblastine produced by N. sphaerica has a high cytotoxicity activity even though the concentration of vinblastine produced by this endophytic fungus was only 0.868 μg ml-1 .
    Matched MeSH terms: Ascomycota/isolation & purification*; Ascomycota/metabolism*
  9. Fulltext Endophytic filamentous fungi from a Catharanthus roseus: Identification and its hydrolytic enzymes
    Ayob FW, Simarani K
    Saudi Pharm J, 2016 May;24(3):273-8.
    PMID: 27275114 DOI: 10.1016/j.jsps.2016.04.019
    This paper reported on the various filamentous fungi strains that were isolated from a wild grown Catharanthus roseus. Based on the morphological characteristics and molecular technique through a Polymerase Chain Reaction and DNA sequencing method using internal transcribed spacer (ITS), these fungi had been identified as a Colletotrichum sp., Macrophomina phaseolina, Nigrospora sphaerica and Fusarium solani. The ultrastructures of spores and hyphae were observed under a Scanning Electron Microscope. The hydrolytic enzyme test showed that all strains were positive in secreting cellulase. Colletotrichum sp. and F. solani strains also gave a positive result for amylase while only F. solani was capable to secrete protease. These fungi were putatively classified as endophytic fungi since they produced extracellular enzymes that allow them to penetrate plant cell walls and colonize with symbiotic properties.
    Matched MeSH terms: Ascomycota
  10. Toward understanding of rice innate immunity against Magnaporthe oryzae
    Azizi P, Rafii MY, Abdullah SN, Nejat N, Maziah M, Hanafi MM, et al.
    Crit Rev Biotechnol, 2016;36(1):165-74.
    PMID: 25198435 DOI: 10.3109/07388551.2014.946883
    The blast fungus, Magnaporthe oryzae, causes serious disease on a wide variety of grasses including rice, wheat and barley. The recognition of pathogens is an amazing ability of plants including strategies for displacing virulence effectors through the adaption of both conserved and variable pathogen elicitors. The pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) were reported as two main innate immune responses in plants, where PTI gives basal resistance and ETI confers durable resistance. The PTI consists of extracellular surface receptors that are able to recognize PAMPs. PAMPs detect microbial features such as fungal chitin that complete a vital function during the organism's life. In contrast, ETI is mediated by intracellular receptor molecules containing nucleotide-binding (NB) and leucine rich repeat (LRR) domains that specifically recognize effector proteins produced by the pathogen. To enhance crop resistance, understanding the host resistance mechanisms against pathogen infection strategies and having a deeper knowledge of innate immunity system are essential. This review summarizes the recent advances on the molecular mechanism of innate immunity systems of rice against M. oryzae. The discussion will be centered on the latest success reported in plant-pathogen interactions and integrated defense responses in rice.
    Matched MeSH terms: Ascomycota
  11. Fulltext Determining Soil Microbial Communities and Their Influence on Ganoderma Disease Incidences in Oil Palm (Elaeis guineensis) via High-Throughput Sequencing
    Goh YK, Zoqratt MZHM, Goh YK, Ayub Q, Ting ASY
    Biology (Basel), 2020 Nov 27;9(12).
    PMID: 33260913 DOI: 10.3390/biology9120424
    Basal stem rot (BSR), caused by Ganoderma boninense, is the most devastating oil palm disease in South East Asia, costing US$500 million annually. Various soil physicochemical parameters have been associated with an increase in BSR incidences. However, very little attention has been directed to understanding the relationship between soil microbiome and BSR incidence in oil palm fields. The prokaryotic and eukaryotic microbial diversities of two coastal soils, Blenheim soil (Typic Quartzipsamment-calcareous shell deposits, light texture) with low disease incidence (1.9%) and Bernam soil (Typic Endoaquept-non-acid sulfate) with high disease incidence (33.1%), were determined using the 16S (V3-V4 region) and 18S (V9 region) rRNA amplicon sequencing. Soil physicochemical properties (pH, electrical conductivity, soil organic matter, nitrogen, phosphorus, cation exchange capacity, exchangeable cations, micronutrients, and soil physical parameters) were also analyzed for the two coastal soils. Results revealed that Blenheim soil comprises higher prokaryotic and eukaryotic diversities, accompanied by higher pH and calcium content. Blenheim soil was observed to have a higher relative abundance of bacterial taxa associated with disease suppression such as Calditrichaeota, Zixibacteria, GAL15, Omnitrophicaeota, Rokubacteria, AKYG587 (Planctomycetes), JdFR-76 (Calditrichaeota), and Rubrobacter (Actinobacteria). In contrast, Bernam soil had a higher proportion of other bacterial taxa, Chloroflexi and Acidothermus (Actinobacteria). Cercomonas (Cercozoa) and Calcarisporiella (Ascomycota) were eukaryotes that are abundant in Blenheim soil, while Uronema (Ciliophora) and mammals were present in higher abundance in Bernam soil. Some of the bacterial taxa have been reported previously in disease-suppressive and -conducive soils as potential disease-suppressive or disease-inducible bacteria. Furthermore, Cercomonas was reported previously as potential bacterivorous flagellates involved in the selection of highly toxic biocontrol bacteria, which might contribute to disease suppression indirectly. The results from this study may provide valuable information related to soil microbial community structures and their association with soil characteristics and soil susceptibility to Ganoderma.
    Matched MeSH terms: Ascomycota
  12. Fulltext Understanding Host-Pathogen Interactions in Brassica napus in the Omics Era
    Neik TX, Amas J, Barbetti M, Edwards D, Batley J
    Plants (Basel), 2020 Oct 10;9(10).
    PMID: 33050509 DOI: 10.3390/plants9101336
    Brassica napus (canola/oilseed rape/rapeseed) is an economically important crop, mostly found in temperate and sub-tropical regions, that is cultivated widely for its edible oil. Major diseases of Brassica crops such as Blackleg, Clubroot, Sclerotinia Stem Rot, Downy Mildew, Alternaria Leaf Spot and White Rust have caused significant yield and economic losses in rapeseed-producing countries worldwide, exacerbated by global climate change, and, if not remedied effectively, will threaten global food security. To gain further insights into the host-pathogen interactions in relation to Brassica diseases, it is critical that we review current knowledge in this area and discuss how omics technologies can offer promising results and help to push boundaries in our understanding of the resistance mechanisms. Omics technologies, such as genomics, proteomics, transcriptomics and metabolomics approaches, allow us to understand the host and pathogen, as well as the interaction between the two species at a deeper level. With these integrated data in multi-omics and systems biology, we are able to breed high-quality disease-resistant Brassica crops in a more holistic, targeted and accurate way.
    Matched MeSH terms: Ascomycota
  13. Phenology of Infection on Apple Fruit by Sooty Blotch and Flyspeck Species in Iowa Apple Orchards
    Ismail SI, Batzer JC, Harrington TC, Gleason ML
    Plant Dis, 2016 Feb;100(2):352-359.
    PMID: 30694131 DOI: 10.1094/PDIS-02-15-0137-RE
    Sooty blotch and flyspeck (SBFS) is a fungal disease complex that can cause significant economic losses to apple growers by blemishing the fruit surface with dark-colored colonies. Little is known about the phenology of host infection for this diverse group of epiphytes. In 2009 and 2010, we investigated the timing of infection of apple fruit by SBFS species in six commercial apple orchards in Iowa. Five trees in each orchard received no fungicide sprays after fruit set. Within 3 weeks after fruit set, 60 apples per tree were covered with Japanese fruit bags to minimize inoculum deposition. Subsequently, a subsample of bagged apples was exposed for a single 2-week-long period and then rebagged for the remainder of the growing season. Experimental treatments included seven consecutive 2-week-long exposure periods; control treatments were apples that were either bagged or exposed for the entire season. After apples had been stored at 2°C for 6 weeks following harvest, all SBFS colonies on the apples were identified to species using a PCR-RFLP protocol. A total of 15 species were identified. For the seven most prevalent species, the number of infections per cm2 of fruit surface was greatest on apples that had been exposed early in the season. Two SBFS species, Peltaster fructicola and Colletogloeopsis-like FG2, differed significantly from each other in time required to attain 50% of the total number of colonies per apple, and analysis of variance indicated a significant interaction of SBFS taxon with exposure period. Our findings are the first evidence of species-specific patterns in timing of SBFS inoculum deposition and infection on apple fruit, and strengthen previous observations that most SBFS infections resulting in visible colonies at harvest develop from infections that occur early in the fruit development period. By defining taxon-specific phenological patterns of fruit infection, our findings, when combined with knowledge of region-specific patterns of taxon prevalence, provide a foundation for development of more efficient and cost-effective SBFS management tactics.
    Matched MeSH terms: Ascomycota
  14. Fulltext Diversity of microfungi in sandy beach soil of teluk aling, pulau pinang
    Zakaria L, Yee TL, Zakaria M, Salleh B
    Trop Life Sci Res, 2011 May;22(1):71-80.
    PMID: 24575210 MyJurnal
    A total of 82 isolates of microfungi were isolated from 6 sandy soil samples collected from Teluk Aling beach, Pulau Pinang. The soil microfungi were isolated by using direct isolation, debris isolation and soil dilution techniques. Based on morphological characteristics, seven genera of microfungi were identified namely, Fusarium (42%), Aspergillus (24%), Trichoderma (13%), Curvularia (9%), Colletotrichum (6%), Helminthosporium (4%) and Penicillium (2%). The most common species isolated was Fusarium solani followed by Fusarium semitecum, Aspergillus niger, Trichoderma viride, Curvularia clavata, Curvularia lunata, Helminthosporium velutinum, Colletotrichum sp. and Penicillium chrysogenum. From the present study, it appears that the sandy beach contains a microfungi reservoir comprising of a variety of genera which contributes significantly to the ecological functioning of a marine ecosystem.
    Matched MeSH terms: Ascomycota
  15. Fulltext Review of fruit rot diseases of important tropical and some temperate fruit crops
    Nur Baiti Abd Murad, Nur Ain Izzati Mohd Zainudin
    The Pertanika Journal of Scholarly Research Reviews, 2017;3(1):138-156.
    MyJurnal
    Fruit rot is a common disease that affects the quality and quantity of the produced fruits. It may happened during pre-harvest stage and usually the condition of the fruits will become worse at postharvest stage if there are no any precautions taken during the picking, storing, packaging and transporting processes. The disease is mainly caused by the infection of fungi supported by a conducive condition like susceptible hosts, relative humidity and unsuitable temperature, besides other microorganisms such as bacteria, viruses and nematodes. The infection may arise from soilborne, waterborne, windborne and insects bite transmission. Fruit rot diseases have been reported to cause by many fungal species such as Fusarium species, Alternaria species, Lasiodiplodia species, Aspergillus species, Penicillium species, Colletotrichum species and Botrytis species. This review will provide sufficient information about rot diseases on fruit, fungal species that cause the diseases, effective control methods and managements as well as economic losses and health issues related to the diseases.
    Matched MeSH terms: Ascomycota
  16. Chemical profile of compounds from lichens of Bukit Larut, Peninsular Malaysia
    Laily B. Din, Zuriati Zakaria, Mohd Wahid Samsudin, Elix JA
    Sains Malaysiana, 2010;39.
    The lichen collection from Bukit Larut, Taiping, Malaysia in 1999 included Bulbothrix isidiza, Chrysothrix xanthina, Cladonia adspersa, C. verticillata, Coccocarpia palmicola, Heterodermia flabellata, H. japonica, H. obscurata, Hypotrachyna imbricatula, Leptogium azureum, Parmelinella wallichiana, Parmotrema tinctorum, P. clavuliferum, P. reticulatum, Pertusaria sp., Physma byrsaeum, Usnea baileyi and Usnea rubrotincta. Secondary metabolites could not be detected in three lichens, Coccocarpia palmicola, Leptogium azureum and Physma byrsaeum by HPLC and TLC analysis. The other 15 lichen species showed the presence of ten classes of compounds, depsides (10 compounds), depsidones (16), quinones (5), xanthones (2), naphthopyrones (1), pulvinic acid derivatives (1), diphenylethers (1), dibenzofurans (1), aliphatic acids (4) and terpenoids (3).
    Matched MeSH terms: Ascomycota
  17. First Report of Podosphaera fusca Causing Powdery Mildew of Cosmos caudatus in Malaysia
    Siddiqui Y, Sariah M, Kausar H
    Plant Dis, 2011 Apr;95(4):495.
    PMID: 30743349 DOI: 10.1094/PDIS-12-10-0866
    Cosmos caudatus Kunth. (Asteraceae), commonly known as ulam raja, is widely grown as an herbal aromatic shrub. In Malaysia, its young leaves are popularly eaten raw as salad with other greens and have been reported to possess extremely high antioxidant properties, which may be partly responsible for some of its believed medicinal functions. In early 2010, a suspected powdery mildew was observed on ulam raja plants at the Agricultural Park of Universiti Putra Malaysia. Initially, individual, white, superficial colonies were small and almost circular. Later, they enlarged and coalesced to cover the whole abaxial leaf surface. With development of the disease, all green parts (leaves, stems, and petioles) became covered with a continuous mat of mildew, giving a dusty appearance. Newly emerged leaves rapidly became infected. Diseased leaves ultimately senesced and dried up, making them aesthetically unattractive and unmarketable. The pathogen produced conidia in short chains (four to six conidia) on erect conidiophores. Conidiophores were unbranched, cylindrical, 125 to 240 μm long, with a slightly swollen foot cell. Individual conidia were hyaline, ellipsoid, and 25 to 30 (27.5) × 15 to 20 (17.5) μm with fibrosin inclusions. Morphological descriptions were consistent with those described for Sphaerotheca fuliginea or S. fusca, which has lately been reclassified as Podosphaera fusca (1). From extracted genomic DNA of P. fusca UPM UR1, the internal transcribed spacer (ITS) region was amplified with ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3'). A BLAST search of GenBank with an ITS rDNA sequence of this fungus (GenBank Accession No. HQ589357) showed a maximum identity of 98% to the sequences of two P. fusca isolates (GenBank Accession Nos. AB525915.1 and AB525914.1). To satisfy Koch's postulates, the pathogenicity of fungal strain UPM UR1 was verified on 4-week-old plants. Inoculation was carried out by gently rubbing infected leaves onto healthy plants of C. caudatus. Ten pots of inoculated plants were kept under a plastic humid chamber and 10 pots of noninoculated plants, placed under another chamber, served as controls. After 48 h, the plants were then placed under natural conditions (25 to 28°C). Powdery mildew symptoms, similar to those on diseased field plants, appeared after 7 days on all inoculated plants. The white, superficial colonies enlarged and merged to cover large areas within 2 weeks. The infected leaf tissues became necrotic 6 to 8 days after the appearance of the first symptoms. Sporulation of P. fusca was observed on all infected leaves and stems. No symptoms were seen on the control plants. To our knowledge, this is the first report of P. fusca causing powdery mildew on C. caudatus in Malaysia. This pathogen has also been reported previously to be economically important on a number of other hosts. With ulam raja plants, more attention should be given to prevention and control measures to help manage this disease. Reference: (1) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000.
    Matched MeSH terms: Ascomycota
  18. First Report of Curvularia lunata on Red-Fleshed Dragon Fruit (Hylocereus polyrhizus) in Malaysia
    Hawa MM, Salleh B, Latiffah Z
    Plant Dis, 2009 Sep;93(9):971.
    PMID: 30754569 DOI: 10.1094/PDIS-93-9-0971C
    Red-fleshed dragon fruit (Hylocereus polyrhizus [Weber] Britton & Rose) is a newly introduced and potential crop in the Malaysian fruit industry. Besides its nutritious value, the fruit is being promoted as a health crop throughout Southeast Asia. In April of 2007, a new disease was observed in major plantations of H. polyrhizus throughout five states (Kelantan, Melaka, Negeri Sembilan, Penang, and Perak) in Malaysia with 41 and 25% disease incidence and severity, respectively. Stems of H. polyrhizus showed spots or small, circular, faint pink-to-beige necrotic lesions that generally coalesced as symptoms progressed. Symptom margins of diseased stem samples were surface sterilized with a 70% alcohol swab, cut into small blocks (1.5 × 1.5 × 1.5 cm), soaked in 1% sodium hypochlorite (NaOCI) for 3 min, and rinsed in several changes of sterile distilled water (each 1 min). The surface-sterilized tissues were placed onto potato dextrose agar (PDA) and incubated under alternating 12-h daylight and black light for 7 days. A fungus was consistently isolated from the stems of symptomatic H. polyrhizus and identified as Curvularia lunata (Wakker) Beodijn (1-3) that showed pale brown multicelled conidia (phragmoconidia; three to five celled) that formed apically through a pore (poroconidia) in sympodially, elongating, geniculated conidiophores. Conidia are relatively fusiform, cylindrical, or slightly curved, with one of the central cells being larger and darker (26.15 ± 0.05 μm). All 25 isolates of C. lunata obtained from diseased H. polyrhizus are deposited at the Culture Collection Unit, Universiti Sains Malaysia and available on request. Isolates were tested for pathogenicity by injecting conidial suspensions (1 × 106 conidia/ml) and pricking colonized toothpicks on 25 healthy H. polyrhizus stems. Controls were treated with sterile distilled water and noncolonized toothpicks. All inoculated plants and controls were placed in a greenhouse with day and night temperatures of 30 to 35°C and 23 to 30°C, respectively. Development of external symptoms on inoculated plants was observed continuously every 2 days for 2 weeks. Two weeks after inoculation, all plants inoculated with all isolates of C. lunata developed stem lesions similar to those observed in the field. No symptoms were observed on the control plants and all remained healthy. C. lunata was reisolated from 88% of the inoculated stems, completing Koch's postulates. The pathogenicity test was repeated with the same results. To our knowledge, this is the first report of C. lunata causing a disease on H. polyrhizus. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1971. (2) R. R. Nelson and F. A. Hassis. Mycologia 56:316, 1964. (3) C. V. Subramanian. Fungi Imperfecti from Madras V. Curvularia. Proc. Indian Acad. Sci. 38:27, 1955.
    Matched MeSH terms: Ascomycota
  19. Fulltext Effects of silica soil amendment against Exserohilum rostratum, the fungal pathogen of rice brown spot disease in Peninsular Malaysia
    Mahmad-Toher AS, Govender N, Dorairaj D, Wong MY
    Sci Rep, 2022 Sep 20;12(1):15690.
    PMID: 36127366 DOI: 10.1038/s41598-022-19308-z
    Rice brown spot (BS) exerts devastating agronomic effects on grain quality and overall productivity. In Peninsular Malaysia, BS disease incidence is fairly prevalent and little is known about the diversity of BS pathogens in the local granaries. Fifteen isolates from BS symptomatic rice plants were identified at five different rice granaries across Peninsular Malaysia. Based on the morphological and molecular analyses, two isolates were confirmed as Bipolaris oryzae while the rest were identified as Exserohilum rostratum. Phylogenetic tree analysis revealed that BS incidence in rice granaries in Peninsular Malaysia is caused by a pair of closely related fungal pathogens, E. rostratum and B. oryzae, with the former being more predominant. Cultural characterization of E. rostratum isolate KT831962 showed the best growth and sporulation activity on corn meal agar plates incubated in complete darkness. The effects of calcium silicate (CaSiO3) and rice husk ash (RHA) soil amendment against MR219 and MR253 rice varieties were evaluated during rice-E. rostratum interaction. Results showed that soil amelioration using CaSiO3 and RHA singly and in combination with manganese (Mn) significantly reduced rice BS disease severity. The BS disease index was reduced significantly to less than 31.6% in the silicon-treated rice plants relative to the control plants at 41.2%. Likewise, the grain yield at the harvest stage showed significantly higher yield in the Si-treated rice plants in comparison to the control, non-Si treated rice plants. The findings highlight the potential of RHA agro-waste as Si fertilizer in a sustainable rice production system.
    Matched MeSH terms: Ascomycota
  20. Diversity of the cassiicolin gene in Corynespora cassiicola and relation with the pathogenicity in Hevea brasiliensis
    Déon M, Fumanal B, Gimenez S, Bieysse D, Oliveira RR, Shuib SS, et al.
    Fungal Biol, 2014 Jan;118(1):32-47.
    PMID: 24433675 DOI: 10.1016/j.funbio.2013.10.011
    Corynespora cassiicola is an important plant pathogenic Ascomycete causing the damaging Corynespora Leaf Fall (CLF) disease in rubber tree (Hevea brasiliensis). A small secreted glycoprotein named cassiicolin was previously described as an important effector of C. cassiicola. In this study, the diversity of the cassiicolin-encoding gene was analysed in C. cassiicola isolates sampled from various hosts and geographical origins. A cassiicolin gene was detected in 47 % of the isolates, encoding up to six distinct protein isoforms. In three isolates, two gene variants encoding cassiicolin isoforms Cas2 and Cas6 were found in the same isolate. A phylogenetic tree based on four combined loci and elucidating the diversity of the whole collection was strongly structured by the toxin class, as defined by the cassiicolin isoform. The isolates carrying the Cas1 gene (toxin class Cas1), all grouped in the same highly supported clade, were found the most aggressive on two rubber tree cultivars. Some isolates in which no Cas gene was detected could nevertheless generate moderate symptoms, suggesting the existence of other yet uncharacterized effectors. This study provides a useful base for future studies of C. cassiicola population biology and epidemiological surveys in various host plants.
    Matched MeSH terms: Ascomycota/genetics*
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