Displaying publications 21 - 40 of 182 in total

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  1. Toxigenicity of some fusaria associated with plant and human diseases in the Malaysian peninsula
    Salleh B, Strange RN
    J. Gen. Microbiol., 1988 Mar;134(3):841-7.
    PMID: 3183622
    In the course of a plant disease survey of the Malaysian Peninsula (Malaysia comprises the Malaysian Peninsula, Sabah and Sarawak) during the period 1981-1986, more than 1000 isolates of Fusarium were obtained from diseased plants and seeds. Two further isolates were obtained from patients admitted to hospitals in the same area. The occurrences of F. proliferatum, F. nygamai and F. longipes are new records for the Malaysian Peninsula and the association of F. solani and F. oxysporum var. redolens with human diseases does not seem to have been reported previously. Ten representative species which could be classified into seven sections of the genus were selected for studies of their toxigenicity in liquid cultures and/or on rice. Crude toxin preparations from culture filtrates or extracts of the inoculated rice were tested for toxicity to brine shrimp larvae and tobacco mesophyll protoplasts. The protoplasts were more sensitive than the brine shrimp larvae to the toxin preparations, except those from the isolates of F. solani and F. oxysporum var. redolens obtained from either humans or tobacco. The toxicity of the preparations from rice cultures per g rice was always greater than the toxicity per ml of culture filtrates from cultures grown on Czapek-Dox broth, Czapek-Dox supplemented with 1% (w/v) peptone or Czapek-Dox supplemented with 5% (w/v) tobacco extract. The activity of all toxin preparations was stable to heat. It is concluded that the occurrence of toxigenic species of Fusarium in the Malaysian Peninsula is widespread and that they may pose a serious threat to the health of human, animal and plant populations.
    Matched MeSH terms: Plant Diseases*
  2. Fulltext The Possible Biotechnological Use of Edible Mushroom Bioproducts for Controlling Plant and Animal Parasitic Nematodes
    Castañeda-Ramírez GS, Torres-Acosta JFJ, Sánchez JE, Mendoza-de-Gives P, González-Cortázar M, Zamilpa A, et al.
    Biomed Res Int, 2020;2020:6078917.
    PMID: 32685507 DOI: 10.1155/2020/6078917
    The present paper reviewed publications on the nematocidal activity of edible mushrooms (EM) and their potential use as sustainable tools for the control of parasitic nematodes affecting agriculture and livestock industry. Nematodes are organisms living in the soil and animals' guts where they may live as parasites severely affecting economically important crops and farm animals, thus causing economic losses to worldwide agriculture. Traditionally, parasitic nematodes have been controlled using commercial pesticides and anthelmintic (AH) drugs. Over the years, nematodes developed resistance to the AH drugs, reducing the usefulness of many commercial drugs. Also, the use of pesticides/anthelmintic drugs to control nematodes can have important negative impacts on the environment. Different EM have been not only used as food but also studied as alternative methods for controlling several diseases including parasitic nematodes. The present paper reviewed publications from the last decades about the nematocidal activity of EM and assessed their potential use as sustainable tools for the control of nematodes affecting agriculture and livestock industry. A reduced number of reports on the effect of EM against nematodes were found, and an even smaller number of reports regarding the potential AH activity of chemical compounds isolated from EM products were found. However, those studies have produced promising results that certainly deserve further investigation. It is concluded that EM, their fractions and extracts, and some compounds contained in them may have biotechnological application for the control of animal and plant parasitic nematodes.
    Matched MeSH terms: Plant Diseases/parasitology*
  3. ROS Stress and Cell Membrane Disruption are the Main Antifungal Mechanisms of 2-Phenylethanol against Botrytis cinerea
    Zou X, Wei Y, Jiang S, Xu F, Wang H, Zhan P, et al.
    J Agric Food Chem, 2022 Nov 16;70(45):14468-14479.
    PMID: 36322824 DOI: 10.1021/acs.jafc.2c06187
    2-Phenylethanol (2-PE), a common compound found in plants and microorganisms, exhibits broad-spectrum antifungal activity. Using Botrytis cinerea, we demonstrated that 2-PE suppressed mycelium growth in vitro and in strawberry fruit and reduced natural disease without adverse effects to fruit quality. 2-PE caused structural damage to mycelia, as shown by scanning and transmission electron microscopy. From RNA sequencing analysis we found significantly upregulated genes for enzymatic and nonenzymatic reactive oxygen species (ROS) scavenging systems including sulfur metabolism and glutathione metabolism, indicating that ROS stress was induced by 2-PE. This was consistent with results from assays demonstrating an increase ROS and hydrogen peroxide levels, antioxidant enzyme activities, and malondialdehyde content in treated cells. The upregulation of ATP-binding cassette transporter genes, the downregulation of major facilitator superfamily transporters genes, and the downregulation of ergosterol biosynthesis genes indicated a severe disruption of cell membrane structure and function. This was consistent with results from assays demonstrating compromised membrane integrity and lipid peroxidation. To summarize, 2-PE exposure suppressed B. cinerea growth through ROS stress and cell membrane disruption.
    Matched MeSH terms: Plant Diseases/microbiology
  4. Analysis of codon usage patterns and influencing factors in rice tungro bacilliform virus
    Nguyen TH, Wang D, Rahman SU, Bai H, Yao X, Chen D, et al.
    Infect Genet Evol, 2021 06;90:104750.
    PMID: 33548490 DOI: 10.1016/j.meegid.2021.104750
    Rice tungro bacilliform virus (RTBV) belongs to genus Tungrovirus within the family Caulimoviridae harbors circular double-stranded DNA (dsDNA). Rice tungro disease (RTD) caused by RTBV, responsible for severe rice yield losses in South and Southeast Asia. Here, we performed a systematic evolutionary and codon usage bias (CUB) analysis of RTBV genome sequences. We analysed different bioinformatics techniques to calculate the nucleotide compositions, the relative synonymous codon usage (RSCU), and other indices. The results indicated slightly or low codon usage bias in RTBV isolates. Mutation and natural selection pressures have equally contributed to this low codon usage bias. Additionally, multiple factors such as host, geographical distribution also affect codon usage patterns in RTBV genomes. RSCU analysis revealed that RTBV shows mutation bias and prefers A and U ended codons to code amino acids. Codon usage patterns of RTBV were also found to be influenced by its host. This indicates that RTBV have evolved codon usage patterns that are specific to its host. The findings from this study are expected to increase our understanding of factors leading to viral evolution and fitness with respect to hosts and the environment.
    Matched MeSH terms: Plant Diseases/virology*
  5. Pan-genome analysis and molecular docking unveil the biocontrol potential of Bacillus velezensis VB7 against Phytophthora infestans
    Kadiri M, Sevugapperumal N, Nallusamy S, Ragunathan J, Ganesan MV, Alfarraj S, et al.
    Microbiol Res, 2023 Mar;268:127277.
    PMID: 36577205 DOI: 10.1016/j.micres.2022.127277
    Management of late blight of potato incited by Phytophthora infestans remains a major challenge. Coevolution of pathogen with resistant strains and the rise of fungicide resistance have made it more challenging to prevent the spread of P. infestans. Here, the anti-oomycete potential of Bacillus velezensis VB7 against P. infestans through pan-genome analysis and molecular docking were explored. The Biocontrol potential of VB7 against P. infestans was assessed using a confrontational assay. The biomolecules from the inhibition zone were identified and subjected to in silico analysis against P. infestans target proteins. Nucleotide sequences for 54 B. velezensis strains from different geographical locations were used for pan-genome analysis. The confrontational assay revealed the anti-oomycetes potential of VB7 against P. infestans. Molecular docking confirmed that the penicillamine disulfide had the maximum binding energy with eight effector proteins of P. infestans. Besides, scanning electron microscopic observations of P. infestans interaction with VB7 revealed structural changes in hypha and sporangia. Pan-genome analysis between 54 strains of B. velezensis confirmed that the core genome had 2226 genes, and it has an open pan-genome. The present study confirmed the anti-oomycete potential of B. velezensis VB7 against P. infestans and paved the way to explore the genetic potential of VB7.
    Matched MeSH terms: Plant Diseases/prevention & control
  6. Association of soil fungal community composition with incidence of Fusarium wilt of banana in Malaysia
    Jamil FN, Hashim AM, Yusof MT, Saidi NB
    Mycologia, 2023;115(2):178-186.
    PMID: 36893072 DOI: 10.1080/00275514.2023.2180975
    Banana (Musa spp.), an important food crop in many parts of the world, is threatened by a deadly wilt disease caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (TR4). Increasing evidence indicates that plant actively recruits beneficial microbes in the rhizosphere to suppress soil-borne pathogens. Hence, studies on the composition and diversity of the root-associated microbial communities are important for banana health. Research on beneficial microbial communities has focused on bacteria, although fungi can also influence soil-borne disease. Here, high-throughput sequencing targeting the fungal internal transcribed spacer (ITS) was employed to systematically characterize the difference in the soil fungal community associated with Fusarium wilt (FW) of banana. The community structure of fungi in the healthy and TR4-infected rhizospheres was significantly different compared with that of bulk soil within the same farm. The rhizosphere soils of infected plants exhibited higher richness and diversity compared with healthy plants, with significant abundance of Fusarium genus at 14%. In the healthy rhizosphere soil, Penicillium spp. were more abundant at 7% and positively correlated with magnesium. This study produced a detailed description of fungal community structure in healthy and TR4-infected banana soils in Malaysia and identified candidate biomarker taxa that may be associated with FW disease promotion and suppression. The findings also expand the global inventory of fungal communities associated with the components of asymptomatic and symptomatic banana plants infected by TR4.
    Matched MeSH terms: Plant Diseases/microbiology
  7. Fulltext Ginger Essential Oils-Loaded Nanoemulsions: Potential Strategy to Manage Bacterial Leaf Blight Disease and Enhanced Rice Yield
    Adamu A, Ahmad K, Siddiqui Y, Ismail IS, Asib N, Bashir Kutawa A, et al.
    Molecules, 2021 Jun 25;26(13).
    PMID: 34202405 DOI: 10.3390/molecules26133902
    The bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious rice diseases, causing huge yield losses worldwide. Several technologies and approaches have been opted to reduce the damage; however, these have had limited success. Recently, scientists have been focusing their efforts on developing efficient and environmentally friendly nanobactericides for controlling bacterial diseases in rice fields. In the present study, a scanning electron microscope (SEM), transmission electron microscope (TEM), and a confocal laser scanning microscope (CLSM) were utilized to investigate the mode of actions of ginger EOs on the cell structure of Xoo. The ginger EOs caused the cells to grow abnormally, resulting in an irregular form with hollow layers, whereas the dimethylsulfoxide (DMSO) treatment showed a typical rod shape for the Xoo cell. Ginger EOs restricted the growth and production of biofilms by reducing the number of biofilms generated as indicated by CLSM. Due to the instability, poor solubility, and durability of ginger EOs, a nanoemulsions approach was used, and a glasshouse trial was performed to assess their efficacy on BLB disease control. The in vitro antibacterial activity of the developed nanobactericides was promising at different concentration (50-125 µL/mL) tested. The efficacy was concentration-dependent. There was significant antibacterial activity recorded at higher concentrations. A glasshouse trial revealed that developed nanobactericides managed to suppress BLB disease severity effectively. Treatment at a concentration of 125 μL/mL was the best based on the suppression of disease severity index, AUDPC value, disease reduction (DR), and protection index (PI). Furthermore, findings on plant growth, physiological features, and yield parameters were significantly enhanced compared to the positive control treatment. In conclusion, the results indicated that ginger essential oils loaded-nanoemulsions are a promising alternative to synthetic antibiotics in suppressing Xoo growth, regulating the BLB disease, and enhancing rice yield under a glasshouse trial.
    Matched MeSH terms: Plant Diseases/microbiology*
  8. Fulltext Understanding the Quorum-Sensing Bacterium Pantoea stewartii Strain M009 with Whole-Genome Sequencing Analysis
    Tan WS, Chang CY, Yin WF, Chan KG
    Genome Announc, 2015;3(1).
    PMID: 25635007 DOI: 10.1128/genomeA.01509-14
    Pantoea stewartii is known to be the causative agent of Stewart's wilt, which usually affects sweet corn (Zea mays) with the corn flea beetle as the transmission vector. In this work, we present the whole-genome sequence of Pantoea stewartii strain M009, isolated from a Malaysian tropical rainforest waterfall.
    Matched MeSH terms: Plant Diseases
  9. Introgression of blast resistance genes into the elite rice variety MR263 through marker-assisted backcrossing
    Hasan MM, Rafii MY, Ismail MR, Mahmood M, Alam MA, Abdul Rahim H, et al.
    J Sci Food Agric, 2016 Mar 15;96(4):1297-305.
    PMID: 25892666 DOI: 10.1002/jsfa.7222
    Blast caused by the fungus Magnaporthe oryzae is a significant disease threat to rice across the world and is especially prevalent in Malaysia. An elite, early-maturing, high-yielding Malaysian rice variety, MR263, is susceptible to blast and was used as the recurrent parent in this study. To improve MR263 disease resistance, the Pongsu Seribu 1 rice variety was used as donor of the blast resistance Pi-7(t), Pi-d(t)1 and Pir2-3(t) genes and qLN2 quantitative trait locus (QTL). The objective was to introgress these blast resistance genes into the background of MR263 using marker-assisted backcrossing with both foreground and background selection.
    Matched MeSH terms: Plant Diseases/genetics*; Plant Diseases/microbiology*; Plant Diseases/prevention & control
  10. Precipitation Impacts Dissemination of Three Sooty Blotch and Flyspeck Taxa on Apple Fruit
    Rosli H, Batzer JC, Hernández E, Beruski G, Dixon PM, Gleason ML
    Plant Dis, 2020 Sep;104(9):2398-2405.
    PMID: 32689919 DOI: 10.1094/PDIS-11-19-2340-RE
    The spatial dissemination of three prevalent taxa of sooty blotch and flyspeck (SBFS) fungi under several levels of precipitation was compared during 2015 and 2016 in an Iowa apple orchard. Overhead irrigation was used to supplement ambient precipitation in order to insure SBFS spore dissemination and colony development. There were five irrigation levels, involving 1-min-long periods of irrigation that were imposed either once or twice per hour at intervals of 3, 6, or 12 h, as well as a nonirrigated control. Preselected apple fruit were inoculated with one of the three SBFS taxa to serve as sources of inoculum. Dissemination from these inoculated apple fruit was assessed at harvest by counting SBFS colonies on water-sprayed and nontreated fruit. As a further control, additional fruit were enclosed in fruit bags throughout the fruit development period. In both 2015 and 2016, the number of colonies of the SBFS fungus Peltaster gemmifer per apple increased sharply as the duration of irrigation increased, whereas the number of colonies of Microcyclosporella mali increased to a lesser extent and Stomiopeltis sp. RS1 showed no increase. In 2015, the linear relationship between the duration of irrigation-imposed precipitation levels and the number of colonies on the water-sprayed apple fruit was similar for P. gemmifer (slope = 0.09), Stomiopeltis sp. RS1 (slope = 0.07), and Microcyclosporella mali (slope = 0.13); whereas, in 2016, the slope was higher for P. gemmifer (0.28) than for Stomiopeltis sp. RS1 (-0.09) or M. mali (0.06). The results indicated that dissemination of P. gemmifer increased sharply in response to increased irrigation-imposed precipitation, and that dissemination patterns differed considerably among the three SBFS taxa. The apparent advantage of P. gemmifer in precipitation-triggered dissemination may stem from its ability to produce spores rapidly by budding. To our knowledge, this is the first article to assess splash dispersal by SBFS fungi in the field and the first to document taxon-specific patterns of dissemination in this pathogen complex.
    Matched MeSH terms: Plant Diseases
  11. Fulltext Ganoderma boninense Disease Detection by Near-Infrared Spectroscopy Classification: A Review
    Mohd Hilmi Tan MIS, Jamlos MF, Omar AF, Dzaharudin F, Chalermwisutkul S, Akkaraekthalin P
    Sensors (Basel), 2021 Apr 27;21(9).
    PMID: 33925576 DOI: 10.3390/s21093052
    Ganoderma boninense (G. boninense) infection reduces the productivity of oil palms and causes a serious threat to the palm oil industry. This catastrophic disease ultimately destroys the basal tissues of oil palm, causing the eventual death of the palm. Early detection of G. boninense is vital since there is no effective treatment to stop the continuing spread of the disease. This review describes past and future prospects of integrated research of near-infrared spectroscopy (NIRS), machine learning classification for predictive analytics and signal processing towards an early G. boninense detection system. This effort could reduce the cost of plantation management and avoid production losses. Remarkably, (i) spectroscopy techniques are more reliable than other detection techniques such as serological, molecular, biomarker-based sensor and imaging techniques in reactions with organic tissues, (ii) the NIR spectrum is more precise and sensitive to particular diseases, including G. boninense, compared to visible light and (iii) hand-held NIRS for in situ measurement is used to explore the efficacy of an early detection system in real time using ML classifier algorithms and a predictive analytics model. The non-destructive, environmentally friendly (no chemicals involved), mobile and sensitive leads the NIRS with ML and predictive analytics as a significant platform towards early detection of G. boninense in the future.
    Matched MeSH terms: Plant Diseases
  12. Late blight in tomato: insights into the pathogenesis of the aggressive pathogen Phytophthora infestans and future research priorities
    Mazumdar P, Singh P, Kethiravan D, Ramathani I, Ramakrishnan N
    Planta, 2021 May 08;253(6):119.
    PMID: 33963935 DOI: 10.1007/s00425-021-03636-x
    MAIN CONCLUSION: This review provides insights into the molecular interactions between Phytophthora infestans and tomato and highlights research gaps that need further attention. Late blight in tomato is caused by the oomycota hemibiotroph Phytophthora infestans, and this disease represents a global threat to tomato farming. The pathogen is cumbersome to control because of its fast-evolving nature, ability to overcome host resistance and inefficient natural resistance obtained from the available tomato germplasm. To achieve successful control over this pathogen, the molecular pathogenicity of P. infestans and key points of vulnerability in the host plant immune system must be understood. This review primarily focuses on efforts to better understand the molecular interaction between host pathogens from both perspectives, as well as the resistance genes, metabolomic changes, quantitative trait loci with potential for improvement in disease resistance and host genome manipulation via transgenic approaches, and it further identifies research gaps and provides suggestions for future research priorities.
    Matched MeSH terms: Plant Diseases
  13. Marker-assisted introgression of broad-spectrum blast resistance genes into the cultivated MR219 rice variety
    Miah G, Rafii MY, Ismail MR, Puteh AB, Rahim HA, Latif MA
    J Sci Food Agric, 2017 Jul;97(9):2810-2818.
    PMID: 27778337 DOI: 10.1002/jsfa.8109
    BACKGROUND: The rice cultivar MR219 is famous for its better yield and long and fine grain quality; however, it is susceptible to blast disease. The main objective of this study was to introgress blast resistance genes into MR219 through marker-assisted selection (MAS). The rice cultivar MR219 was used as the recurrent parent, and Pongsu Seribu 1 was used as the donor.

    RESULTS: Marker-assisted foreground selection was performed using RM6836 and RM8225 to identify plants possessing blast resistance genes. Seventy microsatellite markers were used to estimate recurrent parent genome (RPG) recovery. Our analysis led to the development of 13 improved blast resistant lines with Piz, Pi2 and Pi9 broad-spectrum blast resistance genes and an MR219 genetic background. The RPG recovery of the selected improved lines was up to 97.70% with an average value of 95.98%. Selected improved lines showed a resistance response against the most virulent blast pathogen pathotype, P7.2. The selected improved lines did not express any negative effect on agronomic traits in comparison with MR219.

    CONCLUSION: The research findings of this study will be a conducive approach for the application of different molecular techniques that may result in accelerating the development of new disease-resistant rice varieties, which in turn will match rising demand and food security worldwide. © 2016 Society of Chemical Industry.

    Matched MeSH terms: Plant Diseases/genetics*; Plant Diseases/immunology; Plant Diseases/prevention & control
  14. A preliminary study to identify and distinguish southern tropical populations of Ganoderma boninense from oil palm via mating assays, sequence data, and microsatellite markers
    Pilotti CA, Killah G, Rama D, Gorea EA, Mudge AM
    Mycologia, 2021 03 03;113(3):574-585.
    PMID: 33656969 DOI: 10.1080/00275514.2020.1858687
    Morphological studies suggest that the major pathogen causing basal stem rot of oil palm in Papua New Guinea and Solomon Islands is Ganoderma boninense. This study presents the first evidence for conspecificity of G. boninense from four countries where basal stem rot is prevalent. Seventy-three dikaryotic isolates of Ganoderma boninense from Indonesia, Malaysia, Papua New Guinea, and Solomon Islands were studied via mating tests, analyses of nuc internal transcribed spacer ITS1-5.8S-ITS2 sequences, and microsatellite genotyping. Sequence similarity in the ITS1-5.8S-ITS2 region was >99%, and all exotic isolates successfully mated with Papua New Guinea tester strains. Transfer of nuclei during mating was also confirmed via microsatellite markers for the first time in this species. Four microsatellite primers were used to generate evidence for 33 alleles in the four populations. All isolates studied had unique genetic fingerprints but alleles were also shared, suggesting gene flow. Heterozygosities were lower than expected in Indonesian and Papua New Guinea populations, consistent with the possibility of localized inbreeding.
    Matched MeSH terms: Plant Diseases
  15. Fulltext Maize Dwarf Mosaic Virus: From Genome to Disease Management
    Kannan M, Ismail I, Bunawan H
    Viruses, 2018 09 13;10(9).
    PMID: 30217014 DOI: 10.3390/v10090492
    Maize dwarf mosaic virus (MDMV) is a serious maize pathogen, epidemic worldwide, and one of the most common virus diseases for monocotyledonous plants, causing up to 70% loss in corn yield globally since 1960. MDMV belongs to the genus Potyvirus (Potyviridae) and was first identified in 1964 in Illinois in corn and Johnsongrass. MDMV is a single stranded positive sense RNA virus and is transmitted in a non-persistent manner by several aphid species. MDMV is amongst the most important virus diseases in maize worldwide. This review will discuss its genome, transmission, symptomatology, diagnosis and management. Particular emphasis will be given to the current state of knowledge on the diagnosis and control of MDMV, due to its importance in reducing the impact of maize dwarf mosaic disease, to produce an enhanced quality and quantity of maize.
    Matched MeSH terms: Plant Diseases/prevention & control; Plant Diseases/therapy; Plant Diseases/virology*
  16. Ancestral state reconstruction infers phytopathogenic origins of sooty blotch and flyspeck fungi on apple
    Ismail SI, Batzer JC, Harrington TC, Crous PW, Lavrov DV, Li H, et al.
    Mycologia, 2016 Mar-Apr;108(2):292-302.
    PMID: 26740537 DOI: 10.3852/15-036
    Members of the sooty blotch and flyspeck (SBFS) complex are epiphytic fungi in the Ascomycota that cause economically damaging blemishes of apples worldwide. SBFS fungi are polyphyletic, but approx. 96% of SBFS species are in the Capnodiales. Evolutionary origins of SBFS fungi remain unclear, so we attempted to infer their origins by means of ancestral state reconstruction on a phylogenetic tree built utilizing genes for the nuc 28S rDNA (approx. 830 bp from near the 59 end) and the second largest subunit of RNA polymerase II (RPB2). The analyzed taxa included the well-known genera of SBFS as well as non-SBFS fungi from seven families within the Capnodiales. The non-SBFS taxa were selected based on their distinct ecological niches, including plant-parasitic and saprophytic species. The phylogenetic analyses revealed that most SBFS species in the Capnodiales are closely related to plant-parasitic fungi. Ancestral state reconstruction provided strong evidence that plant-parasitic fungi were the ancestors of the major SBFS lineages. Knowledge gained from this study may help to better understand the ecology and evolution of epiphytic fungi.
    Matched MeSH terms: Plant Diseases/microbiology*
  17. Application of arbuscular mycorrhizal fungi with Pseudomonas aeruginosa UPMP3 reduces the development of Ganoderma basal stem rot disease in oil palm seedlings
    Sundram S, Meon S, Seman IA, Othman R
    Mycorrhiza, 2015 Jul;25(5):387-97.
    PMID: 25492807 DOI: 10.1007/s00572-014-0620-5
    The effect of arbuscular mycorrhizal fungi (AMF) in combination with endophytic bacteria (EB) in reducing development of basal stem rot (BSR) disease in oil palm (Elaeis guineensis) was investigated. BSR caused by Ganoderma boninense leads to devastating economic loss and the oil palm industry is struggling to control the disease. The application of two AMF with two EB as biocontrol agents was assessed in the nursery and subsequently, repeated in the field using bait seedlings. Seedlings pre-inoculated with a combination of Glomus intraradices UT126, Glomus clarum BR152B and Pseudomonas aeruginosa UPMP3 significantly reduced disease development measured as the area under disease progression curve (AUDPC) and the epidemic rate (R L) of disease in the nursery. A 20-month field trial using similar treatments evaluated disease development in bait seedlings based on the rotting area/advancement assessed in cross-sections of the seedling base. Data show that application of Glomus intraradices UT126 singly reduced disease development of BSR, but that combination of the two AMF with P. aeruginosa UPMP3 significantly improved biocontrol efficacy in both nursery and fields reducing BSR disease to 57 and 80%, respectively. The successful use of bait seedlings in the natural environment to study BSR development represents a promising alternative to nursery trial testing in the field with shorter temporal assessment.
    Matched MeSH terms: Plant Diseases/microbiology*
  18. Molecular phylogeny of Rigidoporus microporus isolates associated with white rot disease of rubber trees (Hevea brasiliensis)
    Oghenekaro AO, Miettinen O, Omorusi VI, Evueh GA, Farid MA, Gazis R, et al.
    Fungal Biol, 2014 May-Jun;118(5-6):495-506.
    PMID: 24863478 DOI: 10.1016/j.funbio.2014.04.001
    Rigidoporus microporus (Polyporales, Basidiomycota) syn. Rigidoporus lignosus is the most destructive root pathogen of rubber plantations distributed in tropical and sub-tropical regions. Our primary objective was to characterize Nigerian isolates from rubber tree and compare them with other West African, Southeast Asian and American isolates. To characterize the 20 isolates from Nigeria, we used sequence data of the nuclear ribosomal DNA ITS and LSU, β-tubulin and translation elongation factor 1-α (tef1) gene sequences. Altogether, 40 isolates of R. microporus were included in the analyses. Isolates from Africa, Asia and South/Central America formed three distinctive clades corresponding to at least three species. No phylogeographic pattern was detected among R. microporus collected from West and Central African rubber plantations suggesting continuous gene flow among these populations. Our molecular phylogenetic analysis suggests the presence of two distinctive species associated with the white rot disease. Phylogenetic analyses placed R. microporus in the Hymenochaetales in the vicinity of Oxyporus. This is the first study to characterize R. microporus isolates from Nigeria through molecular phylogenetic techniques, and also the first to compare isolates from rubber plantations in Africa and Asia.
    Matched MeSH terms: Plant Diseases/microbiology*
  19. Morphological characteristics and pathogenicity of fungi associated with Roselle (Hibiscus Sabdariffa) diseases in Penang, Malaysia
    Eslaminejad T, Zakaria M
    Microb Pathog, 2011 Nov;51(5):325-37.
    PMID: 21839160 DOI: 10.1016/j.micpath.2011.07.007
    Roselle, or Jamaica sorrel (Hibiscus sabdariffa) is a popular vegetable in many tropical regions, cultivated for its leaves, seeds, stems and calyces which, the dried calyces are used to prepare tea, syrup, jams and jellies and as beverages. The main objectives of this study were to identify and characterise fungal pathogens associated with Roselle diseases based on their morphological and cultural characteristics and to determine the pathogenicity of four fungi infecting Roselle seedlings, namely Phoma exigua, Fusarium nygamai, Fusarium tgcq and Rhizoctonia solani in Penang. A total of 200 fungal isolates were obtained from 90 samples of symptomatic Roselle tissues. The isolates were identified based on cultural and morphological characteristics, as well as their pathogenicity. The fungal pathogen most frequently isolated was P. exigua (present in 45% of the samples), followed by F. nygamai (25%), Rhizoctonia solani (19%) and F. camptoceras (11%). Pathogenicity tests showed that P. exigua, F. nygamai, F. camptoceras and R. solani were able to infect both wounded and unwounded seedlings with different degrees of severity as indicated by the Disease severity (DS). R. solani was the most pathogenic fungus affecting both wounded and unwounded Roselle seedlings, followed by P. exigua that was highly pathogenic on wounded seedlings. F. nygamai was less pathogenic while the least pathogenic fungus was F. camptoceras, infecting only the unwounded seedlings but, surprisingly, not the wounded plants.
    Matched MeSH terms: Plant Diseases/microbiology*
  20. Fulltext Erwinia mallotivora sp., a new pathogen of papaya (Carica papaya) in Peninsular Malaysia
    Amin NM, Bunawan H, Redzuan RA, Jaganath IB
    Int J Mol Sci, 2010;12(1):39-45.
    PMID: 21339975 DOI: 10.3390/ijms12010039
    Erwinia mallotivora was isolated from papaya infected with dieback disease showing the typical symptoms of greasy, water-soaked lesions and spots on leaves. Phylogenetic analysis of 16S rRNA gene sequences showed that the strain belonged to the genus Erwinia and was united in a monophyletic group with E. mallotivora DSM 4565 (AJ233414). Earlier studies had indicated that the causal agent for this disease was E. papayae. However, our current studies, through Koch's postulate, have confirmed that papaya dieback disease is caused by E. mallotivora. To our knowledge, this is the first new discovery of E. mallotivora as a causal agent of papaya dieback disease in Peninsular Malaysia. Previous reports have suggested that E. mallotivora causes leaf spot in Mallotus japonicus. However, this research confirms it also to be pathogenic to Carica papaya.
    Matched MeSH terms: Plant Diseases/microbiology*
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