Displaying publications 1 - 20 of 182 in total

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  1. Classification of the guava wilt fungus Myxosporium psidii, the palm pathogen Gliocladium vermoesenii and the persimmon wilt fungus Acremonium diospyri in Nalanthamala
    Schroers HJ, Geldenhuis MM, Wingfield MJ, Schoeman MH, Yen YF, Shen WC, et al.
    Mycologia, 2005 Mar-Apr;97(2):375-95.
    PMID: 16396346
    Psidium guajava wilt is known from South Africa, Malaysia and Taiwan. The fungus causing this disease, Myxosporium psidii, forms dry chains of conidia on surfaces of pseudoparenchymatous sporodochia, which develop in blisters on bark. Similar sporodochia are characteristic of Nalanthamala madreeya, the type species of Nalanthamala. Nalanthamala, therefore, is the appropriate anamorph genus for Myxosporium psidii, while Myxosporium is a nomen nudum (based on M. croceum). For M. psidii the combination Nalanthamala psidii is proposed. Nalanthamala psidii, the palm pathogen Gliocladium (Penicillium) vermoesenii, another undescribed anamorphic species from palm, two species of Rubrinectria and the persimmon pathogen Acremonium diospyri are monophyletic and belong to the Nectriaceae (Hypocreales) based on partial nuclear large subunit ribosomal DNA (LSU rDNA) analyses. Rubrinectria, therefore, is the teleomorph of Nalanthamala, in which the anamorphs are classified as N. vermoesenii, N. diospyri or Nalanthamala sp. Nalanthamala squamicola, the only other Nalanthamala species, has affinities with the Bionectriaceae and is excluded from this group. Rubrinectria/Nalanthamala species form dimorphic conidiophores and conidia in culture. Fusiform, cylindrical, or allantoid conidia arise in colorless liquid heads on acremonium-like conidiophores; ovoidal conidia with somewhat truncated ends arise in long, persistent, dry chains on penicillate conidiophores. No penicillate but irregularly branched conidiophores were observed in N. diospyri. Conidia of N. psidii that are held in chains are shorter than those of N. madreeya, of which no living material is available. Nalanthamala psidii and N. diospyri are pathogenic specifically to their hosts. They form pale yellow to pale orange or brownish orange colonies, respectively, and more or less white conidial masses. Most strains of Rubrinectria sp., Nalanthamala sp. and N. vermoesenii originate from palm hosts, form mostly greenish or olive-brown colonies and white-to-salmon conidial masses. They form a monophyletic clade to which Nalanthamala psidii and N. diospyri are related based on analyses of the internal transcribed spacer regions and 5.8S rDNA (ITS rDNA), LSU rDNA, and partial beta-tubulin gene. Few polymorphic sites in the ITS rDNA and beta-tubulin gene indicate that Nalanthamala psidii comprises two lineages, one of which has been detected only in South Africa.
    Matched MeSH terms: Plant Diseases/microbiology*
  2. Virulence, Host-Selective Toxin Production, and Development of Three Cochliobolus Phytopathogens Lacking the Sfp-Type 4'-Phosphopantetheinyl Transferase Ppt1
    Zainudin NA, Condon B, De Bruyne L, Van Poucke C, Bi Q, Li W, et al.
    Mol Plant Microbe Interact, 2015 Oct;28(10):1130-41.
    PMID: 26168137 DOI: 10.1094/MPMI-03-15-0068-R
    The Sfp-type 4'-phosphopantetheinyl transferase Ppt1 is required for activation of nonribosomal peptide synthetases, including α-aminoadipate reductase (AAR) for lysine biosynthesis and polyketide synthases, enzymes that biosynthesize peptide and polyketide secondary metabolites, respectively. Deletion of the PPT1 gene, from the maize pathogen Cochliobolus heterostrophus and the rice pathogen Cochliobolus miyabeanus, yielded strains that were significantly reduced in virulence to their hosts. In addition, ppt1 mutants of C. heterostrophus race T and Cochliobolus victoriae were unable to biosynthesize the host-selective toxins (HST) T-toxin and victorin, respectively, as judged by bioassays. Interestingly, ppt1 mutants of C. miyabeanus were shown to produce tenfold higher levels of the sesterterpene-type non-HST ophiobolin A, as compared with the wild-type strain. The ppt1 strains of all species were also reduced in tolerance to oxidative stress and iron depletion; both phenotypes are associated with inability to produce extracellular siderophores biosynthesized by the nonribosomal peptide synthetase Nps6. Colony surfaces were hydrophilic, a trait previously associated with absence of C. heterostrophus Nps4. Mutants were decreased in asexual sporulation and C. heterostrophus strains were female-sterile in sexual crosses; the latter phenotype was observed previously with mutants lacking Nps2, which produces an intracellular siderophore. As expected, mutants were albino, since they cannot produce the polyketide melanin and were auxotrophic for lysine because they lack an AAR.
    Matched MeSH terms: Plant Diseases/microbiology*
  3. Genetic variation, heritability, divergence and biomass accumulation of rice genotypes resistant to bacterial blight revealed by quantitative traits and ISSR markers
    Mazid MS, Rafii MY, Hanafi MM, Rahim HA, Latif MA
    Physiol Plant, 2013 Nov;149(3):432-47.
    PMID: 23521023 DOI: 10.1111/ppl.12054
    A field experiment was carried out in order to evaluate genetic diversity of 41 rice genotypes using physiological traits and molecular markers. All the genotypes unveiled variations for crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR), yield per hill (Yhill(-1)), total dry matter (TDM), harvest index (HI), photosynthetic rate (PR), leaf area index (LAI), chlorophyll-a and chlorophyll-b at maximum tillering stage. The CGR values varied from 0.23 to 0.76 gm cm(-2) day(-1). The Yhill(-1) ranged from 15.91 to 92.26 g, while TDM value was in the range of 7.49 to 20.45 g hill(-1). PR was found to vary from 9.40 to 22.34 µmol m(-2) s(-1). PR expressed positive relation with Yhill(-1). Significant positive relation was found between CGR and TDM (r = 0.61**), NAR and CGR (r = 0.62**) and between TDM and NAR (r = 0.31**). High heritability was found in RGR and Yhill(-1). Cluster analysis based on the traits grouped 41 rice genotypes into seven clusters. A total of 310 polymorphic loci were detected across the 20 inter-simple sequence repeats (ISSR) markers. The UPGMA dendrogram grouped 41 rice genotypes into 11 clusters including several sub-clusters. The Mantel test revealed positive correlation between quantitative traits and molecular markers (r = 0.41). On the basis of quantitative traits and molecular marker analyses parental genotypes, IRBB54 with MR84, IRBB60 with MR84, Purbachi with MR263, IRBB65 with BR29, IRBB65 with Pulut Siding and MRQ74 with Purbachi could be hybridized for future breeding program.
    Matched MeSH terms: Plant Diseases
  4. Mapping of the quantitative trait locus (QTL) conferring partial resistance to rice leaf blast disease
    Ashkani S, Rafii MY, Rahim HA, Latif MA
    Biotechnol Lett, 2013 May;35(5):799-810.
    PMID: 23315158 DOI: 10.1007/s10529-012-1130-1
    Malaysian rice, Pongsu Seribu 2, has wide-spectrum resistance against blast disease. Chromosomal locations conferring quantitative resistance were detected by linkage mapping with SSRs and quantitative trait locus (QTL) analysis. For the mapping population, 188 F3 families were derived from a cross between the susceptible cultivar, Mahsuri, and a resistant variety, Pongsu Seribu 2. Partial resistance to leaf blast in the mapping population was assessed. A linkage map covering ten chromosomes and consisting of 63 SSR markers was constructed. 13 QTLs, including 6 putative and 7 putative QTLs, were detected on chromosomes 1, 2, 3, 5, 6, 10, 11 and 12. The resulting phenotypic variation due to a single QTL ranged from 2 to 13 %. These QTLs accounted for approx. 80 % of the total phenotypic variation within the F3 population. Therefore, partial resistance to blast in Pongsu Seribu 2 is due to combined effects of multiple loci with major and minor effects.
    Matched MeSH terms: Plant Diseases
  5. Genotypic character relationship and phenotypic path coefficient analysis in chili pepper genotypes grown under tropical condition
    Usman MG, Rafii MY, Martini MY, Oladosu Y, Kashiani P
    J Sci Food Agric, 2017 Mar;97(4):1164-1171.
    PMID: 27290898 DOI: 10.1002/jsfa.7843
    BACKGROUND: Studies on genotypic and phenotypic correlations among characters of crop plants are useful in planning, evaluating and setting selection criteria for the desired characters in a breeding program. The present study aimed to estimate the phenotypic correlation coefficients among yield and yield attributed characters and to work out the direct and indirect effects of yield-related characters on yield per plant using path coefficient analysis. Twenty-six genotypes of chili pepper were laid out in a randomized complete block design with three replications.

    RESULTS: Yield per plant showed positive and highly significant (P ≤ 0.01) correlations with most of the characters studied at both the phenotypic and genotypic levels. By contrast, disease incidence and days to flowering showed a significant negative association with yield. Fruit weight and number of fruits exerted positive direct effect on yield and also had a positive and significant (P ≤ 0.01) correlation with yield per plant. However, fruit length showed a low negative direct effect with a strong and positive indirect effect through fruit weight on yield and had a positive and significant association with yield.

    CONCLUSION: Longer fruits, heavy fruits and a high number of fruits are variables that are related to higher yields of chili pepper under tropical conditions and hence could be used as a reliable indicator in indirect selection for yield. © 2016 Society of Chemical Industry.

    Matched MeSH terms: Plant Diseases
  6. Fulltext Ornamental exterior versus therapeutic interior of Madagascar periwinkle (Catharanthus roseus): the two faces of a versatile herb
    Nejat N, Valdiani A, Cahill D, Tan YH, Maziah M, Abiri R
    ScientificWorldJournal, 2015;2015:982412.
    PMID: 25667940 DOI: 10.1155/2015/982412
    Catharanthus roseus (L.) known as Madagascar periwinkle (MP) is a legendary medicinal plant mostly because of possessing two invaluable antitumor terpenoid indole alkaloids (TIAs), vincristine and vinblastine. The plant has also high aesthetic value as an evergreen ornamental that yields prolific blooms of splendid colors. The plant possesses yet another unique characteristic as an amiable experimental host for the maintenance of the smallest bacteria found on earth, the phytoplasmas and spiroplasmas, and serves as a model for their study. Botanical information with respect to synonyms, vernacular names, cultivars, floral morphology, and reproduction adds to understanding of the plant while the geography and ecology of periwinkle illustrate the organism's ubiquity. Good agronomic practices ensure generous propagation of healthy plants that serve as a source of bioactive compounds and multitudinous horticultural applications. The correlation between genetic diversity, variants, and TIA production exists. MP is afflicted with a whole range of diseases that have to be properly managed. The ethnobotanical significance of MP is exemplified by its international usage as a traditional remedy for abundant ailments and not only for cancer. TIAs are present only in micro quantities in the plant and are highly poisonous per se rendering a challenge for researchers to increase yield and reduce toxicity.
    Matched MeSH terms: Plant Diseases/statistics & numerical data*
  7. Fulltext Identification of proteins of altered abundance in oil palm infected with Ganoderma boninense
    Al-Obaidi JR, Mohd-Yusuf Y, Razali N, Jayapalan JJ, Tey CC, Md-Noh N, et al.
    Int J Mol Sci, 2014;15(3):5175-92.
    PMID: 24663087 DOI: 10.3390/ijms15035175
    Basal stem rot is a common disease that affects oil palm, causing loss of yield and finally killing the trees. The disease, caused by fungus Ganoderma boninense, devastates thousands of hectares of oil palm plantings in Southeast Asia every year. In the present study, root proteins of healthy oil palm seedlings, and those infected with G. boninense, were analyzed by 2-dimensional gel electrophoresis (2-DE). When the 2-DE profiles were analyzed for proteins, which exhibit consistent significant change of abundance upon infection with G. boninense, 21 passed our screening criteria. Subsequent analyses by mass spectrometry and database search identified caffeoyl-CoA O-methyltransferase, caffeic acid O-methyltransferase, enolase, fructokinase, cysteine synthase, malate dehydrogenase, and ATP synthase as among proteins of which abundances were markedly altered.
    Matched MeSH terms: Plant Diseases/microbiology
  8. Involvement of metabolites in early defense mechanism of oil palm (Elaeis guineensis Jacq.) against Ganoderma disease
    Nusaibah SA, Siti Nor Akmar A, Idris AS, Sariah M, Mohamad Pauzi Z
    Plant Physiol Biochem, 2016 Dec;109:156-165.
    PMID: 27694009 DOI: 10.1016/j.plaphy.2016.09.014
    Understanding the mechanism of interaction between the oil palm and its key pathogen, Ganoderma spp. is crucial as the disease caused by this fungal pathogen leads to a major loss of revenue in leading palm oil producing countries in Southeast Asia. Here in this study, we assess the morphological and biochemical changes in Ganoderma disease infected oil palm seedling roots in both resistant and susceptible progenies. Rubber woodblocks fully colonized by G. boninense were applied as a source of inoculum to artificially infect the roots of resistant and susceptible oil palm progenies. Gas chromatography-mass spectrometry was used to measure an array of plant metabolites in 100 resistant and susceptible oil palm seedling roots treated with pathogenic Ganoderma boninense fungus. Statistical effects, univariate and multivariate analyses were used to identify key-Ganoderma disease associated metabolic agitations in both resistant and susceptible oil palm root tissues. Ganoderma disease related defense shifts were characterized based on (i) increased antifungal activity in crude extracts, (ii) increased lipid levels, beta- and gamma-sitosterol particularly in the resistant progeny, (iii) detection of heterocyclic aromatic organic compounds, benzo [h] quinoline, pyridine, pyrimidine (iv) elevation in antioxidants, alpha- and beta-tocopherol (iv) degraded cortical cell wall layers, possibly resulting from fungal hydrolytic enzyme activity needed for initial penetration. The present study suggested that plant metabolites mainly lipids and heterocyclic aromatic organic metabolites could be potentially involved in early oil palm defense mechanism against G. boninense infection, which may also highlight biomarkers for disease detection, treatment, development of resistant variety and monitoring.
    Matched MeSH terms: Plant Diseases/microbiology*
  9. Morphological and molecular characterization, sexual reproduction, and pathogenicity of Setosphaeria rostrata isolates from rice leaf spot
    Kusai NA, Azmi MM, Zainudin NA, Yusof MT, Razak AA
    Mycologia, 2016 09;108(5):905-914.
    PMID: 27474518
    Setosphaeria rostrata, a common plant pathogen causing leaf spot disease, affects a wide range of plant species, mainly grasses. Fungi were isolated from brown spots on rice leaves throughout Peninsular Malaysia, and 45 isolates were identified as Setosphaeria rostrata The isolates were then characterized using morphological and molecular approaches. The mating type was determined using PCR amplification of the mating type alleles, and isolates of opposite mating types were crossed to examine sexual reproduction. Based on nuclear ribosomal DNA ITS1-5.8S-ITS2 region (ITS) and beta-tubulin (BT2) sequences, two phylogenetic trees were constructed using the maximum likelihood method; S. rostrata was clustered in one well-supported clade. Pathogenicity tests showed that S. rostrata isolates are pathogenic, suggesting that it is the cause of the symptoms. Mating-type analyses indicated that three isolates carried the MAT1-1 allele, and the other 42 isolates carried MAT1-2 After isolates with opposite mating types were crossed on Sach's medium and incubated for 3 wk, six crosses produced pseudothecia that contained eight mature ascospores, and 12 other crosses produced numerous pseudothecia with no ascospores. To our knowledge, this is the first report on S. rostrata isolated from leaf spots on rice.
    Matched MeSH terms: Plant Diseases/microbiology*
  10. Molecular characterization of Phytophthora palmivora responsible for bud rot disease of oil palm in Colombia
    Maizatul-Suriza M, Dickinson M, Idris AS
    World J Microbiol Biotechnol, 2019 Feb 27;35(3):44.
    PMID: 30810828 DOI: 10.1007/s11274-019-2618-9
    Bud rot disease is a damaging disease of oil palm in Colombia. The pathogen responsible for this disease is a species of oomyctes, Phytophthora palmivora which is also the causal pathogen of several tropical crop diseases such as fruit rot and stem canker of cocoa, rubber, durian and jackfruit. No outbreaks of bud rot have been reported in oil palm in Malaysia or other Southeast Asian countries, despite this particular species being present in the region. Analysis of the genomic sequences of several genetic markers; the internal transcribe spacer regions (ITS) of the ribosomal RNA gene cluster, beta-tubulin gene, translation elongation factor 1 alpha gene (EF-1α), cytochrome c oxidase subunit I & II (COXI and COXII) gene cluster along with amplified fragment length polymorphism (AFLP) analyses have been carried out to investigate the genetic diversity and variation of P. palmivora isolates from around the world and from different hosts in comparison to Colombian oil palm isolates, as one of the steps in understanding why this species of oomycetes causes devastating damage to oil palm in Latin America but not in other regions. Phylogenetic analyses of these regions showed that the Colombian oil palm isolates were not separated from Malaysian isolates. AFLP analysis and a new marker PPHPAV, targeting an unclassified hypothetical protein, was found to be able to differentiate Malaysian and Colombian isolates and showed a clear clade separations. Despite this, pathogenicity studies did not show any significant differences in the level of aggressiveness of different isolates against oil palm in glasshouse tests.
    Matched MeSH terms: Plant Diseases/microbiology*
  11. Diversity of microbiota associated with symptomatic and non-symptomatic bacterial wilt-diseased banana plants determined using 16S rRNA metagenome sequencing
    Suhaimi NSM, Goh SY, Ajam N, Othman RY, Chan KG, Thong KL
    World J Microbiol Biotechnol, 2017 Aug 21;33(9):168.
    PMID: 28828756 DOI: 10.1007/s11274-017-2336-0
    Banana is one of the most important fruits cultivated in Malaysia, and it provides many health benefits. However, bacterial wilt disease, which attacks bananas, inflicts major losses on the banana industry in Malaysia. To understand the complex interactions of the microbiota of bacterial wilt-diseased banana plants, we first determined the bacterial communities residing in the pseudostems of infected (symptomatic) and diseased-free (non-symptomatic) banana plants. We characterized the associated microorganisms using the targeted 16S rRNA metagenomics sequencing on the Illumina MiSeq platform. Taxonomic classifications revealed 17 and nine known bacterial phyla in the tissues of non-symptomatic and symptomatic plants, respectively. Cyanobacteria and Proteobacteria (accounted for more than 99% of the 16S rRNA gene fragments) were the two most abundant phyla in both plants. The five major genera found in both plant samples were Ralstonia, Sphingomonas, Methylobacterium, Flavobacterium, and Pseudomonas. Ralstonia was more abundant in symptomatic plant (59% out of the entire genera) as compared to those in the non-symptomatic plant (only 36%). Our data revealed that 102 bacterial genera were only assigned to the non-symptomatic plant. Overall, this study indicated that more diverse and abundant microbiota were associated with the non-symptomatic bacterial wilt-diseased banana plant as compared to the symptomatic plant. The higher diversity of endophytic microbiota in the non-symptomatic banana plant could be an indication of pathogen suppression which delayed or prevented the disease expression. This comparative study of the microbiota in the two plant conditions might provide caveats for potential biological control strategies.
    Matched MeSH terms: Plant Diseases/microbiology*
  12. An in vitro study of the antifungal activity of Trichoderma virens 7b and a profile of its non-polar antifungal components released against Ganoderma boninense
    Angel LP, Yusof MT, Ismail IS, Ping BT, Mohamed Azni IN, Kamarudin NH, et al.
    J Microbiol, 2016 Nov;54(11):732-744.
    PMID: 27796927
    Ganoderma boninense is the causal agent of a devastating disease affecting oil palm in Southeast Asian countries. Basal stem rot (BSR) disease slowly rots the base of palms, which radically reduces productive lifespan of this lucrative crop. Previous reports have indicated the successful use of Trichoderma as biological control agent (BCA) against G. boninense and isolate T. virens 7b was selected based on its initial screening. This study attempts to decipher the mechanisms responsible for the inhibition of G. boninense by identifying and characterizing the chemical compounds as well as the physical mechanisms by T. virens 7b. Hexane extract of the isolate gave 62.60% ± 6.41 inhibition against G. boninense and observation under scanning electron microscope (SEM) detected severe mycelial deformation of the pathogen at the region of inhibition. Similar mycelia deformation of G. boninense was observed with a fungicide treatment, Benlate(®) indicating comparable fungicidal effect by T. virens 7b. Fraction 4 and 5 of hexane active fractions through preparative thin layer chromatography (P-TLC) was identified giving the best inhibition of the pathogen. These fractions comprised of ketones, alcohols, aldehydes, lactones, sesquiterpenes, monoterpenes, sulphides, and free fatty acids profiled through gas chromatography mass spectrometry detector (GC/MSD). A novel antifungal compound discovery of phenylethyl alcohol (PEA) by T. virens 7b is reported through this study. T. virens 7b also proved to be an active siderophore producer through chrome azurol S (CAS) agar assay. The study demonstrated the possible mechanisms involved and responsible in the successful inhibition of G. boninense.
    Matched MeSH terms: Plant Diseases/microbiology
  13. Fulltext Growth modulation and metabolic responses of Ganoderma boninense to salicylic acid stress
    Ong CE, Ahmad R, Goh YK, Azizan KA, Baharum SN, Goh KJ
    PLoS One, 2021;16(12):e0262029.
    PMID: 34972183 DOI: 10.1371/journal.pone.0262029
    Various phenolic compounds have been screened against Ganoderma boninense, the fungal pathogen causing basal stem rot in oil palms. In this study, we focused on the effects of salicylic acid (SA) on the growth of three G. boninense isolates with different levels of aggressiveness. In addition, study on untargeted metabolite profiling was conducted to investigate the metabolomic responses of G. boninense towards salicylic acid. The inhibitory effects of salicylic acid were both concentration- (P < 0.001) and isolate-dependent (P < 0.001). Also, growth-promoting effect was observed in one of the isolates at low concentrations of salicylic acid where it could have been utilized by G. boninense as a source of carbon and energy. Besides, adaptation towards salicylic acid treatment was evident in this study for all isolates, particularly at high concentrations. In other words, inhibitory effect of salicylic acid treatment on the fungal growth declined over time. In terms of metabolomics response to salicylic acid treatment, G. boninense produced several metabolites such as coumarin and azatyrosine, which suggests that salicylic acid modulates the developmental switch in G. boninense towards the defense mode for its survival. Furthermore, the liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) analysis showed that the growth of G. boninense on potato dextrose agar involved at least four metabolic pathways: amino acid metabolism, lipid pathway, tryptophan pathway and phenylalanine pathway. Overall, there were 17 metabolites that contributed to treatment separation, each with P<0.005. The release of several antimicrobial metabolites such as eudistomin I may enhance G. boninense's competitiveness against other microorganisms during colonisation. Our findings demonstrated the metabolic versatility of G. boninense towards changes in carbon sources and stress factors. G. boninense was shown to be capable of responding to salicylic acid treatment by switching its developmental stage.
    Matched MeSH terms: Plant Diseases/microbiology
  14. Fulltext Comparative chemical screening and genetic analysis reveal tentoxin as a new virulence factor in Cochliobolus miyabeanus, the causal agent of brown spot disease on rice
    De Bruyne L, Van Poucke C, Di Mavungu DJ, Zainudin NA, Vanhaecke L, De Vleesschauwer D, et al.
    Mol Plant Pathol, 2016 Aug;17(6):805-17.
    PMID: 26456797 DOI: 10.1111/mpp.12329
    Brown spot disease, caused by Cochliobolus miyabeanus, is currently considered to be one of the most important yield reducers of rice (Oryza sativa L.). Despite its agricultural importance, little is known about the virulence mechanisms deployed by the fungus. Therefore, we set out to identify novel virulence factors with a role in disease development. This article reports, for the first time, the production of tentoxin by C. miyabeanus as a virulence factor during brown spot disease and the identification of the non-ribosomal protein synthetase (NRPS) CmNps3, responsible for tentoxin biosynthesis. We compared the chemical compounds produced by C. miyabeanus strains differing in virulence ability using ultra-high-performance liquid chromatography (UHPLC) coupled to high-resolution Orbitrap mass spectrometry (HRMS). The production of tentoxin by a highly virulent strain was revealed by principal component analysis of the detected ions and confirmed by UHPLC coupled to tandem-quadrupole mass spectrometry (MS/MS). The corresponding NRPS was identified by in silico genome analysis and confirmed by gene deletion. Infection tests with wild-type and Cmnps3 mutants showed that tentoxin acts as a virulence factor and is correlated with chlorosis development during the second phase of infection. Although rice has previously been classified as a tentoxin-insensitive plant species, our data demonstrate that tentoxin production by C. miyabeanus affects symptom development.
    Matched MeSH terms: Plant Diseases/microbiology*
  15. Sequence analysis and gene expression of putative exo- and endo-glucanases from oil palm (Elaeis guineensis) during fungal infection
    Yeoh KA, Othman A, Meon S, Abdullah F, Ho CL
    J Plant Physiol, 2012 Oct 15;169(15):1565-70.
    PMID: 22854183 DOI: 10.1016/j.jplph.2012.07.006
    Glucanases are enzymes that hydrolyze a variety β-d-glucosidic linkages. Plant β-1,3-glucanases are able to degrade fungal cell walls; and promote the release of cell-wall derived fungal elicitors. In this study, three full-length cDNA sequences encoding oil palm (Elaeis guineensis) glucanases were analyzed. Sequence analyses of the cDNA sequences suggested that EgGlc1-1 is a putative β-d-glucan exohydolase belonging to glycosyl hydrolase (GH) family 3 while EgGlc5-1 and EgGlc5-2 are putative glucan endo-1,3-β-glucosidases belonging to GH family 17. The transcript abundance of these genes in the roots and leaves of oil palm seedlings treated with Ganoderma boninense and Trichoderma harzianum was profiled to investigate the involvement of these glucanases in oil palm during fungal infection. The gene expression of EgGlc1-1 in the root of oil palm seedlings was increased by T. harzianum but suppressed by G. boninense; while the gene expression of both EgGlc5-1 and EgGlc5-2 in the roots of oil palm seedlings was suppressed by G. boninense or/and T. harzianum.
    Matched MeSH terms: Plant Diseases/immunology*
  16. Expression and the antigenicity of recombinant coat proteins of tungro viruses expressed in Escherichia coli
    Yee SF, Chu CH, Poili E, Sum MSH
    J Virol Methods, 2017 02;240:69-72.
    PMID: 27923590 DOI: 10.1016/j.jviromet.2016.12.001
    Rice tungro disease (RTD) is a recurring disease affecting rice farming especially in the South and Southeast Asia. The disease is commonly diagnosed by visual observation of the symptoms on diseased plants in paddy fields and by polymerase chain reaction (PCR). However, visual observation is unreliable and PCR can be costly. High-throughput as well as relatively cheap detection methods are important for RTD management for screening large number of samples. Due to this, detection by serological assays such as immunoblotting assays and enzyme-linked immunosorbent assay are preferred. However, these serological assays are limited by lack of continuous supply of antibodies as reagents due to the difficulty in preparing sufficient purified virions as antigens. This study aimed to generate and evaluate the reactivity of the recombinant coat proteins of Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV) as alternative antigens to generate antibodies. The genes encoding the coat proteins of both viruses, RTBV (CP), and RTSV (CP1, CP2 and CP3) were cloned and expressed as recombinant fusion proteins in Escherichia coli. All of the recombinant fusion proteins, with the exception of the recombinant fusion protein of the CP2 of RTSV, were reactive against our in-house anti-tungro rabbit serum. In conclusion, our study showed the potential use of the recombinant fusion coat proteins of the tungro viruses as alternative antigens for production of antibodies for diagnostic purposes.
    Matched MeSH terms: Plant Diseases/virology
  17. Cgl-SLT2 is required for appressorium formation, sporulation and pathogenicity in Colletotrichum gloeosporioides
    Yong HY, Bakar FD, Illias RM, Mahadi NM, Murad AM
    Braz J Microbiol, 2013 Dec;44(4):1241-50.
    PMID: 24688518
    The mitogen-activated protein (MAP) kinase pathways has been implicated in the pathogenicity of various pathogenic fungi and plays important roles in regulating pathogenicity-related morphogenesis. This work describes the isolation and characterization of MAP kinase gene, Cgl-SLT2, from Colletotrichum gloeosporioides. A DNA sequence, including 1,633 bp of Cgl-SLT2 open-reading frame and its promoter and terminator regions, was isolated via DNA walking and cloned. To analyze gene function, a gene disruption cassette containing hygromycin-resistant gene was constructed, and Cgl-SLT2 was inactivated via gene deletion. Analysis on Cgl-slt2 mutant revealed a defect in vegetative growth and sporulation as compared to the wild-type strain. When grown under nutrient-limiting conditions, hyperbranched hyphal morphology was observed in the mutant. Conidia induction for germination on rubber wax-coated hard surfaces revealed no differences in the percentage of conidial germination between the wild-type and Cgl-slt2 mutant. However, the percentage of appressorium formation in the mutant was greatly reduced. Bipolar germination in the mutant was higher than in the wild-type at 8-h post-induction. A pathogenicity assay revealed that the mutant was unable to infect either wounded or unwounded mangoes. These results suggest that the Cgl-SLT2 MAP kinase is required for C. gloeosporioides conidiation, polarized growth, appressorium formation and pathogenicity.
    Matched MeSH terms: Plant Diseases/microbiology
  18. Expression of rice thaumatin-like protein gene in transgenic banana plants enhances resistance to fusarium wilt
    Mahdavi F, Sariah M, Maziah M
    Appl Biochem Biotechnol, 2012 Feb;166(4):1008-19.
    PMID: 22183565 DOI: 10.1007/s12010-011-9489-3
    The possibility of controlling Fusarium wilt--caused by Fusarium oxysporum sp. cubensec (race 4)--was investigated by genetic engineering of banana plants for constitutive expression of rice thaumatin-like protein (tlp) gene. Transgene was introduced to cauliflower-like bodies' cluster, induced from meristemic parts of male inflorescences, using particle bombardment with plasmid carrying a rice tlp gene driving by the CaMV 35S promoter. Hygromycin B was used as the selection reagent. The presence and integration of rice tlp gene in genomic DNA confirmed by PCR and Southern blot analyses. RT-PCR revealed the expression of transgene in leaf and root tissues in transformants. Bioassay of transgenic banana plants challenged with Fusarium wilt pathogen showed that expression of TLP enhanced resistance to F. oxysporum sp. cubensec (race 4) compared to control plants.
    Matched MeSH terms: Plant Diseases/immunology; Plant Diseases/microbiology
  19. Fulltext CaWRKY30 Positively Regulates Pepper Immunity by Targeting CaWRKY40 against Ralstonia solanacearum Inoculation through Modulating Defense-Related Genes
    Hussain A, Khan MI, Albaqami M, Mahpara S, Noorka IR, Ahmed MAA, et al.
    Int J Mol Sci, 2021 Nov 08;22(21).
    PMID: 34769521 DOI: 10.3390/ijms222112091
    The WRKY transcription factors (TFs) network is composed of WRKY TFs' subset, which performs a critical role in immunity regulation of plants. However, functions of WRKY TFs' network remain unclear, particularly in non-model plants such as pepper (Capsicum annuum L.). This study functionally characterized CaWRKY30-a member of group III Pepper WRKY protein-for immunity of pepper against Ralstonia solanacearum infection. The CaWRKY30 was detected in nucleus, and its transcriptional expression levels were significantly upregulated by R. solanacearum inoculation (RSI), and foliar application ethylene (ET), abscisic acid (ABA), and salicylic acid (SA). Virus induced gene silencing (VIGS) of CaWRKY30 amplified pepper's vulnerability to RSI. Additionally, the silencing of CaWRKY30 by VIGS compromised HR-like cell death triggered by RSI and downregulated defense-associated marker genes, like CaPR1, CaNPR1, CaDEF1, CaABR1, CaHIR1, and CaWRKY40. Conversely, transient over-expression of CaWRKY30 in pepper leaves instigated HR-like cell death and upregulated defense-related maker genes. Furthermore, transient over-expression of CaWRKY30 upregulated transcriptional levels of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40. On the other hand, transient over-expression of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40 upregulated transcriptional expression levels of CaWRKY30. The results recommend that newly characterized CaWRKY30 positively regulates pepper's immunity against Ralstonia attack, which is governed by synergistically mediated signaling by phytohormones like ET, ABA, and SA, and transcriptionally assimilating into WRKY TFs networks, consisting of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40. Collectively, our data will facilitate to explicate the underlying mechanism of crosstalk between pepper's immunity and response to RSI.
    Matched MeSH terms: Plant Diseases/immunology*; Plant Diseases/microbiology
  20. Morphological and transcript changes in the biosynthesis of lignin in oil palm (Elaeis guineensis) during Ganoderma boninense infections in vitro
    Goh KM, Dickinson M, Supramaniam CV
    Physiol Plant, 2018 Mar;162(3):274-289.
    PMID: 28940509 DOI: 10.1111/ppl.12645
    Lignification of the plant cell wall could serve as the first line of defense against pathogen attack, but the molecular mechanisms of virulence and disease between oil palm and Ganoderma boninense are poorly understood. This study presents the biochemical, histochemical, enzymology and gene expression evidences of enhanced lignin biosynthesis in young oil palm as a response to G. boninense (GBLS strain). Comparative studies with control (T1), wounded (T2) and infected (T3) oil palm plantlets showed significant accumulation of total lignin content and monolignol derivatives (syringaldehyde and vanillin). These derivatives were deposited on the epidermal cell wall of infected plants. Moreover, substantial differences were detected in the activities of enzyme and relative expressions of genes encoding phenylalanine ammonia lyase (EC 4.3.1.24), cinnamate 4-hydroxylase (EC 1.14.13.11), caffeic acid O-methyltransferase (EC 2.1.1.68) and cinnamyl alcohol dehydrogenase (CAD, EC 1.1.1.195). These enzymes are key intermediates dedicated to the biosynthesis of lignin monomers, the guaicyl (G), syringyl (S) and ρ-hydroxyphenyl (H) subunits. Results confirmed an early, biphasic and transient positive induction of all gene intermediates, except for CAD enzyme activities. These differences were visualized by anatomical and metabolic changes in the profile of lignin in the oil palm plantlets such as low G lignin, indicating a potential mechanism for enhanced susceptibility toward G. boninense infection.
    Matched MeSH terms: Plant Diseases/genetics*; Plant Diseases/microbiology
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