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  1. 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 Leaves/microbiology
  2. Characterization and pathogenicity of Fusarium species associated with leaf spot of mango (Mangifera indica L.)
    Omar NH, Mohd M, Mohamed Nor NMI, Zakaria L
    Microb Pathog, 2018 Jan;114:362-368.
    PMID: 29233777 DOI: 10.1016/j.micpath.2017.12.026
    Leaf spot diseases are mainly caused by fungi including Fusarium. In the present study several species of Fusarium were isolated from the leaf spot lesion of mango (Mangifera indica L.) Based on morphological characteristics, TEF-1α sequences and phylogenetic analysis, five species were identified as F. proliferatum, F. semitectum, F. mangiferae, F. solani and F. chlamydosporum. Pathogenicity test indicated that representative isolates of F. proliferatum, F. semitectum and F. chlamydosporum were pathogenic on mango leaves causing leaf spot with low to moderate virulence. Nevertheless, abundance of spots on the leaf can disrupt photosynthesis which in turn reduced growth, and lead to susceptibility to infection by opportunistic pathogens due to weakening of the plant. Fusarium solani and F. mangiferae were non-pathogenic and it is possible that both species are saprophyte which associated with nutrient availability on the surface of the leaf through decaying leave tissues. The occurrence of Fusarium spp. on the leaf spot lesion and the effect from the disease needs to be considered when developing disease management method of mango cultivation as numerous spot on the leaves could effect the photosynthesis process and finally giving low yield and less quality of mango.
    Matched MeSH terms: Plant Leaves/microbiology
  3. Fluorescence-based immunoassay for the detection of Xanthomonas oryzae pv. oryzae in rice leaf
    Awaludin N, Abdullah J, Salam F, Ramachandran K, Yusof NA, Wasoh H
    Anal Biochem, 2020 12 01;610:113876.
    PMID: 32750357 DOI: 10.1016/j.ab.2020.113876
    The identification of rice bacterial leaf blight disease requires a simple, rapid, highly sensitive, and quantitative approach that can be applied as an early detection monitoring tool in rice health. This paper highlights the development of a turn-off fluorescence-based immunoassay for the early detection of Xanthomonas oryzae pv. oryzae (Xoo), a gram-negative bacterium that causes rice bacterial leaf blight disease. Antibodies against Xoo bacterial cells were produced as specific bio-recognition molecules and the conjugation of these antibodies with graphene quantum dots and gold nanoparticles was performed and characterized, respectively. The combination of both these bio-probes as a fluorescent donor and metal quencher led to changes in the fluorescence signal. The immunoreaction between AntiXoo-GQDs, Xoo cells, and AntiXoo-AuNPs in the immuno-aggregation complex led to the energy transfer in the turn-off fluorescence-based quenching system. The change in fluorescence intensity was proportional to the logarithm of Xoo cells in the range of 100-105 CFU mL-1. The limit of detection was achieved at 22 CFU mL-1 and the specificity test against other plant disease pathogens showed high specificity towards Xoo. The detection of Xoo in real plant samples was also performed in this study and demonstrated satisfactory results.
    Matched MeSH terms: Plant Leaves/microbiology
  4. Meroterpenes with toll-like receptor 3 regulating activity from the endophytic fungus Guignardia mangiferae
    Han WB, Dou H, Yuan WH, Gong W, Hou YY, Ng SW, et al.
    Planta Med, 2015 Jan;81(2):145-51.
    PMID: 25519918 DOI: 10.1055/s-0034-1383392
    The endophytic fungus Guignardia mangiferae isolated from Ilex cornuta leaves was shown to produce a family of meroterpenes with toll-like receptor 3 regulating activity (1-9), of which 1-3 possessed new structures. The absolute stereochemistry of 1-3 was assigned through a combination of nuclear magnetic resonance experiments, chemical derivation, CD spectra, and single-crystal X-ray diffraction analyses (CuK α ). The precursor labeled cultivation suggests that these meroterpenes are most likely assembled through terpenoid-shikimate pathways. Moreover, meroterpenes 1-3, 5-7, and 9 selectively upregulate, but 4 and 8 downregulate the toll-like receptor 3 expression in mouse dendritic cells at 10.0 µM.
    Matched MeSH terms: Plant Leaves/microbiology
  5. Fulltext Secondary Metabolites Profiling of Acinetobacter baumannii Associated with Chili (Capsicum annuum L.) Leaves and Concentration Dependent Antioxidant and Prooxidant Properties
    Monowar T, Rahman MS, Bhore SJ, Raju G, Sathasivam KV
    Biomed Res Int, 2019;2019:6951927.
    PMID: 30868071 DOI: 10.1155/2019/6951927
    Secondary bioactive compounds of endophytes are inevitable biomolecules of therapeutical importance. In the present study, secondary metabolites profiling of an endophytic bacterial strain, Acinetobacter baumannii, were explored using GC-MS study. Presence of antioxidant substances and antioxidant properties in chloroform (CHL), diethyl ether (DEE), and ethyl acetate (EA) crude extracts of the endophytic bacteria were studied. Total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and ferrous ion chelating assay were evaluated. A total of 74 compounds were identified from the GC-MS analysis of the EA extract representing mostly alkane compounds followed by phenols, carboxylic acids, aromatic heterocyclic compounds, ketones, aromatic esters, aromatic benzenes, and alkenes. Among the two phenolic compounds, namely, phenol, 2,4-bis(1,1-dimethylethyl)- and phenol, 3,5-bis(1,1-dimethylethyl)-, the former was found in abundance (11.56%) while the latter was found in smaller quantity (0.14%). Moreover, the endophytic bacteria was found to possess a number of metal ions including Fe(II) and Cu(II) as 1307.13 ± 2.35 ppb and 42.38 ± 0.352 ppb, respectively. The extracts exhibited concentration dependent antioxidant and prooxidant properties at high and low concentrations, respectively. The presence of phenolic compounds and metal ions was believed to play an important role in the antioxidant and prooxidant potentials of the extracts. Further studies are suggested for exploring the untapped resource of endophytic bacteria for the development of novel therapeutic agents.
    Matched MeSH terms: Plant Leaves/microbiology
  6. 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 Leaves/microbiology
  7. Bacterial leaf blight resistance in rice: a review of conventional breeding to molecular approach
    Chukwu SC, Rafii MY, Ramlee SI, Ismail SI, Hasan MM, Oladosu YA, et al.
    Mol Biol Rep, 2019 Feb;46(1):1519-1532.
    PMID: 30628024 DOI: 10.1007/s11033-019-04584-2
    Breeding for disease resistant varieties remains very effective and economical in controlling the bacterial leaf blight (BLB) of rice. Breeders have played a major role in developing resistant rice varieties against the BLB infection which has been adjudged to be a major disease causing significant yield reduction in rice. It would be difficult to select rice crops with multiple genes of resistance using the conventional approach alone. This is due to masking effect of genes including epistasis. In addition, conventional breeding takes a lot of time before a gene of interest can be introgressed. Linkage drag is also a major challenge in conventional approach. Molecular breeding involving markers has facilitated the characterization and introgression of BLB disease resistance genes. Biotechnology has brought another innovation in form of genetic engineering (transgenesis) of rice. Although, molecular breeding cannot be taken as a substitute for conventional breeding, molecular approach for combating BLB disease in rice is worthwhile given the demand for increased production of rice in a fast growing population of our society. This present article highlights the recent progress from conventional to molecular approach in breeding for BLB disease resistant rice varieties.
    Matched MeSH terms: Plant Leaves/microbiology*
  8. 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 Leaves/microbiology
  9. Comparative proteomic analysis of oil palm leaves infected with Ganoderma boninense revealed changes in proteins involved in photosynthesis, carbohydrate metabolism, and immunity and defense
    Jeffery Daim LD, Ooi TE, Ithnin N, Mohd Yusof H, Kulaveerasingam H, Abdul Majid N, et al.
    Electrophoresis, 2015 Aug;36(15):1699-710.
    PMID: 25930948 DOI: 10.1002/elps.201400608
    The basidiomycete fungal pathogen Ganoderma boninense is the causative agent for the incurable basal stem rot (BSR) disease in oil palm. This disease causes significant annual crop losses in the oil palm industry. Currently, there is no effective method for disease control and elimination, nor is any molecular marker for early detection of the disease available. An understanding of how BSR affects protein expression in plants may help identify and/or assist in the development of an early detection protocol. Although the mode of infection of BSR disease is primarily via the root system, defense-related genes have been shown to be expressed in both the root and leafs. Thus, to provide an insight into the changes in the global protein expression profile in infected plants, comparative 2DE was performed on leaf tissues sampled from palms with and without artificial inoculation of the Ganoderma fungus. Comparative 2DE revealed that 54 protein spots changed in abundance. A total of 51 protein spots were successfully identified by LC-QTOF MS/MS. The majority of these proteins were those involved in photosynthesis, carbohydrate metabolism as well as immunity and defense.
    Matched MeSH terms: Plant Leaves/microbiology
  10. Chitinasiproducens palmae gen. nov., sp. nov., a new member of the family Burkholderiaceae isolated from leaf tissues of oil palm (Elaeis guineensis Jacq.)
    Madhaiyan M, See-Too WS, Ee R, Saravanan VS, Wirth JS, Alex THH, et al.
    Int J Syst Evol Microbiol, 2020 Apr;70(4):2640-2647.
    PMID: 32202992 DOI: 10.1099/ijsem.0.004084
    A Gram-stain-negative, aerobic, rod-shaped, leaf-associated bacterium, designated JS23T, was isolated from surface-sterilized leaf tissue of an oil palm grown in Singapore and was investigated by polyphasic taxonomy. Phylogenetic analyses based on 16S rRNA gene sequences and 180 conserved genes in the genome of several members of Burkholderiaceae revealed that strain JS23T formed a distinct evolutionary lineage independent of other taxa within the family Burkholderiaceae. The predominant ubiquinone was Q-8. The primary polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and an unidentified aminophospholipid. The major fatty acids were C16 : 0, summed feature 3 (C16 : 1 ω7c /C16 : 1 ω6c) and summed feature 8 (C18 : 1 ω7c /C18 : 1 ω6c). The size of the genome is 5.36 Mbp with a DNA G+C content of 66.2 mol%. Genomic relatedness measurements such as average nucleotide identity, genome-to-genome distance and digital DNA-DNA hybridization clearly distinguished strain JS23T from the closely related genera Burkholderia, Caballeronia, Mycetohabitans, Mycoavidus, Pandoraea, Paraburkholderia, Robbsia and Trinickia. Furthermore, average amino acid identity values and the percentages of conserved proteins, 56.0-68.4 and 28.2-45.5, respectively, were well below threshold values for genus delineation and supported the assignment of JS23T to a novel genus. On the basis of the phylogenetic, biochemical, chemotaxonomic and phylogenomic evidence, strain JS23T is proposed to represent a novel species of a new genus within the family Burkholderiaceae, for which the name Chitinasiproducens palmae gen. nov., sp. nov., is proposed with the type strain of JS23T (= DSM 27307T=KACC 17592T).
    Matched MeSH terms: Plant Leaves/microbiology*
  11. Fingerprints of resistant Escherichia coli O157:H7 from vegetables and environmental samples
    Abakpa GO, Umoh VJ, Kamaruzaman S, Ibekwe M
    J Sci Food Agric, 2018 Jan;98(1):80-86.
    PMID: 28543177 DOI: 10.1002/jsfa.8441
    BACKGROUND: Some routes of transmission of Escherichia coli O157:H7 to fresh produce include contaminated irrigation water and manure polluted soils. The aim of the present study was to determine the genetic relationships of E. coli O157:H7 isolated from some produce growing region in Nigeria using enterobacterial repetitive intergenic consensus (ERIC) DNA fingerprinting analysis. A total of 440 samples comprising leafy greens, irrigation water, manure and soil were obtained from vegetable producing regions in Kano and Plateau States, Nigeria. Genes coding for the quinolone resistance-determinant (gyrA) and plasmid (pCT) coding for multidrug resistance (MDR) were determined using polymerase chain reaction (PCR) in 16 isolates that showed MDR.

    RESULTS: Cluster analysis of the ERIC-PCR profiles based on band sizes revealed six main clusters from the sixteen isolates analysed. The largest cluster (cluster 3) grouped isolates from vegetables and manure at a similarity coefficient of 0.72.

    CONCLUSION: The present study provides data that support the potential transmission of resistant strains of E. coli O157:H7 from vegetables and environmental sources to humans with potential public health implications, especially in developing countries. © 2017 Society of Chemical Industry.

    Matched MeSH terms: Plant Leaves/microbiology
  12. Fulltext Rare Kodamaea ohmeri keratitis following a trivial vegetative trauma
    Saud Al-Abbas AH, Ling JL, Muhammed J, Hussein A
    BMJ Case Rep, 2019 Jun 22;12(6).
    PMID: 31229985 DOI: 10.1136/bcr-2019-229660
    Kodamaea ohmeri keratitis is an opportunistic pathogen seen in patients who have undergone invasive procedures and immunocompromised state. It has been identified in septicemia patients, resulting in mortality. To the best of our knowledge, we identified the first case of K. ohmeri keratitis following an injury with vegetative material. A 57-year-old woman with underlying, poorly controlled diabetes mellitus was gardening when a tree leaf accidentally poked her in the eye. Two weeks later, the patient presented with right eye pain, redness and progressive blurring of vision due to a traumatised right cornea. Slit-lamp examination showed a small inferior paracentral corneal stromal infiltrate with overlying epithelial defect. A corneal scraping sample yielded K. ohmeri from Analytical Profile Index (API) 20C yeast identification system. She was treated with intensive topical amphotericin B and fluconazole. After 6 weeks of treatment, the keratitis resolved with faint scar tissue, and her visual acuity improved.
    Matched MeSH terms: Plant Leaves/microbiology
  13. Biofilm formation enhances Helicobacter pylori survivability in vegetables
    Ng CG, Loke MF, Goh KL, Vadivelu J, Ho B
    Food Microbiol, 2017 Apr;62:68-76.
    PMID: 27889168 DOI: 10.1016/j.fm.2016.10.010
    To date, the exact route and mode of transmission of Helicobacter pylori remains elusive. The detection of H. pylori in food using molecular approaches has led us to postulate that the gastric pathogen may survive in the extragastric environment for an extended period. In this study, we show that H. pylori prolongs its survival by forming biofilm and micro-colonies on vegetables. The biofilm forming capability of H. pylori is both strain and vegetable dependent. H. pylori strains were classified into high and low biofilm formers based on their highest relative biofilm units (BU). High biofilm formers survived longer on vegetables compared to low biofilm formers. The bacteria survived better on cabbage compared to other vegetables tested. In addition, images captured on scanning electron and confocal laser scanning microscopes revealed that the bacteria were able to form biofilm and reside as micro-colonies on vegetable surfaces, strengthening the notion of possible survival of H. pylori on vegetables for an extended period of time. Taken together, the ability of H. pylori to form biofilm on vegetables (a common food source for human) potentially plays an important role in its survival, serving as a mode of transmission of H. pylori in the extragastric environment.
    Matched MeSH terms: Plant Leaves/microbiology
  14. Bacterial communities associated with the pitcher fluids of three Nepenthes (Nepenthaceae) pitcher plant species growing in the wild
    Chou LY, Clarke CM, Dykes GA
    Arch Microbiol, 2014 Oct;196(10):709-17.
    PMID: 25005571 DOI: 10.1007/s00203-014-1011-1
    Nepenthes pitcher plants produce modified jug-shaped leaves to attract, trap and digest insect prey. We used 16S rDNA cloning and sequencing to compare bacterial communities in pitcher fluids of each of three species, namely Nepenthes ampullaria, Nepenthes gracilis and Nepenthes mirabilis, growing in the wild. In contrast to previous greenhouse-based studies, we found that both opened and unopened pitchers harbored bacterial DNA. Pitchers of N. mirabilis had higher bacterial diversity as compared to other Nepenthes species. The composition of the bacterial communities could be different between pitcher types for N. mirabilis (ANOSIM: R = 0.340, p < 0.05). Other Nepenthes species had similar bacterial composition between pitcher types. SIMPER showed that more than 50 % of the bacterial taxa identified from the open pitchers of N. mirabilis were not found in other groups. Our study suggests that bacteria in N. mirabilis are divided into native and nonnative groups.
    Matched MeSH terms: Plant Leaves/microbiology*
  15. Antimicrobial Exploration Between Counterpart Endosymbiont and Host Plant (Tamarindus indica Linn.)
    Chigurupati S, Vijayabalan S, Selvarajan KK, Aldubayan M, Alhowail A, Mani V, et al.
    Curr Pharm Biotechnol, 2020;21(5):384-389.
    PMID: 31657678 DOI: 10.2174/1389201020666191028105325
    BACKGROUND: Endophytic bacteria produce various bioactive secondary metabolites, which benefit human health. Tamarindus indica L. is well known for its medicinal value in human health care. Several studies have reported on its biological effects from various parts of T. indica, but only a few studies have been devoted to examining the biological activity of endophytes of T. indica.

    OBJECTIVES: In the present study, an endophyte was isolated from the leaves of T. indica and screened for its antimicrobial potential.

    METHODS: The selected endophyte was identified by 16s rRNA partial genome sequencing and investigated for their antimicrobial potency. The preliminary phytochemical tests were conducted for the affirmation of phytoconstituents in the endophytic crude ethyl acetate extract of T. indica (TIM) and total phenolic content was performed. The antimicrobial potential of TIM was evaluated against human pathogenic ATCC gram-positive and gram-negative bacterial strains.

    RESULTS: TIM exhibited an appreciable amount of gallic acid equivalent phenolic content (21.6 ± 0.04 mg GAE/g of crude extract). TIM showed the Minimum Inhibitory Concentration (MIC) at 250 μg/mL and Minimum Bactericidal Concentration (MBC) at 500 μg/mL among the selected human pathogenic ATCC strains. At MIC of 500 μg/mL, TIM displayed a significant zone of inhibition against P. aeruginosa and N. gonorrhoeae.

    CONCLUSION: The results from our study highlighted for the first time the antimicrobial potential of endophytic bacterial strain Bacillus velezensis in T. indica leaves and it could be further explored as a source of natural antimicrobial agents.

    Matched MeSH terms: Plant Leaves/microbiology
  16. Fulltext Residual analysis of chitosan-based agronanofungicides as a sustainable alternative in oil palm disease management
    Maluin FN, Hussein MZ, Yusof NA, Fakurazi S, Maznah Z, Idris AS, et al.
    Sci Rep, 2020 12 18;10(1):22323.
    PMID: 33339951 DOI: 10.1038/s41598-020-79335-6
    The nanoformulations of pesticides have shown great interest from many parties due to their slow release capability and site-specific delivery. Hence, in this work, a new nanoformulation of a fungicide, namely chitosan-hexaconazole nanoparticles with a mean diameter size of 18 nm was subjected to the residual analysis on oil palm tissue, leaf and palm oil (crude palm oil and crude palm kernel oil) using a quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with the gas chromatography-micro electron capture detector (GC-µECD). The chitosan-hexaconazole nanoparticles were applied using the trunk injection method at 4.5 g a.i./palm (standard single dose) and 9.0 g a.i./palm (double dose). The fungicide residue was analyzed at 0 (6 h after application), 1, 3, 7, 14, 30, 60, 90, and 120 days after treatment. The palm oil matrices; the crude palm oil (CPO) and crude palm kernel oil (CPKO) were found to be residue-free. However, it was observed that high accumulation of the fungicide in the stem tissue and leaf after the treatment using the chitosan-hexaconazole nanoparticles, which is good for better bioavailability for the treatment of the fungi, Ganoderma boninense. The dissipation kinetic at double dose treatment in the tissue and leaf was found to govern by the second-order kinetic with half-lives (t1/2) of 383 and 515 days, respectively.
    Matched MeSH terms: Plant Leaves/microbiology
  17. Fulltext Bacteria as a source of oviposition attractant for Aedes aegypti mosquitoes
    Arbaoui AA, Chua TH
    Trop Biomed, 2014 Mar;31(1):134-42.
    PMID: 24862053 MyJurnal
    Since a safe and effective mass vaccination program against dengue fever is not presently available, a good way to prevent and control dengue outbreaks depends mainly on controlling the mosquito vectors. Aedes aegypti mosquito populations can be monitored and reduced by using ovitraps baited with organic infusions. A series of laboratory experiments were conducted which demonstrated that the bacteria in bamboo leaf infusion produce volatile attractants and contact chemical stimulants attractive to the female mosquitoes. The results showed that the female mosquitoes laid most of their eggs (59.9 ± 8.1 vs 2.9 ± 2.8 eggs, P<0.001) in bamboo leaf infusions when compared to distilled water. When the fresh infusion was filtered with a 0.45 μm filter membrane, the female mosquitoes laid significantly more eggs (64.1 ± 6.6 vs 4.9 ± 2.6 eggs, P<0.001) in unfiltered infusion. However when a 0.8 μm filter membrane was used, the female laid significantly more eggs (62.0 ± 4.3 vs 10.1 ± 7.8 eggs, P<0.001) in filtrate compared to a solution containing the residue. We also found that a mixture of bacteria isolated from bamboo leaf infusion serve as potent oviposition stimulants for gravid Aedes mosquitoes. Aedes aegypti laid significantly more eggs (63.3 ± 6.5 vs 3.1 ± 2.4 eggs, P<0.001) in bacteria suspension compared to sterile R2A medium. Our results suggest microbial activity has a role in the production of odorants that mediate the oviposition response of gravid mosquitoes.
    Matched MeSH terms: Plant Leaves/microbiology
  18. Differential expression of oil palm pathology genes during interactions with Ganoderma boninense and Trichoderma harzianum
    Alizadeh F, Abdullah SN, Khodavandi A, Abdullah F, Yusuf UK, Chong PP
    J Plant Physiol, 2011 Jul 01;168(10):1106-13.
    PMID: 21333381 DOI: 10.1016/j.jplph.2010.12.007
    The expression profiles of Δ9 stearoyl-acyl carrier protein desaturase (SAD1 and SAD2) and type 3 metallothionein (MT3-A and MT3-B) were investigated in seedlings of oil palm (Elaeis guineensis) artificially inoculated with the pathogenic fungus Ganoderma boninense and the symbiotic fungus Trichoderma harzianum. Expression of SAD1 and MT3-A in roots and SAD2 in leaves were significantly up-regulated in G. boninense inoculated seedlings at 21 d after treatment when physical symptoms had not yet appeared and thereafter decreased to basal levels when symptoms became visible. Our finding demonstrated that the SAD1 expression in leaves was significantly down-regulated to negligible levels at 42 and 63 d after treatment. The transcripts of MT3 genes were synthesized in G. boninense inoculated leaves at 42 d after treatment, and the analyses did not show detectable expression of these genes before 42 d after treatment. In T. harzianum inoculated seedlings, the expression levels of SAD1 and SAD2 increased gradually and were stronger in roots than leaves, while for MT3-A and MT3-B, the expression levels were induced in leaves at 3d after treatment and subsequently maintained at same levels until 63d after treatment. The MT3-A expression was significantly up-regulated in roots at 3d after treatment and thereafter were maintained at this level. Both SAD and MT3 expression were maintained at maximum levels or at levels higher than basal. This study demonstrates that oil palm was able to distinguish between pathogenic and symbiotic fungal interactions, thus resulting in different transcriptional activation profiles of SAD and MT3 genes. Increases in expression levels of SAD and MT3 would lead to enhanced resistance against G. boninense and down-regulation of genes confer potential for invasive growth of the pathogen. Differences in expression profiles of SAD and MT3 relate to plant resistance mechanisms while supporting growth enhancing effects of symbiotic T. harzianum.
    Matched MeSH terms: Plant Leaves/microbiology
  19. Fulltext Quorum sensing activity of Enterobacter asburiae isolated from lettuce leaves
    Lau YY, Sulaiman J, Chen JW, Yin WF, Chan KG
    Sensors (Basel), 2013 Oct 22;13(10):14189-99.
    PMID: 24152877 DOI: 10.3390/s131014189
    Bacterial communication or quorum sensing (QS) is achieved via sensing of QS signaling molecules consisting of oligopeptides in Gram-positive bacteria and N-acyl homoserine lactones (AHL) in most Gram-negative bacteria. In this study, Enterobacteriaceae isolates from Batavia lettuce were screened for AHL production. Enterobacter asburiae, identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was found to produce short chain AHLs. High resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS) analysis of the E. asburiae spent supernatant confirmed the production of N-butanoyl homoserine lactone (C4-HSL) and N-hexanoyl homoserine lactone (C6-HSL). To the best of our knowledge, this is the first report of AHL production by E. asburiae.
    Matched MeSH terms: Plant Leaves/microbiology*
  20. Fulltext Cloning and characterization of short-chain N-acyl homoserine lactone-producing Enterobacter asburiae strain L1 from lettuce leaves
    Lau YY, How KY, Yin WF, Chan KG
    Microbiologyopen, 2018 Dec;7(6):e00610.
    PMID: 29982994 DOI: 10.1002/mbo3.610
    In gram-negative bacteria, bacterial communication or quorum sensing (QS) is achieved using common signaling molecules known as N-acyl homoserine lactones (AHL). We have previously reported the genome of AHL-producing bacterium, Enterobacter asburiae strain L1. In silico analysis of the strain L1 genome revealed the presence of a pair of luxI/R genes responsible for AHL-type QS, designated as easIR. In this work, the 639 bp luxI homolog, encoding 212 amino acids, have been cloned and overexpressed in Escherichia coli BL21 (DE3)pLysS. The purified protein (~25 kDa) shares high similarity to several members of the LuxI family among different E asburiae strains. Our findings showed that the heterologously expressed EasI protein has activated violacein production by AHL biosensor Chromobacterium violaceum CV026 as the wild-type E. asburiae. The mass spectrometry analysis showed the production of N-butanoyl homoserine lactone and N-hexanoyl homoserine lactone from induced E. coli harboring the recombinant EasI, suggesting that EasI is a functional AHL synthase. E. asburiae strain L1 was also shown to possess biofilm-forming characteristic activity using crystal violet binding assay. This is the first report on cloning and characterization of the luxI homolog from E. asburiae.
    Matched MeSH terms: Plant Leaves/microbiology
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