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Oryzae
Kinds of Oryzae Terms modified by Oryzae Selected AbstractsInheritance of resistance against biotype 2 of the Asian rice gall midge, Orseolia oryzaeENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2000J. Pani Abstract The inheritance of resistance in the rice cultivars Phalguna, ARC5984, ARC 5158, Veluthacheera, and T1477 to the Asian rice gall midge biotype 2 was studied under both natural and artificial infestation conditions against the susceptible cultivars Jaya and IR20. A single recessive gene in Veluthacheera and two recessive complementary genes in T1477 control resistance. Phalguna and ARC5984 possess a single dominant gene while ARC5158 has a single dominant and a single recessive gene for resistance. Allelism studies showed that genes for resistance in Veluthacheera and T1477 are allelic but non-allelic to the resistance genes in Phalguna and ARC5984, which are allelic to each other. Genes for resistance in ARC5158 are allelic to resistance genes of the other four donors. There was no cytoplasmic inhibition of resistance by the susceptible parents. [source] Molecular characterization and antifungal activity of a family 46 chitosanase from Amycolatopsis sp.FEMS MICROBIOLOGY LETTERS, Issue 1 2009CsO- Abstract An actinomycete strain, Amycolatopsis sp. CsO-2, produces a 27-kDa chitosanase. To reveal the molecular characteristics of the enzyme, its corresponding gene ctoA was cloned by a reverse genetic technique, based on the N-terminal amino acid sequence of the protein. The encoded CtoA protein was deduced to be composed of 286 amino acids, including a putative signal peptide (1,48), and exhibited 83% identity in the amino acid sequence with the family 46 chitosanases from Streptomyces sp. N174 or Nocardioides sp. N106. The active recombinant CtoA protein was successfully overproduced in Escherichia coli. The mutant protein E22Q, in which the glutamic acid residue 22 was replaced with glutamine, abolished the chitosanase activity, showing that the Glu22 residue is required for the enzymatic activity. CtoA exhibited antifungal activity against Rhizopus oryzae, which is known to produce chitosan probably as a cell wall component. In contrast, E22Q did not inhibit the growth of the fungus, suggesting that chitosan-hydrolyzing activity is essential for the antifungal activity. It is noteworthy that the antifungal effect of CtoA against R. oryzae was drastically enhanced by the simultaneous addition of the family 19 chitinase ChiC from Streptomyces griseus. [source] Development of a novel quadruple auxotrophic host transformation system by argB gene disruption using adeA gene and exploiting adenine auxotrophy in Aspergillus oryzaeFEMS MICROBIOLOGY LETTERS, Issue 1 2004Feng Jie Jin Abstract We previously designed a triple auxotrophic host-vector system in Aspergillus oryzae by isolating red-colored adenine auxotrophic mutants upon UV mutagenesis of a double auxotrophic host (niaD,sC,). In the present study an effort to exploit this system and construct a novel quadruple auxotrophic host was made by disrupting the argB gene involved in arginine biosynthesis. The argB gene-disruption cassette was generated by fusion PCR, which required only two steps of PCR to insert the selectable marker, adeA, into the target argB gene. The chimeric DNA fragment was transformed into the triple auxotrophic strain (niaD,sC,adeA,) and the argB disruptants were obtained with a high rate of efficiency (approximately 40%). The argB disruptants were characterized by normal colony color and reversal of arginine auxotrophy by introduction of the wild-type argB gene. Quadruple auxotrophic strains (niaD,sC,,argB adeA, or niaD,sC,,argB adeB,) were subsequently isolated upon UV mutagenesis of the triple auxotrophic strain (niaD,sC,,argB) followed by screening of red-colored colonies for adenine auxotrophy. The results obtained showed that the adeA gene served as an efficient selection marker in developing a novel host-vector system with quadruple auxotrophy in A. oryzae, thus providing a powerful tool to breed multiple auxotrophic mutants from a deuteromycete wherein sexual crossing is impossible. [source] Cloning and sequence analysis of cnaA gene encoding the catalytic subunit of calcineurin from Aspergillus oryzaeFEMS MICROBIOLOGY LETTERS, Issue 1 2001Praveen Rao Juvvadi Abstract Calcineurin has been implicated in ion-homeostasis, stress adaptation in yeast and for hyphal growth in filamentous fungi. Genomic DNA and cDNA encoding the catalytic subunit of calcineurin (cnaA) were isolated from Aspergillus oryzae. The cnaA open reading frame extended to 1727 bp and encoded a putative protein of 514 amino acids. Comparative analysis of the nucleotide sequence of cnaA genomic DNA and cDNA confirmed the presence of three introns and a highly conserved calmodulin binding domain. The deduced amino acid sequence was homologous to calcineurin A from Aspergillus nidulans (92%), Neurospora crassa (84%), human (67%), Saccharomyces cerevisiae (58%) and Schizosaccharomyces pombe (54%). Further, A. oryzae cnaA cDNA complemented S. cerevisiae calcineurin disruptant strain (,cmp1,cmp2), which was not viable in the presence of high concentrations of NaCl (1.2 M) and at alkaline pH 8.5. [source] Aspergillus oryzae in solid-state and submerged fermentationsFEMS YEAST RESEARCH, Issue 2 2002Progress report on a multi-disciplinary project Abstract We report the progress of a multi-disciplinary research project on solid-state fermentation (SSF) of the filamentous fungus Aspergillus oryzae. The molecular and physiological aspects of the fungus in submerged fermentation (SmF) and SSF are compared and we observe a number of differences correlated with the different growth conditions. First, the aerial hyphae which occur only in SSFs are mainly responsible for oxygen uptake. Second, SSF is characterised by gradients in temperature, water activity and nutrient concentration, and inside the hyphae different polyols are accumulating. Third, pelleted growth in SmF and mycelial growth in SSF show different gene expression and protein secretion patterns. With this approach we aim to expand our knowledge of mechanisms of fungal growth on solid substrates and to exploit the biotechnological applications. [source] Fumigant toxicity of Korean medicinal plant essential oils and components from Asiasarum sieboldi root against Sitophilus oryzae L.FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2008Junheon Kim Abstract Medicinal plant essential oils and components from Asiasarum sieboldi were tested for their insecticidal activities against the rice weevil Sitophilus oryzae, using a fumigation bioassay. Responses varied with plant material and concentration. The LC50 value of A. sieboldi essential oil against rice weevil was 2.37 µg/ml air. Analysis by gas chromatography,mass spectrometry led to the identification of 20 compounds from A. sieboldi essential oil. Among identified compounds, five main compounds were tested for their insecticidal activity against rice weevil and compared to the toxicity of dichlorvos. Responses varied with compound and dose. Eucarvone was the most toxic, followed by safrole, with LC50 values of 3.32 and 11.27 µg/ml, respectively. LC50 values of other compounds were >25 µg/ml. The LC50 value of dichlorvos was 0.0081 µg/ml. Copyright © 2008 John Wiley & Sons, Ltd. [source] Promiscuous Acylases-Catalyzed Markovnikov Addition of N-Heterocycles to Vinyl Esters in Organic MediaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4-5 2006Wei-Bo Wu Abstract Three acylases, including D -aminoacylase from Escherichia coli, acylase "Amano" from Aspergillus oryzae and immobilized penicillin G acylase from Escherichia coli have been found to possess novel activity to catalyze the Markovnikov addition reaction of N-heterocycles to vinyl esters. The aza-Markovnikov addition reactions of 4-nitroimidazle to vinyl acetate catalyzed by D -aminoacylase, acylase "Amano" and immobilized penicillin G acylase were up to 1260-fold, 720-fold and 320-fold faster than the respective non-enzymatic reaction. Some control experiments have been designed to demonstrate the catalytic specificity of acylases. Under the catalysis of these promiscuous acylases, a number of N-heterocycles, including some pentacyclic N-heterocycles, pyrimidines and purines, were successfully added to a series of vinyl esters in moderate to excellent yields to prepare N-heterocycle derivatives. The acylase-catalyzed Markovnikov addition reaction has provided a new strategy to perform the Markovnikov addition and expanded the application of biocatalysts. [source] Combined Application of Galactose Oxidase and ,- N -Acetylhexosaminidase in the Synthesis of Complex Immunoactive N -Acetyl- D -galactosaminidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2005Pavla Fialovį Abstract A high-yield preparatory procedure for the synthesis of p -nitrophenyl 2-acetamido-2-deoxy-,- D - galacto -hexodialdo-1,5-pyranoside (2) using the galactose oxidase from Dactylium dendroides in a batch reactor was developed. Enzymatic recognition of this aldehyde and the respective uronic acid 3 obtained by NaClO2 oxidation was studied using a set of 36 fungal ,- N -acetylhexosaminidases from Acremonium, Aspergillus, Penicillium and Talaromyces genera. The aldehyde 2 was readily hydrolysed by all tested ,- N -acetylhexosaminidases but neither the uronic acid 3 nor its methyl ester 4 were accepted. Molecular modelling with docking into the active centre of the ,- N -acetylhexosaminidase from Aspergillus oryzae revealed that the aldehyde 2 is processed as a C-6 geminal diol by the enzyme. The aldehyde 2 was tested for transglycosylation reactions using GlcNAc as an acceptor. The ,- N -acetylhexosaminidase from Talaromyces flavus gave the best yields (37%) of the transglycosylation product 2-acetamido-2-deoxy-,- D - galacto -hexodialdo-1,5-pyranosyl-(1,4)-2-acetamido- 2-deoxy- D -glucopyranose, which was oxidised in situ to yield the final product 2-acetamido-2-deoxy-,- D -galactopyranosyluronic acid-(1,4)-2-acetamido-2-deoxy- D -glucopyranose (6). Compounds 3 and 6 were shown to be high-affinity ligands for two natural killer cell activation receptors, NKR-P1A and CD69. For the latter receptor they turned out to be among the best ligands described so far. This increase was obviously due to the presence of a carboxy moiety. [source] Lipase-mediated methanolysis of soybean oils for biodiesel productionJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2008Xin Chen Abstract BACKGROUND: Biodiesel is increasingly perceived as an important component of solutions to the important current issues of fossil fuel shortages and environmental pollution. Biocatalysis of soybean oils using soluble lipase offers an alternative approach to lipase-catalyzed biodiesel production using immobilized enzyme or whole-cell catalysis. The central composite design (CCD) of response surface methodology (RSM) was used here to evaluate the effects of enzyme concentration, temperature, molar ratio of methanol to oil and stirring rate on the yield of fatty methyl ester. RESULTS: Lipase NS81006 from a genetically modified Aspergillus oryzae was utilized as the catalyst for the transesterification of soybean oil for biodiesel production. The experimental data showed that enzyme concentration, molar ratio of methanol to oil and stirring rate had the most significant impact on the yield of fatty methyl ester; a quadratic polynomial equation was obtained for methyl ester yield by multiple regression analysis. The predicted biodiesel yield was 0.928 (w/w) under the optimal conditions and the subsequent verification experiments with biodiesel yield of 0.936 ± 0.014 (w/w) confirmed the validity of the predicted model. CONCLUSION: RSM and CCD were suitable techniques to optimize the transesterification of soybean oil for biodiesel production by soluble lipase NS81006. The related lipase NS81006 reuse stability, chemical or genetic modification, and transesterification mechanism should be taken into consideration. Copyright © 2007 Society of Chemical Industry [source] Production of L -methionine by immobilized pellets of Aspergillus oryzae in a packed bed reactorJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2002Ying-Jin Yuan Abstract Production of L -methionine by immobilized pellets of Aspergillus oryzae in a packed bed reactor was investigated. Based on the determination of relative enzymatic activity in the immobilized pellets, the optimum pH and temperature for the resolution reaction were 8.0 and 60,°C, respectively. The effects of substrate concentration on the resolution reaction were also investigated and the kinetic constants (Km and Vm) of immobilized pellets were found to be 7.99,mmol,dm,3 and 1.38,mmol,dm,3 h,1, respectively. The maximum substrate concentration for the resolution reaction without inhibition was 0.2,mol,dm,3. The L -methionine conversion rate reached 94% and 78% when substrate concentrations were 0.2 and 0.4,mol,dm,3, respectively, at a flow rate of 7.5,cm3,h,1 using the small-scale packed bed reactor developed. The half-life of the L -aminoacylase in immobilized pellets was 70 days in continuous operation. All the results obtained in this paper exhibit a practical potential of using immobilized pellets of Aspergillus oryzae in the production of L -methionine. © 2002 Society of Chemical Industry [source] Effect of Combining Proteolysis and Lactic Acid Bacterial Fermentation on the Characteristics of Minced MackerelJOURNAL OF FOOD SCIENCE, Issue 3 2005Li-Jung Yin ABSTRACT: To improve the quality of fish muscle, mackerel muscle protein was hydrolyzed by proteases from Aspergillus oryzae, and then fermented by lactic acid bacteria (LAB). The highest protease activities were obtained from A. oryzae after 72 h incubation at 25°C. Acidic protease activity was much higher than neutral and alkaline proteases. SDS-PAGE indicated the degradation of muscle proteins after 1 or 2 h hydrolysis by A. oryzae proteases at 50°C. During 48 h fermentation by Pediococcus pentosaceus L and S at 37°C, rapid growth of LAB, decline in pH, and suppression in the growth of microflora, Enterobacteriaceae, Staphylococcus, and Pseudomonas, occurred while increases in whiteness, nonprotein nitrogen, sensory quality, and free amino acids were observed. These data suggested that the acceptability of LAB -fermented mackerel hydrolysates could be substantially improved. [source] Insect growth-reducing and antifeedant activity in Eastern North America hardwood species and bioassay-guided isolation of active principles from Prunus serotinaAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2000S. Omar Abstract 1 Thirty extracts of wood and bark of hardwood trees from Eastern North America were examined for insect growth-reducing activity in a bioassay with European corn borer, Ostrinia nubilalis, and an antifeedant bioassay with the rice weevil, Sitophilus oryzae. 2 Nine of the bark extracts and four of the wood extracts showed significant growth reducing effects at 0.5% in meridic diets, whereas only two bark extracts and one wood extract showed significant antifeedant effect at the same concentration. 3 Slower growing tree species were more biologically active than fast growing ones. Isolation of the bioactive compounds in one of the active species, Prunus serotina, showed that naringenin, its derivative methoxynaringenin, and eriodictyol were responsible for the antifeedant effects. [source] A new regioselective synthesis and bioactivity of 1H -pyrazolo[3,4- d]pyrimidin-4(5H)-one derivativesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 3 2004Hong-Qing Wang A series of new 1H -pyrazolo[3,4- d]pyrimidin-4(5H)-one Derivatives 5 has been designed and regio-selectively synthesized via a tandem aza-Wittig reaction. The structures of all compounds prepared have been confirmed by 1H NMR, IR, EI-MS spectroscopy and elemental analyses. The results of preliminary bioassay indicate that most compounds 5 possess an inhibition effect against Botrytis cinereapers and Pyricularia oryzae at the concentration of 50 mg/L. [source] Status of Streptomycin Resistance Development in Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola in China and their Resistance CharactersJOURNAL OF PHYTOPATHOLOGY, Issue 9 2010Ying Xu Abstract Rice leaves with bacterial blight or bacterial leaf streak symptoms were collected in southern China in 2007 and 2008. Five hundred and thirty-four single-colony isolates of Xanthomonas oryzae pv. oryzae and 827 single-colony isolates of Xanthomonas oryzae pv. oryzicola were obtained and tested on plates for sensitivity to streptomycin. Four strains (0.75%) of X. oryzae pv. oryzae isolated from the same county of Province Yunnan were resistant to streptomycin, and the resistance factor (the ratio of the mean median effective concentration inhibiting growth of resistant isolates to that of sensitive isolates) was approximately 226. The resistant isolate also showed streptomycin resistance in vivo. In addition to resistant isolates, isolates of less sensitivity were also present in the population of X. oryzae pv. oryzae from Province Yunnan. However, no isolates with decreased streptomycin-sensitivity were obtained from the population of X. oryzae pv. oryzicola. Mutations in the rpsL (encoding S12 protein) and rrs genes (encoding 16S rRNA) and the presence of the strA gene accounting for streptomycin resistance in other phytopathogens or animal and human pathogenic bacteria were examined on sensitive and resistant strains of X. oryzae pv. oryzae by polymerase chain reaction amplification and sequencing. Neither the presence of the strA gene nor mutations in the rpsL or rrs were found, suggesting that different resistance mechanisms are involved in the resistant isolates of X. oryzae pv. oryzae. [source] Accumulation of Defence Response-related and Unique Expressed Sequence Tags during the Incompatible Interaction in the Oryza sativa,Magnaporthe oryzae PathosystemJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2009Rekha Dixit Abstract Resistance gene-dependent accumulation of expressed sequence tags (ESTs) was studied in a blast resistant, Oryza sativa ssp. indica cv. Tetep after challenge inoculation with an incompatible race of Magnaporthe oryzae. The nucleotide sequence of 287 randomly selected cDNA clones from the rice cDNA library constructed from the RNA isolated after challenge inoculation of the host was obtained and submitted in NCBI Genbank (Accession Nos. DN475717,DN475431). Of these, 184 (63%) ESTs were highly representative of the rice transcriptomes. A set of 178 unique transcripts was identified after assembly of 287 ESTs into unigenes. These unigenes were categorized into 17 functional groups. Analysis of this EST library illustrated a broad functional representation. Twenty-one unigenes were identified as putative homologues of the genes that were up regulated during host,pathogen interaction. Similarity search of 178 unigenes with NCBI database of 14 plants unigenes showed similarity ranging from 29,100%. The unigenes obtained in this study were physically located on the pseudomolecules of rice genome. This information can be used for determining the arrays of genes being expressed during Oryza sativa,M. oryzae interactions, which will be helpful in understanding the molecular basis of disease resistance. [source] Analysis of Pathotypic and Genotypic Diversity of Xanthomonas oryzae pv. oryzae in ChinaJOURNAL OF PHYTOPATHOLOGY, Issue 4 2009Gang Li Abstract Virulence analysis and restriction fragment length polymorphism (RFLP) were used to evaluated the population structure of Xanthomonas oryzae pv. oryzae (Xoo) from the main rice-growing region in China. The pathotype of Xoo was determined for 103 strains by inoculating 13 near-isogenic rice lines using IR24 as the recurrent parent. Sixty-one pathotypes was shared by these strains, on the basis of the consensus of three clustering statistics, and four clusters for pathotype were formed. Cluster 2 consists of strains with high molecular polymorphorism and many pathotypes that are either virulent to a majority of the 13 major resistance (R) genes or avirulent only to Xa21, and is geographically dispersed. The resistance gene Xa21 has broader resistance than others to the strains tested. A probe from a member of the avrBs3/pthA type III effector family, 1376 bp SphI-digested fragment, was used to screen the genomes of 52 strains tested. Four common bands were found in the DNA fingerprint pattern of Xoo, suggesting basic patterns of evolutionary relationship for members of avrBs3/pthA family and/or the pathogen. Each distinct RFLP banding pattern of each strain was considered as a haplotype; 42 haplotypes were revealed by the probe and divided into four lineages by the same statistics method. It was observed that some isolates with different pathotypes shared the same haplotype and others with different haplotypes harboured identical pathotype. There was a weak correlation between virulent pathotypes and molecular haplotypes. [source] Increased Susceptibility of Rice Following Insertion of Amylopullulanase Gene, to Brown Spot Caused by Bipolaris oryzaeJOURNAL OF PHYTOPATHOLOGY, Issue 9 2008M.-Y. Ting Abstract Transgenic rice expressing an amylopullulanase (APU) from the bacterium Thermoanaerobacter ethanolicus 39E produces grains which are less expensive to process for production of sugar syrup and protein-enriched flour. During risk assessment of the transgenic line in a field test, brown spot disease caused by Bipolaris oryzae was found more severe on the transgenic line APU than on its parental line TNG67. When lines APU and TNG67 were inoculated at seedling, tillering or heading stage with B. oryzae isolated from line TNG67, the disease was more severe on line APU than on line TNG67 at heading stage, but not at the seedling or tillering stage. However, when B. oryzae isolated from line APU was used in the inoculation tests, the disease was more severe on line APU than on line TNG67 at seedling stage, but not at the tillering or heading stage. To our knowledge, this is the first report of an unintended change in a transgenic plant to become more susceptible to a disease than the non-transgenic plant. [source] A Comparison of Three Experimental Designs for the Field Assessment of Resistance to Rice Blast Disease (Pyricularia oryzae)JOURNAL OF PHYTOPATHOLOGY, Issue 4 2007D. Katsantonis Abstract The reliability and the effectiveness of three field experimental designs for the assessment of varietal resistance to Pyricularia oryzae was studied for 2 years. Plants were arranged in the field using two sets of three designs: randomized compete block (RCB), adjacent control (AC) and honeycomb (HC). In the first set, plants were inoculated with the fungus and in the second one, plants were naturally infected. Four varieties were used, Maratelli (susceptible control), Roxani, Selenio and Senia (main varieties). Disease progress was recorded as leaf and neck blast. The number of plants of the main varieties required in each design was higher for RCB (90) and lower for AC and HC (30 and 32, respectively). Results showed that disease severity was significantly different in the varieties studied and it was consistent and not affected by the plant arrangement in the field. All experimental designs were reliable and effective for the assessment of leaf and neck blast under inoculation or natural infection. AC and HC designs had the advantage of requiring fewer plants over RCB one. This could be important in cases where seed availability is a limiting factor. [source] Influence of amylases on the rheological and molecular properties of partially damaged wheat starchJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2006Pedro Leman Abstract The effects of Bacillus subtilis, porcine pancreatic and Aspergillus oryzae ,-amylases, sweet potato ,-amylase and Bacillus stearothermophilus maltogenic amylase (BStA) on the rheological properties (measured with a Rapid Visco Analyser) of partially damaged wheat starch were studied and the accompanying changes in starch molecular properties were analysed by high-performance size exclusion chromatography. Pasting and gelation of starch slurries (with an increased level of damaged starch) were significantly affected by the supplemented amylases and greatly depended on the mode of action and properties of the enzymes added. In general, at low endo-amylase concentrations, peak, hot paste and cold paste viscosities were more reduced for enzyme-supplemented partially damaged starch than for enzyme-supplemented native wheat starch, demonstrating the significance of damaged starch levels in determining amylase functionality. Higher dosages of thermostable amylases ruled out most of the differences between amylase-supplemented native starch and partially damaged starches, except for BStA. Furthermore, the (limited) endo-action of BStA determines to a great extent the rheological properties of the starch paste. These results contribute to a better understanding of (maltogenic) amylase functionality in processing (damaged) starch-containing foods. Copyright © 2006 Society of Chemical Industry [source] l -leucine aminopeptidase production by filamentous Aspergillus fungiLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2005K.M. Nampoothiri Abstract Aims:, To screen various filamentous fungi belonging to Aspergillus spp. producing leucine and methionine aminopeptidases. Methods and Results:, Twenty-eight Aspergillus strains representing 14 species within the genus were screened for l -leucine aminopeptidase (LAP) production in two media in shake flask fermentation. Two Aspergillus sojae (NRRL 1988 and NRRL 6271) and one Aspergillus oryzae (NRRL 6270) strains were selected as the best producers for further studies. The peak LAP activities were 2·61, 2·59 and 1·30 IU ml,1 for the three fungi on days 2, 5 and 4 respectively. In addition to LAP, l -methionine aminopeptidase (MAP) activity was also detected. Apart from submerged fermentation, the highest LAP yields by solid-state fermentation were 11·39, 17·40 and 13·02 IU g,1 dry matter for the above fungi. The temperature and pH optimum of the enzyme was found to be in the range of 65,75°C at pH 8·0,9·0 for all three fungi. Metal ions, Co2+ and Fe2+ in 2 mmol l,1 concentration apparently enhanced the relative enzyme activity and heat stability. Conclusions:, Two A. sojae (NRRL 1988 and NRRL 6271) and one A. oryzae (NRRL 6270) strains were found to be the best producers of LAP and MAP. The preliminary characterization studies revealed that the enzyme is considerably thermostable and belongs to the class metalloenzymes. Significance and Impact of the Study:, A good number of aspergilli were screened and the ability of the fungal aminopeptidase to release a particular N-terminal amino acid along with its high thermal stability, makes them interesting for controlling the degree of hydrolysis and flavour development for a wide range of substrate. [source] Transcription activator-like type III effector AvrXa27 depends on OsTFIIA,5 for the activation of Xa27 transcription in rice that triggers disease resistance to Xanthomonas oryzae pv. oryzaeMOLECULAR PLANT PATHOLOGY, Issue 6 2009KEYU GU SUMMARY The transcription activator-like (TAL) type III effector AvrXa27 from Xanthomonas oryzae pv. oryzae (Xoo) strain PXO99A activates the transcription of the host resistance gene Xa27, which results in disease resistance to bacterial blight (BB) in rice. In this study, we show that AvrXa27-activated Xa27 transcription requires host general transcription factor OsTFIIA,5. The V39E substitution in OsTFIIA,5, encoded by the recessive resistance gene xa5 in rice, greatly attenuates this activation in xa5 and Xa27 double homozygotes on inoculation with Xa27 -incompatible strains. The xa5 gene also causes attenuation in the induction of Xa27 by AvrXa27 expressed in rice. The xa5 -mediated attenuation of Xa27 -mediated resistance to PXO99A is recessive. Intriguingly, xa5 -mediated resistance to xa5 -incompatible strains is also down-regulated in the xa5 and Xa27 double homozygotes. In addition, AvrXa27 expressed in planta shows weak virulence activity in the xa5 genetic background and causes enhanced susceptibility of the plants to BB inoculation. The results suggest that TAL effectors target host general transcription factors to directly manipulate the host transcriptional machinery for virulence and/or avirulence. The identification of xa5 -mediated attenuation of Xa27 -mediated resistance to Xoo provides a guideline for breeding resistance to BB when pyramiding xa5 with other resistance genes. [source] Phospholipase C-mediated calcium signalling is required for fungal development and pathogenicity in Magnaporthe oryzaeMOLECULAR PLANT PATHOLOGY, Issue 3 2009HEE-SOOL RHO SUMMARY Calcium signalling has profound implications in the fungal infection of plants and animals, during which a series of physiological and morphological transitions are required. In this article, using a model fungal pathogen, Magnaporthe oryzae, we demonstrate that the regulation of the intracellular calcium concentration ([Ca2+]int) is essential for fungal development and pathogenesis. Imaging of [Ca2+]int showed that infection-specific morphogenesis is highly correlated with the spatiotemporal regulation of calcium flux. Deletion of the fungal phospholipase C gene (M. oryzae phospholipase C 1, MoPLC1) suppressed calcium flux, resulting in a fungus defective in developmental steps, including appressorium formation and pathogenicity. Surprisingly, the PLC-,1 gene of mouse was able to functionally substitute for MoPLC1 by restoring the calcium flux, suggesting the evolutionary conservation of the phospholipase C-mediated regulation of calcium flux. Our results reveal that MoPLC1 is a conserved modulator of calcium flux that is essential for the regulation of key steps in fungal development and pathogenesis. [source] Enhanced biocontrol activity of Trichoderma virens transformants constitutively coexpressing ,-1,3- and ,-1,6-glucanase genesMOLECULAR PLANT PATHOLOGY, Issue 4 2007SLAVICA DJONOVI SUMMARY Evidence for the role of chitinases, proteases and ,-1,3- and ,-1,6-glucanases in mycoparasitism by Trichoderma species has been well documented. Moreover, constitutive over-expression of genes encoding individual cell-wall-degrading enzymes (CWDEs) has been shown to improve the potential of biological agents. In this study, we generated transformants of T. virens in which ,-1,3- and ,-1,6-glucanase genes, TvBgn2 and TvBgn3, respectively, were constitutively coexpressed in the same genetic T. virens Gv29.8 wild-type background. The double over-expression transformants (dOEs) grow and sporulate slower than the wild-type (WT). However, the reduction in growth did not seem to affect their mycoparasitic and biocontrol capabilities, as dOEs displayed much higher levels of total ,-1,3- and ,-1,6-glucanase activity than the WT. This higher enzymatic activity of dOEs positively correlated with observed in vitro inhibition of Pythium ultimum and Rhizoctonia solani mycelia, and with enhanced bioprotection of cotton seedlings against P. ultimum, R. solani and Rhizopus oryzae. Besides effective biocontrol of all pathogens at an original inoculum level, the performance of dOEs was highly enhanced (up to 312% of WT performance) when pathogen pressure was greater (i.e. concentration of inoculum was higher or pathogens applied in combination). These results demonstrate that the strategy of introducing multiple lytic enzyme-encoding genes through transformation of a given biocontrol strain can be successfully used to achieve better biocontrol. [source] Magnaporthe oryzae isolates causing gray leaf spot of perennial ryegrass possess a functional copy of the AVR1-CO39 avirulence geneMOLECULAR PLANT PATHOLOGY, Issue 3 2006REBECCA PEYYALA SUMMARY Gray leaf spot of perennial ryegrass (Lolium perenne) is a severe foliar disease caused by the ascomycete fungus Magnaporthe oryzae (formerly known as Magnaporthe grisea). Control of gray leaf spot is completely dependent on the use of fungicides because currently available perennial ryegrass cultivars lack genetic resistance to this disease. M. oryzae isolates from perennial ryegrass (prg) were unable to cause disease on rice cultivars CO39 and 51583, and instead triggered a hypersensitive response. Southern hybridization analysis of DNA from over 50 gray leaf spot isolates revealed that all of them contain sequences corresponding to AVR1-CO39, a host specificity gene that confers avirulence to rice cultivar CO39, which carries the corresponding resistance gene Pi-CO39(t). There was also an almost complete lack of restriction site polymorphism at the avirulence locus. Cloning and sequencing of the AVR1-CO39 gene (AVR1-CO39Lp) from 16 different gray leaf spot isolates revealed just two point mutations, both of which were located upstream of the predicted open reading frame. When an AVR1-CO39Lp gene copy was transferred into ML33, a rice pathogenic isolate that is highly virulent to rice cultivar CO39, the transformants were unable to cause disease on CO39 but retained their virulence to 51583, a rice cultivar that lacks Pi-CO39(t). These data demonstrate that the AVR1-CO39 gene in the gray leaf spot pathogens is functional, and suggest that interaction of AVR1-CO39Lp and Pi-CO39(t) is responsible, at least in part, for the host specificity expressed on CO39. This indicates that it may be possible to use the Pi-CO39(t) resistance gene as part of a transgenic strategy to complement the current deficiency of gray leaf spot resistance in prg. Furthermore, our data indicate that, if Pi-CO39(t) can function in prg, the resistance provided should be broadly effective against a large proportion of the gray leaf spot pathogen population. [source] Characterization of four rice mutants with alterations in the defence response pathwayMOLECULAR PLANT PATHOLOGY, Issue 1 2005M. A. CAMPBELL SUMMARY A fast-neutron mutagenized population of rice seedlings was screened with Magnaporthe grisea, the causal agent of rice blast disease, to identify mutants with alterations in the defence response. Three mutant lines, ebr1, ebr2 and ebr3 (enhanced blast resistance) were identified that display enhanced resistance to M. grisea. ebr1 and ebr3 also confer enhanced resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). ebr3 develops a lesion mimic (LM) phenotype upon inoculation with M. grisea, and the phenotype is also induced by a shift in environmental conditions. The fourth mutant line, ncr1 (necrosis in rice), has an LM phenotype under all conditions tested and lacks enhanced resistance to either M. grisea or Xoo. Complementation testing using the mutant lines ebr3 and ncr1 indicates that the ebr3 and ncr1 loci are nonallelic and recessive. ebr1 and ebr2 display no alterations in expression of the rice pathogenesis-related (PR) genes PBZ1 and PR1, compared to wild-type CO39. ebr3 has an elevated expression of PBZ1 and PR1 only in tissue displaying the LM phenotype. ncr1 strongly expresses PBZ1 in tissue displaying the LM phenotype, whereas PR1 expression in this tissue is similar to wild-type CO39. [source] Xanthomonas citri: breaking the surfaceMOLECULAR PLANT PATHOLOGY, Issue 3 2003Asha M. Brunings SUMMARY Taxonomy: Bacteria; Proteobacteria, Gammaproteobacteria; Xanthomonadales; Xanthomonadaceae, Xanthomonas. Microbiological properties: Gram-negative, obligately aerobic, straight rods, motile by a single polar flagellum, yellow pigment. Related species:X. campestris , X. axonopodis , X. oryzae , X. albilineans . Host range: Affects Rutaceous plants, primarily Citrus spp., Fortunella spp., and Poncirus spp., world-wide. Quarantined pathogen in many countries. Economically important hosts are cultivated orange, grapefruit, lime, lemon, pomelo and citrus rootstock. Disease symptoms: On leaves, first appearance is as oily looking, 2,10 mm, similarly sized, circular spots, usually on the abaxial surface. On leaves, stems, thorns and fruit, circular lesions become raised and blister-like, growing into white or yellow spongy pustules. These pustules then darken and thicken into a light tan to brown corky canker, which is rough to the touch. On stems, pustules may coalesce to split the epidermis along the stem length, and occasionally girdling of young stems may occur. Older lesions on leaves and fruit tend to have more elevated margins and are at times surrounded by a yellow chlorotic halo (that may disappear) and a sunken centre. Sunken craters are especially noticeable on fruit, but the lesions do not penetrate far into the rind. Defoliation and premature abscission of affected fruit occurs on heavily infected trees. Useful websites: Interaction of amphotericin B lipid formulations and triazoles with human polymorphonuclear leucocytes for antifungal activity against ZygomycetesMYCOSES, Issue 2 2008Maria Simitsopoulou Summary The frequency of zygomycosis has increased considerably over recent years mainly in immunocompromised and diabetic patients. Little is known about the effects of host innate immunity against different Zygomycetes especially under the influence of antifungal agents. The antifungal activity of human polymorphonuclear leucocytes (PMN) in combination with liposomal amphotericin B (LAMB), amphotericin B lipid complex (ABLC), voriconazole (VRC) and posaconazole (PSC) against Rhizopus oryzae and Rhizopus microsporus, frequently isolated Zygomycetes, were studied and compared with Absidia corymbifera, a less pathogenic Zygomycete. Antifungal activity was evaluated as per cent of hyphal damage using the XTT metabolic assay. While A. corymbifera was more susceptible to PMN than the other two Zygomycetes, R. microsporus appeared to be the most susceptible to combined effects of amphotericin B formulations and VRC with PMN. LAMB exhibited synergistic activity with PMN in inducing hyphal damage to R. microsporus but not to the other fungi. In contrast, ABLC exhibited synergistic or additive activity with PMN against all three fungi. Among triazoles, only VRC exhibited additive effect with PMN against R. microsporus. Lipid formulations of amphotericin B and particularly ABLC interact with PMN predominantly in inducing augmented hyphal damage to three different species of Zygomycetes. [source] Zygomycosis , a case report and overview of the disease in IndiaMYCOSES, Issue 4 2007Amit Diwakar Summary A case of zygomycosis caused by Rhizopus oryzae in a diabetic patient previously misdiagnosed as invasive pulmonary aspergillosis and an overview of the disease in India are presented. The case was diagnosed by direct microscopy, histopathologic examination and culture. Following surgical resection of pulmonary cavity under cover of amphotericin B administration, the patient recovered completely. Of 461 cases reported to-date, approximately 70% had been diagnosed at the Postgraduate Institute of Medical Education and Research, Chandigarh, in north India. This may be attributed to better awareness, expertise and infrastructural facilities for mycological diagnosis than to any particular regional preponderance of the disease. Rhino-orbito-cerebral manifestations were the most common feature of zygomycosis (269 cases), followed by cutaneous disease (66 cases), which is in conformity with the pattern prevalent worldwide. The etiologic agents encountered were Rhizopus oryzae, Apophysomyces elegans, Saksenaea vasiformis, Cunninghamella bertholletiae, Absidia corymbifera, Basidiobolus ranarum and Conidiobolus coronatus. In contrast to cases from the developed world where transplant recipients and patients with haematological malignancies seem to be most vulnerable to zygomycosis, the most common risk factor in India was uncontrolled diabetes mellitus. Amphotericin B was the mainstay of various treatment modalities employed. The relevance of a strong clinical suspicion and early diagnosis of zygomycosis for favourable prognosis can hardly be over-emphasised. [source] Complete resolution of pulmonary Rhizopus oryzae infection with itraconazole treatment: more evidence of the utility of azoles for zygomycosisMYCOSES, Issue 3-4 2004D. P. Eisen Rhizopus oryzae; Zygomykose; Itraconazol Summary Zygomycosis often requires aggressive surgical and antifungal therapy. We report a non-neutropenic patient with myelodysplastic syndrome and iron overload receiving cytotoxic therapy who presented with pulmonary Rhizopus oryzae infection. This patient was cured through the use of itraconazole alone and the literature on the utility of azole antifungals for zygomycosis is reviewed. Zusammenfassung Die Zygomykosen erfordern aggressive chirurgische und antimykotische Therapie. Wir berichten über einen nicht-neutropenischen Patienten mit myelodysplastischem Syndrom und Eisenüberladung unter cytotoxischer Therapie, der eine pulmonale Rhizopus oryae Infektion entwick. Der Patient wurde durch Itraconazol geheilt. Es wird eine Literaturübersicht über den Wert von Azol-Antimykotika zur Zygomykose-Behandlung gegeben. [source] Promoter elements of rice susceptibility genes are bound and activated by specific TAL effectors from the bacterial blight pathogen, Xanthomonas oryzae pv. oryzaeNEW PHYTOLOGIST, Issue 4 2010Patrick Römer Summary ,Plant pathogenic bacteria of the genus Xanthomonas inject transcription activator-like effector (TALe) proteins that bind to and activate host promoters, thereby promoting disease or inducing plant defense. TALes bind to corresponding UPT (up-regulated by TALe) promoter boxes via tandemly arranged 34/35-amino acid repeats. Recent studies uncovered the TALe code in which two amino acid residues of each repeat define specific pairing to UPT boxes. ,Here we employed the TALe code to predict potential UPT boxes in TALe-induced host promoters and analyzed these via ,-glucuronidase (GUS) reporter and electrophoretic mobility shift assays (EMSA). ,We demonstrate that the Xa13, OsTFX1 and Os11N3 promoters from rice are induced directly by the Xanthomonas oryzae pv. oryzae TALes PthXo1, PthXo6 and AvrXa7, respectively. We identified and functionally validated a UPT box in the corresponding rice target promoter for each TALe and show that box mutations suppress TALe-mediated promoter activation. Finally, EMSA demonstrate that code-predicted UPT boxes interact specifically with corresponding TALes. ,Our findings show that variations in the UPT boxes of different rice accessions correlate with susceptibility or resistance of these accessions to the bacterial blight pathogen. [source]
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