Publications

characterization of a divinyl ether biosynthetic pathway specifically associated with pathogenesis in tobacco.	in tobacco (nicotiana tabacum), an elicitor- and pathogen-induced 9-lipoxygenase (lox) gene, ntlox1, is essential for full resistance to pathogens, notably to an incompatible race of phytophthora parasitica var. nicotianae (ppn race 0). in this work, we aimed to identify those oxylipins induced during attempted infection by ppn race 0 and down-regulated in ntlox1 antisense plants. here we show that colneleic and colnelenic acids, which significantly inhibit germination of ppn zoospores, are prod ...	2007	17085514
transgenic sequences are frequently lost in phytophthora parasitica transformants without reversion of the transgene-induced silenced state.	little data exist on the mechanism and stability of transformation in phytophthora parasitica, a major oomycete parasite of plants. here, we studied the stability of drug-resistant protoplast transformants by analyzing single-zoospore derivatives. we show that the transgenic sequences are not stably integrated into the chromosomes, resulting in the loss of drug resistance in single-zoospore derivatives. however, in strains where the p. parasitica gene encoding the cbel elicitor was silenced by t ...	2007	17496962
cladosporium fulvum cfhnni1 induces hypersensitive necrosis, defence gene expression and disease resistance in both host and nonhost plants.	nonhost resistance as a durable and broad-spectrum defence strategy is of great potential for agricultural applications. we have previously isolated a cdna showing homology with genes encoding bzip transcription factors from tomato leaf mould pathogen cladosporium fulvum. upon expression, the cdna results in necrosis in c. fulvum host tomato and nonhost tobacco plants and is thus named cfhnni1 (for c . f ulvum host and nonhost plant necrosis inducer 1). in the present study we report the inducti ...	2007	17273821
exploration of the late stages of the tomato-phytophthora parasitica interactions through histological analysis and generation of expressed sequence tags.	the oomycete phytophthora parasitica is a soilborne pathogen infecting numerous plants. the infection process includes an initial biotrophic stage, followed by a necrotrophic stage. the aim here was to identify genes that are involved in the late stages of infection. using the host tomato and a transformed strain of p. parasitica expressing the green fluorescent protein (gfp), the various infection steps from recognition of the host to the colonization of plant tissues were studied. this late st ...	2008	18028297
functional characterization of a gene family encoding polygalacturonases in phytophthora parasitica.	phytophthora parasitica is an oomycete plant pathogen that causes severe disease in a wide variety of plant species. in our previous study, we discovered a multigene family encoding endopolygalacturonases (endopg) in phytophthora parasitica. here, we screened the genomic library of phytophthora parasitica for the genes encoding endopg named pppg2 through pppg10, and analyzed their functions. results obtained by real-time quantitative reverse transcriptase-polymerase chain reaction demonstrated t ...	2008	18321193
silencing of acidic pathogenesis-related pr-1 genes increases extracellular beta-(1->3)-glucanase activity at the onset of tobacco defence reactions.	the class 1 pathogenesis-related (pr) proteins are thought to be involved in plant defence responses, but their molecular functions are unknown. the function of pr-1 was investigated in tobacco by generating stable pr-1a-silenced lines in which other acidic pr-1 genes (pr-1b and pr-1c) were silenced. plants lacking extracellular pr-1s were more susceptible than wild-type plants to the oomycete phytophthora parasitica but displayed unaffected systemic acquired resistance and developmental resista ...	2008	18390849
phytophthora parasitica biofilm formation: installation and organization of microcolonies on the surface of a host plant.	zoospores of the oomycete phytophthora parasitica establish microbial spheroid microcolonies and biofilms on the surface of wounded leaves of their host, nicotiana tabacum. the formation of microcolonies involves the movement of some zoospores towards attractants from wound sites, followed by their irreversible adsorption and the formation of a cluster of cells. these cells drive the migration of a second wave of zoospores (several hundreds cells) by setting up an external chemotactic gradient l ...	2008	18430009
overexpression of a rice diacylglycerol kinase gene osbidk1 enhances disease resistance in transgenic tobacco.	a rice diacylglycerol kinase (dgk) gene, osbidk1, which encodes a 499-amino acid protein, was cloned and characterized. osbidk1 contains a conserved dgk domain, consisting of a diacylglycerol kinase catalytic subdomain and a diacylglycerol kinase accessory subdomain. expression of osbidk1 in rice seedlings was induced by treatment with benzothiadiazole (bth), a chemical activator of the plant defense response, and by infection with magnaporthe grisea, causal agent of blast disease. in bth-treate ...	2008	18679055
mammalian pro-apoptotic bax gene enhances tobacco resistance to pathogens.	emerging evidence suggests that plants and animals may share certain biochemical commonalities in apoptosis, or programmed cell death (pcd) pathways, though plants lack key animal apoptosis related genes. in plants, pcd has many important functions including a role in immunity and resistance to pathogen infection. in this study, a rice phenylalanine ammonia-lyase promoter is used to regulate the expression of the mouse pro-apoptotic bax gene in transgenic tobacco plants. ectopic expression of th ...	2008	18509654
transgenic tobacco and peanut plants expressing a mustard defensin show resistance to fungal pathogens.	defensins are small positively charged, antimicrobial peptides (approximately 5 kda in size) and some of them exhibit potent antifungal activity. we have cloned the complete cdna containing an orf of 243 bp of a defensin of mustard. the deduced amino acid sequence of the peptide showed more than 90% identity to the amino acid sequence of the well-characterized defensins, rsafp-1 and rsafp-2 of raphanus sativus. we have generated and characterized transgenic tobacco and peanut plants constitutive ...	2008	18758784
possibilities of the use of vinasses in the control of fungi phytopathogens.	the purpose of this research was to study the biocide effect of three agroindustrial subproducts, concretely sugar beet, sugar cane and wine vinasse. results from in vitro testing determined that wine vinasse is what shows a 100% capacity to suppress fungal growth with concentrations between 5% and 7% for fusarium oxysporum f.sp. melonis race 0 and 1, sclerotinia sclerotiorum, pythium aphanidermatum and phytophthora parasitica and 10-15% for f. oxysporum f.sp. radicis-cucumerinum. on the other h ...	2008	18519163
ectopic expression of an annexin from brassica juncea confers tolerance to abiotic and biotic stress treatments in transgenic tobacco.	plant annexins belong to a multigene family and are suggested to play a role in stress responses. a full-length cdna for a gene encoding an annexin protein was isolated and characterized from brassica juncea (annbj1). annbj1 message levels were regulated by abscisic acid, ethephon, salicylic acid, and methyl jasmonate as well as chemicals that induce osmotic stress (nacl, mannitol or peg), heavy metal stress (cdcl(2)) and oxidative stress (methyl viologen or h(2)o(2)). in order to determine if a ...	2008	18768323
[screening, identification and antagonistic activity of a siderophore-producing bacteria g-229-21t from rhizosphere of tobacco].	to screen antagonistic bacteria from rhizosphere of tobacco against phytophthora parasitica var. nicotianae (breda de hann) tucker and to analyze its antagonistic activity.	2008	18652295
strategies of attack and defense in plant-oomycete interactions, accentuated for phytophthora parasitica dastur (syn. p. nicotianae breda de haan).	oomycetes from the genus phytophthora are fungus-like plant pathogens that are devastating for agriculture and natural ecosystems. due to their particular physiological characteristics, no efficient treatments against diseases caused by these microorganisms are presently available. to develop such treatments, it appears essential to dissect the molecular mechanisms that determine the interaction between phytophthora species and host plants. available data are scarce, and genomic approaches were ...	2008	17766006
a common toxin fold mediates microbial attack and plant defense.	many plant pathogens secrete toxins that enhance microbial virulence by killing host cells. usually, these toxins are produced by particular microbial taxa, such as bacteria or fungi. in contrast, many bacterial, fungal and oomycete species produce necrosis and ethylene-inducing peptide 1 (nep1)-like proteins (nlps) that trigger leaf necrosis and immunity-associated responses in various plants. we have determined the crystal structure of an nlp from the phytopathogenic oomycete pythium aphanider ...	2009	19520828
nadph oxidase-mediated reactive oxygen species production: subcellular localization and reassessment of its role in plant defense.	chemiluminescence detection of reactive oxygen species (ros) triggered in tobacco by-2 cells by the fungal elicitor cryptogein was previously demonstrated to be abolished in cells transformed with an antisense construct of the plasma membrane nadph oxidase, ntrbohd. here, using electron microscopy, it has been confirmed that the first hydrogen peroxide production occurring a few minutes after challenge of tobacco cells with cryptogein is plasma membrane located and ntrbohd mediated. furthermore, ...	2009	19522569
black shank resistant tobacco by silencing of glutathione s-transferase.	a glutathione s-transferase gene was amplified from cdna of nicotiana tabacum roots infected with phytophthora parasitica var. nicotianae. the gene was cloned in sense and anti-sense orientation to an rnai vector for induced gene silencing, and reduced expression of the gene was detected by rt-pcr. a statistically significant increase in resistance of n. tabacum to infection following gene silencing was found for glutathione s-transferase-silenced plants compared with control plants. some defens ...	2009	19577539
engineered polyamine catabolism preinduces tolerance of tobacco to bacteria and oomycetes.	polyamine oxidase (pao) catalyzes the oxidative catabolism of spermidine and spermine, generating hydrogen peroxide. in wild-type tobacco (nicotiana tabacum 'xanthi') plants, infection by the compatible pathogen pseudomonas syringae pv tabaci resulted in increased pao gene and corresponding pao enzyme activities; polyamine homeostasis was maintained by induction of the arginine decarboxylase pathway and spermine was excreted into the apoplast, where it was oxidized by the enhanced apoplastic pao ...	2009	19218362
ectopic expression of a rice protein phosphatase 2c gene osbipp2c2 in tobacco improves disease resistance.	protein phosphatase 2cs (pp2cs) have been demonstrated to play critical roles in regulation of plant growth/development, abscisic acid signaling pathway and adaptation to environmental stresses. here we report the cloning and molecular characterization of a novel rice protein phosphatase 2c gene, osbipp2c2 (oryza sativa l. bth-induced protein phosphatase 2c 2). osbipp2c2 has three alternatively spliced transcripts and the largest transcript osbipp2c2a encodes a 380 aa protein containing all 11 c ...	2009	19381642
cloning, structural features, and expression analysis of resistance gene analogs in tobacco.	using degenerate primers based on the conserved nucleotide binding site (nbs) and protein kinase domain (pkd), 100 resistance gene analogs (rgas) were isolated from tobacco variety nicotiana repanda. blastx search against the genbank database revealed that 27 belong to the nbs class and 73 belong to the protein kinase (pk) class. cluster analysis and multiple sequence alignment of the deduced protein sequences indicate that rgas of the nbs class can be divided into two groups: toll/interleukin r ...	2010	19728156
cellular and molecular characterization of phytophthora parasitica appressorium-mediated penetration.	data on plant pathogenic oomycetes are scarce and little is known about the early events leading to the onset of infection. the aim of this work was to analyze the penetration process of the soil-borne plant pathogen phytophthora parasitica, which has a wide host range. here, we performed a cytological analysis of the colonization of the first plant cell and developed an inoculation assay for characterizing the entire penetration process through cellular and molecular analyses. we showed that p. ...	2010	19807870
the immediate activation of defense responses in arabidopsis roots is not sufficient to prevent phytophthora parasitica infection.	summary: the outcome of plant-microbe interactions is determined by a fine-tuned molecular interplay between the two partners. little is currently known about the molecular dialogue between plant roots and filamentous pathogens. we describe here a new pathosystem for the analysis of molecular mechanisms occurring during the establishment of a compatible interaction between arabidopsis thaliana roots and a root-infecting oomycete. we performed cytological and genetic analyses of root infection ...	2010	20456058
identification of a novel npr1-like gene from nicotiana glutinosa and its role in resistance to fungal, bacterial and viral pathogens.	the npr1 or npr1-like genes play a pivotal role in systemic acquired resistance in plants. here, we isolated and identified a novel tobacco (nicotiana glutinosa) npr1-like gene (designated as ngnpr3). the full-length cdna is 2049 bp in length with a 1767 bp open reading frame which encodes a 588 amino acids protein with an estimated molecular mass of 66 kda and a calculated pi of 7.14. homology analysis suggested that the ngnpr3 protein shares significant similarity to atnpr3 of arabidopsis. tra ...	2010	20653885
ntkti1, a kunitz trypsin inhibitor with antifungal activity from nicotiana tabacum, plays an important role in tobacco's defense response.	a cdna library from tobacco inoculated with rhizoctonia solani was constructed, and several cdna fragments were identified by differential hybridization screening. one cdna clone that was dramatically repressed, ntkti1, was confirmed as a member of the kunitz plant proteinase inhibitor family. rt-pcr analysis revealed that ntkti1 was constitutively expressed throughout the whole plant and preferentially expressed in the roots and stems. furthermore, rt-pcr analysis showed that ntkti1 expression ...	2010	20735473
infection of arabidopsis thaliana by phytophthora parasitica and identification of variation in host specificity.	oomycete pathogens cause severe damage to a wide range of agriculturally important crops and natural ecosystems. they represent a unique group of plant pathogens that are evolutionarily distant from true fungi. in this study, we established a new plant-oomycete pathosystem in which the broad host range pathogen phytophthora parasitica was demonstrated to be capable of interacting compatibly with the model plant arabidopsis thaliana. water-soaked lesions developed on leaves within 3 days and nume ...	2010	21199568
global gene expression of poncirus trifoliata, citrus sunki and their hybrids under infection of phytophthora parasitica.	gummosis and root rot caused by phytophthora are among the most economically important diseases in citrus. four f1 resistant hybrids (pool r), and four f1 susceptible hybrids (pool s) to p. parasitica, were selected from a cross between susceptible citrus sunki and resistant poncirus trifoliata cv. rubidoux. we investigated gene expression in pools of four resistant and four susceptible hybrids in comparison with their parents 48 hours after p. parasitica inoculation. we proposed that genes diff ...	2011	21241495
elicitin-membrane interaction is driven by a positive charge on the protein surface: role of lys13 residue in lipids loading and resistance induction.	elicitins are family of small proteins secreted by species of the pathogenic fungus phytophthora inducing a defence reaction in plants. they contain a hydrophobic cavity capable of binding sterols and fatty acids, and on the basis of their pi they are classified as either a-elicitins or more necrotising ß-elicitins. the residue lys13 was previously identified as a key determinant of the necrotising activity of basic elicitins. in the present study we describe changes in the ability of cryptogein ...	2011	21296584
revealing complexity and specificity in the activation of lipase-mediated oxylipin biosynthesis: a specific role of the nicotiana attenuata gla1 lipase in the activation of ja biosynthesis in leaves and roots.	the identity and number of the lipases involved in the activation of oxylipin biosynthesis remain controversial. in this study we demonstrate that nagla1 in nicotiana attenuata is a specific supplier of trienoic fatty acids for ja biosynthesis in leaves and roots after wounding and simulated herbivory and that it utilizes multiple glycerolipid substrates as a source of trienoic fatty acids. alternative functions for nagla1 were revealed by the analysis of the regulation of nades1 and nalox1 gene ...	2011	21554327
expression and purification of a biologically active phytophthora parasitica cellulose binding elicitor lectin in pichia pastoris.	the phytophthora parasitica cellulose-binding elicitor lectin, (cbel), is a cell wall-localized protein playing a key role in cell wall organization and adhesion of the mycelium to cellulosic substrates. cbel is a potent elicitor of plant immune responses and this activity is linked to its ability to bind plant cell wall components. in order to scale up the production of active cbel, we reported here the cloning and expression of a his-tagged version of cbel in the yeast pichia pastoris. selecti ...	2011	21820056
synthesis and anti-fungal activity of seven oleanolic acid glycosides.	in order to develop potential anti-fungal agents, seven glycoconjugates composed of a-l-rhamnose, 6-deoxy-a-l-talose, ß-d-galactose, a-d-mannose, ß-d-xylose-(1?4)-6-deoxy-a-l-talose, ß-d-galactose-(1?4)-a-l-rhamnose, ß-d-galactose-(1?3)-ß-d-xylose-(1?4)-6-deoxy-a-l-talose as the glycone and oleanolic acid as the aglycone were synthesized in an efficient and practical way using glycosyl trichloroacetimidates as donors. the structures of the new compounds were confirmed by ms, ¹h-nmr and ¹³c-nmr.p ...	2011	21270731
A Rapid Microbioassay for Discovery of Antagonistic Bacteria for Phytophthora parasitica var. nicotianae.	A simple, rapid, small-scale microbioassay for infection of tobacco seedlings by Phytophthora parasitica var. nicotianae was developed here. This assay uses tobacco seedlings cultivated in Petri dishes for a standardized method for quantitation of initial zoospore inocula and high-throughput screening of antagonistic bacteria. Zoospore inocula between 102 to 105 spores per Petri dish were inoculated on 14-day-old tobacco seedlings for the susceptibility test. One thousand zoospores' treatment wa ...	2011	22046969
in vitro selection of calli of citrus jambhiri lush. for tolerance to culture filtrate of phytophthora parasitica and their regeneration.	the present study deals with the selection of phytophthora tolerant lines of citrus jambhiri and their regeneration. cotyledon derived calli were cultured on selective ms medium supplemented with 5-100 % of culture filtrate (cf), to estimate the critical concentration of the selective agent. the survived calli under stress were subcultured for mass propagation for 20 days on callus multiplication medium (2,4-d 2 mg/l + ba 0.75 mg/l) without culture filtrate. after multiplication, these calli wer ...	2011	23572994
a novel screening method of cellulase-producing bacteria.	cellulase is the key to utilize the renewable and abundant cellulose resource, cellulase-producing microorganism is an important source of cellulase. the traditional screening method of cellulase-producing microorganism is low efficacy and not macroscopic. the screening method in this study was based on the interactive culture character between cellulase-producing bacteria and phytophthora parasitica var. nicotianae on plates, the results indicated that the inhibition zone and cellulase activity ...	2011	21438471
differential gene expression in arachis diogoi upon interaction with peanut late leaf spot pathogen, phaeoisariopsis personata and characterization of a pathogen induced cyclophilin.	the wild relatives of peanut are resistant to various economically important diseases including late leaf spot (lls) caused by phaeoisariopsis personata, compared with the susceptible cultivated peanut (arachis hypogaea l.). the interaction of the late leaf spot pathogen, phaeoisariopsis personata and the highly resistant, diploid peanut wild species, arachis diogoi was analyzed at the molecular level by differential gene expression studies. genes up-regulated with in 48 h of pathogen challenge ...	2011	21298396
ecosystem screening approach for pathogen-associated microorganisms affecting host disease.	the microbial community in which a pathogen evolves is fundamental to disease outcome. species interacting with a pathogen on the host surface shape the distribution, density, and genetic diversity of the inoculum, but the role of these species is rarely determined. the screening method developed here can be used to characterize pathogen-associated species affecting disease. this strategy involves three steps: (i) constitution of the microbial community, using the pathogen as a trap; (ii) commun ...	2011	21742919
Production of dsRNA Sequences in the Host Plant Is Not Sufficient to Initiate Gene Silencing in the Colonizing Oomycete Pathogen Phytophthora parasitica.	Species of the oomycete genus Phytophthora are destructive pathogens, causing extensive losses in agricultural crops and natural ecosystems. A potential disease control approach is the application of RNA silencing technology which has proven to be effective in improving plant resistance against a wide range of pests including parasitic plants, nematodes, insects and fungi. In this study, we tested the potential application of RNA silencing in improving plant disease resistance against oomycete p ...	2011	22140518
a gene for plant protection: expression of a bean polygalacturonase inhibitor in tobacco confers a strong resistance against rhizoctonia solani and two oomycetes.	we have tested whether a gene encoding a polygalacturonase-inhibiting protein (pgip) protects tobacco against a fungal pathogen (rhizoctonia solani) and two oomycetes (phytophthora parasitica var. nicotianae and peronospora hyoscyami f. sp. tabacina). the trials were performed in greenhouse conditions for r. solani and p. parasitica and in the field for p. hyoscyami. our results show that expression of pgip is a powerful way of engineering a broad-spectrum disease resistance.	2012	23264779