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1

Molecular characterization of pathogenic Fusarium species in cucurbit plants from Kermanshah province, Iran  

PubMed Central

Fusarium is one of the important phytopathogenic genera of microfungi causing serious losses on cucurbit plants in Kermanshah province, the largest area of cucurbits plantation in Iran. Therefore, the objectives in this study were to isolate and identify disease-causing Fusarium spp. from infected cucurbit plants, to ascertain their pathogenicity, and to determine their phylogenetic relationships. A total of 100 Fusarium isolates were obtained from diseased cucurbit plants collected from fields in different geographic regions in Kermanshah province, Iran. According to morphological characters, all isolates were identified as Fusarium oxysporum, Fusarium proliferatum, Fusarium equiseti, Fusarium semitectum and Fusarium solani. All isolates of the five Fusarium spp. were evaluated for their pathogenicity on healthy cucumber (Cucumis sativus) and honeydew melon (Cucumis melo) seedlings in the glasshouse. F. oxysporum caused damping-off in 20–35 days on both cucurbit seedlings tested. Typical stem rot symptoms were observed within 15 days after inoculation with F. solani on both seedlings. Based on the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA) restriction fragment length polymorphism (RFLP) analysis, the five Fusarium species were divided into two major groups. In particular, isolates belonging to the F. solani species complex (FSSC) were separated into two RFLP types. Grouping among Fusarium strains derived from restriction analysis was in agreement with criteria used in morphological classification. Therefore, the PCR-ITS-RFLP method provides a simple and rapid procedure for the differentiation of Fusarium strains at species level. This is the first report on identification and pathogenicity of major plant pathogenic Fusarium spp. causing root and stem rot on cucurbits in Iran.

Chehri, K.; Salleh, B.; Yli-Mattila, T.; Reddy, K.R.N.; Abbasi, S.

2011-01-01

2

Hairpin Plasmids from the Plant Pathogenic Fungi Rhizoctonia solani and Fusarium oxysporum  

Microsoft Academic Search

This review focuses on the biology of the hairpin plasmids from the plant pathogenic fungi Rhizoctonia solani and Fusarium oxysporum. R. solani\\u000a linear plasmid is single-stranded with covalently closed hairpin loops at each end. F. oxysporum\\u000a plasmid, however, has a clothespin structure, which includes a terminal hairpin and noncovalently\\u000a linked ends at the other terminus. We present the nucleotide sequence of the hairpin

Teruyoshi Hashiba; Atsushi Nagasaka

3

Impact of Transgenic Bt Maize Residues on the Mycotoxigenic Plant Pathogen Fusarium graminearum and the Biocontrol Agent Trichoderma atroviride  

Microsoft Academic Search

Transformation of maize with genes encoding for insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) could have an impact on the saprophytic survival of plant pathogens and their antagonists on crop residues. We assessed potential effects on the mycotoxin de- oxynivalenol (DON)-producing wheat and maize pathogen Fusarium graminearum and on the biocontrol agent Trichoderma atroviride. Purified Cry1Ab protein caused no

Andreas Naef; Thierry Zesiger; Genevieve Defago

2006-01-01

4

Gene expression profile of the plant pathogen Fusarium graminearum under the antagonistic effect of Pantoea agglomerans.  

PubMed

The pathogenic fungus Fusarium graminearum is an ongoing threat to agriculture, causing losses in grain yield and quality in diverse crops. Substantial progress has been made in the identification of genes involved in the suppression of phytopathogens by antagonistic microorganisms; however, limited information regarding responses of plant pathogens to these biocontrol agents is available. Gene expression analysis was used to identify differentially expressed transcripts of the fungal plant pathogen F. graminearum under antagonistic effect of the bacterium Pantoea agglomerans. A macroarray was constructed, using 1014 transcripts from an F. graminearum cDNA library. Probes consisted of the cDNA of F. graminearum grown in the presence and in the absence of P. agglomerans. Twenty-nine genes were either up (19) or down (10) regulated during interaction with the antagonist bacterium. Genes encoding proteins associated with fungal defense and/or virulence or with nutritional and oxidative stress responses were induced. The repressed genes coded for a zinc finger protein associated with cell division, proteins containing cellular signaling domains, respiratory chain proteins, and chaperone-type proteins. These data give molecular and biochemical evidence of response of F. graminearum to an antagonist and could help develop effective biocontrol procedures for pathogenic plant fungi. PMID:20623455

Pandolfi, V; Jorge, E C; Melo, C M R; Albuquerque, A C S; Carrer, H

2010-07-06

5

FGDB: a comprehensive fungal genome resource on the plant pathogen Fusarium graminearum  

PubMed Central

The MIPS Fusarium graminearum Genome Database (FGDB) is a comprehensive genome database on one of the most devastating fungal plant pathogens of wheat and barley. FGDB provides information on two gene sets independently derived by automated annotation of the F.graminearum genome sequence. A complete manually revised gene set will be completed within the near future. The initial results of systematic manual correction of gene calls are already part of the current gene set. The database can be accessed to retrieve information from bioinformatics analyses and functional classifications of the proteins. The data are also organized in the well established MIPS catalogs and novel query techniques are available to search the data. The comprehensive set of gene calls was also used for the design of an Affymetrix GeneChip. The resource is accessible on .

Guldener, Ulrich; Mannhaupt, Gertrud; Munsterkotter, Martin; Haase, Dirk; Oesterheld, Matthias; Stumpflen, Volker; Mewes, Hans-Werner; Adam, Gerhard

2006-01-01

6

Interactions between Fusarium verticillioides, Ustilago maydis, and Zea mays: an endophyte, a pathogen, and their shared plant host.  

PubMed

Highly diverse communities of microbial symbionts occupy eukaryotic organisms, including plants. While many well-studied symbionts may be characterized as either parasites or as mutualists, the prevalent but cryptic endophytic fungi are less easily qualified because they do not cause observable symptoms of their presence within their host. Here, we investigate the interactions of an endophytic fungus, Fusarium verticillioides with a pathogen, Ustilago maydis, as they occur within maize (Zea mays). We used experimental inoculations to evaluate metabolic mechanisms by which these three organisms might interact. We assessed the impacts of fungal-fungal interactions on endophyte and pathogen growth within the plant, and on plant growth. We find that F. verticillioides modulates the growth of U. maydis and thus decreases the pathogen's aggressiveness toward the plant. With co-inoculation of the endophyte with the pathogen, plant growth is similar to that which would be gained without the pathogen present. However, the endophyte may also break down plant compounds that limit U. maydis growth, and obtains a growth benefit from the presence of the pathogen. Thus, an endophyte such as F. verticillioides may function as both a defensive mutualist and a parasite, and express nutritional modes that depend on ecological context. PMID:22587948

Rodriguez Estrada, Alma E; Jonkers, Wilfried; Kistler, H Corby; May, Georgiana

2012-05-12

7

Use of molecular markers to compare Fusarium verticillioides pathogenic strains isolated from plants and humans.  

PubMed

Fusarium verticillioides is a pathogen of agriculturally important crops, especially maize. It is considered one of the most important pathogens responsible for fumonisin contamination of food products, which causes severe, chronic, and acute intoxication in humans and animals. Moreover, it is recognized as a cause of localized infections in immunocompetent patients and disseminated infections among severely immunosuppressed patients. Several molecular tools have been used to analyze the intraspecific variability of fungi. The objective of this study was to use molecular markers to compare pathogenic isolates of F. verticillioides and isolates of the same species obtained from clinical samples of patients with Fusarium mycoses. The molecular markers that we used were inter-simple sequence repeat markers (primers GTG5 and GACA4), intron splice site primer (primer EI1), random amplified polymorphic DNA marker (primer OPW-6), and restriction fragment length polymorphism-internal transcribed spacer (ITS) from rDNA. From the data obtained, clusters were generated based on the UPGMA clustering method. The amplification products obtained using primers ITS4 and ITS5 and loci ITS1-5.8-ITS2 of the rDNA yielded fragments of approximately 600 bp for all the isolates. Digestion of the ITS region fragment using restriction enzymes such as EcoRI, DraI, BshI, AluI, HaeIII, HinfI, MspI, and PstI did not permit differentiation among pathogenic and clinical isolates. The inter-simple sequence repeat, intron splice site primer, and random amplified polymorphic DNA markers presented high genetic homogeneity among clinical isolates in contrast to the high variability found among the phytopathogenic isolates of F. verticillioides. PMID:24065642

Chang, S C; Macędo, D P C; Souza-Motta, C M; Oliveira, N T

2013-08-12

8

THE ROLE OF FUSARIUM BIODIVERSITY IN PLANT PATHOGENICITY AND BIOLOGICAL CONTROL  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Fusarium disease complexes of maize, wheat, and other cereal grains are biologically highly diverse. This biodiversity is believed to have a major impact on the types and levels of mycotoxins in food grains. The first dimension of complexity is at the Fusarium species level. Identification an...

9

The Predicted Secretome of the Plant Pathogenic Fungus Fusarium graminearum: A Refined Comparative Analysis  

PubMed Central

The fungus Fusarium graminearum forms an intimate association with the host species wheat whilst infecting the floral tissues at anthesis. During the prolonged latent period of infection, extracellular communication between live pathogen and host cells must occur, implying a role for secreted fungal proteins. The wheat cells in contact with fungal hyphae subsequently die and intracellular hyphal colonisation results in the development of visible disease symptoms. Since the original genome annotation analysis was done in 2007, which predicted the secretome using TargetP, the F. graminearum gene call has changed considerably through the combined efforts of the BROAD and MIPS institutes. As a result of the modifications to the genome and the recent findings that suggested a role for secreted proteins in virulence, the F. graminearum secretome was revisited. In the current study, a refined F. graminearum secretome was predicted by combining several bioinformatic approaches. This strategy increased the probability of identifying truly secreted proteins. A secretome of 574 proteins was predicted of which 99% was supported by transcriptional evidence. The function of the annotated and unannotated secreted proteins was explored. The potential role(s) of the annotated proteins including, putative enzymes, phytotoxins and antifungals are discussed. Characterisation of the unannotated proteins included the analysis of Pfam domains and features associated with known fungal effectors, for example, small size, cysteine-rich and containing internal amino acid repeats. A comprehensive comparative genomic analysis involving 57 fungal and oomycete genomes revealed that only a small number of the predicted F. graminearum secreted proteins can be considered to be either species or sequenced strain specific.

Brown, Neil A.; Antoniw, John; Hammond-Kosack, Kim E.

2012-01-01

10

Impact of transgenic Bt maize residues on the mycotoxigenic plant pathogen Fusarium graminearum and the biocontrol agent Trichoderma atroviride.  

PubMed

Transformation of maize with genes encoding for insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) could have an impact on the saprophytic survival of plant pathogens and their antagonists on crop residues. We assessed potential effects on the mycotoxin deoxynivalenol (DON)-producing wheat and maize pathogen Fusarium graminearum and on the biocontrol agent Trichoderma atroviride. Purified Cry1Ab protein caused no growth inhibition of these fungi on agar plates. Cry1Ab concentrations above levels common in Bt maize tissue stimulated the growth of F. graminearum. The fungi were also grown on gamma-radiation-sterilized leaf tissue of four Bt maize hybrids and their non transgenic isolines collected at maize maturity on a field trial in 2002 and 2003. Both fungi degraded the Cry1Ab protein in Bt maize tissue. Fungal biomass quantification with microsatellite-based polymerase chain reaction (PCR) assays revealed differential fungal growth on leaf tissue of different maize varieties but no consistent difference between corresponding Bt and non-Bt hybrids. Generally, year of maize tissue collection had a greater impact on biomass production than cultivar or Bt transformation. The mycotoxin DON levels observed in maize tissue experiments corresponded with patterns in F. graminearum biomass, indicating that Bt transformation has no impact on DON production. In addition to bioassays, maize leaf tissue was analyzed with a mass spectrometer-based electronic nose, generating fingerprints of volatile organic compounds. Chemical fingerprints of corresponding Bt and non-Bt leaf tissues differed only for those hybrid pairs that caused differential fungal biomass production in the bioassays. Our results suggest that Cry1Ab protein in maize residues has no direct effect on F. graminearum and T. atroviride but some corresponding Bt/non-Bt maize hybrids differ more in composition than Cry protein content alone, which can affect the saprophytic growth of fungi on crop residues. PMID:16738384

Naef, Andreas; Zesiger, Thierry; Défago, Genevičve

2006-05-31

11

Heterochromatin influences the secondary metabolite profile in the plant pathogen Fusarium graminearum  

PubMed Central

Chromatin modifications and heterochromatic marks have been shown to be involved in the regulation of secondary metabolism gene clusters in the fungal model system Aspergillus nidulans. We examine here the role of HEP1, the heterochromatin protein homolog of Fusarium graminearum, for the production of secondary metabolites. Deletion of Hep1 in a PH-1 background strongly influences expression of genes required for the production of aurofusarin and the main tricothecene metabolite DON. In the Hep1 deletion strains AUR genes are highly up-regulated and aurofusarin production is greatly enhanced suggesting a repressive role for heterochromatin on gene expression of this cluster. Unexpectedly, gene expression and metabolites are lower for the trichothecene cluster suggesting a positive function of Hep1 for DON biosynthesis. However, analysis of histone modifications in chromatin of AUR and DON gene promoters reveals that in both gene clusters the H3K9me3 heterochromatic mark is strongly reduced in the Hep1 deletion strain. This, and the finding that a DON-cluster flanking gene is up-regulated, suggests that the DON biosynthetic cluster is repressed by HEP1 directly and indirectly. Results from this study point to a conserved mode of secondary metabolite (SM) biosynthesis regulation in fungi by chromatin modifications and the formation of facultative heterochromatin.

Reyes-Dominguez, Yazmid; Boedi, Stefan; Sulyok, Michael; Wiesenberger, Gerlinde; Stoppacher, Norbert; Krska, Rudolf; Strauss, Joseph

2012-01-01

12

Arabidopsis is susceptible to the cereal ear blight fungal pathogens Fusarium graminearum and Fusarium culmorum.  

PubMed

The fungal pathogens Fusarium graminearum and F. culmorum cause ear blight disease on cereal crops worldwide. The disease lowers both grain quality and grain safety. Disease prevalence is increasing due to changes in cropping practices and the difficulties encountered by plant breeders when trying to introgress the polygene-based resistance. The molecular basis of resistance to Fusarium ear blight in cereal species is poorly understood. This is primarily due to the large size of cereal genomes and the expensive resources required to undertake gene function studies in cereals. We therefore explored the possibility of developing various model floral infection systems that would be more amenable to experimental manipulation and high-throughput gene function studies. The floral tissues of tobacco, tomato, soybean and Arabidopsis were inoculated with Fusarium conidia and this resulted in disease symptoms on anthers, anther filaments and petals in each plant species. However, only in Arabidopsis did this initial infection then spread into the developing siliques and seeds. A survey of 236 Arabidopsis ecotypes failed to identify a single genotype that was extremely resistant or susceptible to Fusarium floral infections. Three Arabidopsis floral mutants that failed to develop anthers and/or functional pollen (i.e. agamous-1, apetala1-3 and dad1) were significantly less susceptible to Fusarium floral infection than wild type. Deoxynivalenol (DON) mycotoxin production was also detected in Fusarium-infected flowers at >1 ppm. This novel floral pathosystem for Arabidopsis appears to be highly representative of a serious cereal crop disease. PMID:12492838

Urban, Martin; Daniels, Steve; Mott, Ellie; Hammond-Kosack, Kim

2002-12-01

13

A combined ąH nuclear magnetic resonance and electrospray ionization-mass spectrometry analysis to understand the basal metabolism of plant-pathogenic Fusarium spp.  

PubMed

Many ascomycete Fusarium spp. are plant pathogens that cause disease on both cereal and noncereal hosts. Infection of wheat ears by Fusarium graminearum and F. culmorum typically results in bleaching and a subsequent reduction in grain yield. Also, a large proportion of the harvested grain can be spoiled when the colonizing Fusarium mycelia produce trichothecene mycotoxins, such as deoxynivalenol (DON). In this study, we have explored the intracellular polar metabolome of Fusarium spp. in both toxin-producing and nonproducing conditions in vitro. Four Fusarium spp., including nine well-characterized wild-type field isolates now used routinely in laboratory experimentation, were explored. A metabolic "triple-fingerprint" was recorded using (1)H nuclear magnetic resonance and direct-injection electrospray ionization-mass spectroscopy in both positive- and negative-ionization modes. These combined metabolomic analyses revealed that this technique is sufficient to resolve different wild-type isolates and different growth conditions. Principal components analysis was able to resolve the four species explored-F. graminearum, F. culmorum, F. pseudograminearum, and F. venenatum-as well as individual isolate differences from the same species. The external nutritional environment was found to have a far greater influence on the metabolome than the genotype of the organism. Conserved responses to DON-inducing medium were evident and included increased abundance of key compatible solutes, such as glycerol and mannitol. In addition, the concentration of ?-aminobutyric acid was elevated, indicating that the cellular nitrogen status may be affected by growth on DON-inducing medium. PMID:20718668

Lowe, Rohan G T; Allwood, J William; Galster, Aimee M; Urban, Martin; Daudi, Arsalan; Canning, Gail; Ward, Jane L; Beale, Michael H; Hammond-Kosack, Kim E

2010-12-01

14

Antagonistic bacteria of composted agro-industrial residues exhibit antibiosis against soil-borne fungal plant pathogens and protection of tomato plants from Fusarium oxysporum f.sp. radicis-lycopersici  

Microsoft Academic Search

Rhizospheric and root-associated\\/endophytic (RAE) bacteria were isolated from tomato plants grown in three suppressive compost-based\\u000a plant growth media derived from the olive mill, winery and Agaricus bisporus production agro-industries. Forty-four (35 rhizospheric and 9 RAE) out of 329 bacterial strains showed in vitro antagonistic\\u000a activity against at least one of the soil-borne fungal pathogens, Fusarium oxysporum f.sp. radicis-lycopersici (FORL), F.

Nektarios Kavroulakis; Spyridon Ntougias; Maria I. Besi; Pelagia Katsou; Athanasia Damaskinou; Constantinos Ehaliotis; Georgios I. Zervakis; Kalliope K. Papadopoulou

2010-01-01

15

Plant Disease Lesson: Fusarium head blight (FHB) or scab  

NSDL National Science Digital Library

This plant disease lesson on Fusarium head blight (FHB) or scab (caused by the fungus Fusarium graminearum (anamorph) Gibberella zeae (teleomorph)) includes information on symptoms and signs, pathogen biology, disease cycle and epidemiology, disease management, and the significance of the disease. Selected references are listed and a glossary is also available for use with this resource.

David G. Schmale III (Cornell University;); Gary C. Bergstrom (Cornell University;)

2003-06-12

16

Germination of Fusarium oxysporum in root exudates from tomato plants challenged with different Fusarium oxysporum strains  

Microsoft Academic Search

The response of microconidia from pathogenic and non-pathogenic Fusarium oxysporum to root exudates from tomato plants inoculated with different pathogenic and non-pathogenic F. oxysporum strains was studied. Root exudates from non-inoculated tomatoes highly stimulated the microconidial germination of the two\\u000a tomato pathogens, F. oxysporum f.sp. lycopersici strain Fol 007 and F. oxysporum f.sp. radicis-lycopersici strain Forl 101587. In root exudates

Siegrid Steinkellner; Roswitha Mammerler; Horst Vierheilig

2008-01-01

17

Autophagy provides nutrients for nonassimilating fungal structures and is necessary for plant colonization but not for infection in the necrotrophic plant pathogen Fusarium graminearum.  

PubMed

The role of autophagy in necrotrophic fungal physiology and infection biology is poorly understood. We have studied autophagy in the necrotrophic plant pathogen Fusarium graminearum in relation to development of nonassimilating structures and infection. We identified an ATG8 homolog F. graminearum ATG8 whose first 116 amino acids before the predicted ATG4 cleavage site are 100% identical to Podospora anserina ATG8. We generated a ?Fgatg8 mutant by gene replacement and showed that this cannot form autophagic compartments. The strain forms no perithecia, has reduced conidia production and the aerial mycelium collapses after a few days in culture. The collapsing aerial mycelium contains lipid droplets indicative of nitrogen starvation and/or an inability to use storage lipids. The capacity to use carbon/energy stored in lipid droplets after a shift from carbon rich conditions to carbon starvation is severely inhibited in the ?Fgatg8 strain demonstrating autophagy-dependent lipid utilization, lipophagy, in fungi. Radial growth rate of the ?Fgatg8 strain is reduced compared with the wild type and the mutant does not grow over inert plastic surfaces in contrast to the wild type. The ability to infect barley and wheat is normal but the mutant is unable to spread from spikelet to spikelet in wheat. Complementation by inserting the F. graminearum atg8 gene into a region adjacent to the actin gene in ?Fgatg8 fully restores the WT phenotype. The results showed that autophagy plays a pivotal role for supplying nutrients to nonassimilating structures necessary for growth and is important for plant colonization. This also indicates that autophagy is a central mechanism for fungal adaptation to nonoptimal C/N ratios. PMID:22240663

Josefsen, Lone; Droce, Aida; Sondergaard, Teis Esben; Sřrensen, Jens Laurids; Bormann, Jörg; Schäfer, Wilhelm; Giese, Henriette; Olsson, Stefan

2012-01-13

18

GENOMIC ANALYSIS OF HOST-PATHOGEN INTERACTION BETWEEN FUSARIUM GRAMINEARUM AND WHEAT DURING EARLY STAGES OF DISEASE DEVELOPMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium graminearum strains responsible for causing the plant disease Fusarium head blight vary greatly in their ability to cause disease and produce mycotoxins on wheat. With the goal of understanding fungal gene expression related to pathogenicity, three cDNA libraries were created by suppression...

19

Genomic analysis of host-pathogen interaction between Fusarium graminearum and wheat during early stages of disease development  

Microsoft Academic Search

Fusarium graminearum strains responsible for causing the plant disease Fusarium head blight vary greatly in their ability to cause disease and produce mycotoxins on wheat. With the goal of understanding fungal gene expression related to pathogenicity, three cDNA libraries were created by suppression subtractive hybridization using wheat heads inoculated with a highly aggressive strain and either water or a less

Rubella S. Goswami; Jin-Rong Xu; Frances Trail; Karen Hilburn; H. Corby Kistler

2006-01-01

20

Chromosome Complement of the Fungal Plant Pathogen Fusarium graminearum Based on Genetic and Physical Mapping and Cytological Observations  

PubMed Central

A genetic map of the filamentous fungus Fusarium graminearum (teleomorph: Gibberella zeae) was constructed to both validate and augment the draft whole-genome sequence assembly of strain PH-1. A mapping population was created from a cross between mutants of the sequenced strain (PH-1, NRRL 31084, originally isolated from Michigan) and a field strain from Minnesota (00-676, NRRL 34097). A total of 111 ascospore progeny were analyzed for segregation at 235 loci. Genetic markers consisted of sequence-tagged sites, primarily detected as dCAPS or CAPS (n = 131) and VNTRs (n = 31), in addition to AFLPs (n = 66) and 7 other markers. While most markers exhibited Mendelian inheritance, segregation distortion was observed for 25 predominantly clustered markers. A linkage map was generated using the Kosambi mapping function, using a LOD threshold value of 3.5. Nine linkage groups were detected, covering 1234 cM and anchoring 99.83% of the draft sequence assembly. The nine linkage groups and the 22 anchored scaffolds from the sequence assembly could be assembled into four chromosomes, leaving only five smaller scaffolds (59,630 bp total) of the nuclear DNA unanchored. A chromosome number of four was confirmed by cytological karyotyping. Further analysis of the genetic map data identified variation in recombination rate in different genomic regions that often spanned several hundred kilobases.

Gale, L. R.; Bryant, J. D.; Calvo, S.; Giese, H.; Katan, T.; O'Donnell, K.; Suga, H.; Taga, M.; Usgaard, T. R.; Ward, T. J.; Kistler, H. C.

2005-01-01

21

Response of endophytic bacterial communities in banana tissue culture plantlets to Fusarium wilt pathogen infection.  

PubMed

Endophytic bacteria reside within plant hosts without having pathogenic effects, and various endophytes have been found to functionally benefit plant disease suppressive ability. In this study, the influence of banana plant stress on the endophytic bacterial communities, which was achieved by infection with the wilt pathogen Fusarium oxysporum f. sp. cubense, was examined by cultivation-independent denaturing gradient gel electrophoresis analysis of 16S ribosomal DNA directly amplified from plant tissue DNA. Community analysis clearly demonstrated increased bacterial diversity in pathogen-infected plantlets compared to that in control plantlets. By sequencing, bands most similar to species of Bacillus and Pseudomonas showed high density in the pathogen-treated pattern. In vitro screening of the isolates for antagonistic activity against Fusarium wilt pathogen acquired three strains of endophytic bacteria which were found to match those species that obviously increased in the pathogen infection process; moreover, the most inhibitive strain could also interiorly colonize plantlets and perform antagonism. The evidence obtained from this work showed that antagonistic endophytic bacteria could be induced by the appearance of a host fungal pathogen and further be an ideal biological control agent to use in banana Fusarium wilt disease protection. PMID:18497482

Lian, Jie; Wang, Zifeng; Zhou, Shining

2008-04-01

22

Fusarium Pathogenomics  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium is a genus of filamentous fungi that contains many agronomically important plant pathogens, mycotoxin producers, and opportunistic human pathogens. Comparative analyses have revealed compartmentalization of genomes into regions responsible for metabolism and reproduction (core genome) and p...

23

Entomogenous Fusarium species  

Microsoft Academic Search

Fusarium species are known for their abundance in nature and their diverse associations with both living and dead plants and animals. Among animals Fusarium is found primarily in relationship with insects. This literature review of the past 50 years includes both non-pathogenic and pathogenic relationships between Fusarium and insects. Special attention is given to the host range, particularly between plant-

Gertrud H. Teetor-Barsch; Donald W. Roberts

1983-01-01

24

The transcription factor FgStuAp influences spore development, pathogenicity, and secondary metabolism in Fusarium graminearum  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium graminearum is an important plant-pathogenic fungus and the major cause of cereal head blight. Here, we report the functional analysis of FgStuA, the gene for a transcription factor with homology to key developmental regulators in fungi. The deletion mutant was greatly reduced in pathogenic...

25

Night-time spore deposition of the fusarium head blight pathogen, Gibberella zeae, in rotational wheat fields  

Microsoft Academic Search

Many fungal plant pathogens rely on atmospheric motion systems for transport. The movement of these pathogens in the atmosphere is characterized by processes of liberation, drift, and deposition. We observed temporal patterns of viable spore deposition of Gibberella zeae, causal agent of fusarium head blight (FHB) of wheat, over rotational wheat fields (with no visible residues of corn or wheat,

David G. Schmale III; Gary C. Bergstrom; Elson J. Shields

2006-01-01

26

Pathogen Phytosensing: Plants to Report Plant Pathogens  

PubMed Central

Real-time systems that provide evidence of pathogen contamination in crops can be an important new line of early defense in agricultural centers. Plants possess defense mechanisms to protect against pathogen attack. Inducible plant defense is controlled by signal transduction pathways, inducible promoters and cis-regulatory elements corresponding to key genes involved in defense, and pathogen-specific responses. Identified inducible promoters and cis-acting elements could be utilized in plant sentinels, or ‘phytosensors’, by fusing these to reporter genes to produce plants with altered phenotypes in response to the presence of pathogens. Here, we have employed cis-acting elements from promoter regions of pathogen inducible genes as well as those responsive to the plant defense signal molecules salicylic acid, jasmonic acid, and ethylene. Synthetic promoters were constructed by combining various regulatory elements supplemented with the enhancer elements from the Cauliflower mosaic virus (CaMV) 35S promoter to increase basal level of the GUS expression. The inducibility of each synthetic promoter was first assessed in transient expression assays using Arabidopsis thaliana protoplasts and then examined for efficacy in stably transgenic Arabidopsis and tobacco plants. Histochemical and fluorometric GUS expression analyses showed that both transgenic Arabidopsis and tobacco plants responded to elicitor and phytohormone treatments with increased GUS expression when compared to untreated plants. Pathogen-inducible phytosensor studies were initiated by analyzing the sensitivity of the synthetic promoters against virus infection. Transgenic tobacco plants infected with Alfalfa mosaic virus showed an increase in GUS expression when compared to mock-inoculated control plants, whereas Tobacco mosaic virus infection caused no changes in GUS expression. Further research, using these transgenic plants against a range of different pathogens with the regulation of detectable reporter gene could provide biological evidence to define the functional differences between pathogens, and provide new technology and applications for transgenic plants as phytosensors.

Mazarei, Mitra; Teplova, Irina; Hajimorad, M. Reza; Stewart, C. Neal

2008-01-01

27

Aquatic Plant Control Research Program. Evaluation of Fusarium Roseum 'Culmorum' as a Biological Control Agent for Hydrilla verticillata.  

National Technical Information Service (NTIS)

An isolate of Fusarium roseum 'Culmorum' was isolated in 1974 from diseased stratiotes aloides (Hydrocharitaceae) plants found new Wageningen, The Netherlands. In laboratory tests conducted in Gainesville, it was found to be pathogenic to a relative of S....

R. Charudattan T. E. Freeman R. E. Cullen F. M. Hofmeister

1984-01-01

28

Predominance and association of pathogenic fungi causing Fusarium ear blightin wheat in four European countries  

Microsoft Academic Search

Two years of field sampling aimed to establish the predominance and association among the fungal pathogens causing Fusarium ear blight (FEB) in four European countries (Hungary, Ireland, Italy and the UK). A PCR-based method was used to detect four Fusarium species and two varieties of Microdochium nivale present in the samples. The prevalence of FEB pathogens differed significantly between countries.

X.-M. Xu; D. W. Parry; P. Nicholson; M. A. Thomsett; D. Simpson; S. G. Edwards; B. M. Cooke; F. M. Doohan; J. M. Brennan; A. Moretti; G. Tocco; G. Mule; L. Hornok; G. Giczey; J. Tatnell

2005-01-01

29

Improved Colonization of East African Highland Musa Tissue Culture Plants by Endophytic Fusarium oxysporum  

Microsoft Academic Search

Non-pathogenic endophytic Fusarium oxysporum inoculated into banana (Musa spp.) tissue culture plants can provide protection against banana weevils (Cosmopolites sordidus) and nematodes (Radopholus similis). The degree of control probably depends, in part, upon the level of endophyte establishment following inoculation. In this study, we compared three methods of inoculating endophytic fungi into eight week-old tissue culture plants: (1) Dipping the

P. Paparu; T. Dubois; C. S. Gold; B. Niere; E. Adipala; D. L. Coyne

2006-01-01

30

Plant pathogen resistance  

SciTech Connect

Azelaic acid or its derivatives or analogs induce a robust and a speedier defense response against pathogens in plants. Azelaic acid treatment alone does not induce many of the known defense-related genes but activates a plant's defense signaling upon pathogen exposure.

Greenberg, Jean T; Jung, Ho Won; Tschaplinski, Timothy

2012-11-27

31

Plant pathogenic Pseudomonas species  

Microsoft Academic Search

In the current taxonomy, plant pathogenic Pseudomonas species are restricted to rRNA group I organisms belonging to the Gamma subclass of Proteobacteria. Currently, about 21 validly described plant pathogenic Pseudomonas species are known. The most important species is P. syringae with more than 50 described pathovars. The pathovar concept is confusing and the taxonomy of P. syringae needs revision. P.

Monica Höfte; PAUL DE VOS

32

Occurrence, pathogenicity and distribution of Fusarium spp. in stored wheat seeds Kermanshah Province, Iran.  

PubMed

Fusarium is one of the most important pathogenic and toxigenic fungi widely distributed all over the world, including Iran. Fusarium species are found frequently in stored agriculture products especially wheat. The objective of this study was to identify Fusarium species associated with stored wheat seeds and their pathogenicity on root and head of wheat in Kermanshah, the leading province in wheat production in Iran. In this survey 75 seed samples of stored wheat were collected from 10 different regions during 2006-2008 and tested for the presence of Fusarium. Fusarium spp. were found in 51 (68%) of 75 samples. A total of 580 Fusarium strains were isolated, identified and preserved. All these strains belong to 20 Fusarium spp. according to morphological characters. Each conidial suspension of selected strains representing all species was evaluated for their pathogenicity on roots and spikes of healthy wheat var. Fallat in the greenhouse. F. graminearum, F. crookwellense, F. trichothecioides, F. culmorum and F. verticillioides were the most pathogenic to wheat's head. Foot rot assessment revealed that F. pseudograminearum and F. culmorum were the most damaging species. Of the Fusarium isolates, F. graminearum was the most prevalent followed by F. verticillioides and F. proliferatum. This is the first comprehensive report on identity and distribution of Fusarium spp. from stored wheat seeds in Iran while F. nelsonii was reported for the first time from wheat seeds in Iran. PMID:21313898

Chehri, K; Salleh, B; Yli-Mattila, T; Soleimani, M J; Yousefi, A R

2010-12-15

33

Transposon-tagging identifies novel pathogenicity genes in Fusarium graminearum.  

PubMed

With the increase of sequenced fungal genomes, high-throughput methods for functional analyses of genes are needed. We assessed the potential of a new transposon mutagenesis tool deploying a Fusarium oxysporum miniature inverted-repeat transposable element mimp1, mobilized by the transposase of impala, a Tc1-like transposon, to obtain knock-out mutants in Fusarium graminearum. We localized 91 mimp1 insertions which showed good distribution over the entire genome. The main exception was a major hotspot on chromosome 2 where independent insertions occurred at exactly the same nucleotide position. Furthermore insertions in promoter regions were over-represented. Screening 331 mutants for sexual development, radial growth and pathogenicity on wheat resulted in 19 mutants (5.7%) with altered phenotypes. Complementation with the original gene restored the wild-type phenotype in two selected mutants demonstrating the high tagging efficiency. This is the first report of a MITE transposon tagging system as an efficient mutagenesis tool in F. graminearum. PMID:18926918

Dufresne, Marie; van der Lee, Theo; Ben M'barek, Sarrah; Xu, Xiude; Zhang, Xu; Liu, Taiguo; Waalwijk, Cees; Zhang, Wenwei; Kema, Gert H J; Daboussi, Marie-Josée

2008-09-23

34

The Sfp-Type 4?-Phosphopantetheinyl Transferase Ppt1 of Fusarium fujikuroi Controls Development, Secondary Metabolism and Pathogenicity  

Microsoft Academic Search

The heterothallic ascomycete Fusarium fujikuroi is a notorious rice pathogen causing super-elongation of plants due to the production of terpene-derived gibberellic acids (GAs) that function as natural plant hormones. Additionally, F. fujikuroi is able to produce a variety of polyketide- and non-ribosomal peptide-derived metabolites such as bikaverins, fusarubins and fusarins as well as metabolites from yet unidentified biosynthetic pathways, e.g.

Philipp Wiemann; Sabine Albermann; Eva-Maria Niehaus; Lena Studt; Katharina W. von Bargen; Nelson L. Brock; Hans-Ulrich Humpf; Jeroen S. Dickschat; Bettina Tudzynski

2012-01-01

35

Influence of Climatic Factors on Fusarium Species Pathogenic to Cereals  

Microsoft Academic Search

Fusarium head blight of small-grain cereals, ear rot of maize, seedling blight and foot rot of cereals are important diseases throughout the world. Fusarium graminearum, F. culmorum, F. poae, F. avenaceum and Microdochium nivale (formerly known as F. nivale) predominantly cause Fusarium diseases of small-grain cereals. Maize is predominantly attacked by F. graminearum, F. moniliforme, F. proliferatum and F. subglutinans.

F. M. Doohan; J. Brennan; B. M. Cooke

2003-01-01

36

Studies on in vitro Growth and Pathogenicity of European Fusarium Fungi  

Microsoft Academic Search

The effect of temperature on the in vitro growth rates and pathogenicity of a European Fusarium collection consisting of isolates of Fusarium graminearum,F. culmorum,F. avenaceum, F. poae and Microdochium nivale was examined. Irrespective of geographic origin, the optimum temperature for the growth of F. graminearum, F. culmorum and F. poae was 25 °C, while that for F. avenaceum and M.

J. M. Brennan; B. Fagan; A. van Maanen; B. M. Cooke; F. M. Doohan

2003-01-01

37

Visualizing and quantifying Fusarium oxysporum in the plant host.  

PubMed

Host-specific forms of Fusarium oxysporum infect the roots of numerous plant species. I present a novel application of familiar methodology to visualize and quantify F. oxysporum in roots. Infection in the roots of Arabidopsis thaliana, tomato, and cotton was detected with colorimetric reagents that are substrates for Fusarium spp.-derived arabinofuranosidase and N-acetyl-glucosaminidase activities and without the need for genetic modification of either plant host or fungal pathogen. Similar patterns of blue precipitation were produced by treatment with 5-bromo-4-chloro-3-indoxyl-?-l-arabinofuranoside and 5-bromo-4-chloro-3-indoxyl-2-acetamido-2-deoxy-?-d-glucopyranoside, and these patterns were consistent with prior histological descriptions of F. oxysporum in roots. Infection was quantified in roots of wild-type and mutant Arabidopsis using 4-nitrophenyl-?-l-arabinofuranoside. In keeping with an expectation that disease severity above ground is correlated with F. oxysporum infection below ground, elevated levels of arabinofuranosidase activity were measured in the roots of susceptible agb1 and rfo1 while a reduced level was detected in the resistant eir1. In contrast, disease severity and F. oxysporum infection were uncoupled in tir3. The distribution of staining patterns in roots suggests that AGB1 and RFO1 restrict colonization of the vascular cylinder by F. oxysporum whereas EIR1 promotes colonization of root apices. PMID:22894177

Diener, Andrew

2012-12-01

38

The Fusarium Graminearum Genome Reveals a Link Between Localized Polymorphism and Pathogen Specialization  

SciTech Connect

We sequenced and annotated the genome of the filamentous fungus Fusarium graminearum, a major pathogen of cultivated cereals. Very few repetitive sequences were detected, and the process of repeat-induced point mutation, in which duplicated sequences are subject to extensive mutation, may partially account for the reduced repeat content and apparent low number of paralogous (ancestrally duplicated) genes. A second strain of F. graminearum contained more than 10,000 single-nucleotide polymorphisms, which were frequently located near telomeres and within other discrete chromosomal segments. Many highly polymorphic regions contained sets of genes implicated in plant-fungus interactions and were unusually divergent, with higher rates of recombination. These regions of genome innovation may result from selection due to interactions of F. graminearum with its plant hosts.

Cuomo, Christina A.; Guldener, Ulrich; Xu, Jin Rong; Trail, Frances; Turgeon, Barbara G.; Di Pietro, Antonio; Walton, Johnathan D.; Ma, Li Jun; Baker, Scott E.; Rep, Martijn; Adam, Gerhard; Antoniw, John; Baldwin, Thomas; Calvo, Sarah; Chang, Yueh Long; DeCaprio, David; Gale, Liane R.; Gnerre, Sante; Goswami, Rubella S.; Hammond-Kossack, Kim; Harris, Linda J.; Hilburn, Karen; Kennell, John C.; Kroken, Scott; Magnuson, Jon K.; Mannhaupt, Gertrud; Mauceli, Evan; Mewes, Hans Werner; Mitterbauer, Rudolf; Muehlbauer, Gary; Munsterkotter, Martin; Nelson, David; O'Donnell, Kerry; Ouellet, Therese; Qi, Weihong; Quesneville, Hadi; Roncero, M. Isabel; Seong, Kye Yong; Tetko, Igor V.; Urban, Martin; Waalwijk, Cees; Ward, Todd J.; Yao, Jiqiang; Birren, Bruce W.; Kistler, H. Corby

2007-09-07

39

The Fusarium graminearum genome reveals a link between localized polymorphism and pathogen specialization.  

PubMed

We sequenced and annotated the genome of the filamentous fungus Fusarium graminearum, a major pathogen of cultivated cereals. Very few repetitive sequences were detected, and the process of repeat-induced point mutation, in which duplicated sequences are subject to extensive mutation, may partially account for the reduced repeat content and apparent low number of paralogous (ancestrally duplicated) genes. A second strain of F. graminearum contained more than 10,000 single-nucleotide polymorphisms, which were frequently located near telomeres and within other discrete chromosomal segments. Many highly polymorphic regions contained sets of genes implicated in plant-fungus interactions and were unusually divergent, with higher rates of recombination. These regions of genome innovation may result from selection due to interactions of F. graminearum with its plant hosts. PMID:17823352

Cuomo, Christina A; Güldener, Ulrich; Xu, Jin-Rong; Trail, Frances; Turgeon, B Gillian; Di Pietro, Antonio; Walton, Jonathan D; Ma, Li-Jun; Baker, Scott E; Rep, Martijn; Adam, Gerhard; Antoniw, John; Baldwin, Thomas; Calvo, Sarah; Chang, Yueh-Long; Decaprio, David; Gale, Liane R; Gnerre, Sante; Goswami, Rubella S; Hammond-Kosack, Kim; Harris, Linda J; Hilburn, Karen; Kennell, John C; Kroken, Scott; Magnuson, Jon K; Mannhaupt, Gertrud; Mauceli, Evan; Mewes, Hans-Werner; Mitterbauer, Rudolf; Muehlbauer, Gary; Münsterkötter, Martin; Nelson, David; O'donnell, Kerry; Ouellet, Thérčse; Qi, Weihong; Quesneville, Hadi; Roncero, M Isabel G; Seong, Kye-Yong; Tetko, Igor V; Urban, Martin; Waalwijk, Cees; Ward, Todd J; Yao, Jiqiang; Birren, Bruce W; Kistler, H Corby

2007-09-01

40

MEMBERS OF THE FUSARIUM SOLANI SPECIES COMPLEX CAUSING INFECTIONS IN BOTH HUMANS AND PLANTS ARE THOSE MOST COMMONLY ENCOUNTERED IN THE ENVIRONMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Members of the Fusarium solani species complex (FSSC) are increasingly implicated as the causative agents of human mycoses, particularly in the expanding immunocompromised and immunosuppressed patient populations. Best known as ubiquitous plant pathogens and saprotrophs, members of FSSC comprise ov...

41

Role of fusaric acid in the virulence of cotton wilt pathogen Fusarium Oxysporum f. sp. Vasinfectum  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusaric acid is a potent phytotoxin to cotton. It has also long been implicated in the pathogenesis of Fusarium wilt for a number of plant species including cotton, tomato, watermelon, and flax. The Australian biotype isolates of Fusarium oxysporum f. sp. vasinfectum (Fov) produce copious amount of ...

42

Antifungal properties of essential oils from Thai medical plants against rice pathogenic fungi  

Microsoft Academic Search

This in vitro study was aimed to evaluate the mycelium growth and spore germination inhibition properties of essential oils. Two Thai medicinal plants; Frankincense oil (Boswellia carteri Bird.) and Cassia oil (Acacia farnesiana Linn) were applied against 7 species of economically important rice pathogenic fungi; Alternaria brassicicola, Aspergillus flavus, Bipolaris oryzae, Fusarium moniliforme, Fusarium proliferatum, Pyricularia arisea and Rhizoctonia solani.

Apinya Piyo; Pitipong Thobunluepop

43

Pathogenicity and real-time PCR detection of Fusarium spp. in wheat and barley roots  

Microsoft Academic Search

The pathogenicity of five Fusarium spp. frequently isolated from wheat and barley roots in southern Idaho was investigated during four growth-chamber experiments and two field studies. A real-time PCR assay for quantifying the presence of F. culmorum from infected root tissue was also developed based on nucleotide sequence for the tri5 gene. Fusarium culmorum, followed by F. acuminatum and F.

Carl A. Strausbaugh; Ken Overturf; Anita C. Koehn

2005-01-01

44

Genotype Response of Soybean (Glycine max) Whole Plants and Hairy Roots to Fusarium solani f. sp. glycines Infection  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium solani f. sp. Glycines, a soilborne fungus, infects soybean roots and causes sudden death syndrome. The response of 13 soybean genotypes to the pathogen infection was tested with potted greenhouse grown plants and with cultured hairy roots. The taproots of all genotypes grown plants measure...

45

Mode of action of a non-pathogenic Fusarium oxysporum strain against Verticillium dahliae using Real Time QPCR analysis and biomarker transformation  

Microsoft Academic Search

Verticillium wilt is a devastating disease of a wide range of herbaceous and woody plant hosts. It is incited by the soilborne fungus Verticillium dahliae. Management strategies are mainly focused on preventive measures. In a previous study, the efficacy of a non-pathogenic Fusarium oxysporum strain, designated as F2, isolated from a suppressive compost amendment, has been reported to reduce Verticillium

Iakovos S. Pantelides; Sotirios E. Tjamos; Ioannis A. Striglis; Iordanis Chatzipavlidis; Epaminondas J. Paplomatas

2009-01-01

46

Suppression of fusarium wilts by fluorescent pseudomonads: Mechanisms and applications  

Microsoft Academic Search

Fluorescent pseudomonads are involved in the natural suppressiveness of some soils to fusarium wilts. These bacteria have been applied successfully to suppress fusarium wilts of various plant species grown in conducive soils and growing substrates. Suppression of fusarium wilts by fluorescent pseudomonads can be ascribed to direct and indirect effects against pathogenic Fusarium oxysporum. Direct effects are expressed by a

P. Lemanceau; C. Alabouvette

1993-01-01

47

Microbiological and SYBR green real-time PCR detection of major Fusarium head blight pathogens on wheat ears.  

PubMed

Fusarium head blight (FHB) caused by several Fusarium species is one of the most serious diseases affecting wheat throughout the world. The efficiency of microbiological assays and real-time PCRto quantify major FHB pathogens in wheat ears after inoculation with F. graminearum, F. culmorum, F. avenaceum and F. poae undergreenhouse and field conditions were evaluated. The frequency of infected kernel, content of fungal biomass, disease severity and kernel weight were determined. To measure the fungal biomass an improved DNA extraction method and a SYBR Green real-time PCR were developed. The SYBR Green real-time PCR proved to be highly specific for individual detection of the species in a matrix including fungal and plant DNA. The effect of Fusarium infection on visible FHB severity, frequency of infected kernels and thousand-kernel mass (TKM) significantly depended on the Fusarium species/isolate. F. graminearum resulted in highest disease level, frequency of infected kernels, content of fungal biomass, and TKM reduction followed by F. culmorum, EF avenaceum and F. poae, respectively. The comparison of frequency and intensity of kernel colonization proved differences in aggressiveness and development of the fungi in the kernels. Only for F. graminearum, the most aggressive isolate, application of microbiological and real-time PCR assays gave similar results. For the other species, the intensity of kernel colonization was lower than expected from the frequency of infection. PMID:21090507

Moradi, M; Oerke, E C; Steiner, U; Tesfaye, D; Schellander, K; Dehne, H-W

48

The Wor1-like Protein Fgp1 Regulates Pathogenicity, Toxin Synthesis and Reproduction in the Phytopathogenic Fungus Fusarium graminearum  

PubMed Central

WOR1 is a gene for a conserved fungal regulatory protein controlling the dimorphic switch and pathogenicity determents in Candida albicans and its ortholog in the plant pathogen Fusarium oxysporum, called SGE1, is required for pathogenicity and expression of key plant effector proteins. F. graminearum, an important pathogen of cereals, is not known to employ switching and no effector proteins from F. graminearum have been found to date that are required for infection. In this study, the potential role of the WOR1-like gene in pathogenesis was tested in this toxigenic fungus. Deletion of the WOR1 ortholog (called FGP1) in F. graminearum results in greatly reduced pathogenicity and loss of trichothecene toxin accumulation in infected wheat plants and in vitro. The loss of toxin accumulation alone may be sufficient to explain the loss of pathogenicity to wheat. Under toxin-inducing conditions, expression of genes for trichothecene biosynthesis and many other genes are not detected or detected at lower levels in ?fgp1 strains. FGP1 is also involved in the developmental processes of conidium formation and sexual reproduction and modulates a morphological change that accompanies mycotoxin production in vitro. The Wor1-like proteins in Fusarium species have highly conserved N-terminal regions and remarkably divergent C-termini. Interchanging the N- and C- terminal portions of proteins from F. oxysporum and F. graminearum resulted in partial to complete loss of function. Wor1-like proteins are conserved but have evolved to regulate pathogenicity in a range of fungi, likely by adaptations to the C-terminal portion of the protein.

Jonkers, Wilfried; Dong, Yanhong; Broz, Karen; Corby Kistler, H.

2012-01-01

49

The Wor1-like protein Fgp1 regulates pathogenicity, toxin synthesis and reproduction in the phytopathogenic fungus Fusarium graminearum.  

PubMed

WOR1 is a gene for a conserved fungal regulatory protein controlling the dimorphic switch and pathogenicity determents in Candida albicans and its ortholog in the plant pathogen Fusarium oxysporum, called SGE1, is required for pathogenicity and expression of key plant effector proteins. F. graminearum, an important pathogen of cereals, is not known to employ switching and no effector proteins from F. graminearum have been found to date that are required for infection. In this study, the potential role of the WOR1-like gene in pathogenesis was tested in this toxigenic fungus. Deletion of the WOR1 ortholog (called FGP1) in F. graminearum results in greatly reduced pathogenicity and loss of trichothecene toxin accumulation in infected wheat plants and in vitro. The loss of toxin accumulation alone may be sufficient to explain the loss of pathogenicity to wheat. Under toxin-inducing conditions, expression of genes for trichothecene biosynthesis and many other genes are not detected or detected at lower levels in ?fgp1 strains. FGP1 is also involved in the developmental processes of conidium formation and sexual reproduction and modulates a morphological change that accompanies mycotoxin production in vitro. The Wor1-like proteins in Fusarium species have highly conserved N-terminal regions and remarkably divergent C-termini. Interchanging the N- and C- terminal portions of proteins from F. oxysporum and F. graminearum resulted in partial to complete loss of function. Wor1-like proteins are conserved but have evolved to regulate pathogenicity in a range of fungi, likely by adaptations to the C-terminal portion of the protein. PMID:22693448

Jonkers, Wilfried; Dong, Yanhong; Broz, Karen; Kistler, H Corby

2012-05-31

50

Functional genomic studies of pathogenicity in Fusarium graminearum  

Technology Transfer Automated Retrieval System (TEKTRAN)

Head blight or scab caused by Fusarium graminearum is a disease of wheat and barley that occurs worldwide and that has great impact on U.S. agriculture and society. Infested cereals are often contaminated with trichothecene and estrogenic mycotoxins. To better understand fungal pathogenesis and deve...

51

The AMT1 Arginine Methyltransferase Gene Is Important for Plant Infection and Normal Hyphal Growth in Fusarium graminearum  

Microsoft Academic Search

Arginine methylation of non-histone proteins by protein arginine methyltransferase (PRMT) has been shown to be important for various biological processes from yeast to human. Although PRMT genes are well conserved in fungi, none of them have been functionally characterized in plant pathogenic ascomycetes. In this study, we identified and characterized all of the four predicted PRMT genes in Fusarium graminearum,

Guanghui Wang; Chenfang Wang; Rui Hou; Xiaoying Zhou; Guotian Li; Shijie Zhang; Jin-Rong Xu

2012-01-01

52

BIOLOGICAL, PATHOGENIC, AND MOLECULAR CHARACTERIZATION OF FUSARIUM SOLANI F. SP. GLYCINES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soybean sudden death syndrome (SDS) is caused by Fusarium solani f. sp. glycines (FSG). Over the last 5 years an internationsl collection of FSG isolates has been established and maintained at the National Soybean Pathogen Collection Center. FSG isolates grew slowly and appeared reddish light blue t...

53

Auxin signaling and transport promote susceptibility to the root-infecting fungal pathogen Fusarium oxysporum in Arabidopsis.  

PubMed

Fusarium oxysporum is a root-infecting fungal pathogen that causes wilt disease on a broad range of plant species, including the model plant Arabidopsis thaliana. Currently, very little is known about the molecular or physiological processes that are activated in the host during infection and the roles these processes play in resistance and susceptibility to F. oxysporum. In this study, we analyzed global gene expression profiles of F. oxysporum-infected Arabidopsis plants. Genes involved in jasmonate biosynthesis as well as jasmonate-dependent defense were coordinately induced by F. oxysporum. Similarly, tryptophan pathway genes, including those involved in both indole-glucosinolate and auxin biosynthesis, were upregulated in both the leaves and the roots of inoculated plants. Analysis of plants expressing the DR5:GUS construct suggested that root auxin homeostasis was altered during F. oxysporum infection. However, Arabidopsis mutants with altered auxin and tryptophan-derived metabolites such as indole-glucosinolates and camalexin did not show an altered resistance to this pathogen. In contrast, several auxin-signaling mutants were more resistant to F. oxysporum. Chemical or genetic alteration of polar auxin transport also conferred increased pathogen resistance. Our results suggest that, similarly to many other pathogenic and nonpathogenic or beneficial soil organisms, F. oxysporum requires components of auxin signaling and transport to colonize the plant more effectively. Potential mechanisms of auxin signaling and transport-mediated F. oxysporum susceptibility are discussed. PMID:21281113

Kidd, Brendan N; Kadoo, Narendra Y; Dombrecht, Bruno; Tekeoglu, Mücella; Gardiner, Donald M; Thatcher, Louise F; Aitken, Elizabeth A B; Schenk, Peer M; Manners, John M; Kazan, Kemal

2011-06-01

54

Petunia Floral Defensins with Unique Prodomains as Novel Candidates for Development of Fusarium Wilt Resistance in Transgenic Banana Plants  

Microsoft Academic Search

Antimicrobial peptides are a potent group of defense active molecules that have been utilized in developing resistance against a multitude of plant pathogens. Floral defensins constitute a group of cysteine-rich peptides showing potent growth inhibition of pathogenic filamentous fungi especially Fusarium oxysporum in vitro. Full length genes coding for two Petunia floral defensins, PhDef1 and PhDef2 having unique C- terminal

Siddhesh B. Ghag; Upendra K. Singh Shekhawat; Thumballi R. Ganapathi

2012-01-01

55

The mutualistic fungus Piriformospora indica protects barley roots from a loss of antioxidant capacity caused by the necrotrophic pathogen Fusarium culmorum.  

PubMed

Fusarium culmorum causes root rot in barley (Hordeum vulgare), resulting in severely reduced plant growth and yield. Pretreatment of roots with chlamydospores of the mutualistic root-colonizing basidiomycete Piriformospora indica (subdivision Agaricomycotina) prevented necrotization of root tissues and plant growth retardation commonly associated with Fusarium root rot. Quantification of Fusarium infections with a real-time polymerase chain reaction assay revealed a correlation between root rot symptoms and the relative amount of fungal DNA. Fusarium-infected roots showed reduced levels of ascorbate and glutathione (GSH), along with reduced activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, GSH reductase, dehydroascorbate reductase, and monodehydroascorbate reductase. Consistent with this, Fusarium-infected roots showed elevated levels of lipid hydroperoxides and decreased ratios of reduced to oxidized forms of ascorbate and GSH. In clear contrast, roots treated with P. indica prior to inoculation with F. culmorum showed levels of ascorbate and GSH that were similar to controls. Likewise, lipid peroxidation and the overall reduction in antioxidant enzyme activities were largely attenuated by P. indica in roots challenged by F. culmorum. These results suggest that P. indica protects roots from necrotrophic pathogens, at least partly, through activating the plant's antioxidant capacity. PMID:23405867

Harrach, Borbála D; Baltruschat, Helmut; Barna, Balázs; Fodor, József; Kogel, Karl-Heinz

2013-05-01

56

The Fusarium graminearum MAP1 gene is essential for pathogenicity and development of perithecia.  

PubMed

SUMMARY Fusarium graminearum is the causal agent of ear blight disease of cereals. Infection occurs at anthesis when ascospores and/or conidia directly penetrate exposed anther and ovary tissue. The hemibiotrophic hyphae colonize floral tissues and developing grains to cause premature ear senescence. During infection, Fusarium hyphae can also produce hazardous trichothecene mycotoxins, thereby posing a threat to human and animal health and safety. The Fusarium MAP1 gene was identified using a PCR approach by its homology to a known pathogenicity gene of Magnaporthe grisea, the mitogen-activated protein kinase gene PMK1. Gene replacement F. graminearum map1 mutants were non-pathogenic on wheat flowers and roots, and also could not infect wounded wheat floral tissue or tomato fruits. Unlike the wild-type strain, map1 mutant inoculations did not compromise grain yield. Map1 mutants lost their ability to form perithecia in vitro, but their rate of asexual conidiation was unaffected. DON mycotoxin production in planta was still detected. Collectively, the observed phenotypes suggest that the Map1 signalling protein controls multiple events in disease establishment and propagation. Novel approaches to control Fusarium ear blight disease by blocking perithecial development are discussed. PMID:20569395

Urban, Martin; Mott, Ellie; Farley, Tom; Hammond-Kosack, Kim

2003-09-01

57

High Consequence Plant Pathogens  

Microsoft Academic Search

Threatening pathogens present a great concern since they can impact agriculture, economy, international trade and environmental\\u000a diversity. Among the pathogens which cause increased agricultural and social concern are new or re-emerging pathogens. Most\\u000a of the important agricultural crops have spread during the last two centuries outside their original environment all over\\u000a the world. An immediate and parallel trend is the

Abraham Gamliel

58

A Novel Antifungal Furanone from Pseudomonas aureofaciens, a Biocontrol Agent of Fungal Plant Pathogens  

Microsoft Academic Search

Pseudomonas aureofaciens (= P. chlororaphis) strain 63-28 is a biocontrol agent active against many soil-borne fungal plant pathogens and shows antifungal activity in culture assays. 3-(1-Hexenyl)-5-methyl-2-(5H)furanone was isolated from culture filtrates of this bacterium. The purified furanone showed antifungal activity against Pythium ultimum, Fusarium solani, Fusarium oxysporum, and Thielaviopsis basicola. The ED50S for spore germination of these fungi were 45,

Timothy Paulitz; Brian Nowak-Thompson; Pascale Gamard; Evelyn Tsang; Joyce Loper

2000-01-01

59

Comparative study of the pathogenicity of seabed isolates of Fusarium equiseti and the effect of the composition of the mineral salt medium and temperature on mycelial growth.  

PubMed

The pathogenicity of seven strains of Fusarium equiseti isolated from seabed soil was evaluated on different host plants showing pre and post emergence damage. Radial growth of 27 strains was measured on culture media previously adjusted to different osmotic potentials with either KCl or NaCl (-1.50 to -144.54 bars) at 15°, 25° and 35° C. Significant differences and interactive effects were observed in the response of mycelia to osmotic potential and temperature. PMID:24031710

Palmero, D; de Cara, M; Iglesias, C; Gálvez, L; Tello, J C

2011-09-01

60

Production of plant growth regulators by some Fusarium species  

Microsoft Academic Search

About 10 species ofFusarium were screened and tested for their growth regulatory activity on oat coleoptile straight growth test. Culture filtrates of\\u000a four species contained growthstimulating factors while others showed growth-inhibition responses on oat sections. On the whole,F. moniliforme was found to be produce higher stimulatory effects. Chromatographic analysis revealed the presence of several indole auxin\\u000a and gibberellin-like plant-growth regulators

M. S. Thakur; K. M. Vyas

1983-01-01

61

Entomogenous Fusarium species.  

PubMed

Fusarium species are known for their abundance in nature and their diverse associations with both living and dead plants and animals. Among animals Fusarium is found primarily in relationship with insects. This literature review of the past 50 years includes both non-pathogenic and pathogenic relationships between Fusarium and insects. Special attention is given to the host range, particularly between plant- and insect-hosts, and to the possible microbial potential of the fungus to control insect pests. Correct classification of this fungus has been difficult because of its diverse and non-uniform morphological features. However, by now a usable and reliable taxonomic system has been developed. The fungus can be easily cultured and mass produced. Among the non-pathogenic associations mutualism and allotrophy are found between Fusarium and wood-inhabiting and flour beetles, respectively, enhancing development and production of beetle larvae. Some insects contribute to the dispersal of the fungus in the environment by means of spore passage through their guts. Plant-pathogenic Fusarium species gain access to host tissue by plant-feeding insects. A large number of Fusarium spp. are entomopathogenic; some are weak, facultative pathogens, especially of the lepidopteran and coleopteran orders, and they will colonize their dead hosts as saprophytes. In a few cases pathogenicity to both plant and insect by one isolate was found. Strong pathogens were reported primarily from homopterans and dipterans from field observations of natural mortalities as well as from pathogenicity tests. Potential Fusarium isolates which cause high insect mortalities also show high host specificity and no damage to crop plants. The question of host invasion has been addressed by few investigators. Entrance of the fungus via the oral route, oviposition tubes, wounds, or ectoparasitic activity, were stated, but no claim for penetration of the insect cuticle. Mycotoxins, such as trichothecenes (T-2) and other secondary metabolites, contributed to mortalities of termites, mealworms, flour beetles, maize borers and blow flies, while zearalenone (F-2) exhibited a beneficial effect on egg production in flour beetles and a detrimental effect on fecundity in mammals. Studies on adverse effects of the fungus on beneficial organisms (including mammals and plants) revealed that both harmful as well as safe Fusarium isolates exist in nature. Highly host-specific and strongly entomopathogenic Fusarium isolates should be more extensively studied and tested for their possible use in biological control. PMID:6369143

Teetor-Barsch, G H; Roberts, D W

1983-12-01

62

Bacillus subtilis SQR 9 can control Fusarium wilt in cucumber by colonizing plant roots  

Microsoft Academic Search

Fusarium wilt is one of the major constraints on cucumber production worldwide. Several strategies have been used to control the causative\\u000a pathogen, Fusarium oxysporum f. sp. cucumerinum J. H. Owen, including soil solarization, fungicide seed treatment and biological control. In this study, F. oxysporum f. sp. cucumerinum was successfully controlled by a newly isolated strain, Bacillus subtilis SQR 9, in

Yun Cao; Zhenhua Zhang; Ning Ling; Yujuan Yuan; Xinyan Zheng; Biao Shen; Qirong Shen

2011-01-01

63

THE ROLE OF MAP KINASE IN FUSARIUM ASSOCIATION WITH CONTACT LENSES  

Microsoft Academic Search

Fusarium solani is a soil-borne pathogen devastating agricultural crops throughout the world. While most pathogens are host specific, the fusaria are able to infect both plants and animals. In 2004, an outbreak of Fusarium occurred in association with contact lens wear. Several species of Fusarium were involved but F. solani and F. oxysporum were most prominent. In this work, we

BROOK ALICIA DANBOISE

64

Genetic variability of Fusarium wilt pathogen isolates of chickpea (Cicer arietinum L.) assessed by molecular markers.  

PubMed

Genetic variability among 43 isolates of Fusarium oxysporum f.sp. ciceri, the chickpea wilt pathogen, collected from nine states of India including the four well-characterized races of the pathogen were assessed using the molecular markers, RAPDs and AFLP. Principal coordinate analysis of the similarity index data generated from the molecular marker studies mostly gave three different clusters: Of these two clusters represented race-1 and race-2, and the third cluster consisted of race-3 and race-4 pathogen isolates. In RAPDs a fourth cluster was seen which did not go with any of the four races of the pathogen. The molecular markers established the distinctness of race-1 and race-2 pathogen isolates and the close similarity of pathogen isolates of race-3 with that of race-4. AFLP was found to be more informative as it differentiated more number of the pathogen isolates with the known races with minimum of outliers. The high levels of DNA polymorphism observed with the molecular markers suggest the rapid evolution of new recombinants of the pathogen in the chickpea growing fields. PMID:12617504

Sivaramakrishnan, S; Kannan, Seetha; Singh, S D

2002-01-01

65

Use of ELISA and GUS?transformed strains to study competition between pathogenic and non?pathogenic Fusarium oxysporum for root colonization  

Microsoft Academic Search

To characterize the ability of different strains of Fusarium oxysporum to colonize roots, and to analyze competition for root colonization between pathogenic and non?pathogenic strains of F. oxysporum, it was necessary to develop specific labelling techniques for quantification of root colonization. Two methods were selected: the production of polyclonal antibodies, and the use of GUS?transformed strains of F. oxysporum. The

A. Eparvier; C. Alabouvette

1994-01-01

66

Microbiological and Sybr® Green real-time PCR detection of major Fusarium head blight pathogens on wheat ears  

Microsoft Academic Search

Fusarium head blight (FHB) caused by several Fusarium species is one of the most serious diseases affecting wheat throughout the world. The efficiency of microbiological assays\\u000a and real-time PCR to quantify major FHB pathogens in wheat ears after inoculation with F. graminearum, F. culmorum, F. avenaceum and F. poae under greenhouse and field conditions were evaluated. The frequency of infected

M. Moradi; E.-C. Oerke; U. Steiner; D. Tesfaye; K. Schellander; H.-W. Dehne

2010-01-01

67

Detection of Fusarium wilt pathogens of Psidium guajava L. in soil using culture independent PCR (ciPCR).  

PubMed

Traditional culturing methods take a long time for identification of pathogenic isolates. A protocol has been developed for the detection of Fusarium from soil samples in the early stage of infection. Seventeen soil samples from different locations were collected before the onset of rains to find out the presence of Fusarium spp. population present in the soil of guava orchards and to correlate its presence with incidence of wilt. A PCR based method was developed for the molecular characterization of Fusarium using Fusarium spp. specific primer. DNA extracted by this method was free from protein and other contaminations and the yield was sufficient for PCR amplification. The primer developed in this study was amplifying ?230 bp in all infected samples while not in healthy soil. The specificity and sensitivity of primer were tested on several Fusarium spp. and found that this primer was amplifying 10(-6) dilution of the fungal DNA. The present study facilitates the rapid detection of Fusarium spp. from infected soil samples of guava collected from different agroclimatic regions in India. A rapid detection method for pathogens and a diagnostic assay for disease would facilitate an early detection of pathogen and lead to more effective control strategies. PMID:23961219

Mishra, Rupesh K; Pandey, Brajesh K; Muthukumar, M; Pathak, Neelam; Zeeshan, Mohammad

2012-11-10

68

Detection of Fusarium wilt pathogens of Psidium guajava L. in soil using culture independent PCR (ciPCR)  

PubMed Central

Traditional culturing methods take a long time for identification of pathogenic isolates. A protocol has been developed for the detection of Fusarium from soil samples in the early stage of infection. Seventeen soil samples from different locations were collected before the onset of rains to find out the presence of Fusarium spp. population present in the soil of guava orchards and to correlate its presence with incidence of wilt. A PCR based method was developed for the molecular characterization of Fusarium using Fusarium spp. specific primer. DNA extracted by this method was free from protein and other contaminations and the yield was sufficient for PCR amplification. The primer developed in this study was amplifying ?230 bp in all infected samples while not in healthy soil. The specificity and sensitivity of primer were tested on several Fusarium spp. and found that this primer was amplifying 10?6 dilution of the fungal DNA. The present study facilitates the rapid detection of Fusarium spp. from infected soil samples of guava collected from different agroclimatic regions in India. A rapid detection method for pathogens and a diagnostic assay for disease would facilitate an early detection of pathogen and lead to more effective control strategies.

Mishra, Rupesh K.; Pandey, Brajesh K.; Muthukumar, M.; Pathak, Neelam; Zeeshan, Mohammad

2012-01-01

69

Proteomics of Plant Pathogenic Fungi  

PubMed Central

Plant pathogenic fungi cause important yield losses in crops. In order to develop efficient and environmental friendly crop protection strategies, molecular studies of the fungal biological cycle, virulence factors, and interaction with its host are necessary. For that reason, several approaches have been performed using both classical genetic, cell biology, and biochemistry and the modern, holistic, and high-throughput, omic techniques. This work briefly overviews the tools available for studying Plant Pathogenic Fungi and is amply focused on MS-based Proteomics analysis, based on original papers published up to December 2009. At a methodological level, different steps in a proteomic workflow experiment are discussed. Separate sections are devoted to fungal descriptive (intracellular, subcellular, extracellular) and differential expression proteomics and interactomics. From the work published we can conclude that Proteomics, in combination with other techniques, constitutes a powerful tool for providing important information about pathogenicity and virulence factors, thus opening up new possibilities for crop disease diagnosis and crop protection.

Gonzalez-Fernandez, Raquel; Prats, Elena; Jorrin-Novo, Jesus V.

2010-01-01

70

Colonization of Tomato Root by Pathogenic and Nonpathogenic Fusarium oxysporum Strains Inoculated Together and Separately into the Soil  

PubMed Central

In soil, fungal colonization of plant roots has been traditionally studied by indirect methods such as microbial isolation that do not enable direct observation of infection sites or of interactions between fungal pathogens and their antagonists. Confocal laser scanning microscopy was used to visualize the colonization of tomato roots in heat-treated soil and to observe the interactions between a nonpathogenic strain, Fo47, and a pathogenic strain, Fol8, inoculated onto tomato roots in soil. When inoculated separately, both fungi colonized the entire root surface, with the exception of the apical zone. When both strains were introduced together, they both colonized the root surface and were observed at the same locations. When Fo47 was introduced at a higher concentration than Fol8, it colonized much of the root surface, but hyphae of Fol8 could still be observed at the same location on the root. There was no exclusion of the pathogenic strain by the presence of the nonpathogenic strain. These results are not consistent with the hypothesis that specific infection sites exist on the root for Fusarium oxysporum and instead support the hypothesis that competition occurs for nutrients rather than for infection sites.

Olivain, Chantal; Humbert, Claude; Nahalkova, Jarmila; Fatehi, Jamshid; L'Haridon, Floriane; Alabouvette, Claude

2006-01-01

71

Shifts in banana root exudate profiles after colonization with the non-pathogenic Fusarium oxysporum strain Fo162.  

PubMed

The non-pathogenic fungus Fusorium oxysporum strain Fo162 can efficiently colonize banana roots and reduce infecting by the burrowing nematode Radopholus similis. It is assumed that the fungus triggers a systemic reaction in the plant, which is affecting the biochemical composition of the root exudates and is thus causing the reduction in nematode colonization. To characterize these shifts, a continuous flow experiment was set up to collect root metabolites on a matrix (XAD-4). Based on HPLC analysis, the extracts, collected from the XAD-4, showed no differences in the composition of the root exudates between plants colonized by the endophyte and the controls. However, the accumulation of several compounds differed significantly. When these extracts were used in a bioassay with Radopholus similis none of the sample-treatment combinations had a significant attracting or repelling effect on the nematodes. This experiment shows that non-pathogenic Fusarium oxysporum strain Fo162 is able to upregulate the synthesis of at least some, so far unidentified compounds released by banana roots under hydroponic conditions. Further studies and optimization of the experimental setup are required to determine whether or not increase in metabolite concentration can affect nematode responses in vitro and ultimately in vivo. PMID:20222617

Kurtz, Andreas; Schouten, Alexander

2009-01-01

72

Mycotoxigenic Fusarium species in animal feed  

Microsoft Academic Search

Fusarium species are among the most studied plant-pathogenic fungi, with several species causing diseases on maize, wheat, barley, and other food and feed grains. Decreased yield, as well as diminished quality and value of the grain, results in significant worldwide economic losses. Additionally, Fusarium species produce a chemically diverse array of mycotoxins such as diacetoxyscirpenol, deoxynivalenol, nivalenol, T-2 toxin, zearalenone,

A. E. Glenn

2007-01-01

73

Fusarium azukicola sp. nov., an exotic azuki bean root-rot pathogen in Hokkaido, Japan.  

PubMed

We report on the phenotypic, molecular phylogenetic and pathogenic characterization of a novel azuki bean (Vigna angularis) root-rot (BRR) pathogen from Hokkaido, Japan, which formally is described herein as Fusarium azukicola. This species can be distinguished phenotypically from the other Phaseolus/Vigna BRR and soybean sudden-death syndrome (SDS) pathogens by the production of wider and longer four-septate conidia cultured on SNA. Molecular phylogenetic analyses of four anonymous intergenic loci, a portion of the translation elongation factor (EF-1?) gene and the nuclear ribosomal intergenic spacer region (IGS rDNA) strongly support the genealogical exclusivity of F. azukicola with respect to the other soybean SDS and BRR pathogens within Clade 2 of the F. solani species complex (FSSC). Evolutionary relationships of F. azukicola to other members of the SDS-BRR clade, however, are unresolved by phylogenetic analyses of the individual and combined datasets, with the exception of the IGS rDNA partition, which strongly supports it as a sister of the soybean SDS pathogen F. brasiliense. A multilocus genotyping assay is updated to include primer probes that successfully distinguish F. azukicola from the other soybean SDS and BRR pathogens. Results of a pathogenicity experiment reveal that the F. azukicola isolates are able to induce root-rot symptoms on azuki bean, mung bean (Vigna radiata), kidney bean (Phaseolus vulgaris) and soybean (Glycine max), as well as typical SDS foliar symptoms on soybean. Our hypothesis is that F. azukicola evolved in South America and was introduced to Hokkaido, Japan, on azuki bean but its possible route of introduction remains unknown. PMID:22492403

Aoki, Takayuki; Tanaka, Fumio; Suga, Haruhisa; Hyakumachi, Mitsuro; Scandiani, María Mercedes; O'Donnell, Kerry

2012-04-09

74

Characterization of Fusarium verticillioides strains isolated from maize in Italy: fumonisin production, pathogenicity and genetic variability.  

PubMed

Fusarium verticillioides (teleomorph Gibberella moniliformis) is the main fungal agent of ear and kernel rot of maize (Zea mays L.) worldwide, including Italy. F.verticillioides is a highly toxigenic species since it is able to produce the carcinogenic mycotoxins fumonisins. In this study, 25 F. verticillioides strains, isolated from maize in different regions of Italy were analyzed for their ability to produce fumonisins, their pathogenicity and their genetic variability. A further referenced strain of G. moniliformis isolated from maize in USA was also used as outgroup. The fumonisins B?, B?, and B? were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pathogenicity tests were carried out by symptom observation and determination of growth parameters after inoculation of maize seeds, seedlings and wounded detached leaves. Total genomic DNA was used for Amplified Fragment Length Polymorphism (AFLP) analysis. About 20% of the analyzed strains were unable to produce fumonisins in in vitro experiments on inoculated maize flour, while, among fumonisin producers, a great variability was observed, with values ranging from 1 to 115 mg kg?ą. The different analyzed strains showed a wide range of pathogenicity in terms of effect on seed germination, seedling development and of symptoms produced on detached leaves, which were not correlated with the different in vitro fumonisin production. AFLP analysis indicated the presence of genetic diversity not only between the Italian strains and the American reference but also among the Italian isolates. PMID:22475938

Covarelli, Lorenzo; Stifano, Simonetta; Beccari, Giovanni; Raggi, Lorenzo; Lattanzio, Veronica Maria Teresa; Albertini, Emidio

2012-02-13

75

Antibody-mediated Prevention of Fusarium Mycotoxins in the Field  

PubMed Central

Fusarium mycotoxins directly accumulated in grains during the infection of wheat and other cereal crops by Fusarium head blight (FHB) pathogens are detrimental to humans and domesticated animals. Prevention of the mycotoxins via the development of FHB-resistant varieties has been a challenge due to the scarcity of natural resistance against FHB pathogens. Various antibodies specific to Fusarium fungi and mycotoxins are widely used in immunoassays and antibody-mediated resistance in planta against Fusarium pathogens has been demonstrated. Antibodies fused to antifungal proteins have been shown to confer a very significantly enhanced Fusarium resistance in transgenic plants. Thus, antibody fusions hold great promise as an effective tool for the prevention of mycotoxin contaminations in cereal grains. This review highlights the utilization of protective antibodies derived from phage display to increase endogenous resistance of wheat to FHB pathogens and consequently to reduce mycotoxins in field. The role played by Fusarium-specific antibody in the resistance is also discussed.

Hu, Zu-Quan; Li, He-Ping; Zhang, Jing-Bo; Glinka, Elena; Liao, Yu-Cai

2008-01-01

76

Antibody-mediated prevention of Fusarium mycotoxins in the field.  

PubMed

Fusarium mycotoxins directly accumulated in grains during the infection of wheat and other cereal crops by Fusarium head blight (FHB) pathogens are detrimental to humans and domesticated animals. Prevention of the mycotoxins via the development of FHB-resistant varieties has been a challenge due to the scarcity of natural resistance against FHB pathogens. Various antibodies specific to Fusarium fungi and mycotoxins are widely used in immunoassays and antibody-mediated resistance in planta against Fusarium pathogens has been demonstrated. Antibodies fused to antifungal proteins have been shown to confer a very significantly enhanced Fusarium resistance in transgenic plants. Thus, antibody fusions hold great promise as an effective tool for the prevention of mycotoxin contaminations in cereal grains. This review highlights the utilization of protective antibodies derived from phage display to increase endogenous resistance of wheat to FHB pathogens and consequently to reduce mycotoxins in field. The role played by Fusarium-specific antibody in the resistance is also discussed. PMID:19325726

Hu, Zu-Quan; Li, He-Ping; Zhang, Jing-Bo; Glinka, Elena; Liao, Yu-Cai

2008-10-09

77

Controlling fusarium wilt disease of cucumber plants via antagonistic microorganisms in free and immobilized states  

Microsoft Academic Search

The causative agent of cucumber wilt was isolated from a diseased cucumber plant, grown under green house conditions and identified as Fusarium oxysporum.Forty isolates of exospore-forming actinomycetes and endospore-forming bacteria (twenty isolates each) were randomly isolated from the rhizosphere soil of a healthy cucumber plant. Among these isolates, 8 actinomycetes and 6 spore-forming bacterial isolates exhibited antagonistic activities against Fusarium

A. M. M. Hammad; M. A. O. El-Mohandes

1999-01-01

78

Physiological and biochemical aspects of the resistance of banana plants to Fusarium wilt potentiated by silicon.  

PubMed

Silicon amendments to soil have resulted in a decrease of diseases caused by several soilborne pathogens affecting a wide number of crops. This study evaluated the physiological and biochemical mechanisms that may have increased resistance of banana to Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense, after treatment with silicon (Si) amendment. Plants from the Grand Nain (resistant to F. oxysporum f. sp. cubense) and "Maçă" (susceptible to F. oxysporum f. sp. cubense) were grown in plastic pots amended with Si at 0 or 0.39 g/kg of soil (-Si or +Si, respectively) and inoculated with race 1 of F. oxysporum f. sp. cubense. Relative lesion length (RLL) and asymptomatic fungal colonization in tissue (AFCT) were evaluated at 40 days after inoculation. Root samples were collected at different times after inoculation with F. oxysporum f. sp. cubense to determine the level of lipid peroxidation, expressed as equivalents of malondialdehyde (MDA), hydrogen peroxide (H(2)O(2)), pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids), total soluble phenolics (TSP), and lignin-thioglycolic acid (LTGA) derivatives; the activities of the enzymes phenylalanine ammonia-lyases glucanases (PALs), peroxidases (POXs), polyphenoloxidases (PPOs), ?-1,3-glucanases (GLUs), and chitinases (CHIs); and Si concentration in roots. Root Si concentration was significantly increased by 35.3% for the +Si treatment compared with the -Si treatment. For Grand Nain, the root Si concentration was significantly increased by 12.8% compared with "Maçă." Plants from Grand Nain and "Maçă" in the +Si treatment showed significant reductions of 40.0 and 57.2%, respectively, for RLL compared with the -Si treatment. For the AFCT, there was a significant reduction of 18.5% in the +Si treatment compared with the -Si treatment. The concentration of MDA significantly decreased for plants from Grand Nain and "Maçă" supplied with Si compared with the -Si treatment while the concentrations of H(2)O(2) on roots and pigments on leaves significantly increased. The concentrations of TSP and LTGA derivatives as well as the PALs, PPOs, POXs, GLUs, and CHIs activities significantly increased on roots of plants from Grand Nain and "Maçă" from the +Si treatment compared with the -Si treatment. Results of this study suggest that the symptoms of Fusarium wilt on roots of banana plants supplied with Si decreased due to an increase in the concentrations of H(2)O(2), TSP, and LTGA derivatives and greater activities of PALs, PPOs, POXs, GLUs, and CHIs. PMID:22784251

Fortunato, Alessandro Antonio; Rodrigues, Fabrício Ávila; do Nascimento, Kelly Juliane Teles

2012-10-01

79

The Sfp-type 4'-phosphopantetheinyl transferase Ppt1 of Fusarium fujikuroi controls development, secondary metabolism and pathogenicity.  

PubMed

The heterothallic ascomycete Fusarium fujikuroi is a notorious rice pathogen causing super-elongation of plants due to the production of terpene-derived gibberellic acids (GAs) that function as natural plant hormones. Additionally, F. fujikuroi is able to produce a variety of polyketide- and non-ribosomal peptide-derived metabolites such as bikaverins, fusarubins and fusarins as well as metabolites from yet unidentified biosynthetic pathways, e.g. moniliformin. The key enzymes needed for their production belong to the family of polyketide synthases (PKSs) and non-ribosomal peptide synthases (NRPSs) that are generally known to be post-translationally modified by a Sfp-type 4'phosphopantetheinyl transferase (PPTase). In this study we provide evidence that the F. fujikuroi Sfp-type PPTase FfPpt1 is essentially involved in lysine biosynthesis and production of bikaverins, fusarubins and fusarins, but not moniliformin as shown by analytical methods. Concomitantly, targeted Ffppt1 deletion mutants reveal an enhancement of terpene-derived metabolites like GAs and volatile substances such as ?-acorenol. Pathogenicity assays on rice roots using fluorescent labeled wild-type and Ffppt1 mutant strains indicate that lysine biosynthesis and iron acquisition but not PKS and NRPS metabolism is essential for establishment of primary infections of F. fujikuroi. Additionally, FfPpt1 is involved in conidiation and sexual mating recognition possibly by activating PKS- and/or NRPS-derived metabolites that could act as diffusible signals. Furthermore, the effect on iron acquisition of Ffppt1 mutants led us to identify a previously uncharacterized putative third reductive iron uptake system (FfFtr3/FfFet3) that is closely related to the FtrA/FetC system of A. fumigatus. Functional characterization provides evidence that both proteins are involved in iron acquisition and are liable to transcriptional repression of the homolog of the Aspergillus GATA-type transcription factor SreA under iron-replete conditions. Targeted deletion of the first Fusarium homolog of this GATA-type transcription factor-encoding gene, Ffsre1, strongly indicates its involvement in regulation of iron homeostasis and oxidative stress resistance. PMID:22662164

Wiemann, Philipp; Albermann, Sabine; Niehaus, Eva-Maria; Studt, Lena; von Bargen, Katharina W; Brock, Nelson L; Humpf, Hans-Ulrich; Dickschat, Jeroen S; Tudzynski, Bettina

2012-05-25

80

Variation in the Trichothecene Mycotoxin Biosynthetic Gene Cluster in Fusarium  

Technology Transfer Automated Retrieval System (TEKTRAN)

Trichothecene mycotoxins are produced by some plant pathogenic species of the fungus Fusarium and can contribute to its virulence on some plants. In Fusarium graminearum and F. sporotrichioides trichothecene biosynthetic enzymes are encoded at three loci: the single-gene TRI101 locus; the two-gene ...

81

Xylella Genomics and Bacterial Pathogenicity to Plants  

PubMed Central

Xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. Inspection of the sequence reveals high relatedness to many genes of other pathogens, notably Xanthomonas campestris. Based on this, we suggest that Xylella possesses certain easily testable properties that contribute to pathogenicity. We also present some general considerations for deriving information on pathogenicity from bacterial genomics.

Dow, J. M.

2000-01-01

82

Petunia Floral Defensins with Unique Prodomains as Novel Candidates for Development of Fusarium Wilt Resistance in Transgenic Banana Plants  

PubMed Central

Antimicrobial peptides are a potent group of defense active molecules that have been utilized in developing resistance against a multitude of plant pathogens. Floral defensins constitute a group of cysteine-rich peptides showing potent growth inhibition of pathogenic filamentous fungi especially Fusarium oxysporum in vitro. Full length genes coding for two Petunia floral defensins, PhDef1 and PhDef2 having unique C- terminal 31 and 27 amino acid long predicted prodomains, were overexpressed in transgenic banana plants using embryogenic cells as explants for Agrobacterium–mediated genetic transformation. High level constitutive expression of these defensins in elite banana cv. Rasthali led to significant resistance against infection of Fusarium oxysporum f. sp. cubense as shown by in vitro and ex vivo bioassay studies. Transgenic banana lines expressing either of the two defensins were clearly less chlorotic and had significantly less infestation and discoloration in the vital corm region of the plant as compared to untransformed controls. Transgenic banana plants expressing high level of full-length PhDef1 and PhDef2 were phenotypically normal and no stunting was observed. In conclusion, our results suggest that high-level constitutive expression of floral defensins having distinctive prodomains is an efficient strategy for development of fungal resistance in economically important fruit crops like banana.

Ghag, Siddhesh B.; Shekhawat, Upendra K. Singh; Ganapathi, Thumballi R.

2012-01-01

83

Chemosensitization of plant pathogenic fungi to agricultural fungicides.  

PubMed

A common consequence of using agricultural fungicides is the development of resistance by fungal pathogens, which undermines reliability of fungicidal effectiveness. A potentially new strategy to aid in overcoming or minimizing this problem is enhancement of pathogen sensitivity to fungicides, or "chemosensitization." Chemosensitization can be accomplished by combining a commercial fungicide with a certain non- or marginally fungicidal substance at levels where, alone, neither compound would be effective. Chemosensitization decreases the probability of the pathogen developing resistance, reduces the toxic impact on the environment by lowering effective dosage levels of toxic fungicides, and improves efficacy of antifungal agents. The present study shows that the antifungal activity of azole and strobilurin fungicides can be significantly enhanced through their co-application with certain natural or synthetic products against several economically important plant pathogenic fungi. Quadris (azoxystrobin) combined with thymol at a non-fungitoxic concentration produced much higher growth inhibition of Bipolaris sorokiniana, Phoma glomerata, Alternaria sp. and Stagonospora nodorum than the fungicide alone. The effect of Dividend (difenoconazole) applied with thymol significantly enhanced antifungal activity against B. sorokiniana and S. nodorum. Folicur (tebuconazole) combined with 4-hydroxybenzaldehyde (4-HBA), 2,3-dihydroxybenzaldehyde or thymol significantly inhibited growth of Alternaria alternata, at a much greater level than the fungicide alone. In addition, co-application of Folicur and 4-HBA resulted in a similar enhancement of antifungal activity against Fusarium culmorum. Lastly, we discovered that metabolites in the culture liquid of Fusarium sambucinum biocontrol isolate FS-94 also had chemosensitizing activity, increasing S. nodorum sensitivity to Folicur and Dividend. PMID:22408641

Dzhavakhiya, Vitaly; Shcherbakova, Larisa; Semina, Yulia; Zhemchuzhina, Natalia; Campbell, Bruce

2012-03-09

84

Chemosensitization of Plant Pathogenic Fungi to Agricultural Fungicides  

PubMed Central

A common consequence of using agricultural fungicides is the development of resistance by fungal pathogens, which undermines reliability of fungicidal effectiveness. A potentially new strategy to aid in overcoming or minimizing this problem is enhancement of pathogen sensitivity to fungicides, or “chemosensitization.” Chemosensitization can be accomplished by combining a commercial fungicide with a certain non- or marginally fungicidal substance at levels where, alone, neither compound would be effective. Chemosensitization decreases the probability of the pathogen developing resistance, reduces the toxic impact on the environment by lowering effective dosage levels of toxic fungicides, and improves efficacy of antifungal agents. The present study shows that the antifungal activity of azole and strobilurin fungicides can be significantly enhanced through their co-application with certain natural or synthetic products against several economically important plant pathogenic fungi. Quadris (azoxystrobin) combined with thymol at a non-fungitoxic concentration produced much higher growth inhibition of Bipolaris sorokiniana, Phoma glomerata, Alternaria sp. and Stagonospora nodorum than the fungicide alone. The effect of Dividend (difenoconazole) applied with thymol significantly enhanced antifungal activity against B. sorokiniana and S. nodorum. Folicur (tebuconazole) combined with 4-hydroxybenzaldehyde (4-HBA), 2,3-dihydroxybenzaldehyde or thymol significantly inhibited growth of Alternaria alternata, at a much greater level than the fungicide alone. In addition, co-application of Folicur and 4-HBA resulted in a similar enhancement of antifungal activity against Fusarium culmorum. Lastly, we discovered that metabolites in the culture liquid of Fusarium sambucinum biocontrol isolate FS-94 also had chemosensitizing activity, increasing S. nodorum sensitivity to Folicur and Dividend.

Dzhavakhiya, Vitaly; Shcherbakova, Larisa; Semina, Yulia; Zhemchuzhina, Natalia; Campbell, Bruce

2012-01-01

85

Inhibitory Effect of Algal Extracts on Mycelial Growth of the Tomato-Wilt Pathogen, Fusarium oxysporum f. sp. lycopersici  

PubMed Central

The present study was undertaken to explore the inhibitory effect of cyanobacterial extracts of Nostoc commune FA-103 against the tomato-wilt pathogen, Fusarium oxysporum f. sp. lycopersici. In an optimal medium, cell growth, antifungal activity, and antifungal compound production could be increased 2.7-fold, 4.1-fold, and 13.4-fold, respectively. A crude algal extract had a similar effect as mancozeb at the recommended dose, both in laboratory and pot tests. In vitro and in vivo fungal growth, spore sporulation and fungal infection of wilt pathogen in tomato seeds were significantly inhibited by cyanobacterial extracts. Nostoc commune FA-103 extracts have potential for the suppression of Fusarium oxysporum f. sp. lycopersici.

Kim, Jiyoung

2008-01-01

86

PGPR: Prospective Biocontrol Agents of Plant Pathogens  

Microsoft Academic Search

Plant growth promoting rhizobacteria (PGPR) are indigenous to soil and the plant rhizosphere and play a major role in the biocontrol of plant pathogens. PGPR can profoundly improve seed germination, root development and water utilization by plants. These rhizobacteria can stimulate plant growth directly by producing growth hormones and improving nutrient uptake or indirectly by changing microbial balance in the

ZAKI A. SIDDIQUI

87

Pathogenic variability in Ethiopian isolates of Fusarium oxysporum f. sp. ciceris and reaction of chickpea improved varieties to the isolates  

Microsoft Academic Search

Twenty-four isolates of Fusarium oxysporum f. sp. ciceris were isolated from wilted chickpea plants obtained from different districts and ‘wilt sickplots’ of central Ethiopia to assess variability in pathogenecity of the populations. Each isolate was tested on 10 different chickpea lines and eight improved chickpea varieties. Isolates showed highly significant variation in wilt severity on the differential lines and improved

Meki Shehabu; Seid Ahmed; Parshotam K. Sakhuja

2008-01-01

88

Genomic clustering and co-regulation of transcriptional networks in the pathogenic fungus Fusarium graminearum  

PubMed Central

Background Genes for the production of a broad range of fungal secondary metabolites are frequently colinear. The prevalence of such gene clusters was systematically examined across the genome of the cereal pathogen Fusarium graminearum. The topological structure of transcriptional networks was also examined to investigate control mechanisms for mycotoxin biosynthesis and other processes. Results The genes associated with transcriptional processes were identified, and the genomic location of transcription-associated proteins (TAPs) analyzed in conjunction with the locations of genes exhibiting similar expression patterns. Highly conserved TAPs reside in regions of chromosomes with very low or no recombination, contrasting with putative regulator genes. Co-expression group profiles were used to define positionally clustered genes and a number of members of these clusters encode proteins participating in secondary metabolism. Gene expression profiles suggest there is an abundance of condition-specific transcriptional regulation. Analysis of the promoter regions of co-expressed genes showed enrichment for conserved DNA-sequence motifs. Potential global transcription factors recognising these motifs contain distinct sets of DNA-binding domains (DBDs) from those present in local regulators. Conclusions Proteins associated with basal transcriptional functions are encoded by genes enriched in regions of the genome with low recombination. Systematic searches revealed dispersed and compact clusters of co-expressed genes, often containing a transcription factor, and typically containing genes involved in biosynthetic pathways. Transcriptional networks exhibit a layered structure in which the position in the hierarchy of a regulator is closely linked to the DBD structural class.

2013-01-01

89

Use of the Plant Defense Protein Osmotin To Identify Fusarium oxysporum Genes That Control Cell Wall Properties ? ‡  

PubMed Central

Fusarium oxysporum is the causative agent of fungal wilt disease in a variety of crops. The capacity of a fungal pathogen such as F. oxysporum f. sp. nicotianae to establish infection on its tobacco (Nicotiana tabacum) host depends in part on its capacity to evade the toxicity of tobacco defense proteins, such as osmotin. Fusarium genes that control resistance to osmotin would therefore reflect coevolutionary pressures and include genes that control mutual recognition, avoidance, and detoxification. We identified FOR (Fusarium Osmotin Resistance) genes on the basis of their ability to confer osmotin resistance to an osmotin-sensitive strain of Saccharomyces cerevisiae. FOR1 encodes a putative cell wall glycoprotein. FOR2 encodes the structural gene for glutamine:fructose-6-phosphate amidotransferase, the first and rate-limiting step in the biosynthesis of hexosamine and cell wall chitin. FOR3 encodes a homolog of SSD1, which controls cell wall composition, longevity, and virulence in S. cerevisiae. A for3 null mutation increased osmotin sensitivity of conidia and hyphae of F. oxysporum f. sp. nicotianae and also reduced cell wall ?-1,3-glucan content. Together our findings show that conserved fungal genes that determine cell wall properties play a crucial role in regulating fungal susceptibility to the plant defense protein osmotin.

Lee, Hyeseung; Damsz, Barbara; Woloshuk, Charles P.; Bressan, Ray A.; Narasimhan, Meena L.

2010-01-01

90

Lack of the plant signalling component SGT1b enhances disease resistance to Fusarium culmorum in Arabidopsis buds and flowers.  

PubMed

Fusarium culmorum causes ear blight disease on cereal crops resulting in considerable losses to grain yield, quality and safety. This fungus can also infect Arabidopsis floral tissues. In this study, the Arabidopsis floral infection model was used to assess the impact of five defence mutants on disease.Fusarium culmorum was spray inoculated onto the floral tissues of the mutantseds1, lms1, rar1, sgt1a and sgt1b involved in basal and resistance gene-mediated defence to pathogens. Floral disease development was assessed quantitatively.Only the sgt1b mutant exhibited a significantly different interaction phenotype compared with wild-type plants. The buds and flowers were more resistant to infection and developed milder symptoms, but had wild-type levels of deoxynivalenol (DON)mycotoxin. Microscopic studies indicated that to cause disease, F. culmorum requires plant cells in the invaded tissues to be competent to activate both a cell death response and a sustained oxidative burst. The sgt1a mutant exhibited a weak trend towards greater disease resistance in the new silique tissues. This study highlights that the SGT1-mediated signalling cascade(s), which had previously only been demonstrated to be required for Arabidopsis resistance against biotrophic pathogens, is causally involved in F. culmorum disease symptom development. PMID:19140951

Cuzick, Alayne; Maguire, Kerry; Hammond-Kosack, Kim E

2009-03-01

91

Hyperkeratotic Warty Skin Lesion of Foot Caused by Fusarium oxysporum  

PubMed Central

Fusarium species are common soil-inhabiting organisms and plant pathogens. Human infections are usually precipitated by local or systemic predisposing factors, and disseminated infection is associated with impaired immune responses. Skin infections caused by Fusarium spp. include keratitis, onychomycosis, mycetoma, painful discrete erythematous nodules. Hyperkeratotic skin lesions caused by Fusarium spp. are, however, rarely reported. We report a case of hyperkeratotic verrucous warty skin lesion in the foot of a 50-year-old immunocompetent male, farmer by occupation.

Kaur, Ravinder; Maheshwari, Megha

2013-01-01

92

Hyperkeratotic Warty Skin Lesion of Foot Caused by Fusarium oxysporum.  

PubMed

Fusarium species are common soil-inhabiting organisms and plant pathogens. Human infections are usually precipitated by local or systemic predisposing factors, and disseminated infection is associated with impaired immune responses. Skin infections caused by Fusarium spp. include keratitis, onychomycosis, mycetoma, painful discrete erythematous nodules. Hyperkeratotic skin lesions caused by Fusarium spp. are, however, rarely reported. We report a case of hyperkeratotic verrucous warty skin lesion in the foot of a 50-year-old immunocompetent male, farmer by occupation. PMID:23716829

Kaur, Ravinder; Maheshwari, Megha

2013-03-01

93

REMI MUTAGENESIS IN FUSARIUM GRAMINEARUM  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium graminearum is an important pathogen of small grains and maize in many areas of the world. Infected grains are often contaminated with mycotoxins harmful to humans and animals. To better understand the molecular mechanism of plant infection and virulence of F. graminearum, we used the REM...

94

The velvet complex governs mycotoxin production and virulence of Fusarium oxysporum on plant and mammalian hosts.  

PubMed

Fungal pathogens provoke devastating losses in agricultural production, contaminate food with mycotoxins and give rise to life-threatening infections in humans. The soil-borne ascomycete Fusarium oxysporum attacks over 100 different crops and can cause systemic fusariosis in immunocompromised individuals. Here we functionally characterized VeA, VelB, VelC and LaeA, four components of the velvet protein complex which regulates fungal development and secondary metabolism. Deletion of veA, velB and to a minor extent velC caused a derepression of conidiation as well as alterations in the shape and size of microconidia. VeA and LaeA were required for full virulence of F.?oxysporum on tomato plants and on immunodepressed mice. A critical contribution of velvet consists in promoting chromatin accessibility and expression of the biosynthetic gene cluster for beauvericin, a depsipeptide mycotoxin that functions as a virulence determinant. These results reveal a conserved role of the velvet complex during fungal infection on plants and mammals. PMID:23106229

López-Berges, Manuel S; Hera, Concepción; Sulyok, Michael; Schäfer, Katja; Capilla, Javier; Guarro, Josep; Di Pietro, Antonio

2012-11-19

95

Plant Growth-Promoting Rhizobacteria Strain Bacillus amyloliquefaciens NJN-6-Enriched Bio-organic Fertilizer Suppressed Fusarium Wilt and Promoted the Growth of Banana Plants.  

PubMed

Bacillus amyloliquefaciens strain NJN-6 is an important plant growth-promoting rhizobacteria (PGPR) which can produce secondary metabolites antagonistic to several soil-borne pathogens. In this study, the ability of a bio-organic fertilizer (BIO) containing NJN-6 strain to promote the growth and suppress Fusarium wilt of banana plants was evaluated in a pot experiment. The results showed that the application of BIO significantly decreased the incidence of Fusarium wilt and promoted the growth of banana plants compared to that for the organic fertilizer (OF). To determine the beneficial mechanism of the strain, the colonization of NJN-6 strain on banana roots was evaluated using scanning electron microscopy (SEM). The plant growth-promoting hormones indole-3-acetic acid (IAA) and gibberellin A3 (GA3), along with antifungal lipopeptides iturin A, were detected when the NJN-6 strain was incubated in both Landy medium with additional l-tryptophan and in root exudates of banana plants. In addition, some antifungal volatile organic compounds and iturin A were also detected in BIO. In summary, strain NJN-6 could colonize the roots of banana plants after the application of BIO and produced active compounds which were beneficial for the growth of banana plants. PMID:23541032

Yuan, Jun; Ruan, Yunze; Wang, Beibei; Zhang, Jian; Waseem, Raza; Huang, Qiwei; Shen, Qirong

2013-04-10

96

Contribution of proteomics to the study of plant pathogenic fungi.  

PubMed

Phytopathogenic fungi are one of the most damaging plant parasitic organisms, and can cause serious diseases and important yield losses in crops. The study of the biology of these microorganisms and the interaction with their hosts has experienced great advances in recent years due to the development of moderm, holistic and high-throughput -omic techniques, together with the increasing number of genome sequencing projects and the development of mutants and reverse genetics tools. We highlight among these -omic techniques the importance of proteomics, which has become a relevant tool in plant-fungus pathosystem research. Proteomics intends to identify gene products with a key role in pathogenicity and virulence. These studies would help in the search of key protein targets and in the development of agrochemicals, which may open new ways for crop disease diagnosis and protection. In this review, we made an overview on the contribution of proteomics to the knowledge of life cycle, infection mechanisms, and virulence of the plant pathogenic fungi. Data from current, innovative literature, according to both methodological and experimental systems, were summarized and discussed. Specific sections were devoted to the most studied fungal phytopathogens: Botrytis cinerea, Sclerotinia sclerotiorum, and Fusarium graminearum. PMID:22085090

Gonzalez-Fernandez, Raquel; Jorrin-Novo, Jesus V

2011-11-28

97

Microsatellite markers in plant pathogenic fungi  

Technology Transfer Automated Retrieval System (TEKTRAN)

Knowing the genetic diversity of plant pathogenic fungi is essential in the management of crops and disease. The genetic variability of fungal pathogens can be evaluated using molecular markers, among which, microsatellites are a relatively inexpensive source of information. We have developed an e...

98

Effect of azoxystrobin on activities of antioxidant enzymes and alternative oxidase in wheat head blight pathogens Fusarium graminearum and Microdochium nivale  

Microsoft Academic Search

Wheat head blight pathogens Fusarium graminearum and Microdochium nivale have distinct sensitivities to strobilurin fungicides, which inhibit activity of complex III in the mitochondrial electron\\u000a transport chain. When mycelia were cultured in medium with the strobilurin fungicide azoxystrobin (AZ), F. graminearum increased its oxygen-consumption, but M. nivale, which is more sensitive than Fusarium species to strobilurins, did not. There was

Isao Kaneko; Hideo Ishii

2009-01-01

99

Genomic Organization of Fungal Plant Pathogenicity  

Technology Transfer Automated Retrieval System (TEKTRAN)

The recent large scale genomic sequencing of fungal phytopathogens has revolutionized the study of plant pathogenesis. Initially, having whole genome sequence (WGS) data for individual fungal genomes has accelerated classical forward and reverse genetic approaches for identifying pathogenicity genes...

100

Pathogenicity of Fusarium semitectum against crop pests and its biosafety to non-target organisms.  

PubMed

Microbial control is receiving more attention, since these alternative tactics, compared to chemical control methods, are energy saving, non polluting, ecologically sound and sustainable. A mycopathogen, Fusarium semitectum Berk. and Rav. (ARSEF 7233) was isolated from diseased cadavers of aphid (Aphis gossypii) and cultured in Saboraud Maltose Agar supplemented with Yeast extract medium (SMAY). Being isolated first time from the chilli ecosystem its potential was evaluated. Experiments were conducted to understand its pathogenicity against crop pests as well as to ensure its safety to non target organisms such as silk worm (Bombyx mor), honey bee (Apis indica) and earthworm (Eisenia foetida). A paper-thrips-paper sandwich method for thrips and detached-leaf bioassay method for mites were used. Test insects and mites either reared in laboratory or obtained from the field were topically applied with spore suspension of F. semitectum (1x10(9) spores/ml). Mortality was recorded and dead animals were surface sterilized with 0.5% NaOCl and placed in SMAY medium to confirm pathogenicity. Mulberry leaves sprayed with the fungal suspension were fed to larvae of B. mori and reared. Newly emerged A. indica were topically applied with fungus. The fungus grown in cow dung for two weeks was used to assess the composting ability of E. foetida. F. semitectum produced mycosis and caused mortality to sucking pests such as chilli thrips (Scirtothrips dorsalis), broad mite (Polyphagotarsonemus latus), sugarcane wooly aphid (Ceratavacuna lanigera), spiraling whitefly (Aleyrodicus disperses), whitefly (Bemisia tabaci, A. gossypii and coconut mite (Aceria guerroronis). The fungus did not cause mortality on larvae of lepidopteran insect pests and ladybird beetle (Menochilus sexmaculatus), predatory mite (Amblysius ovalis) and larval parasitoid (Goniozus nephantidis). F. semitectum failed to infect the larvae of B. mori and newly emerged A. indica and its brood. The mycopathogen had no influence on the composting ability and growth of E. foetida. F. semitectum, in general, expressed its selectivity against sucking pests and proved its eco-friendly characteristics to the beneficial organisms and especially safe to Sericulture, Apiculture and Vermiculture industries in Karnataka, India. This novel fungus can be well incorporated as a viable tactics into the integrated management programmes of crop pests. PMID:17385514

Mikunthan, G; Manjunatha, M

2006-01-01

101

Adhesion Mechanisms of Plant-Pathogenic Xanthomonadaceae  

Microsoft Academic Search

\\u000a The family Xanthomonadaceae is a wide-spread family of bacteria belonging to the gamma subdivision of the Gram-negative proteobacteria, including the\\u000a two plant-pathogenic genera Xanthomonas and Xylella, and the related genus Stenotrophomonas. Adhesion is a widely conserved virulence mechanism among Gram-negative bacteria, no matter whether they are human, animal\\u000a or plant pathogens, since attachment to the host tissue is one of

Nadia Mhedbi-Hajri; Marie-Agnčs Jacques; Ralf Koebnik

102

Filamentous plant pathogen effectors in action.  

PubMed

Live-cell imaging assisted by fluorescent markers has been fundamental to understanding the focused secretory 'warfare' that occurs between plants and biotrophic pathogens that feed on living plant cells. Pathogens succeed through the spatiotemporal deployment of a remarkably diverse range of effector proteins to control plant defences and cellular processes. Some effectors can be secreted by appressoria even before host penetration, many enter living plant cells where they target diverse subcellular compartments and others move into neighbouring cells to prepare them before invasion. This Review summarizes the latest advances in our understanding of the cell biology of biotrophic interactions between plants and their eukaryotic filamentous pathogens based on in planta analyses of effectors. PMID:24129511

Giraldo, Martha C; Valent, Barbara

2013-10-16

103

The Fusarium Mycotoxin Deoxynivalenol Can Inhibit Plant Apoptosis-Like Programmed Cell Death  

PubMed Central

The Fusarium genus of fungi is responsible for commercially devastating crop diseases and the contamination of cereals with harmful mycotoxins. Fusarium mycotoxins aid infection, establishment, and spread of the fungus within the host plant. We investigated the effects of the Fusarium mycotoxin deoxynivalenol (DON) on the viability of Arabidopsis cells. Although it is known to trigger apoptosis in animal cells, DON treatment at low concentrations surprisingly did not kill these cells. On the contrary, we found that DON inhibited apoptosis-like programmed cell death (PCD) in Arabidopsis cells subjected to abiotic stress treatment in a manner independent of mitochondrial cytochrome c release. This suggested that Fusarium may utilise mycotoxins to suppress plant apoptosis-like PCD. To test this, we infected Arabidopsis cells with a wild type and a DON-minus mutant strain of F. graminearum and found that only the DON producing strain could inhibit death induced by heat treatment. These results indicate that mycotoxins may be capable of disarming plant apoptosis-like PCD and thereby suggest a novel way that some fungi can influence plant cell fate.

Diamond, Mark; Reape, Theresa J.; Rocha, Olga; Doyle, Siamsa M.; Kacprzyk, Joanna; Doohan, Fiona M.; McCabe, Paul F.

2013-01-01

104

[Species composition of Fusarium Link et Fr. fungal genera affecting agricultural plants and weeds in Uzbekistan].  

PubMed

Phytopathogenic fungi of the Fusarium genus are represented on the agricultural plants and weeds by 17 species and 10 subspecies from the sections Roseum, Discolor, Sporotrichiella, Elegans, Martiella, Arachniotes in Uzbekistan. As to their occurrence frequency F. javanicum, F. lateritium, F. solani, F. oxysporum, F. heterosporum, F. moniliforme, F. gibbosum species are dominating ones. F. merismoides, F. redolens, F. nivale species occurred often F. sporotichiella, F. semitectum, F. culmorum, F. bucharicum, F. graminearum, F. avenaceum species occurred rarely. It was shown that the Fusarium species were more numerous in the central and southern regions of Uzbekistan than in the northern region. PMID:11785262

Sheraliev, A Sh; Bukharov, K; Kholmuradov, Ch

105

Punctuated changes in plant pathogen populations associated with passage of atmospheric Lagrangian coherent structures  

NASA Astrophysics Data System (ADS)

The atmospheric transport of airborne microorganisms (e.g., plant pathogens) is poorly understood, yet necessary to assess their ecological roles in agricultural ecosystems and to evaluate risks posed by invasive species. The atmospheric transport of plant pathogens can be roughly divided into three phases: liberation of pathogen spores, drift (transport in the atmosphere) and deposition. If liberated spores escape into the planetary boundary layer, they could be transported over thousands of kilometers before being deposited. The drift phase is poorly understood, due to the complex nature of atmospheric transport and relative lack of observational data. In this talk, we present a framework of Lagrangian coherent structures to determine the important atmospheric transport barriers (ATBs) that partition the atmosphere and systematically organize the mesoscale transport problem. Using autonomous unmanned aerial vehicles, we measure the concentration of spores of a plant pathogenic fungus (Fusarium) sampled in the atmosphere above Virginia Tech's Kentland Farm. We report correlations between concentrations of Fusarium with the local movement of ATBs determined from archived meteorological data.

Ross, Shane; Tallapragada, Phanindra; Schmale, David

2010-11-01

106

Induction of systemic resistance by Pseudomonas fluorescens in radish cultivars differing in susceptibility to fusarium wilt, using a novel bioassay  

Microsoft Academic Search

Pseudomonas fluorescens-mediated induction of systemic resistance in radish against fusarium wilt (Fusarium oxysporum f. sp.raphani) was studied in a newly developed bioassay using a rockwool system. In this bioassay the pathogen and bacterium were confirmed to be confined to spatially separate locations on the plant root, throughout the experiment. Pathogen inoculum obtained by mixing peat with microconidia and subsequent incubation

M. Leeman; J. A. van Pelt; F. M. den Ouden; M. Heinsbroek; P. A. H. M. Bakker; B. Schippers

1995-01-01

107

Coevolutionary genetics of plants and pathogens  

Microsoft Academic Search

Summary The genetic polymorphism maintained by host-pathogen coevolution is analysed in a multilocus model. The model assumes gene-for-gene interactions of the type commonly observed between host plants and their fungal pathogens. Unstable (epidemic) systems maintain more resistance genes, fewer virulence genes, and less overall genetic diversity than stable (endemic) diseases. The stability of the system depends primarily on demographic parameters,

Steven A. Frank

1993-01-01

108

Incidence of Fusarium wilt in Cucumis sativus  L. is promoted by cinnamic acid, an autotoxin in root exudates  

Microsoft Academic Search

The effects of Fusarium oxysporum f. sp. cucumerinum, the pathogen causing Fusarium wilt in cucumber and cinnamic acid, a principal autotoxic component in the root exudates of cucumber (Cucumis sativus L.), on plant growth, Photosynthesis and incidence of Fusarium wilt in cucumber were studied in order to elucidate the interaction of autotoxins and soil-borne pathogens in the soil sickness. F. oxysporum. f. sp. cucumerinum

S. F. Ye; J. Q. Yu; Y. H. Peng; J. H. Zheng; L. Y. Zou

2004-01-01

109

In vitro generation of somaclonal variant plants of sugarcane for tolerance to Fusarium sacchari.  

PubMed

KEY MESSAGE : A combination of in vitro culture and mutagenesis using ethyl methanesulfonate (EMS) followed by culture filtrate-mediated selection produced variant sugarcane plants tolerant and resistant to Fusarium sacchari. Eldana saccharina is a destructive pest of the sugarcane crop in South Africa. Fusarium sacchari PNG40 (a fungal strain harmful to E. saccharina) has the potential to be an endophytic biological control agent of the stalk borer. However, the fungus causes Fusarium stalk rot in sugarcane. In the current study, sugarcane plants tolerant and resistant to F. sacchari PNG40 were produced by exposing embryogenic calli to the chemical mutagen ethyl methanesulfonate (EMS), followed by in vitro selection during somatic embryogenesis and plantlet regeneration on media containing F. sacchari culture filtrates (CF). The incorporation of 100 ppm CF in the culture media at the embryo maturation stage, at germination, or at both, resulted in callus necrosis and consequent reduced plantlet yield. Subsequent trimming of the roots of regenerated plants and their exposure to 1,500 ppm CF served as a further selection treatment. Plants produced from EMS-treated calli displayed improved root re-growth in the presence of CF pressure compared with those from non-treated calli. The tolerance of CF-selected plants was confirmed in greenhouse tests by inoculation with F. sacchari PNG40, re-isolation of Fusarium spp. from undamaged tissue of asymptomatic plants and establishment of the identity of fungal isolates as PNG40 using molecular analysis. The restriction of PNG40 presence to the inoculation lesion in some plants suggested their resistance to the fungus. Genotypes exhibiting symptomless endophytic colonization by PNG40 were identified and will be utilised for testing biological control strategies against E. saccharina. PMID:23090725

Mahlanza, Tendekai; Rutherford, R Stuart; Snyman, Sandy J; Watt, M Paula

2012-10-23

110

Deciphering the cryptic genome: genome-wide analyses of the rice pathogen Fusarium fujikuroi reveal complex regulation of secondary metabolism and novel metabolites.  

PubMed

The fungus Fusarium fujikuroi causes "bakanae" disease of rice due to its ability to produce gibberellins (GAs), but it is also known for producing harmful mycotoxins. However, the genetic capacity for the whole arsenal of natural compounds and their role in the fungus' interaction with rice remained unknown. Here, we present a high-quality genome sequence of F. fujikuroi that was assembled into 12 scaffolds corresponding to the 12 chromosomes described for the fungus. We used the genome sequence along with ChIP-seq, transcriptome, proteome, and HPLC-FTMS-based metabolome analyses to identify the potential secondary metabolite biosynthetic gene clusters and to examine their regulation in response to nitrogen availability and plant signals. The results indicate that expression of most but not all gene clusters correlate with proteome and ChIP-seq data. Comparison of the F. fujikuroi genome to those of six other fusaria revealed that only a small number of gene clusters are conserved among these species, thus providing new insights into the divergence of secondary metabolism in the genus Fusarium. Noteworthy, GA biosynthetic genes are present in some related species, but GA biosynthesis is limited to F. fujikuroi, suggesting that this provides a selective advantage during infection of the preferred host plant rice. Among the genome sequences analyzed, one cluster that includes a polyketide synthase gene (PKS19) and another that includes a non-ribosomal peptide synthetase gene (NRPS31) are unique to F. fujikuroi. The metabolites derived from these clusters were identified by HPLC-FTMS-based analyses of engineered F. fujikuroi strains overexpressing cluster genes. In planta expression studies suggest a specific role for the PKS19-derived product during rice infection. Thus, our results indicate that combined comparative genomics and genome-wide experimental analyses identified novel genes and secondary metabolites that contribute to the evolutionary success of F. fujikuroi as a rice pathogen. PMID:23825955

Wiemann, Philipp; Sieber, Christian M K; von Bargen, Katharina W; Studt, Lena; Niehaus, Eva-Maria; Espino, Jose J; Huß, Kathleen; Michielse, Caroline B; Albermann, Sabine; Wagner, Dominik; Bergner, Sonja V; Connolly, Lanelle R; Fischer, Andreas; Reuter, Gunter; Kleigrewe, Karin; Bald, Till; Wingfield, Brenda D; Ophir, Ron; Freeman, Stanley; Hippler, Michael; Smith, Kristina M; Brown, Daren W; Proctor, Robert H; Münsterkötter, Martin; Freitag, Michael; Humpf, Hans-Ulrich; Güldener, Ulrich; Tudzynski, Bettina

2013-06-27

111

Comparison of inoculation methods for characterizing relative aggressiveness of two soybean sudden-death syndrome pathogens, Fusarium virguliforme and F. tucumaniae  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium tucumaniae and F. virguliforme are the primary etiological agents of sudden-death syndrome (SDS) of soybean in Argentina and the United States, respectively. Five isolates of F. tucumaniae and four of F. virguliforme were tested for pathogenicity to soybeans, by comparing a toothpick method...

112

Defense-related gene expression in susceptible and tolerant bananas ( Musa spp.) following inoculation with non-pathogenic Fusarium oxysporum endophytes and challenge with Radopholus similis  

Microsoft Academic Search

Radopholus similis is a major pest of East African highland cooking bananas (Musa spp.) in Uganda. Non-pathogenic Fusarium oxysporum endophytes, isolated from bananas in farmers’ fields, have shown potential to reduce R. similis numbers in tissue culture banana. The mechanism through which endophytes confer resistance to nematodes has previously been demonstrated to involve induced resistance. In this study, the expression

Pamela Paparu; Thomas Dubois; Danny Coyne; Altus Viljoen

2007-01-01

113

[RAPD analysis of plant pathogenic coryneform bacteria].  

PubMed

RAPD analysis was used for the taxonomy of plant pathogenic coryneform bacteria, especially for the classification of two new pathogens (Curtobacterium flaccumfaciens pv. basellae pv. nov. and Curtobacterium flaccumfaciens pv. beticola pv. nov.). 20 random primers were screened from 50 ones to detect polymorphism among the total strains used. 80.4% were polymorphic bands among the 225 ones produced. The results of pairwise similarity and UPGMA cluster analysis suggest that the two new pathovars of sugar beet (Beta vulgaris var. saccharifera) and malabar spinach (Basella rubra) are genetically close related with Curtobacterium flacumfaciens, and the minimal similarity coefficient is 0.6511. According to the RAPD analysis and previous research, some newly made taxonomic changes of the plant pathogenic coryneform bacteria are discussed. PMID:16496687

Yin, Yan-Ni; Chen, Yong-Fang; Li, Shi-Mo; Guo, Jian-Hua

2005-12-01

114

Comparative analysis of twelve Dothideomycete plant pathogens  

SciTech Connect

The Dothideomycetes are one of the largest and most diverse groups of fungi. Many are plant pathogens and pose a serious threat to agricultural crops grown for biofuel, food or feed. Most Dothideomycetes have only a single host and related Dothideomycete species can have very diverse host plants. Twelve Dothideomycete genomes have currently been sequenced by the Joint Genome Institute and other sequencing centers. They can be accessed via Mycocosm which has tools for comparative analysis

Ohm, Robin; Aerts, Andrea; Salamov, Asaf; Goodwin, Stephen B.; Grigoriev, Igor

2011-03-11

115

Transgenic tobacco and peanut plants expressing a mustard defensin show resistance to fungal pathogens.  

PubMed

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 constitutively expressing the mustard defensin. Transgenic tobacco plants were resistant to the fungal pathogens, Fusarium moniliforme and Phytophthora parasitica pv. nicotianae. Transgenic peanut plants showed enhanced resistance against the pathogens, Pheaoisariopsis personata and Cercospora arachidicola, which jointly cause serious late leaf spot disease. These observations indicate that the mustard defensin gene can be deployed for deriving fungal disease resistance in transgenic crops. PMID:18758784

Swathi Anuradha, T; Divya, K; Jami, S K; Kirti, P B

2008-08-29

116

[Successful treatment of Fusarium-associated keratitis with multiresistant pathogen and multimorbid patient.  

PubMed

A 75-year-old man (not a contact lens wearer) presented with Fusarium-associated hypopyon keratitis. After several weeks of empirical and subsequently targeted antimycotic treatment, no considerable improvement was observed. However, after sclerokeratoplasty (11.2?×?11.2 mm) combined with prolonged antimycotic therapy a good local result with relapse-free long-term follow-up was achieved. PMID:23774966

Alnawaiseh, M; Böhm, M R R; Idelevich, E A; Becker, K; Grewe, S; Grenzebach, U H; Eter, N

2013-06-19

117

Adhesion mechanisms of plant-pathogenic Xanthomonadaceae.  

PubMed

The family Xanthomonadaceae is a wide-spread family of bacteria belonging to the gamma subdivision of the Gram-negative proteobacteria, including the two plant-pathogenic genera Xanthomonas and Xylella, and the related genus Stenotrophomonas. Adhesion is a widely conserved virulence mechanism among Gram-negative bacteria, no matter whether they are human, animal or plant pathogens, since attachment to the host tissue is one of the key early steps of the bacterial infection process. Bacterial attachment to surfaces is mediated by surface structures that are anchored in the bacterial outer membrane and cover a broad group of fimbrial and non-fimbrial structures, commonly known as adhesins. In this chapter, we discuss recent findings on candidate adhesins of plant-pathogenic Xanthomonadaceae, including polysaccharidic (lipopolysaccharides, exopolysaccharides) and proteineous structures (chaperone/usher pili, type IV pili, autotransporters, two-partner-secreted and other outer membrane adhesins), their involvement in the formation of biofilms and their mode of regulation via quorum sensing. We then compare the arsenals of adhesins among different Xanthomonas strains and evaluate their mode of selection. Finally, we summarize the sparse knowledge on specific adhesin receptors in plants and the possible role of RGD motifs in binding to integrin-like plant molecules. PMID:21557058

Mhedbi-Hajri, Nadia; Jacques, Marie-Agnčs; Koebnik, Ralf

2011-01-01

118

Paleogene Radiation of a Plant Pathogenic Mushroom  

PubMed Central

Background The global movement and speciation of fungal plant pathogens is important, especially because of the economic losses they cause and the ease with which they are able to spread across large areas. Understanding the biogeography and origin of these plant pathogens can provide insights regarding their dispersal and current day distribution. We tested the hypothesis of a Gondwanan origin of the plant pathogenic mushroom genus Armillaria and the currently accepted premise that vicariance accounts for the extant distribution of the species. Methods The phylogeny of a selection of Armillaria species was reconstructed based on Maximum Parsimony (MP), Maximum Likelihood (ML) and Bayesian Inference (BI). A timeline was then placed on the divergence of lineages using a Bayesian relaxed molecular clock approach. Results Phylogenetic analyses of sequenced data for three combined nuclear regions provided strong support for three major geographically defined clades: Holarctic, South American-Australasian and African. Molecular dating placed the initial radiation of the genus at 54 million years ago within the Early Paleogene, postdating the tectonic break-up of Gondwana. Conclusions The distribution of extant Armillaria species is the result of ancient long-distance dispersal rather than vicariance due to continental drift. As these finding are contrary to most prior vicariance hypotheses for fungi, our results highlight the important role of long-distance dispersal in the radiation of fungal pathogens from the Southern Hemisphere.

Coetzee, Martin P. A.; Bloomer, Paulette; Wingfield, Michael J.; Wingfield, Brenda D.

2011-01-01

119

Hexose Transporters of a Hemibiotrophic Plant Pathogen  

PubMed Central

Plant pathogenic fungi use a wide range of different strategies to gain access to the carbon sources of their host plants. The hemibiotrophic maize pathogen Colletotrichum graminicola (teleomorph Glomerella graminicola) colonizes its host plants, and, after a short biotrophic phase, switches to destructive, necrotrophic development. Here we present the identification of five hexose transporter genes from C. graminicola, CgHXT1 to CgHXT5, the functional characterization of the encoded proteins, and detailed expression studies for these genes during vegetative and pathogenic development. Whereas CgHXT4 is expressed under all conditions analyzed, transcript abundances of CgHXT1 and CgHXT3 are transiently up-regulated during the biotrophic phase, and CgHXT2 and CgHXT5 are expressed exclusively during necrotrophic development. Analyses of the encoded proteins characterized CgHXT5 as a low-affinity/high-capacity hexose transporter with a narrow substrate specificity for glucose and mannose. In contrast, CgHXT1 to CgHXT3 are high affinity/low capacity transporters that also accept other substrates, including fructose, galactose, or xylose. CgHXT4, the largest of the identified proteins, has only little transport activity and may function as a sugar sensor. Phylogenetic studies revealed hexose transporters closely related to the five CgHXT proteins also in other pathogenic fungi suggesting conserved functions of these proteins during fungal pathogenesis.

Lingner, Ulrike; Munch, Steffen; Deising, Holger B.; Sauer, Norbert

2011-01-01

120

A Case of Primary Localized Cutaneous Infection Due to Fusarium oxysporum  

Microsoft Academic Search

Fusarium is a ubiquitous hyalohyphomycete isolated from food, widespread in the environment (plants, soil) and present at all latitudes.\\u000a Fusarium oxysporum and Fusarium solani are the most frequent pathogenic species, followed by F. moniliforme and F. chlamydosporum. Infections due to this mold may be disseminated or localized. Localized forms include cutaneous and subcutaneous infection,\\u000a onychomycosis, endophtalmitis, otitis, sinusitis, arthritis, osteomyelitis,

C. Romano; P. Caposciutti; A. Ghilardi; C. Miracco; M. Fimiani

2010-01-01

121

HISTOLOGY AND PHYSIOLOGY OF FUSARIUM HEAD BLIGHT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight re-emerged as a devastating disease of wheat and barley in the 1990s in the midwestern U.S. Research efforts to control the disease have been hampered by limited knowledge of how the fungal head blight pathogens infect and damage head tissue and what natural defenses the plant h...

122

SPORE KILLER POLYMORPHISM IN FUSARIUM MONILIFORME  

Microsoft Academic Search

A Spore killer trait, which exhibits genetic and cytological properties analo- gous to those previously found in Neurospora, exists in natural populations of the fungal plant pathogen Fusarium moniliforme. The genogeography of the polymorphism in F. moniliforme differs from the situation in Neurospora intermedia. It is more akin to the situation in N. sitophila, although more extreme with respect to

SOPHIA KATHARIOU; PHILIP T. SPIETH

1982-01-01

123

Antagonistic interactions between fungal rice pathogen Fusarium Verticillioides (Sacc.) Nirenberg and Trichoderma harzianum Rifai  

Microsoft Academic Search

Trichoderma harzianum has been found to be a competitor and mycoparasite ofFusarium verticillioides which causes foot rot disease on rice. The experiment was undertaken macroscopically and microscopically. In total 6 treatments\\u000a were performed combining three water activities (0.95, 0.98, 0.995) and two temperatures (15 and 25 °C). At all conditions\\u000a tested, except at 0.95a\\u000a w and 15 °C.Trichoderma harzianum acted

Francisca Sempere; María Pilar Santamarina

2009-01-01

124

Genome Sequences of Six Wheat-Infecting Fusarium Species Isolates  

PubMed Central

Fusarium pathogens represent a major constraint to wheat and barley production worldwide. To facilitate future comparative studies of Fusarium species that are pathogenic to wheat, the genome sequences of four Fusarium pseudograminearum isolates, a single Fusarium acuminatum isolate, and an organism from the Fusarium incarnatum-F. equiseti species complex are reported.

Moolhuijzen, Paula M.; Manners, John M.; Wilcox, Stephen A.; Bellgard, Matthew I.

2013-01-01

125

Genome sequences of six wheat-infecting fusarium species isolates.  

PubMed

Fusarium pathogens represent a major constraint to wheat and barley production worldwide. To facilitate future comparative studies of Fusarium species that are pathogenic to wheat, the genome sequences of four Fusarium pseudograminearum isolates, a single Fusarium acuminatum isolate, and an organism from the Fusarium incarnatum-F. equiseti species complex are reported. PMID:24009115

Moolhuijzen, Paula M; Manners, John M; Wilcox, Stephen A; Bellgard, Matthew I; Gardiner, Donald M

2013-09-05

126

Gall midges (Hessian flies) as plant pathogens.  

PubMed

Gall midges constitute an important group of plant-parasitic insects. The Hessian fly (HF; Mayetiola destructor), the most investigated gall midge, was the first insect hypothesized to have a gene-for-gene interaction with its host plant, wheat (Triticum spp.). Recent investigations support that hypothesis. The minute larval mandibles appear to act in a manner that is analogous to nematode stylets and the haustoria of filamentous plant pathogens. Putative effector proteins are encoded by hundreds of genes and expressed in the HF larval salivary gland. Cultivar-specific resistance (R) genes mediate a highly localized plant reaction that prevents the survival of avirulent HF larvae. Fine-scale mapping of HF avirulence (Avr) genes provides further evidence of effector-triggered immunity (ETI) against HF in wheat. Taken together, these discoveries suggest that the HF, and other gall midges, may be considered biotrophic, or hemibiotrophic, plant pathogens, and they demonstrate the potential that the wheat-HF interaction has in the study of insect-induced plant gall formation. PMID:22656645

Stuart, Jeff J; Chen, Ming-Shun; Shukle, Richard; Harris, Marion O

2012-05-29

127

Pathogens promote plant diversity through a compensatory response  

Microsoft Academic Search

Pathogens are thought to promote diversity in plant communities by preventing competitive exclusion. Previous studies have focussed primarily on single-plant, single- pathogen interactions, yet the interactions between multiple pathogens and multiple hosts may have non-additive impacts on plant community composition. Here, we report that both a bacterial and a fungal pathogen maintained the diversity of a four-species plant community across

Devon J. Bradley; Gregory S. Gilbert; Jennifer B. H. Martiny

2008-01-01

128

Plants, plant pathogens, and microgravity--a deadly trio.  

PubMed

Plants grown in spaceflight conditions are more susceptible to colonization by plant pathogens. The underlying causes for this enhanced susceptibility are not known. Possibly the formation of structural barriers and the activation of plant defense response components are impaired in spaceflight conditions. Either condition would result from altered gene expression of the plant. Because of the tools available, past studies focused on a few physiological responses or biochemical pathways. With recent advances in genomics research, new tools, including microarray technologies, are available to examine the global impact of growth in the spacecraft on the plant's gene expression profile. In ground-based studies, we have developed cDNA subtraction libraries of rice that are enriched for genes induced during pathogen infection and the defense response. Arrays of these genes are being used to dissect plant defense response pathways in a model system involving wild-type rice plants and lesion mimic mutants. The lesion mimic mutants are ideal experimental tools because they erratically develop defense response-like lesions in the absence of pathogens. The gene expression profiles from these ground-based studies will provide the molecular basis for understanding the biochemical and physiological impacts of spaceflight on plant growth, development and disease defense responses. This, in turn, will allow the development of strategies to manage plant disease for life in the space environment. PMID:11865865

Leach, J E; Ryba-White, M; Sun, Q; Wu, C J; Hilaire, E; Gartner, C; Nedukha, O; Kordyum, E; Keck, M; Leung, H; Guikema, J A

2001-06-01

129

Integrated management strategies for tomato fusarium wilt.  

PubMed

Fusarium wilt is caused by the fungal pathogens, Fusarium oxysporum or Fusarium solani. It is a devastating disease that affects many important food and vegetable crops and a major source of loss to farmers worldwide. Initial strategies developed to combat this devastating plant disease include the use of cultural, physical and chemical control. None of these strategies have been able to give the best results of completely ameliorating the situation except for the cultural method which is mainly preventive. A good knowledge of the nature, behaviour and environmental conditions of growth of the disease agent is very important to controlling the disease development in that case. Biological control has been shown to be an environmentally friendly alternative. It makes use of rhizospheric and endophytic microorganisms that can survive and compete favourably well with the Fusarium wilt pathogen. They include plant growth-promoting rhizobacteria ?PGPR? such as Bacillus spp. and Pseudomonas spp.. For PGPR to control or inhibit the growth of the Fusarium wilt pathogen, they make use of mechanisms such as indole acetic acid production, siderophore production, phosphate solublilization, systemic resistance induction and antifungal volatile production among others. PMID:24077535

Ajilogba, Caroline F; Babalola, Olubukola O

2013-01-01

130

Inhibitory effects of essential oils of medicinal plants from growth of plant pathogenic fungi.  

PubMed

Plant cells produce a vast amount of secondary metabolites. Production of some compounds is restricted to a single species. Some compounds are nearly always found only in certain specific plant organs and during a specific developmental period of the plant. Some secondary metabolites of plants serve as defensive compounds against invading microorganisms. Nowadays, it is attempted to substitute the biological and natural agents with chemically synthesized fungicides. In the present research, the antifungal activities of essential oils of seven medicinal plants on mycelial growth of three soilborne plant pathogenic fungi were investigated. The plants consisted of Zataria multiflora, Thymus carmanicus, Mentha pieperata, Satureja hortensis, Lavandual officinolis, Cuminum cyminum and Azadirachta indica. The first five plants are from the family Labiatae. Examined fungi, Fusarium oxysporum f.sp. lycopersici, Fusarium solani and Rhizoctonia solani are the causal agents of tomato root rot. Essential oils of Z. multiflora, T. carmanicus, M. pieperata, S. hortensis and C. cyminum were extracted by hydro-distillation method. Essential oils of L. officinalis and A. indica were extracted by vapor-distillation method. A completely randomized design with five replicates was used to examine the inhibitory impact of each concentration (300, 600 and 900 ppm) of each essential oil. Poisoned food assay using potato dextrose agar (PDA) medium was employed. Results showed that essential oils of A. indica, Z. multiflora, T. carmanicus and S. hortensis in 900 ppm at 12 days post-inoculation, when the control fungi completely covered the plates, prevented about 90% from mycelial growth of each of the fungi. While, the essential oils of M. pieperata, C. cyminum and L. officinalis in the same concentration and time prevented 54.86, 52.77 and 48.84%, respectively, from F. solani growth. These substances did not prevent from F. oxysporum f.sp. lycopersici and R. solani growth. Minimum inhibitory concentration (MIC) of essential oils of T. carmanicus, Z. multiflora and A. indica from R. solani and F. solani growth was 900 and 600 ppm, respectively. In addition, the MIC of essential oils of these plants and essential oil of S. hortensis from F. oxysporum f.sp. lycopersici growth was 900 ppm. The MIC of essential oils of M. pieperata, C. cyminum and L. officinalis from F. solani growth was 900 ppm. PMID:22702190

Panjehkeh, N; Jahani Hossein-Abadi, Z

2011-01-01

131

Top 10 plant pathogenic bacteria in molecular plant pathology.  

PubMed

Many plant bacteriologists, if not all, feel that their particular microbe should appear in any list of the most important bacterial plant pathogens. However, to our knowledge, no such list exists. The aim of this review was to survey all bacterial pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate the bacterial pathogens they would place in a 'Top 10' based on scientific/economic importance. The survey generated 458 votes from the international community, and allowed the construction of a Top 10 bacterial plant pathogen list. The list includes, in rank order: (1) Pseudomonas syringae pathovars; (2) Ralstonia solanacearum; (3) Agrobacterium tumefaciens; (4) Xanthomonas oryzae pv. oryzae; (5) Xanthomonas campestris pathovars; (6) Xanthomonas axonopodis pathovars; (7) Erwinia amylovora; (8) Xylella fastidiosa; (9) Dickeya (dadantii and solani); (10) Pectobacterium carotovorum (and Pectobacterium atrosepticum). Bacteria garnering honourable mentions for just missing out on the Top 10 include Clavibacter michiganensis (michiganensis and sepedonicus), Pseudomonas savastanoi and Candidatus Liberibacter asiaticus. This review article presents a short section on each bacterium in the Top 10 list and its importance, with the intention of initiating discussion and debate amongst the plant bacteriology community, as well as laying down a benchmark. It will be interesting to see, in future years, how perceptions change and which bacterial pathogens enter and leave the Top 10. PMID:22672649

Mansfield, John; Genin, Stephane; Magori, Shimpei; Citovsky, Vitaly; Sriariyanum, Malinee; Ronald, Pamela; Dow, Max; Verdier, Valérie; Beer, Steven V; Machado, Marcos A; Toth, Ian; Salmond, George; Foster, Gary D

2012-06-05

132

Fusarium Solani: A Causative Agent of Skin and Nail Infections  

PubMed Central

Fusarium spp are non-dermatophytic hyaline moulds found as saprophytes and plant pathogens. Human infections are probably a result of various precipitating predisposing factors of impaired immune status. Immunocompetent individuals of late are also vulnerable to various unassuming saprophytic and plant pathogens. To stress the need to identify correctly and institute appropriate antifungal therapy in newly emerging human fungal infectious agents. Repeated mycological sampling of the skin and nails of the suspected fungal infection were processed as per the standard format including direct microscopy and fungal culture on Sabouraud's dextrose agar. The fungus was isolated as Fusarium solani. Fusarium is an important plant pathogen and soil saprophyte. Infection is acquired by direct inoculation or inhalation of spores. It is associated with a variety of diseases like keratitis, onychomycosis, eumycetoma, skin lesions and disseminated diseases.

Kuruvilla, Thomas S; Dias, Meena

2012-01-01

133

Fusarium infections of the skin.  

PubMed

Fusarium species are ubiquitous and may be found in the soil, air and on plants. Fusarium species can cause mycotoxicosis in humans following ingestion of food that has been colonized by the fungal organism. In humans, Fusarium species can also cause disease that is localized, focally invasive or disseminated. The pathogen generally affects immunocompromised individuals with infection of immunocompetent persons being rarely reported. Localized infection includes septic arthritis, endophthalmitis, osteomyelitis, cystitis and brain abscess. In these situations relatively good response may be expected following appropriate surgery and oral antifungal therapy. Disseminated infection occurs when two or more noncontiguous sites are involved. Over eighty cases have been reported, many of which had a hematologic malignancy including neutropenia. The species most commonly involved include Fusarium solani, Fusarium oxysporum, and Fusarium moniliforme (also termed F. verticillioides). The diagnosis of Fusarium infection may be made on histopathology, gram stain, mycology, blood culture, or serology. Portals of entry of disseminated infection include the respiratory tract, the gastrointestinal tract, and cutaneous sites.The skin can be an important and an early clue to diagnosis since cutaneous lesions may be observed at an early stage of the disease and in about seventy-five cases of disseminated Fusarium infection. Typical skin lesions may be painful red or violaceous nodules, the center of which often becomes ulcerated and covered by a black eschar. The multiple necrotizing lesions are often observed on the trunk and the extremities. Onychomycosis most commonly due to F. oxysporum or F. solani has been reported. The onychomycosis may be of several types: distal and lateral subungual (DLSO), white superficial (WSO), and proximal subungual (PSO). In proximal subungual onychomycosis there may be associated leukonychia and/or periungual inflammation. Patients with Fusarium onychomycosis have been cured following therapy with itraconazole, terbinafine, ciclopirox olamine lacquer, or topical antifungal agent. In other instances nail avulsion plus antifungal therapy has been successful. In patients with hematologic malignancy or bone marrow transplant, who may experience prolonged or severe neutropenia during the course of therapy, the skin and nails should be carefully examined and consideration given to treating potential infection sites that may serve as portals for systemic dissemination. When disseminated Fusarium infection is present therapy with antifungal agents has generally been disappointing with the chances of a successful resolution being enhanced if the neutropenia can be corrected in a timely manner. PMID:11964778

Gupta, Aditya K.; Baran, Robert; Summerbell, Richard C.

2000-04-01

134

Fusarium nygamai.A causal agent of root rot of Vicia faba L. in the Sudan.  

PubMed

Wilted and rotted plants of Vicia faba were received from different localities in the Sudan. Among several Fusarium spp., Fusarium nygamai was recovered. Conspicuous symptoms were among others black root rot, associated with rot and death of the lateral root system. Severely infected plants showed black neck canker at soil level. These symptoms were usually accompanied by loss of the leaves' turgor, these then turned brown and died. Death of intact leaves also occurred. Most of the strains proved to be pathogenic to Vicia faba. Disease intensity varied between 28-100%. This is the first report of Fusarium nygamai as a pathogen of Vicia faba. PMID:12701431

Kurmut, A M; Nirenberg, H I; Bochow, H; Büttner, C

2002-01-01

135

ANALYSIS OF EXPRESSED SEQUENCE TAGS FROM GIBBERELLA ZEAE (ANAMORPH FUSARIUM GRAMINEARUM)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium graminearum is a broad host range pathogen that infects many crop plants, including wheat and barley, and causes head blight or rot diseases throughout the world. To better understand fungal development and pathogenicity in this important pathogen, we have now generated over 12,000 ESTs in...

136

Targeting iron acquisition blocks infection with the fungal pathogens Aspergillus fumigatus and Fusarium oxysporum.  

PubMed

Filamentous fungi are an important cause of pulmonary and systemic morbidity and mortality, and also cause corneal blindness and visual impairment worldwide. Utilizing in vitro neutrophil killing assays and a model of fungal infection of the cornea, we demonstrated that Dectin-1 dependent IL-6 production regulates expression of iron chelators, heme and siderophore binding proteins and hepcidin in infected mice. In addition, we show that human neutrophils synthesize lipocalin-1, which sequesters fungal siderophores, and that topical lipocalin-1 or lactoferrin restricts fungal growth in vivo. Conversely, we show that exogenous iron or the xenosiderophore deferroxamine enhances fungal growth in infected mice. By examining mutant Aspergillus and Fusarium strains, we found that fungal transcriptional responses to low iron levels and extracellular siderophores are essential for fungal growth during infection. Further, we showed that targeting fungal iron acquisition or siderophore biosynthesis by topical application of iron chelators or statins reduces fungal growth in the cornea by 60% and that dual therapy with the iron chelator deferiprone and statins further restricts fungal growth by 75%. Together, these studies identify specific host iron-chelating and fungal iron-acquisition mediators that regulate fungal growth, and demonstrate that therapeutic inhibition of fungal iron acquisition can be utilized to treat topical fungal infections. PMID:23853581

Leal, Sixto M; Roy, Sanhita; Vareechon, Chairut; Carrion, Steven deJesus; Clark, Heather; Lopez-Berges, Manuel S; diPietro, Antonio; Schrettl, Marcus; Beckmann, Nicola; Redl, Bernhard; Haas, Hubertus; Pearlman, Eric

2013-07-11

137

Plant pathogenic RNAs and RNA catalysis.  

PubMed Central

The rolling circle replication of small circular plant pathogenic RNAs requires a processing step to convert multimeric intermediates to monomers which are then circularized. Eleven such RNAs are known so far, two are viroids, one is viroid-like and the remainder are satellite RNAs dependent on a helper virus for replication. The processing step is RNA-catalysed in all cases, at least in vitro. All plus forms of these RNAs self-cleave via the hammerhead structure whereas only eight of the minus RNAs self-cleave, five via the hammerhead structure and three via the hairpin structure. There are about 20 other viroids where the processing mechanism has yet to be determined but they are likely candidates for a new type of self-cleavage reaction which is predicted to be conserved in all these viroids. Hepatitis delta RNA is the only circular pathogenic RNA known to self-cleave in the animal kingdom. It is feasible that more single-stranded circular pathogenic RNAs are waiting to be discovered and these could be prospective for new types of self-cleavage reactions.

Symons, R H

1997-01-01

138

A Phenome-Based Functional Analysis of Transcription Factors in the Cereal Head Blight Fungus, Fusarium graminearum  

Microsoft Academic Search

Fusarium graminearum is an important plant pathogen that causes head blight of major cereal crops. The fungus produces mycotoxins that are harmful to animal and human. In this study, a systematic analysis of 17 phenotypes of the mutants in 657 Fusarium graminearum genes encoding putative transcription factors (TFs) resulted in a database of over 11,000 phenotypes (phenome). This database provides

Hokyoung Son; Young-Su Seo; Kyunghun Min; Ae Ran Park; Jungkwan Lee; Jian-Ming Jin; Yang Lin; Peijian Cao; Sae-Yeon Hong; Eun-Kyung Kim; Seung-Ho Lee; Aram Cho; Seunghoon Lee; Myung-Gu Kim; Yongsoo Kim; Jung-Eun Kim; Jin-Cheol Kim; Gyung Ja Choi; Sung-Hwan Yun; Jae Yun Lim; Minkyun Kim; Yong-Hwan Lee; Yang-Do Choi; Yin-Won Lee

2011-01-01

139

Field performance of maize grown from Fusarium verticillioides -inoculated seed  

Microsoft Academic Search

Fusarium verticillioides is an important fungus occupying dual roles in the maize plant. The fungus functions as an endophyte, a fungal\\/host interaction beneficial to the growth of some plants. At other times, the fungus may function as a mycotoxin producing pathogen. The advantages and\\/or disadvantages of the endophytic relationship must be established in order to target appropriate sites for controlling

I. E. Yates; N. W. Widstrom; C. W. Bacon; A. Glenn; D. M. Hinton; D. Sparks; A. J. Jaworski

2005-01-01

140

Comparative Genomics Yields Insights into Niche Adaptation of Plant Vascular Wilt Pathogens  

PubMed Central

The vascular wilt fungi Verticillium dahliae and V. albo-atrum infect over 200 plant species, causing billions of dollars in annual crop losses. The characteristic wilt symptoms are a result of colonization and proliferation of the pathogens in the xylem vessels, which undergo fluctuations in osmolarity. To gain insights into the mechanisms that confer the organisms' pathogenicity and enable them to proliferate in the unique ecological niche of the plant vascular system, we sequenced the genomes of V. dahliae and V. albo-atrum and compared them to each other, and to the genome of Fusarium oxysporum, another fungal wilt pathogen. Our analyses identified a set of proteins that are shared among all three wilt pathogens, and present in few other fungal species. One of these is a homolog of a bacterial glucosyltransferase that synthesizes virulence-related osmoregulated periplasmic glucans in bacteria. Pathogenicity tests of the corresponding V. dahliae glucosyltransferase gene deletion mutants indicate that the gene is required for full virulence in the Australian tobacco species Nicotiana benthamiana. Compared to other fungi, the two sequenced Verticillium genomes encode more pectin-degrading enzymes and other carbohydrate-active enzymes, suggesting an extraordinary capacity to degrade plant pectin barricades. The high level of synteny between the two Verticillium assemblies highlighted four flexible genomic islands in V. dahliae that are enriched for transposable elements, and contain duplicated genes and genes that are important in signaling/transcriptional regulation and iron/lipid metabolism. Coupled with an enhanced capacity to degrade plant materials, these genomic islands may contribute to the expanded genetic diversity and virulence of V. dahliae, the primary causal agent of Verticillium wilts. Significantly, our study reveals insights into the genetic mechanisms of niche adaptation of fungal wilt pathogens, advances our understanding of the evolution and development of their pathogenesis, and sheds light on potential avenues for the development of novel disease management strategies to combat destructive wilt diseases.

Klosterman, Steven J.; Subbarao, Krishna V.; Kang, Seogchan; Veronese, Paola; Gold, Scott E.; Thomma, Bart P. H. J.; Chen, Zehua; Henrissat, Bernard; Lee, Yong-Hwan; Park, Jongsun; Garcia-Pedrajas, Maria D.; Barbara, Dez J.; Anchieta, Amy; de Jonge, Ronnie; Santhanam, Parthasarathy; Maruthachalam, Karunakaran; Atallah, Zahi; Amyotte, Stefan G.; Paz, Zahi; Inderbitzin, Patrik; Hayes, Ryan J.; Heiman, David I.; Young, Sarah; Zeng, Qiandong; Engels, Reinhard; Galagan, James; Cuomo, Christina A.; Dobinson, Katherine F.; Ma, Li-Jun

2011-01-01

141

Multilocus Genotyping and Molecular Phylogenetics Resolve a Novel Head Blight Pathogen within the Fusarium graminearum Species Complex from Ethiopia  

Technology Transfer Automated Retrieval System (TEKTRAN)

A survey of Fusarium head blight (FHB)-contaminated wheat in Ethiopia recovered 31 isolates resembling members of the Fusarium graminearum species complex. Results of a multilocus genotyping (MLGT) assay for FHB species and trichothecene chemotype determination suggested that 22 of these isolates m...

142

Variation and selection of quantitative traits in plant pathogens.  

PubMed

The first section presents the quantitative traits of pathogenicity that are most commonly measured by plant pathologists, how the expression of those traits is influenced by environmental factors, and why the traits must be taken into account for understanding pathogen evolution in agricultural systems. Particular attention is given to the shared genetic control of these traits by the host and the pathogen. Next, the review discusses how quantitative traits account for epidemic development and how they can be related to pathogen fitness. The main constraints that influence the evolution of quantitative traits in pathogen populations are detailed. Finally, possible directions for research on the management of pathogen virulence (as defined by evolutionists) and host quantitative resistance are presented. The review evaluates how the theoretical corpus developed by epidemiologists and evolutionists may apply to plant pathogens in the context of agriculture. The review also analyzes theoretical papers and compares the modeling hypotheses to the biological characteristics of plant pathogens. PMID:22702351

Lannou, Christian

2012-06-11

143

Multiplex detection of plant pathogens using a microsphere immunoassay technology.  

PubMed

Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), chilli vein-banding mottle virus (CVbMV, potyvirus), watermelon silver mottle virus (WSMoV, tospovirus serogroup IV) and melon yellow spot virus (MYSV, tospovirus). An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE)-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA) when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour) was much shorter than that of ELISA (4 hours). This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection. PMID:23638044

Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Kumpoosiri, Mallika; Warin, Nuchnard; Oplatowska, Michalina; Gajanandana, Oraprapai; Grant, Irene R; Karoonuthaisiri, Nitsara; Elliott, Christopher T

2013-04-26

144

Oxalate, germins, and higher-plant pathogens.  

PubMed

Earlier surveys (1, B. G. Lane. [1991] FASEB J. 5, 2983-2901; 2, B. G. Lane. [1994] FASEB J. 8, 294-301) helped to uproot entrenched views of plant oxalate as a static substance. It is now recognized that oxalate oxidases (OXOs) found in the "true cereals" (barley, maize, oat, rice, rye, wheat), the so-called germin OXOs (G-OXOs), or simply germins, are involved in cereal defence responses to invasion by fungal pathogens and that they show promise of being valuable agents of plant defence in dicotyledons, where they are not found naturally. G-OXOs have very peculiar properties: (a) their water-soluble oligomeric structures and enzymic activity are stable during SDS-PAGE and nitrocellulose blotting, (b) their undenatured water-soluble forms are refractory to the action of broad-specificity proteases, (c) their water-insoluble forms occur abundantly (approximately 50%) in the extracellular matrix (cell walls) of wheat, and probably in varying amounts in the cell walls of other true cereals. Transfer of the wheat G-OXO coding element to dicotyledons has been found, in all cases so far examined, to result in improved resistance to fungal pathogens. The possible nature of the improved resistance is discussed in relation to (a) generation of microcidal concentrations of hydrogen peroxide when the G-OXOs act on oxalate, (b) elicitation of hypersensitive cell death at lower concentrations of hydrogen peroxide, (c) formation of effective barriers against predator penetration by the hydrogen-peroxide-mediated lignification of cell walls, and (d) destruction of oxalate, which is an inhibitor of the hypersensitive response, a strategy of particular importance in the case of ubiquitous predator organisms such as Sclerotinia sclerotiorum, which secrete high concentrations of oxalate as a toxin. PMID:12049198

Lane, Byron G

2002-02-01

145

Rootstock Potential of Turkish Lagenaria siceraria Germplasm for Watermelon: Plant Growth, Graft Compatibility, and Resistance to Fusarium  

Microsoft Academic Search

The rootstock potential of Turkish Lagenaria siceraria germplasm for watermelon was evaluated. Among 210 accessions, 72 genotypes were selected based on morphological characteristics. Two commercial hybrid rootstocks were also used for comparison. Crimson Tide watermelon cultivar was used as a scion. Emergence rate, hypocotyl morphology, survival rate, and resistance to Fusarium oxysporum f. sp. niveum (FON) were investigated. Grafted plants

Halit YET; Nebahat SARI; Fatih M. TOK

146

Controlling Plant Pathogens with Bacterial/Fungal Antagonist Combinations.  

National Technical Information Service (NTIS)

Fungal/bacterial antagonist combinations, a seed coated with one of the combinations and a plant protected from plant pathogens by one of the combinations. The invention is also a fungal/bacterial antagonist combination comprising a Trichoderma virens fun...

T. D. Johnson

2004-01-01

147

Coevolution of Plants and Their Pathogens in Natural Habitats  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Understanding of plant-pathogen coevolution in natural systems continues to develop as new theories at the population and species level are increasingly informed by studies unraveling the molecular basis of interactions between individual plants and their pathogens.

Jeremy J. Burdon (Commonwealth Scientific and Industrial Research Organization (CSIRO)âÂÂPlant Industry;); Peter H. Thrall (Commonwealth Scientific and Industrial Research Organization (CSIRO)âÂÂPlant Industry;)

2009-05-08

148

Biological, physiological and pathogenic variation in a genetically homogenous population of Fusarium oxysporum f.sp. cubense  

Microsoft Academic Search

Fusarium oxysporum f.sp. cubense (Foc) is the causal agent of Fusarium wilt of banana and is divided into three races and 21 vegetative compatibility groups (VCGs).\\u000a Within a VCG, Foc proved to be genetically homogenous. Previous studies on phenotypic characteristics were performed with isolates that represented\\u000a different races and VCGs from different banana-producing countries. The aim of this study was

S. Groenewald; N. van den Berg; W. F. O. Marasas; A. Viljoen

2006-01-01

149

Apoplastic immunity and its suppression by filamentous plant pathogens.  

PubMed

Microbial plant pathogens have evolved a variety of strategies to enter plant hosts and cause disease. In particular, biotrophic pathogens, which parasitize living plant tissue, establish sophisticated interactions in which they modulate the plant's metabolism to their own good. The prime decision, whether or not a pathogen can accommodate itself in its host tissue, is made during the initial phase of infection. At this stage, the plant immune system recognizes conserved molecular patterns of the invading microbe, which initiate a set of basal immune responses. Induced plant defense proteins, toxic compounds and antimicrobial proteins encounter a broad arsenal of pathogen-derived virulence factors that aim to disarm host immunity. Crucial regulatory processes and protein-protein interactions take place in the apoplast, that is, intercellular spaces, plant cell walls and defined host-pathogen interfaces which are formed between the plant cytoplasm and the specialized infection structures of many biotrophic pathogens. This article aims to provide an insight into the most important principles and components of apoplastic plant immunity and its modulation by filamentous microbial pathogens. PMID:23594392

Doehlemann, Gunther; Hemetsberger, Christoph

2013-04-17

150

Currency notes and coins as a possible source of transmitting fungal pathogens of man and plants.  

PubMed

Currency (notes and coins) handling by people during transaction is one of the most mobile objects within the community, which has a potential of transmitting pathogens. A survey carried out recently in Nanded city (Maharashtra) revealed heavy contamination of currency notes and coins by important fungal pathogens of plants and man, i.e. Aspergillus niger (60.37%), A. flavus (3.98%), A.nidulans (0.2%), Penicillium citrinum (17.80%), Alternaria tenuis (0.20%), Curvularia pallescens (0.20%), Cladosporium cladosporioides (10.69%), Rhizopus stolonifer (1.04%), an unidentified Aspergillus species .1 (0.20%) and another unidentified Aspergillus species.2 (3.14%), Fusarium sp. (0.20%), Trichoderma viride (0.20%),white sterile mycelium (0.62%) and brown sterile mycelium (0.62%). The study highlights the importance of preventing and controlling fungal contamination of currency notes and coins in public health and plant protection. Currency notes or coins are rarely suspected as infection sources and often not quarantined at airport or seaport terminal. Possible transmission of pathogens or "alien", invasive species through currency across borders or across countries needs to be taken into consideration especially under circumstances of serious outbreak of important disease or when there is a threat of biological warfare. PMID:23505834

Wanule, Dinesh; Jalander, Vaghmare; Gachande, B D; Sirsikar, A N

2011-10-01

151

Fusarium proliferatum Soft Tissue Infection at the Site of a Puncture by a Plant: Recovery, Isolation, and Direct Molecular Identification ?  

PubMed Central

After allogeneic stem cell transplantation, a 49-year-old man developed fever and inflammation at the site of a plant puncture on a finger. A hyalohyphomycete was recovered by incubating the plant spine fragment following surgery. Amplification of the internal transcribed spacer region and 5.8S rRNA, ?-tubulin, and translation elongation factor coding genes identified Fusarium proliferatum, which was confirmed later by culture.

Palmore, Tara N.; Shea, Yvonne R.; Childs, Richard W.; Sherry, Richard M.; Walsh, Thomas J.

2010-01-01

152

Fot 1 Insertions in the Fusarium oxysporum f. sp. albedinis Genome Provide Diagnostic PCR Targets for Detection of the Date Palm Pathogen  

PubMed Central

Populations of Fusarium oxysporum f. sp. albedinis, the causal agent of Bayoud disease of date palm, are derivatives of a single clonal lineage and exhibit very similar Fot 1 hybridization patterns. In order to develop a sensitive diagnostic tool for F. oxysporum f. sp. albedinis detection, we isolated several DNA clones containing a copy of the transposable element Fot 1 from a genomic library of the date palm pathogen. Regions flanking the insertion sites were sequenced, and these sequences were used to design PCR primers that amplify the DNA regions at several Fot 1 insertion sites. When tested on a large sample of Fusarium isolates, including 286 F. oxysporum f. sp. albedinis isolates, 17 other special forms, nonpathogenic F. oxysporum isolates from palm grove soils, and 8 other Fusarium species, the primer pair TL3-FOA28 allowed amplification of a 400-bp fragment found only in F. oxysporum f. sp. albedinis. Sequence analysis showed that one of the Fot 1 copies was truncated, lacking 182 bp at its 3? terminus. The primer pair BI03-FOA1 amplified a 204-bp fragment which overlapped the Fot 1 truncated copy and its 3? site of insertion in the F. oxysporum f. sp. albedinis genome and identified 95% of the isolates. The primer pairs BIO3-FOA1 and TL3-FOA28 used in PCR assays thus provide a useful diagnostic tool for F. oxysporum f. sp. albedinis isolates.

Fernandez, Diana; Ouinten, Mohamed; Tantaoui, Abdelaziz; Geiger, Jean-Paul; Daboussi, Marie-Josee; Langin, Thierry

1998-01-01

153

Biological Control Of Fusarium Head Blight Of Wheat And Deoxynivalenol Levels In Grain Via Use Of Microbial Antagonists  

Microsoft Academic Search

\\u000a Efforts to reduce mycotoxin contamination in food logically start with minimizing plant infection by mycotoxin producing pathogens.Fusarium graminearum(perfect state,Gibberella zeae)infects wheat heads at flowering, causing the disease Fusarium head blight (FHB) and losses of over 2.6 billion dollars in\\u000a the U.S. during the last 10 years. The pathogen often produces deoxynivalenol (DON) resulting in grain size and quality reduction.\\u000a Highly

David A. Schisler; Naseem I. Khan; Michael J. Boehm

154

Physiological and biochemical characterization of Trichoderma harzianum, a biological control agent against soilborne fungal plant pathogens.  

PubMed Central

Monoconidial cultures of 15 isolates of Trichoderma harzianum were characterized on the basis of 82 morphological, physiological, and biochemical features and 99 isoenzyme bands from seven enzyme systems. The results were subjected to numerical analysis which revealed four distinct groups. Representative sequences of the internal transcribed spacer 1 (ITS 1)-ITS 2 region in the ribosomal DNA gene cluster were compared between groups confirming this distribution. The utility of the groupings generated from the morphological, physiological, and biochemical data was assessed by including an additional environmental isolate in the electrophoretic analysis. The in vitro antibiotic activity of the T. harzianum isolates was assayed against 10 isolates of five different soilborne fungal plant pathogens: Aphanomyces cochlioides, Rhizoctonia solani, Phoma betae, Acremonium cucurbitacearum, and Fusarium oxysporum f. sp. radicis lycopersici. Similarities between levels and specificities of biological activity and the numerical characterization groupings are both discussed in relation to antagonist-specific populations in known and potential biocontrol species.

Grondona, I; Hermosa, R; Tejada, M; Gomis, M D; Mateos, P F; Bridge, P D; Monte, E; Garcia-Acha, I

1997-01-01

155

An inordinate fondness for Fusarium: phylogenetic diversity of fusaria cultivated by ambrosia beetles in the genus Euwallacea on avocado and other plant hosts.  

PubMed

Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses, as evidenced by the 11 independent origins and 3500 species of ambrosia beetles. Here we document the evolution of a clade within Fusarium associated with ambrosia beetles in the genus Euwallacea (Coleoptera: Scolytinae). Ambrosia Fusarium Clade (AFC) symbionts are unusual in that some are plant pathogens that cause significant damage in naďve natural and cultivated ecosystems, and currently threaten avocado production in the United States, Israel and Australia. Most AFC fusaria produce unusual clavate macroconidia that serve as a putative food source for their insect mutualists. AFC symbionts were abundant in the heads of four Euwallacea spp., which suggests that they are transported within and from the natal gallery in mandibular mycangia. In a four-locus phylogenetic analysis, the AFC was resolved in a strongly supported monophyletic group within the previously described Clade 3 of the Fusarium solani species complex (FSSC). Divergence-time estimates place the origin of the AFC in the early Miocene ?21.2 Mya, which coincides with the hypothesized adaptive radiation of the Xyleborini. Two strongly supported clades within the AFC (Clades A and B) were identified that include nine species lineages associated with ambrosia beetles, eight with Euwallacea spp. and one reportedly with Xyleborus ferrugineus, and two lineages with no known beetle association. More derived lineages within the AFC showed fixation of the clavate (club-shaped) macroconidial trait, while basal lineages showed a mix of clavate and more typical fusiform macroconidia. AFC lineages consisted mostly of genetically identical individuals associated with specific insect hosts in defined geographic locations, with at least three interspecific hybridization events inferred based on discordant placement in individual gene genealogies and detection of recombinant loci. Overall, these data are consistent with a strong evolutionary trend toward obligate symbiosis coupled with secondary contact and interspecific hybridization. PMID:23608321

Kasson, Matthew T; O'Donnell, Kerry; Rooney, Alejandro P; Sink, Stacy; Ploetz, Randy C; Ploetz, Jill N; Konkol, Joshua L; Carrillo, Daniel; Freeman, Stanley; Mendel, Zvi; Smith, Jason A; Black, Adam W; Hulcr, Jiri; Bateman, Craig; Stefkova, Kristyna; Campbell, Paul R; Geering, Andrew D W; Dann, Elizabeth K; Eskalen, Akif; Mohotti, Keerthi; Short, Dylan P G; Aoki, Takayuki; Fenstermacher, Kristi A; Davis, Donald D; Geiser, David M

2013-04-19

156

Plant-pathogen interactions and elevated CO2: morphological changes in favour of pathogens  

PubMed Central

Crop losses caused by pests and weeds have been estimated at 42% worldwide, with plant pathogens responsible for almost $10 billion worth of damage in the USA in 1994 alone. Elevated carbon dioxide [ECO2] and associated climate change have the potential to accelerate plant pathogen evolution, which may, in turn, affect virulence. Plant–pathogen interactions under increasing CO2 concentrations have the potential to disrupt both agricultural and natural systems severely, yet the lack of experimental data and the subsequent ability to predict future outcomes constitutes a fundamental knowledge gap. Furthermore, nothing is known about the mechanistic bases of increasing pathogen agressiveness. In the absence of information on crop species, it is shown here that plant pathogen (Erysiphe cichoracearum) aggressiveness is increased under ECO2, together with changes in the leaf epidermal characteristics of the model plant Arabidopsis thaliana L. Stomatal density, guard cell length, and trichome numbers on leaves developing post-infection are increased under ECO2 in direct contrast to non-infected responses. As many plant pathogens utilize epidermal features for successful infection, these responses provide a positive feedback mechanism facilitating an enhanced susceptibility of newly developed leaves to further pathogen attack. Furthermore, a screen of resistant and susceptible ecotypes suggest inherent differences in epidermal responses to ECO2.

Lake, Janice Ann; Wade, Ruth Nicola

2009-01-01

157

Effect of Endophytic Fusarium oxysporum on Host Preference of Radopholus similis to Tissue Culture Banana Plants.  

PubMed

The burrowing nematode Radopholus similis is one of the major constraints to banana (Musa spp.) production worldwide. Resource-poor farmers can potentially manage R. similis by using naturally occurring banana endophytes, such as nonpathogenic Fusarium oxysporum, that are inoculated into tissue culture banana plantlets. At present, it is unclear at what stage in the R. similis infection process the endophytes are most effective. In this study, the effect of three endophytic F. oxysporum isolates (V5w2, Eny1.31i and Eny7.11o) on R. similis host preference of either endophyte-treated or untreated banana plants was investigated. No differences were observed between the proportion of nematodes attracted to either root segments excised from endophyte-treated or untreated plants, or in experiments using endophyte-treated and untreated tissue culture banana plantlets. These results imply that the early processes of banana plant host recognition by R. similis are not affected by endophyte infection. PMID:19259463

Athman, Shahasi Y; Dubois, Thomas; Coyne, Daniel; Gold, Clifford S; Labuschagne, Nico; Viljoen, Altus

2006-12-01

158

Antifungal activity of nettle (Urtica dioica L.), colocynth (Citrullus colocynthis L. Schrad), oleander (Nerium oleander L.) and konar (Ziziphus spina-christi L.) extracts on plants pathogenic fungi.  

PubMed

Anti-mycotic activity of the ethanol extracts from Nettle (Urtica dioica L.), Colocynth (Citrullus colocynthis L. Schrad), Konar (Ziziphus spina-christi L.) and Oleander (Nerium oleander L.) floral parts were screened in vitro against four important plant pathogenic fungi viz.; Alternaria alternate, Fusarium oxysporum, Fusarium solani and Rizoctonia solani using agar dilution bioassay. Extracts showed antifungal activity against all the tested fungi. Among the plants, Nettle and Colocynth were the most effective against A. alternate and R. solani while Oleander possesses the best inhibition on F. oxysporum and F. solani. Konar was the most effective extract by reducing the growth of Rizoctonia solani than other fungi. These results showed that extracts could be considered suitable alternatives to chemical additives for the control of fungal diseases in plants. PMID:19579919

Hadizadeh, I; Peivastegan, B; Kolahi, M

2009-01-01

159

GLOBAL GENE EXPRESSION DURING PLANT INFECTION AND TOXIN BIOSYNTHESIS IN FUSARIUM GRAMINEARUM  

Technology Transfer Automated Retrieval System (TEKTRAN)

To understand trichothecene accumulation and the infection cycle of the head blight pathogen F. graminearum sensu stricto, fungal gene expression profiles were monitored during plant infection using the F. graminearum Affymetrix GeneChip. Strains containing mutations in genes for three transcription...

160

Plant pathogens and integrated defence responses to infection  

Microsoft Academic Search

Plants cannot move to escape environmental challenges. Biotic stresses result from a battery of potential pathogens: fungi, bacteria, nematodes and insects intercept the photosynthate produced by plants, and viruses use replication machinery at the host's expense. Plants, in turn, have evolved sophisticated mechanisms to perceive such attacks, and to translate that perception into an adaptive response. Here, we review the

Jeffery L. Dangl; Jonathan D. G. Jones

2001-01-01

161

Pathogen-induced systemic plant signal triggers DNA rearrangements  

Microsoft Academic Search

Plant genome stability is known to be affected by various abiotic environmental conditions, but little is known about the effect of pathogens. For example, exposure of maize plants to barley stripe mosaic virus seems to activate transposable elements and to cause mutations in the non-infected progeny of infected plants. The induction by barley stripe mosaic virus of an inherited effect

Igor Kovalchuk; Olga Kovalchuk; Véronique Kalck; Vitaly Boyko; Jody Filkowski; Manfred Heinlein; Barbara Hohn

2003-01-01

162

Common infection strategies of plant and animal pathogenic bacteria  

Microsoft Academic Search

Gram-negative bacterial pathogens use common strategies to invade and colonize plant and animal hosts. In many species, pathogenicity depends on a highly conserved type-III protein secretion system that delivers effector proteins into the eukaryotic cell. Effector proteins modulate a variety of host cellular pathways, such as rearrangements of the cytoskeleton and defense responses. The specific set of effectors varies in

Daniela Büttner; Ulla Bonas

2003-01-01

163

Biological Control of Aquatic Plants with Pathogenic Fungi.  

National Technical Information Service (NTIS)

The endemic fungal plant pathogen Cercospora rodmanii was shown to have a high potential as a biocontrol agent for waterhyacinths (Eichhorniae crassipes). During this study, methods of culturing and dissemination of this fungus for biocontrol purposes wer...

T. E. Freeman R. Charudattan K. E. Conway R. E. Cullen R. D. Martyn

1981-01-01

164

Pollution of Irrigation Reuse Water by Plant Pathogens.  

National Technical Information Service (NTIS)

Systematic sampling of irrigation runoff and reuse systems in Nebraska demonstrated contamination of the water with plant pathogenic fungi and bacteria. In designed reuse systems, nearly 60% of corn fields showing symptoms of Goss's bacterial wilt (Coryne...

J. R. Steadman

1979-01-01

165

Identification of up-regulated genes during zearalenone biosynthesis in Fusarium  

Microsoft Academic Search

The Fusarium genus includes devastating plant pathogenic fungi that cause diseases in cereals around the world. They produce several mycotoxins,\\u000a including the estrogenic compound zearalenone. To better understand the molecular mechanisms determining zearalenone production,\\u000a we performed differential display RT-PCR under conditions where Fusarium graminearum and F. culmorum produced high amounts of zearalenone. We found 133 expressed sequence tags (ESTs) and

Erik Lysře; Karen R. Bone; Sonja S. Klemsdal

2008-01-01

166

Plant physiology meets phytopathology: plant primary metabolism and plant pathogen interactions  

Microsoft Academic Search

Phytopathogen infection leads to changes in second- ary metabolism based on the induction of defence programmes as well as to changes in primary metab- olism which affect growth and development of the plant. Therefore, pathogen attack causes crop yield losses even in interactions which do not end up with disease or death of the plant. While the regulation of defence

Susanne Berger; Alok K. Sinha; Thomas Roitsch

2007-01-01

167

The role of prophage in plant-pathogenic bacteria.  

PubMed

A diverse set of phage lineages is associated with the bacterial plant-pathogen genomes sequenced to date. Analysis of 37 genomes revealed 5,169 potential genes (approximately 4.3 Mbp) of phage origin, and at least 50% had no function assigned or are nonessential to phage biology. Some phytopathogens have transcriptionally active prophage genes under conditions that mimic plant infection, suggesting an association between plant disease and prophage transcriptional modulation. The role of prophages within genomes for cell biology varies. For pathogens such as Pectobacterium, Pseudomonas, Ralstonia, and Streptomyces, involvement of prophage in disease symptoms has been demonstrated. In Xylella and Xanthomonas, prophage activity is associated with genome rearrangements and strain differentiation. For other pathogens, prophage roles are yet to be established. This review integrates available information in a unique interface ( http://propnav.esalq.usp.br ) that may be assessed to improve research in prophage biology and its association with genome evolution and pathogenicity. PMID:23725471

Varani, Alessandro M; Monteiro-Vitorello, Claudia Barros; Nakaya, Helder I; Van Sluys, Marie-Anne

2013-05-24

168

Emerging Plant Pathogenic Bacteria and Global Warming  

Technology Transfer Automated Retrieval System (TEKTRAN)

Several bacteria, previously classified as non-fluorescent, oxidase positive pseudomonads, Ralstonia, Acidovorax, and Burkholdria have emerged as serious problems world-wide. Perhaps the most destructive is R. solanacearum (RS), a soilborne pathogen with a very wide host range. RS race 3, biovar 2...

169

Engineered Resistance Against Fungal Plant Pathogens  

Microsoft Academic Search

Development of genetic engineering technology and molecular characterization of plant defense responses have provided strategies for controlling plant diseases additional to those based on chemical control or classical breeding programs. Most of these alternative strategies are based on the overproduction of one component of the plant's own defense response. Some strategies exploit the hypersensitive response, a rapid, localized death of

Guy Honée

1999-01-01

170

IAA-producing Penicillium sp. NICS01 triggers plant growth and suppresses Fusarium sp.-induced oxidative stress in sesame (Sesamum indicum L.).  

PubMed

Application of rhizospheric fungi is an effective and environmentally friendly method of improving plant growth and controlling many plant diseases. The current study was aimed to identify phytohormone-producing fungi from soil, to understand their roles in sesame plant growth, and to control Fusarium disease. Three predominant fungi (PNF1, PNF2, and PNF3) isolated from the rhizospheric soil of peanut plants were screened for their growth-promoting efficiency on sesame seedlings. Among these isolates, PNF2 significantly increased the shoot length and fresh weight of seedlings compared with controls. Analysis of the fungal culture filtrate showed a higher concentration of indole acetic acid in PNF2 than in the other isolates. PNF2 was identified as Penicillium sp. on the basis of phylogenetic analysis of ITS sequence similarity. The in vitro biocontrol activity of Penicillium sp. against Fusarium sp. was exhibited by a 49% inhibition of mycelial growth in a dual culture bioassay and by hyphal injuries as observed by scanning electron microscopy. In addition, greenhouse experiments revealed that Fusarium inhibited growth in sesame plants by damaging lipid membranes and reducing protein content. Co-cultivation with Penicillium sp. mitigated Fusarium-induced oxidative stress in sesame plants by limiting membrane lipid peroxidation, and by increasing the protein concentration, levels of antioxidants such as total polyphenols, and peroxidase and polyphenoloxidase activities. Thus, our findings suggest that Penicillium sp. is a potent plant growthpromoting fungus that has the ability to ameliorate damage caused by Fusarium infection in sesame cultivation. PMID:23676921

Radhakrishnan, Ramalingam; Shim, Kang-Bo; Lee, Byeong-Won; Hwang, Chung-Dong; Pae, Suk-Bok; Park, Chang-Hwan; Kim, Sung-Up; Lee, Choon-Ki; Baek, In-Youl

2013-06-28

171

Molecular battles between plant and pathogenic bacteria in the phyllosphere  

PubMed Central

The phyllosphere, i.e., the aerial parts of the plant, provides one of the most important niches for microbial colonization. This niche supports the survival and, often, proliferation of microbes such as fungi and bacteria with diverse lifestyles including epiphytes, saprophytes, and pathogens. Although most microbes may complete the life cycle on the leaf surface, pathogens must enter the leaf and multiply aggressively in the leaf interior. Natural surface openings, such as stomata, are important entry sites for bacteria. Stomata are known for their vital role in water transpiration and gas exchange between the plant and the environment that is essential for plant growth. Recent studies have shown that stomata can also play an active role in limiting bacterial invasion of both human and plant pathogenic bacteria as part of the plant innate immune system. As counter-defense, plant pathogens such as Pseudomonas syringae pv. tomato (Pst) DC3000 use the virulence factor coronatine to suppress stomata-based defense. A novel and crucial early battleground in host-pathogen interaction in the phyllosphere has been discovered with broad implications in the study of bacterial pathogenesis, host immunity, and molecular ecology of bacterial diseases.

Baker, C.M.; Chitrakar, R.; Obulareddy, N.; Panchal, S.; Williams, P.; Melotto, M.

2011-01-01

172

Identification of a cis-acting factor modulating the transcription of FUM1, a key fumonisin-biosynthetic gene in the fungal maize pathogen Fusarium verticillioides.  

PubMed

Fumonisins, toxic secondary metabolites produced by some Fusarium spp. and Aspergillus niger, have strong agro-economic and health impacts. The genes needed for their biosynthesis, named FUM, are clustered and co-expressed in fumonisin producers. In eukaryotes, coordination of transcription can be attained through shared transcription factors, whose specificity relies on the recognition of cis-regulatory elements on target promoters. A bioinformatic analysis on FUM promoters in the maize pathogens Fusarium verticillioides and Aspergillus niger identified a degenerated, over-represented motif potentially involved in the cis-regulation of FUM genes, and of fumonisin biosynthesis. The same motif was not found in various FUM homologues of fungi that do not produce fumonisins. Comparison of the transcriptional strength of the intact FUM1 promoter with a synthetic version, where the motif had been mutated, was carried out in vivo and in planta for F. verticillioides. The results showed that the motif is important for efficient transcription of the FUM1 gene. PMID:23219667

Montis, V; Pasquali, M; Visentin, I; Karlovsky, P; Cardinale, F

2012-12-03

173

Types of and genes for resistance to plant pathogenic viruses  

Microsoft Academic Search

A survey on the occurrence of the most important types of resistance of several host plants to plant pathogenic viruses and of the until now described genes for virus resistance is presented. It has been distinguished between the qualitative localizing resistance and the quantitative nonlocalizing resistance. There are host?virus?combinations in which one or other of the types of resistance was

Hartmut Kegler; Dieter Spaar

1993-01-01

174

Fungal entomopathogens with activity against plant pathogens: ecology and evolution  

Technology Transfer Automated Retrieval System (TEKTRAN)

Dual biological control, of both insect pests and plant pathogens, has been reported for the entomopathogenic fungi Beauveria bassiana and Lecanicillium spp. However, the primary mechanisms of plant disease suppression are different for these fungi. Beauveria produces an array of bioactive metabolit...

175

Emerging Plant Pathogenic Bacteria and Global Warming  

Microsoft Academic Search

Several bacteria, previously classified as non-fluorescent, oxidase positive pseudomonads, Ralstonia, Acidovorax, and Burkholderia have emerged as serious problems worldwide. Perhaps the most destructive is R. solanacearum (RS), a soilborne pathogen with a very wide host range. RS race 3, biovar 2 infects potato and geranium during cooler weather\\u000a making it an additional threat. Acidovorax avenae subsp. avenae has emerged as

Norman W. Schaad

176

[Skin infections caused by Fusarium].  

PubMed

Under favorable conditions even molds can cause skin infections. Fusarium spp. belong to this group of agents. Onychomycoses due to Fusarium spp. are regularly encountered and cannot be clinically distinguished from nail infections triggered by dermatophytes. They can occur in otherwise healthy persons. Skin lesions caused by Fusarium spp. may be necrotizing, ulcerating, pustular, vasculitis-like, panniculitis-like or granulomatous. Single lesions can develop after fungal inoculation into damaged tissue; multiple ones are often due to a septic dissemination of Fusarium in severely immunocompromised patients. An immediate verification of the agents can be life-saving in such cases. Pathogenic Fusarium spp. should be identified at the species level and need to be tested for their susceptibility to antimycotics. In case of multiple lesions, systemic therapy is required. Many strains of Fusarium spp. are susceptible to amphotericin B, voriconazole and posaconazole; itraconazole and terbinafine may be helpful in certain cases. PMID:22948296

Brasch, J

2012-11-01

177

The sirodesmin biosynthetic gene cluster of the plant pathogenic fungus Leptosphaeria maculans.  

PubMed

Sirodesmin PL is a phytotoxin produced by the fungus Leptosphaeria maculans, which causes blackleg disease of canola (Brassica napus). This phytotoxin belongs to the epipolythiodioxopiperazine (ETP) class of toxins produced by fungi including mammalian and plant pathogens. We report the cloning of a cluster of genes with predicted roles in the biosynthesis of sirodesmin PL and show via gene disruption that one of these genes (encoding a two-module non-ribosomal peptide synthetase) is essential for sirodesmin PL biosynthesis. Of the nine genes in the cluster tested, all are co-regulated with the production of sirodesmin PL in culture. A similar cluster is present in the genome of the opportunistic human pathogen Aspergillus fumigatus and is most likely responsible for the production of gliotoxin, which is also an ETP. Homologues of the genes in the cluster were also identified in expressed sequence tags of the ETP producing fungus Chaetomium globosum. Two other fungi with publicly available genome sequences, Magnaporthe grisea and Fusarium graminearum, had similar gene clusters. A comparative analysis of all four clusters is presented. This is the first report of the genes responsible for the biosynthesis of an ETP. PMID:15387811

Gardiner, Donald M; Cozijnsen, Anton J; Wilson, Leanne M; Pedras, M Soledade C; Howlett, Barbara J

2004-09-01

178

Caterpillars and Fungal Pathogens: Two Co-Occurring Parasites of an Ant-Plant Mutualism  

PubMed Central

In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia) and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae) as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae) can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs) whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes), that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth.

Roux, Olivier; Cereghino, Regis; Solano, Pascal J.; Dejean, Alain

2011-01-01

179

Caterpillars and fungal pathogens: two co-occurring parasites of an ant-plant mutualism.  

PubMed

In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia) and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae) as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae) can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs) whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes), that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth. PMID:21655182

Roux, Olivier; Céréghino, Régis; Solano, Pascal J; Dejean, Alain

2011-05-31

180

Molecular Phylogenetic Diversity, Multilocus Haplotype Nomenclature, and In Vitro Antifungal Resistance within the Fusarium solani Species Complex  

Microsoft Academic Search

Members of the species-rich Fusarium solani species complex (FSSC) are responsible for approximately two- thirds all fusarioses of humans and other animals. In addition, many economically important phytopathogenic species are nested within this complex. Due to their increasing clinical relevance and because most of the human pathogenic and plant pathogenic FSSC lack Latin binomials, we have extended the multilocus haplotype

Kerry O'Donnell; Deanna A. Sutton; Annette Fothergill; Dora McCarthy; Michael G. Rinaldi

2008-01-01

181

Sphingolipid C-9 Methyltransferases Are Important for Growth and Virulence but Not for Sensitivity to Antifungal Plant Defensins in Fusarium graminearum? †  

PubMed Central

The C-9-methylated glucosylceramides (GlcCers) are sphingolipids unique to fungi. They play important roles in fungal growth and pathogenesis, and they act as receptors for some antifungal plant defensins. We have identified two genes, FgMT1 and FgMT2, that each encode a putative sphingolipid C-9 methyltransferase (C-9-MT) in the fungal pathogen Fusarium graminearum and complement a Pichia pastoris C-9-MT-null mutant. The ?Fgmt1 mutant produced C-9-methylated GlcCer like the wild-type strain, PH-1, whereas the ?Fgmt2 mutant produced 65 to 75% nonmethylated and 25 to 35% methylated GlcCer. No ?Fgmt1?Fgmt2 double-knockout mutant producing only nonmethylated GlcCer could be recovered, suggesting that perhaps C-9-MTs are essential in this pathogen. This is in contrast to the nonessential nature of this enzyme in the unicellular fungus P. pastoris. The ?Fgmt2 mutant exhibited severe growth defects and produced abnormal conidia, while the ?Fgmt1 mutant grew like the wild-type strain, PH-1, under the conditions tested. The ?Fgmt2 mutant also exhibited drastically reduced disease symptoms in wheat and much-delayed disease symptoms in Arabidopsis thaliana. Surprisingly, the ?Fgmt2 mutant was less virulent on different host plants tested than the previously characterized ?Fggcs1 mutant, which lacks GlcCer synthase activity and produces no GlcCer at all. Moreover, the ?Fgmt1 and ?Fgmt2 mutants, as well as the P. pastoris strain in which the C-9-MT gene was deleted, retained sensitivity to the antifungal plant defensins MsDef1 and RsAFP2, indicating that the C-9 methyl group is not a critical structural feature of the GlcCer receptor required for the antifungal action of plant defensins.

Ramamoorthy, Vellaisamy; Cahoon, Edgar B.; Thokala, Mercy; Kaur, Jagdeep; Li, Jia; Shah, Dilip M.

2009-01-01

182

Nucleic Acid Transport in Plant-Pathogen Interactions  

Microsoft Academic Search

\\u000a Transport of nucleic acid molecules is central to many plant-pathogen interactions. Nucleic acids are transported between\\u000a cells when plant viruses move their genomes from the infected into adjacent uninfected cells through plant intercellular connections,\\u000a the plasmodesmata. DNA and RNA molecules are also transported from the host cell cytoplasm into the nucleus during many viral\\u000a infections. In addition, nuclear import of

Robert Lartey; Vitaly Citovsky

183

Pathogen resistance of transgenic tobacco plants producing caffeine  

Microsoft Academic Search

Caffeine (1,3,7-trimethylxanthine) is a typical purine alkaloid, and produced by a variety of plants such as coffee and tea. Its physiological function, however, is not completely understood, but chemical defense against pathogens and herbivores, and allelopathic effects against competing plant species have been proposed. Previously, we constructed transgenic tobacco plants, which produced caffeine up to 5?g per gram fresh weight

Yun-Soo Kim; Hiroshi Sano

2008-01-01

184

Genome sequence of the plant pathogen Ralstonia solanacearum  

Microsoft Academic Search

Ralstonia solanacearum is a devastating, soil-borne plant pathogen with a global distribution and an unusually wide host range. It is a model system for the dissection of molecular determinants governing pathogenicity. We present here the complete genome sequence and its analysis of strain GMI1000. The 5.8-megabase (Mb) genome is organized into two replicons: a 3.7-Mb chromosome and a 2.1-Mb megaplasmid.

M. Salanoubat; S. Genin; F. Artiguenave; J. Gouzy; S. Mangenot; M. Arlat; A. Billault; P. Brottier; J. C. Camus; L. Cattolico; M. Chandler; N. Choisne; C. Claudel-Renard; S. Cunnac; N. Demange; C. Gaspin; M. Lavie; A. Moisan; C. Robert; W. Saurin; T. Schiex; P. Siguier; P. Thébault; M. Whalen; P. Wincker; M. Levy; J. Weissenbach; C. A. Boucher

2002-01-01

185

Pathogenic amoebae in power-plant cooling lakes. Final report  

SciTech Connect

Cooling waters and associated algae and sediments from four northern and four southern/western electric power plants were tested for the presence of pathogenic amoebae. Unheated control waters and algae/sediments from four northern and five southern/western sites were also tested. When comparing results from the test versus control sites, a significantly higher proportion (P less than or equal to 0.05) of the samples from the test sites were positive for thermophilic amoeba, thermophilic Naegleria and pathogenic Naegleria. The difference in number of samples positive for thermophilic Naegleria between heated and unheated waters, however, was attributable predominantly to the northern waters and algae/sediments. While two of four northern test sites yielded pathogenic Naegleria, seven of the eight isolates were obtained from one site. Seasonality effects relative to the isolation of the pathogen were also noted at this site. One pathogen was isolated from a southwestern test site. Pathogens were not isolated from any control sites. Some of the pathogenic isolates were analyzed serologically and classified as pathogenic Naegleria fowleri. Salinity, pH, conductivity, and bacteriological profiles did not obviously correlate with the presence or absence of pathogenic Naegleria. While thermal addition was significantly associated with the presence of thermophilic Naegleria (P less than or equal to 0.05), the data implicate other as yet undefined parameters associated with the presence of the pathogenic thermophile. Until further delineation of these parameters is effected, generalizations cannot be made concerning the effect of thermal impact on the growth of pathogenic amoeba in a particular cooling system.

Tyndall, R.L.; Willaert, E.; Stevens, A.R.

1981-06-01

186

Fungicide resistance assays for fungal plant pathogens.  

PubMed

Fungicide resistance assays are useful to determine if a fungal pathogen has developed resistance to a fungicide used to manage the disease it causes. Laboratory assays are used to determine loss of sensitivity, or resistance, to a fungicide and can explain fungicide failures and for developing successful fungicide recommendations in the field. Laboratory assays for fungicide resistance are conducted by measuring reductions in growth or spore germination of fungi in the presence of fungicide, or by molecular procedures. This chapter describes two techniques for measuring fungicide resistance, using the sugarbeet leaf spot fungus Cercospora beticola as a model for the protocol. Two procedures are described for fungicides from two different classes; growth reduction for triazole (sterol demethylation inhibitor; DMI) fungicides, and inhibition of spore germination for quinone outside inhibitor (QoI) fungicides. PMID:22183666

Secor, Gary A; Rivera, Viviana V

2012-01-01

187

Phytophthora cinnamomi and other fine root pathogens in north temperate pine forests.  

PubMed

A number of fine root pathogens, including Phytophthora cinnamomi, Pythium ultimum var. ultimum, Pythium undulatum, Pythium violae, Fusarium sp., and two incompletely identified Verticillium species, were isolated from soils taken from under Scots pine trees at five sites in north Scotland, including semi-natural forests and plantations. At least two root pathogens were recovered from each forest. Morphological and molecular data supported the identification of Phytophthora cinnamomi from three of the sites investigated. Isolates of Phytophthora cinnamomi, Pythium ultimum var. ultimum and an incompletely identified Fusarium sp. caused growth reductions of Scots pine seedlings, as determined by dry weight; the most virulent species were Phytophthora cinnamomi and Fusarium sp. The most severe disease symptoms were caused by a mixed inoculum containing Phytophthora cinnamomi, Pythium ultimum var. ultimum and Fusarium sp., or by the Fusarium isolate alone. These nonspecific pathogens may persist on the roots of understorey and herbaceous plants in the pine forests. PMID:17937665

Chavarriaga, Didier; Bodles, William J A; Leifert, Carlo; Belbahri, Lassaad; Woodward, Steve

2007-11-01

188

Light affects fumonisin production in strains of Fusarium fujikuroi, Fusarium proliferatum, and Fusarium verticillioides isolated from rice.  

PubMed

Three Fusarium species associated with bakanae disease of rice (Fusarium fujikuroi, Fusarium proliferatum, and Fusarium verticillioides) were investigated for their ability to produce fumonisins (FB1 and FB2) under different light conditions, and for pathogenicity. Compared to darkness, the conditions that highly stimulated fumonisin production were yellow and green light in F. verticillioides strains; white and blue light, and light/dark alternation in F. fujikuroi and F. proliferatum strains. In general, all light conditions positively influenced fumonisin production with respect to the dark. Expression of the FUM1 gene, which is necessary for the initiation of fumonisin production, was in accordance with the fumonisin biosynthetic profile. High and low fumonisin-producing F. fujikuroi strains showed typical symptoms of bakanae disease, abundant fumonisin-producing F. verticillioides strains exhibited chlorosis and stunting of rice plants, while fumonisin-producing F. proliferatum strains were asymptomatic on rice. We report that F. fujikuroi might be an abundant fumonisin producer with levels comparable to that of F. verticillioides and F. proliferatum, highlighting the need of deeper mycotoxicological analyses on rice isolates of F. fujikuroi. Our results showed for the first time the influence of light on fumonisin production in isolates of F. fujikuroi, F. proliferatum, and F. verticillioides from rice. PMID:24055868

Mati?, Slavica; Spadaro, Davide; Prelle, Ambra; Gullino, Maria Lodovica; Garibaldi, Angelo

2013-08-07

189

New grower-friendly methods for plant pathogen monitoring.  

PubMed

Accurate plant disease diagnoses and rapid detection and identification of plant pathogens are of utmost importance for controlling plant diseases and mitigating the economic losses they incur. Technological advances have increasingly simplified the tools available for the identification of pathogens to the extent that, in some cases, this can be done directly by growers and producers themselves. Commercially available immunoprinting kits and lateral flow devices (LFDs) for detection of selected plant pathogens are among the first tools of what can be considered grower-friendly pathogen monitoring methods. Research efforts, spurned on by point-of-care needs in the medical field, are paving the way for the further development of on-the-spot diagnostics and multiplex technologies in plant pathology. Grower-friendly methods need to be practical, robust, readily available, and cost-effective. Such methods are not restricted to on-the-spot testing but extend to laboratory services, which are sometimes more practicable for growers, extension agents, regulators, and other users of diagnostic tests. PMID:22607454

De Boer, Solke H; López, María M

2012-05-15

190

Function of peroxisomes in plant-pathogen interactions.  

PubMed

Peroxisomes are ubiquitous organelles of eukaryotic cells that accomplish a variety of biochemical functions, including ?-oxidation of fatty acids, glyoxylate cycle, etc. Many reports have been accumulating that indicate peroxisome related metabolic functions are essential for pathogenic development of plant pathogenic fungi. They include peroxisome biogenesis proteins, peroxins and preferential destruction of peroxisomes, pexophagy. Gene disrupted mutants of anthracnose disease pathogen Colletotrichum orbiculare or rice blast pathogen Magnaporthe oryzae defective in peroxins or pexophagy showed deficiency in pathogenesis. Woronin body, a peroxisome related cellular organelle that is related to endurance of fungal cells against environmental damage has essential roles in pathogenesis of M. oryzae. Also, peroxisome related metabolisms such as ?-oxidation and glyoxylate cycle are essential for pathogenesis in several plant pathogenic fungi. In addition, secondary metabolisms including polyketide melanin biosynthesis of C. orbiculare and M. oryzae, and host selective toxins produced by necrotrophic pathogen Alternaria alternata have pivotal roles in fungal pathogenesis. Every such factor was listed and their functions for pathogenesis were demonstrated (Table 18.1 and Fig. 18.1). PMID:23821157

Kubo, Yasuyuki

2013-01-01

191

Mycoses of wheat stem sawfly (Hymenoptera: Cephidae) larvae by Fusarium spp. isolates.  

PubMed

A complex of Fusarium spp., including F. pseudograminearum, F. culmorum, F. avenaceum, F. equiseti, and F. acuminatum, was isolated from field-collected larval cadavers of wheat stem sawfly at two locations for 2 yr. The Fusarium spp. isolates caused mortality in both diapausing larvae in a topical bioassay and in developing larvae feeding in infected stems in a greenhouse experiment. Larval mortality was >90% in both experiments at the highest dose. The pattern of correlation between integument discoloration, hyphal growth, and larval mortality showed that the Fusarium spp. isolates actively infect larvae and kill them, rather than colonizing larval tissue as secondary postmortem invaders. The versatility of Fusarium spp. as plant and insect pathogens enables colonization that results in disease in wheat plants and subsequent mortality of the wheat stem sawfly larvae developing within the same tissue. PMID:19389287

Wenda-Piesik, Anna; Sun, Zhitan; Grey, William E; Weaver, David K; Morrill, Wendell L

2009-04-01

192

Molecular aspects of plant responses to pathogens  

Microsoft Academic Search

Plants respond to infection by accumulating many compounds some of which may function in disease resistance. These include:\\u000a phytoalexins, antifungal proteins, chitinases, glucanases, esterases, proteaes, phospholipases, lipoxygenases, ribonucleases,\\u000a peroxidases, phenoloxidases, lignin, callose, hydroxyproline and glycine-rich glycoproteins, phenolic cross-linked polysachcarides,\\u000a melanin-like pigments, salicylic acid, jasmonic acid, ethylene, peptides, oligosaccharides, hydrogen peroxide and active oxygen\\u000a species. Though specific avirulence genes, elicitors and

Joseph Ku?

1997-01-01

193

Early activation of wheat polyamine biosynthesis during Fusarium head blight implicates putrescine as an inducer of trichothecene mycotoxin production  

Microsoft Academic Search

BACKGROUND: The fungal pathogen Fusarium graminearum causes Fusarium Head Blight (FHB) disease on wheat which can lead to trichothecene mycotoxin (e.g. deoxynivalenol, DON) contamination of grain, harmful to mammalian health. DON is produced at low levels under standard culture conditions when compared to plant infection but specific polyamines (e.g. putrescine and agmatine) and amino acids (e.g. arginine and ornithine) are

Donald M Gardiner; Kemal Kazan; Sebastien Praud; Francois J Torney; Anca Rusu; John M Manners

2010-01-01

194

ROOT DEFENSE RESPONSES TO PATHOGENS AND PARASITES: A MOLECULAR PERSPECTIVE  

Technology Transfer Automated Retrieval System (TEKTRAN)

This review will focus on the molecular and genetic mechanisms underlying defense responses of roots to fungal pathogens. Soil-borne pathogens, including Phytophthora, Pythium, Fusarium, and Bipolaris, represent major sources of biotic stress in the rhizosphere and roots of plants. Molecular recog...

195

Unraveling Plant Responses to Bacterial Pathogens through Proteomics  

PubMed Central

Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens.

Zimaro, Tamara; Gottig, Natalia; Garavaglia, Betiana S.; Gehring, Chris; Ottado, Jorgelina

2011-01-01

196

Brassinosteroid enhances resistance to Fusarium diseases of barley.  

PubMed

Fusarium pathogens are amongst the most damaging pathogens of cereals. These pathogens have the ability to attack the roots, seedlings and flowering heads of barley and wheat plants with disease resulting in yield loss and head blight disease also resulting in the contamination of grain with mycotoxins harmful to human and animal health. There is increasing evidence that brassinosteroid (BR) hormones play an important role in plant defense against both biotic and abiotic stress agents and this study set out to determine if and how BR might affect Fusarium diseases of barley. Application of the epibrassinolide (epiBL) to heads of the barley cultivar (cv.) Lux reduced the severity of Fusarium head blight (FHB) caused by Fusarium culmorum by 86 % and reduced the FHB-associated loss in grain weight by 33%. Growth of plants in soil amended with epiBL resulted in a 28% and 35% reduction in Fusarium seedling blight (FSB) symptoms on the barley cvs. Lux and Akashinriki, respectively. Microarray analysis was used to determine if growth in epiBL-amended soil changed the transcriptional profile in stem base tissue during the early stages of FSB development. At 24 and 48 h post-F. culmorum inoculation, there were a total of 146 epiBL-responsive transcripts, the majority being from the 48 h time point (n = 118). Real-time RT-PCR analysis validated the results for eight transcripts, including five defence genes. The results of gene expression studies show that chromatin remodelling, hormonal signaling, photosynthesis and pathogenesis related genes are activated in plants as a result of growth in epiBL. PMID:23777406

Ali, Shahin; Kumar, Sunil; Doohan, Fiona; Khan, Mojibur

2013-06-18

197

Focus on food safety: Human pathogens on plants  

Technology Transfer Automated Retrieval System (TEKTRAN)

This article introduces the first Focus Issue of Phytopathology, a dedicated issue of the journal that highlights a topic of significant interest to our readership. This first Focus Issue addresses the topic of food safety and the biology of human pathogens on plants, a relatively new problem in pla...

198

EFFECTS OF COMPOSTED MUNICIPAL SLUDGE ON SOILBORNE PLANT PATHOGENS  

EPA Science Inventory

The effect of composted municipal sludge (CMS) on soilborne plant pathogens was evaluated in three sets of experiments. Studies with soybeans over three growing seasons investigated the effect of CMS on root rot severity and yield in Phytophthora-infested soil, the effect of appl...

199

ChitinolyticEnterobacter agglomeransAntagonistic to Fungal Plant Pathogens  

Microsoft Academic Search

Three Enterobacter agglomerans strains which produce and excrete proteins with chitinolytic activity were found while screening soil-borne bacteria antagonistic to fungal plant pathogens. The chitinolytic activity was induced when the strains were grown in the presence of colloidal chitin as the sole carbon source. It was quantitated by using assays with chromogenic p-nitrophenyl analogs of disaccharide, trisaccharide, and tetrasaccharide derivatives

LEONID CHERNIN; ZAFAR ISMAILOV; SHOSHAN HARAN; ANDILAN CHET; Otto Warburg

1995-01-01

200

A new plant pathogenic sterile white basidiomycete from Australia  

Microsoft Academic Search

A sterile white fungus was isolated from the healthy looking roots of buffalo grass (Stenotaphrum secundatum) grown on cleared bush land in Perth, Western Australia. The fungal strain was pathogenic on 12 plant species screened under the greenhouse conditions. The clamp connections and dolipore septa indicated that the isolate was a Basidiomycete. Mycelial features, growth rate at different temperatures, as

O. Vinnere; J. Fatehi; K. Sivasithamparam; B. Gerhardson

2005-01-01

201

Microbial populations responsible for specific soil suppressiveness to plant pathogens  

Microsoft Academic Search

Agricultural soils suppressive to soilborne plant pathogens occur worldwide, and for several of these soils the biological basis of suppressiveness has been described. Two classical types of suppressiveness are known. General suppression owes its activity to the total microbial biomass in soil and is not transferable between soils. Specific suppression owes its activity to the effects of individual or select

David M. Weller; Jos M. Raaijmakers; Brian B. McSpadden Gardener; Linda S. Thomashow

2002-01-01

202

EARLY DEFENCE RESPONSES IN PLANTS INFECTED WITH PATHOGENIC ORGANISMS  

Microsoft Academic Search

Plant organisms possess a complex set of defence mechanisms that are responsible for preventing unfavourable interactions with other living organisms in their natural environment or for reducing negative effects of such interactions. They can be classified into two groups: early responses that occur immediately or shortly after contact with a pathogenic organism, usually in the proximity of the infection site,

ANDRZEJ TALARCZYK; JACEK HENNIG

2001-01-01

203

Pathogenicity of and plant immunity to soft rot pectobacteria.  

PubMed

Soft rot pectobacteria are broad host range enterobacterial pathogens that cause disease on a variety of plant species including the major crop potato. Pectobacteria are aggressive necrotrophs that harbor a large arsenal of plant cell wall-degrading enzymes as their primary virulence determinants. These enzymes together with additional virulence factors are employed to macerate the host tissue and promote host cell death to provide nutrients for the pathogens. In contrast to (hemi)biotrophs such as Pseudomonas, type III secretion systems (T3SS) and T3 effectors do not appear central to pathogenesis of pectobacteria. Indeed, recent genomic analysis of several Pectobacterium species including the emerging pathogen Pectobacterium wasabiae has shown that many strains lack the entire T3SS as well as the T3 effectors. Instead, this analysis has indicated the presence of novel virulence determinants. Resistance to broad host range pectobacteria is complex and does not appear to involve single resistance genes. Instead, activation of plant innate immunity systems including both SA (salicylic acid) and JA (jasmonic acid)/ET (ethylene)-mediated defenses appears to play a central role in attenuation of Pectobacterium virulence. These defenses are triggered by detection of pathogen-associated molecular patterns (PAMPs) or recognition of modified-self such as damage-associated molecular patterns (DAMPs) and result in enhancement of basal immunity (PAMP/DAMP-triggered immunity or pattern-triggered immunity, PTI). In particular plant cell wall fragments released by the action of the degradative enzymes secreted by pectobacteria are major players in enhanced immunity toward these pathogens. Most notably bacterial pectin-degrading enzymes release oligogalacturonide (OG) fragments recognized as DAMPs activating innate immune responses. Recent progress in understanding OG recognition and signaling allows novel genetic screens for OG-insensitive mutants and will provide new insights into plant defense strategies against necrotrophs such as pectobacteria. PMID:23781227

Davidsson, Pär R; Kariola, Tarja; Niemi, Outi; Palva, E T

2013-06-11

204

The broad host range pathogen Pseudomonas aeruginosa strain PA14 carries two pathogenicity islands harboring plant and animal virulence genes  

Microsoft Academic Search

The ubiquitous bacterium Pseudomonas aeruginosa is the quintessential opportunistic pathogen. Certain isolates infect a broad range of host organisms, from plants to humans. The pathogenic promiscuity of particular variants may reflect an increased virulence gene repertoire beyond the core P. aeruginosa genome. We have identified and characterized two P. aeruginosa pathogenicity islands (PAPI-1 and PAPI-2) in the genome of PA14,

Jianxin He; Regina L. Baldini; Eric Déziel; Maude Saucier; Qunhao Zhang; Nicole T. Liberati; Daniel Lee; Jonathan Urbach; Howard M. Goodman; Laurence G. Rahme

2004-01-01

205

Simultaneous detection of Fusarium culmorum and F. graminearum in plant material by duplex PCR with melting curve analysis  

PubMed Central

Background Fusarium head blight (FHB) is a disease of cereal crops, which has a severe impact on wheat and barley production worldwide. Apart from reducing the yield and impairing grain quality, FHB leads to contamination of grain with toxic secondary metabolites (mycotoxins), which pose a health risk to humans and livestock. The Fusarium species primarily involved in FHB are F. graminearum and F. culmorum. A key prerequisite for a reduction in the incidence of FHB is an understanding of its epidemiology. Results We describe a duplex-PCR-based method for the simultaneous detection of F. culmorum and F. graminearum in plant material. Species-specific PCR products are identified by melting curve analysis performed in a real-time thermocycler in the presence of the fluorescent dye SYBR Green I. In contrast to multiplex real-time PCR assays, the method does not use doubly labeled hybridization probes. Conclusion PCR with product differentiation by melting curve analysis offers a cost-effective means of qualitative analysis for the presence of F. culmorum and F. graminearum in plant material. This method is particularly suitable for epidemiological studies involving a large number of samples.

Brandfass, Christoph; Karlovsky, Petr

2006-01-01

206

Pathogen and biological contamination management in plant tissue culture: phytopathogens, vitro pathogens, and vitro pests.  

PubMed

The ability to establish and grow plant cell, organ, and tissue cultures has been widely exploited for basic and applied research, and for the commercial production of plants (micro-propagation). Regardless of whether the application is for research or commerce, it is essential that the cultures be established in vitro free of biological contamination and be maintained as aseptic cultures during manipulation, growth, and storage. The risks from microbial contamination are spurious experimental results due to the effects of latent contaminants or losses of valuable experimental or commercial cultures. Much of the emphasis in culture contamination management historically focussed on the elimination of phytopathogens and the maintenance of cultures free from laboratory contamination by environmental bacteria, fungi (collectively referred to as "vitro pathogens", i.e. pathogens or environmental micro-organisms which cause culture losses), and micro-arthropods ("vitro pests"). Microbial contamination of plant tissue cultures is due to the high nutrient availability in the almost universally used Murashige and Skoog (Physiol Plant 15:473-497, 1962) basal medium or variants of it. In recent years, it has been shown that many plants, especially perennials, are at least locally endophytically colonized intercellularly by bacteria. The latter, and intracellular pathogenic bacteria and viruses/viroids, may pass latently into culture and be spread horizontally and vertically in cultures. Growth of some potentially cultivable endophytes may be suppressed by the high salt and sugar content of the Murashige and Skoog basal medium and suboptimal temperatures for their growth in plant tissue growth rooms. The management of contamination in tissue culture involves three stages: disease screening (syn. disease indexing) of the stock plants with disease and endophyte elimination where detected; establishment and pathogen and contaminant screening of established initial cultures; observation, random sampling, and culture screening for micro-organism in multiplication and stored cultures. The increasing accessibility of both broad-spectrum and specific molecular diagnostics has resulted in advances in multiple pathogen and latent contaminant detection. The hazard analysis critical control point management strategy for tissue culture laboratories is underpinned by staff training in aseptic technique and good laboratory practice. PMID:22610620

Cassells, Alan C

2012-01-01

207

Pathogen resistance of transgenic tobacco plants producing caffeine.  

PubMed

Caffeine (1,3,7-trimethylxanthine) is a typical purine alkaloid, and produced by a variety of plants such as coffee and tea. Its physiological function, however, is not completely understood, but chemical defense against pathogens and herbivores, and allelopathic effects against competing plant species have been proposed. Previously, we constructed transgenic tobacco plants, which produced caffeine up to 5 microg per gram fresh weight of leaves, and showed them to repel caterpillars of tobacco cutworms (Spodoptera litura). In the present study, we found that these transgenic plants constitutively expressed defense-related genes encoding pathogenesis-related (PR)-1a and proteinase inhibitor II under non-stressed conditions. We also found that they were highly resistant against pathogens, tobacco mosaic virus and Pseudomonas syringae. Expression of PR-1a and PR-2 was higher in transgenic plants than in wild-type plants during infection. Exogenously applied caffeine to wild-type tobacco leaves exhibited the similar resistant activity. These results suggested that caffeine stimulated endogenous defense system of host plants through directly or indirectly activating gene expression. This assumption is essentially consistent with the idea of chemical defense, in which caffeine may act as one of signaling molecules to activate defense response. It is thus conceivable that the effect of caffeine is bifunctional; direct interference with pest metabolic pathways, and activation of host defense systems. PMID:18036626

Kim, Yun-Soo; Sano, Hiroshi

2007-11-26

208

Functional Analysis of the Kinome of the Wheat Scab Fungus Fusarium graminearum  

Microsoft Academic Search

As in other eukaryotes, protein kinases play major regulatory roles in filamentous fungi. Although the genomes of many plant pathogenic fungi have been sequenced, systematic characterization of their kinomes has not been reported. The wheat scab fungus Fusarium graminearum has 116 protein kinases (PK) genes. Although twenty of them appeared to be essential, we generated deletion mutants for the other

Chenfang Wang; Shijie Zhang; Rui Hou; Zhongtao Zhao; Qian Zheng; Qijun Xu; Dawei Zheng; Guanghui Wang; Huiquan Liu; Xuli Gao; Ji-Wen Ma; H. Corby Kistler; Zhensheng Kang; Jin-Rong Xu

2011-01-01

209

fost12, the Fusarium oxysporum homolog of the transcription factor Ste12, is upregulated during plant infection and required for virulence.  

PubMed

We have identified a Fusarium oxysporum homolog of the Ste12 transcription factor that regulates mating and filamentation in Saccharomyces cerevisiae. The corresponding gene, fost12, from a highly virulent strain of F. oxysporum f. sp. phaseoli, was confirmed to share a high level of similarity and possessed the STE and C2H2 domains characteristic of the fungal Ste12 transcription factor family of proteins. Disruption of fost12 resulted in no visible alterations of colony morphology or in vitro growth characteristics. However, the disruption mutants showed a substantial reduction in virulence when inoculated in common bean seedlings. In planta transcription of fost12 is drastically increased between 12 and 24h after inoculation, as detected by real-time RT-PCR. The results of the transcriptional analyses carried out in several F. oxysporum strains during axenic growth suggest that the fost12 gene product is a virulence factor required to deal with the nutritional stress confronted by the pathogen during host plant colonization. PMID:19941968

Asunción García-Sánchez, M; Martín-Rodrigues, Noemí; Ramos, Brisa; de Vega-Bartol, José J; Perlin, Michael H; Díaz-Mínguez, José María

2009-11-23

210

Fusarium species from the cassava root rot complex in west Africa.  

PubMed

ABSTRACT Fusarium species are a significant component of the set of fungi associated with cassava root rot. Yield losses due to root rot average 0.5 to 1 ton/ha but losses >3 ton/ha, an equivalent of 15 to 20% yield, often occur. This paper reviews previous work on cassava root rot and summarizes a few recent studies on Fusarium species associated with the disease. Our studies in Cameroon showed that 30% of rotted tubers were infected by Fusarium spp. 12 months after planting and represented 25% of all the fungal isolates recovered. Other commonly recovered fungi were Botryodiplodia theobromae and Armillaria spp. Numerous and diverse species of Fusarium were associated with rotted cassava roots in Nigeria and Cameroon. At least 13 distinct amplified fragment length polymorphism (AFLP) groups of Fusarium were distinguishable, each group probably a distinct species, and many of them might represent previously undescribed Fusarium species. The two largest of the AFLP groups correspond to F. oxysporum and F. solani species complex. The distribution of Fusarium spp. varied among countries and among locations within a country, suggesting that germ plasm resistant at one location may not be resistant at another. Fusarium spp. also cause seedling blight of cassava and can be recovered from the stems of infected plants up to 1 m above the ground. Therefore, the pathogen can spread with stems cut as planting material. Fusarium spp. also can colonize Chromolaena odorata, the dominant weed in short fallows, which could further complicate management efforts by serving as an alternative host for strains that colonize cassava. PMID:18943189

Bandyopadhyay, Ranajit; Mwangi, Maina; Aigbe, Sylvester O; Leslie, John F

2006-06-01

211

Human pathogens on plants: designing a multidisciplinary strategy for research.  

PubMed

Recent efforts to address concerns about microbial contamination of food plants and resulting foodborne illness have prompted new collaboration and interactions between the scientific communities of plant pathology and food safety. This article provides perspectives from scientists of both disciplines and presents selected research results and concepts that highlight existing and possible future synergisms for audiences of both disciplines. Plant pathology is a complex discipline that encompasses studies of the dissemination, colonization, and infection of plants by microbes such as bacteria, viruses, fungi, and oomycetes. Plant pathologists study plant diseases as well as host plant defense responses and disease management strategies with the goal of minimizing disease occurrences and impacts. Repeated outbreaks of human illness attributed to the contamination of fresh produce, nuts and seeds, and other plant-derived foods by human enteric pathogens such as Shiga toxin-producing Escherichia coli and Salmonella spp. have led some plant pathologists to broaden the application of their science in the past two decades, to address problems of human pathogens on plants (HPOPs). Food microbiology, which began with the study of microbes that spoil foods and those that are critical to produce food, now also focuses study on how foods become contaminated with pathogens and how this can be controlled or prevented. Thus, at the same time, public health researchers and food microbiologists have become more concerned about plant-microbe interactions before and after harvest. New collaborations are forming between members of the plant pathology and food safety communities, leading to enhanced research capacity and greater understanding of the issues for which research is needed. The two communities use somewhat different vocabularies and conceptual models. For example, traditional plant pathology concepts such as the disease triangle and the disease cycle can help to define cross-over issues that pertain also to HPOP research, and can suggest logical strategies for minimizing the risk of microbial contamination. Continued interactions and communication among these two disciplinary communities is essential and can be achieved by the creation of an interdisciplinary research coordination network. We hope that this article, an introduction to the multidisciplinary HPOP arena, will be useful to researchers in many related fields. PMID:23406434

Fletcher, Jacqueline; Leach, Jan E; Eversole, Kellye; Tauxe, Robert

2013-04-01

212

Population Dynamics and Identification of Endophytic Bacteria Antagonistic Toward Plant-Pathogenic Fungi in Cotton Root  

Microsoft Academic Search

The antagonistic potentials of endophytic bacteria isolated from the roots of six cotton cultivars at different developmental\\u000a stages were determined in vitro toward three pathogens: Verticillium dahliae Kleb V107 and V396 and Fusarium oxysporum f.sp. vasinfectum (F108). The populations of antagonistic endophytic bacteria (AEB) toward V107, V396, and F108 at the flowering and maturation\\u000a stages were significantly higher than those

Chun-Hong Li; Ming-Wen Zhao; Can-Ming Tang; Shun-Peng Li

2010-01-01

213

Screenhouse and Field Persistence of Nonpathogenic Endophytic Fusarium oxysporum in Musa Tissue Culture Plants  

Microsoft Academic Search

Two major biotic constraints to highland cooking banana (Musa spp., genome group AAA-EA) production in Uganda are the banana weevil Cosmopolites sordidus and the burrowing nematode Radopholus similis. Endophytic Fusarium oxysporum strains inoculated into tissue culture banana plantlets have shown control of the banana weevil and the nematode. We conducted\\u000a screenhouse and field experiments to investigate persistence in the roots

Pamela Paparu; Thomas Dubois; Clifford S. Gold; Björn Niere; Ekwamu Adipala; Daniel Coyne

2008-01-01

214

Chlamydospore formation in Fusarium solani f. sp. phaseoli in root extracts of crop plants and their virulence to kidney beans ( Phaseolus vulgaris L.)  

Microsoft Academic Search

A simple root extract method was developed for chlamydospore production by three macroconidial isolates (A-1, S-3 and T-1) of Fusarium solani f. sp. phaseoli. All isolates produced significantly (P = 0.05) more chlamydospores in oat root extracts (5 to 7 × 105 ml?1) than those of other crop plants, sterilized soil extracts (5 × 104 ml?1) or salt solutions (9

Sachindra Nath Mondal; Koji Kageyama; Mitsuro Hyakumachi

1996-01-01

215

Natural competence and recombination in the plant pathogen Xylella fastidiosa.  

PubMed

Homologous recombination is one of many forces contributing to the diversity, adaptation, and emergence of pathogens. For naturally competent bacteria, transformation is one possible route for the acquisition of novel genetic material. This study demonstrates that Xylella fastidiosa, a generalist bacterial plant pathogen responsible for many emerging plant diseases, is naturally competent and able to homologously recombine exogenous DNA into its genome. Several factors that affect transformation and recombination efficiencies, such as nutrient availability, growth stage, and methylation of transforming DNA, were identified. Recombination was observed in at least one out of every 10(6) cells when exogenous plasmid DNA was supplied and one out of every 10(7) cells when different strains were grown together in vitro. Based on previous genomic studies and experimental data presented here, there is mounting evidence that recombination can occur at relatively high rates and could play a large role in shaping the genetic diversity of X. fastidiosa. PMID:21666009

Kung, Stephanie H; Almeida, Rodrigo P P

2011-06-10

216

Natural Competence and Recombination in the Plant Pathogen Xylella fastidiosa ?  

PubMed Central

Homologous recombination is one of many forces contributing to the diversity, adaptation, and emergence of pathogens. For naturally competent bacteria, transformation is one possible route for the acquisition of novel genetic material. This study demonstrates that Xylella fastidiosa, a generalist bacterial plant pathogen responsible for many emerging plant diseases, is naturally competent and able to homologously recombine exogenous DNA into its genome. Several factors that affect transformation and recombination efficiencies, such as nutrient availability, growth stage, and methylation of transforming DNA, were identified. Recombination was observed in at least one out of every 106 cells when exogenous plasmid DNA was supplied and one out of every 107 cells when different strains were grown together in vitro. Based on previous genomic studies and experimental data presented here, there is mounting evidence that recombination can occur at relatively high rates and could play a large role in shaping the genetic diversity of X. fastidiosa.

Kung, Stephanie H.; Almeida, Rodrigo P. P.

2011-01-01

217

Proteomic analysis of fungal host factors differentially expressed by Fusarium graminearum infected with Fusarium graminearum virus-DK21  

Microsoft Academic Search

Fusarium graminearum virus–DK21 (FgV-DK21), which infects the plant pathogenic F. graminearum, perturbs host developmental processes such as sporulation, morphology, pigmentation, and attenuates the virulence (hypovirulence) of the host. To identify the differentially expressed F. graminearum proteins by FgV-DK21 infection, we have used two-dimensional electrophoresis with mass spectrometry using proteins extracted from virus-free and FgV-DK21-infected strains. A total of 148 spots

Sun-Jung Kwon; Sang-Yun Cho; Kyung-Mi Lee; Jisuk Yu; Moonil Son; Kook-Hyung Kim

2009-01-01

218

Plant innate immunity – direct and indirect recognition of general and specific pathogen-associated molecules  

Microsoft Academic Search

Plants have the capacity to recognise and reject pathogens at various stages of their attempted colonisation of the plant. Non-specific rejection often arises as a consequence of the potential pathogen’s attempt to breach the first lines of plant defence. Pathogens able to penetrate beyond this barrier of non-host resistance may seek a subtle and persuasive relationship with the plant. For

David A Jones; Daigo Takemoto

2004-01-01

219

Spore Killer Polymorphism in FUSARIUM MONILIFORME.  

PubMed

A Spore killer trait, which exhibits genetic and cytological properties analogous to those previously found in Neurospora, exists in natural populations of the fungal plant pathogen Fusarium moniliforme. The genogeography of the polymorphism in F. moniliforme differs from the situation in Neurospora intermedia. It is more akin to the situation in N. sitophila, although more extreme with respect to the prevalence of killer alleles: more than 80% of tested isolates of F. moniliforme carry the killer allele. Nevertheless, sensitive alleles are widely distributed and have been found in California, Italy, Greece and Central America. PMID:17246093

Kathariou, S; Spieth, P T

1982-09-01

220

Host resistance and pathogen virulence across a plant hybrid zone  

Microsoft Academic Search

Hybridization between locally adapted plant populations has been postulated to have significant evolutionary consequences,\\u000a and, in particular, may influence host-pathogen interactions with respect to resistance and virulence structure. This study\\u000a investigated patterns of resistance and virulence in a hybrid zone between ”bog” and ”hill” ecotypes of the native Australian\\u000a flax, Linum marginale, where the host is subject to attack by

U. Carlsson-Granér; J. J. Burdon; P. H. Thrall

1999-01-01

221

Refined PCR protocol for detection of plant pathogens in soil  

Microsoft Academic Search

A polymerase chain reaction method to detect soil-borne plant pathogens such as Pythium ultimum, Plasmodiophora brassicae, and Verticillium dahliae in soil was developed and used with a range of soil textures. DNA extraction was based on lyses with alkali buffer (pH 9.0)\\u000a containing sodium dodecyl sulfate, extraction with benzyl chloride, and collection by ethanol precipitation. Four modified\\u000a protocols – purification

Koji Kageyama; Tsutomu Komatsu; Haruhisa Suga

2003-01-01

222

Salmonella, a cross-kingdom pathogen infecting humans and plants.  

PubMed

Infections with non-typhoidal Salmonella strains are constant and are a non-negligible threat to the human population. In the last two decades, salmonellosis outbreaks have increasingly been associated with infected fruits and vegetables. For a long time, Salmonellae were assumed to survive on plants after a more or less accidental infection. However, this notion has recently been challenged. Studies on the infection mechanism in vegetal hosts, as well as on plant immune systems, revealed an active infection process resembling in certain features the infection in animals. On one hand, Salmonella requires the type III secretion systems to effectively infect plants and to suppress their resistance mechanisms. On the other hand, plants recognize these bacteria and react to the infection with an induced defense mechanism similar to the reaction to other plant pathogens. In this review, we present the newest reports on the interaction between Salmonellae and plants. We discuss the possible ways used by these bacteria to infect plants as well as the plant responses to the infection. The recent findings indicate that plants play a central role in the dissemination of Salmonella within the ecosystem. PMID:23488473

Hernández-Reyes, Casandra; Schikora, Adam

2013-04-02

223

Advances in Bacteriophage-Mediated Control of Plant Pathogens  

PubMed Central

There is continuing pressure to maximise food production given a growing global human population. Bacterial pathogens that infect important agricultural plants (phytopathogens) can reduce plant growth and the subsequent crop yield. Currently, phytopathogens are controlled through management programmes, which can include the application of antibiotics and copper sprays. However, the emergence of resistant bacteria and the desire to reduce usage of toxic products that accumulate in the environment mean there is a need to develop alternative control agents. An attractive option is the use of specific bacteriophages (phages), viruses that specifically kill bacteria, providing a more targeted approach. Typically, phages that target the phytopathogen are isolated and characterised to determine that they have features required for biocontrol. In addition, suitable formulation and delivery to affected plants are necessary to ensure the phages survive in the environment and do not have a deleterious effect on the plant or target beneficial bacteria. Phages have been isolated for different phytopathogens and have been used successfully in a number of trials and commercially. In this paper, we address recent progress in phage-mediated control of plant pathogens and overcoming the challenges, including those posed by CRISPR/Cas and abortive infection resistance systems.

Frampton, Rebekah A.; Pitman, Andrew R.; Fineran, Peter C.

2012-01-01

224

Enzymology of Plant Cell Wall Breakdown by Plant Pathogens.  

National Technical Information Service (NTIS)

The enzymatic degradation and structure of higher plant primary cell walls were the subjects of study. The enzymes employed included endopectate lyase, endo-beta-1,4 galactanase, endo-beta-1,4 xylanase and alpha-L-arabinofuranosidase. Cell wall material w...

D. F. Bateman J. R. Aist

1979-01-01

225

Development of a novel multiplex DNA microarray for Fusarium graminearum and analysis of azole fungicide responses  

Microsoft Academic Search

BACKGROUND: The toxigenic fungal plant pathogen Fusarium graminearum compromises wheat production worldwide. Azole fungicides play a prominent role in controlling this pathogen. Sequencing of its genome stimulated the development of high-throughput technologies to study mechanisms of coping with fungicide stress and adaptation to fungicides at a previously unprecedented precision. DNA-microarrays have been used to analyze genome-wide gene expression patterns and

Rayko Becher; Fabian Weihmann; Holger B Deising; Stefan GR Wirsel

2011-01-01

226

Does function follow form? Principal QTLs for Fusarium head blight (FHB) resistance are coincident with QTLs for inflorescence traits and plant height in a doubled-haploid population of barley  

Microsoft Academic Search

Fusarium head blight (FHB), an important disease of barley in many areas of the world, causes losses in grain yield and quality. Deoxynivalenol\\u000a (DON) mycotoxin residues, produced by the primary pathogen Fusarium graminearum, pose potential health risks. Barley producers may not be able to profitably market FHB-infected barley, even though it has\\u000a a low DON level. Three types of FHB

H. Zhu; L. Gilchrist; P. Hayes; A. Kleinhofs; D. Kudrna; Z. Liu; L. Prom; B. Steffenson; T. Toojinda; H. Vivar

1999-01-01

227

TRANSFORMATION TO PRODUCE BARLEY RESISTANT TO FUSARIUM GRAMINEARUM  

Technology Transfer Automated Retrieval System (TEKTRAN)

The fungal pathogen Fusarium graminearum destroys barley and wheat crops by causing scab disease (Fusarium head blight, FHB). Spores infect seed spike tissues, leading to production of mycotoxins. There are no known barleys with biochemical resistance to Fusarium, although some have various levels ...

228

Salmonella colonization activates the plant immune system and benefits from association with plant pathogenic bacteria.  

PubMed

Despite increasing incidences of human salmonellosis caused by consumption of contaminated vegetables, relatively little is known about how the plant immune system responds to and may inhibit Salmonella colonization. Here we show that Salmonella Typhimurium activates the plant immune system primarily due to its recognition of the flg22 region in Salmonella flagellin. Several previously identified plant genes that play a role in immunity were found to affect the host response to Salmonella. The Salmonella flg22 (Seflg22) peptide induced the immune response in leaves which effectively restricted the growth of Salmonella as well as the plant pathogenic bacterium, Pseudomonas syringae pv. tomato. Induction of immune responses by Seflg22 was dependent on the plant FLS2 receptor. Salmonella multiplied poorly on plant tissues similar to other bacteria which are non-pathogenic to plants. However, Salmonella populations increased significantly when co-inoculated with P. syringae pv. tomato but not when co-inoculated with a type III secretion system mutant of this pathogen. Our results suggest that Salmonella benefits from the immune-suppressing effects of plant pathogenic bacteria, and this growth enhancement may increase the risk of salmonellosis. PMID:23517029

Meng, Fanhong; Altier, Craig; Martin, Gregory B

2013-03-21

229

BarleyBase/PLEXdb: A Unified Expression Profiling Database for Plants and Plant Pathogens  

Technology Transfer Automated Retrieval System (TEKTRAN)

BarleyBase (http://barleybase.org/) and its successor, PLEXdb (http://plexdb.org/), are public resources for large-scale gene expression analysis for plants and plant pathogens. BarleyBase/PLEXdb provides a unified web interface to support the functional interpretation of highly parallel microarray...

230

Avirulence proteins of plant pathogens: determinants of victory and defeat.  

PubMed

summary The simplest way to explain the biochemical basis of the gene-for-gene concept is by direct interaction between a pathogen-derived avirulence (Avr) gene product and a receptor protein, which is encoded by the matching resistance (R) gene of the host plant. The number of R genes for which the matching Avr gene has been cloned is increasing. The number of host-pathogen relationships, however, for which a direct interaction between R and Avr gene products could be proven is still very limited. This observation suggests that in various host-pathogen relationships no physical interaction between R and Avr proteins occurs, and that perception of AVR proteins by their matching R gene products is indirect. Indirect perception implies that at least a third component is required. The 'Guard hypothesis' proposes that this third component could be the virulence target of an AVR protein. Binding of the AVR protein to its virulence target is perceived by the matching R protein, which is 'guarding' the virulence target. An intriguing aspect of the 'Guard hypothesis' is that the Avr gene product causes avirulence of the pathogen through interaction with its virulence target in the plant. This would mean that, although AVR proteins are generally thought to be bifunctional (avirulence as well as virulence factors), this dual function might be based on a single biochemical event. This review focuses on the way AVR proteins are perceived by their matching R gene products. The various components that determine the outcome of the interaction will be discussed, with an emphasis on the dual function of AVR proteins. PMID:20573025

Luderer, R; Joosten, M H

2001-11-01

231

Plant immune response to pathogens differs with changing temperatures.  

PubMed

Temperature fluctuation is a key determinant for microbial invasion and host evasion. In contrast to mammals that maintain constant body temperature, plant temperature oscillates on a daily basis. It remains elusive how plants operate inducible defenses in response to temperature fluctuation. Here we report that ambient temperature changes lead to pronounced shifts of the following two distinct plant immune responses: pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Plants preferentially activate ETI signaling at relatively low temperatures (10-23?°C), whereas they switch to PTI signaling at moderately elevated temperatures (23-32?°C). The Arabidopsis arp6 and hta9hta11 mutants, phenocopying plants grown at elevated temperatures, exhibit enhanced PTI and yet reduced ETI responses. As the secretion of bacterial effectors favours low temperatures, whereas bacteria multiply vigorously at elevated temperatures accompanied with increased microbe-associated molecular pattern production, our findings suggest that temperature oscillation might have driven dynamic co-evolution of distinct plant immune signaling responding to pathogen physiological changes. PMID:24067909

Cheng, Cheng; Gao, Xiquan; Feng, Baomin; Sheen, Jen; Shan, Libo; He, Ping

2013-09-26

232

Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper  

PubMed Central

Background and Aims Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Methods Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Key Results Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. Conclusions The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent pathogen attacks.

Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

2012-01-01

233

A ROOT-KNOT NEMATODE PATHOGENIC TO COCK'S COMB, CELOSIA ARGENTEA L  

Microsoft Academic Search

The presence of root-knot nematode, Meloidogyne incognita was assessed on roots and rhizosphere soil of cock's comb (Celosia argentea L.) planted in 5 lawns located at the campus of University of Agriculture, Faisalabad. The infected plants were stunted with galled and rotted roots. Four fungal pathogens including Fusarium, Pythium, Rhizoctonia and Sclerotia were isolated from nematode-fungal complex infected roots. Plant

S. A. ANWAR; A. ZIA; Q. SHAKEEL

234

Oxidative burst: an early plant response to pathogen infection.  

PubMed Central

As plants are confined to the place where they grow, they have to develop a broad range of defence responses to cope with pathogenic infections. The oxidative burst, a rapid, transient, production of huge amounts of reactive oxygen species (ROS), is one of the earliest observable aspects of a plant's defence strategy. First this Review describes the chemistry of ROS (superoxide radical, hydrogen peroxide and hydroxyl radical). Secondly, the role of ROS in defence responses is demonstrated, and some important issues are considered, such as: (1) which of the ROS is a major building element of the oxidative burst; (2) the spatial and temporal regulation of the oxidative burst; and (3) differences in the plant's responses to biotic and abiotic elicitation. Thirdly, the relationships between the oxidative burst and other plant defence responses are indicated. These include: (1) an oxygen consumption, (2) the production of phytoalexins, (3) systemic acquired resistance, (4) immobilization of plant cell wall proteins, (5) changes in membrane permeability and ion fluxes and (6) a putative role in hypersensitive cell death. Wherever possible, the comparisons with models applicable to animal systems are presented. Finally, the question of the origin of ROS in the oxidative burst is considered, and two major hypotheses, (1) the action of NADPH oxidase system analogous to that of animal phagocytes, and (2) the pH-dependent generation of hydrogen peroxide by a cell wall peroxidase, are presented. On the basis of this material, a third 'unifying' hypothesis is presented, where transient changes in the pH of the cell wall compartment are indicated as a core phenomenon in evoking ROS production. Additionally, a germin/oxalate oxidase system which generates H2O2 in response to pathogenic infection is also described.

Wojtaszek, P

1997-01-01

235

Are Molecular Tools Solving the Challenges Posed by Detection of Plant Pathogenic Bacteria and Viruses?  

Microsoft Academic Search

Plant pathogenic bacteria, phytoplasmas, viruses and viroids are difficult to control, and preventive measures are essential to minimize the losses they cause each year in different crops. In this context, rapid and accurate methods for detection and diagnosis of these plant pathogens are required to apply treatments, undertake agronomic measures or proceed with eradication practices, particularly for quarantine pathogens. In

María M. López; Pablo Llop; Antonio Olmos

236

Genomic Cross Comparison of Soybean Pathogens and the Symbiont Bradyrhizobium japonicum  

Technology Transfer Automated Retrieval System (TEKTRAN)

Plants are under constant attack from a variety of pathogens and respond with dramatic changes in gene expression. Some well-studied diseases of soybean include those induced by the pathogens Pseudomonas syringae, Fusarium virguliforme, and Sclerotinia sclerotiorum. To assist in the identification ...

237

Transcription of Genes in the Biosynthetic Pathway for Fumonisin Mycotoxins Is Epigenetically and Differentially Regulated in the Fungal Maize Pathogen Fusarium verticillioides  

PubMed Central

When the fungal pathogen Gibberella moniliformis (anamorph, Fusarium verticillioides) colonizes maize and maize-based products, it produces class B fumonisin (FB) mycotoxins, which are a significant threat to human and animal health. FB biosynthetic enzymes and accessory proteins are encoded by a set of clustered and cotranscribed genes collectively named FUM, whose molecular regulation is beginning to be unraveled by researchers. FB accumulation correlates with the amount of transcripts from the key FUM genes, FUM1, FUM21, and FUM8. In fungi in general, gene expression is often partially controlled at the chromatin level in secondary metabolism; when this is the case, the deacetylation and acetylation (and other posttranslational modifications) of histones are usually crucial in the regulation of transcription. To assess whether epigenetic factors regulate the FB pathway, we monitored FB production and FUM1, FUM21, and FUM8 expression in the presence of a histone deacetylase inhibitor and verified by chromatin immunoprecipitation the relative degree of histone acetylation in the promoter regions of FUM1, FUM21, and FUM8 under FB-inducing and noninducing conditions. Moreover, we generated transgenic F. verticillioides strains expressing GFP under the control of the FUM1 promoter to determine whether its strength under FB-inducing and noninducing conditions was influenced by its location in the genome. Our results indicate a clear and differential role for chromatin remodeling in the regulation of FUM genes. This epigenetic regulation can be attained through the modulation of histone acetylation at the level of the promoter regions of the key biosynthetic genes FUM1 and FUM21, but less so for FUM8.

Visentin, I.; Montis, V.; Doll, K.; Alabouvette, C.; Tamietti, G.; Karlovsky, P.

2012-01-01

238

Methods and compositions comprising Trichoderma atroviride for the biological control of soil borne plant pathogens and promoting plant growth  

US Patent & Trademark Office Database

The present invention relates to Trichoderma atroviride strains and their use as biological control agents or plant growth promoters. Methods and compositions for biological control of soil borne plant pathogens, and increasing plant yield using T. atroviride are also provided.

2013-03-12

239

Disrupting the transmission of a vector-borne plant pathogen.  

PubMed

Approaches to control vector-borne diseases rarely focus on the interface between vector and microbial pathogen, but strategies aimed at disrupting the interactions required for transmission may lead to reductions in disease spread. We tested if the vector transmission of the plant-pathogenic bacterium Xylella fastidiosa was affected by three groups of molecules: lectins, carbohydrates, and antibodies. Although not comprehensively characterized, it is known that X. fastidiosa adhesins bind to carbohydrates, and that these interactions are important for initial cell attachment to vectors, which is required for bacterial transmission from host to host. Lectins with affinity to substrates expected to occur on the cuticular surface of vectors colonized by X. fastidiosa, such as wheat germ agglutinin, resulted in statistically significant reductions in transmission rate, as did carbohydrates with N-acetylglucosamine residues. Presumably, lectins bound to receptors on the vector required for cell adhesion/colonization, while carbohydrate-saturated adhesins on X. fastidiosa's cell surface. Furthermore, antibodies against X. fastidiosa whole cells, gum, and afimbrial adhesins also resulted in transmission blockage. However, no treatment resulted in the complete abolishment of transmission, suggesting that this is a complex biological process. This work illustrates the potential to block the transmission of vector-borne pathogens without directly affecting either organism. PMID:22101059

Killiny, Nabil; Rashed, Arash; Almeida, Rodrigo P P

2011-11-18

240

The FgHOG1 Pathway Regulates Hyphal Growth, Stress Responses, and Plant Infection in Fusarium graminearum  

PubMed Central

Fusarium head blight (FHB) caused by Fusarium graminearum is a destructive disease of wheat and barley worldwide. In a previous study of systematic characterization of protein kinase genes in F. graminearum, mutants of three putative components of the osmoregulation MAP kinase pathway were found to have distinct colony morphology and hyphal growth defects on PDA plates. Because the osmoregulation pathway is not known to regulate aerial hyphal growth and branching, in this study we further characterized the functions of the FgHog1 pathway in growth, pathogenesis, and development. The Fghog1, Fgpbs2, and Fgssk2 mutants were all reduced in growth rate, aerial hyphal growth, and hyphal branching angle. These mutants were not only hypersensitive to osmotic stress but also had increased sensitivity to oxidative, cytoplasm membrane, and cell wall stresses. The activation of FgHog1 was blocked in the Fgpbs2 and Fgssk2 mutants, indicating the sequential activation of FgSsk2-FgPbs2-FgHog1 cascade. Interestingly, the FgHog1 MAPK pathway mutants appeared to be sensitive to certain compounds present in PDA. They were female sterile but retained male fertility. We also used the metabolomics profiling approach to identify compatible solutes that were accumulated in the wild type but not in the Fghog1 deletion mutant. Overall, our results indicate that the FgSsk2-FgPbs2-FgHog1 MAPK cascade is important for regulating hyphal growth, branching, plant infection, and hyperosmotic and general stress responses in F. graminearum.

Zhou, Xiaoying; Wang, Chenfang; Xiang, Ping; Zheng, Qian; Xu, Jin-Rong

2012-01-01

241

Stimulation of nodulation and plant growth of chickpea ( Cicer arietinum L . ) by Pseudomonas spp. antagonistic to fungal pathogens  

Microsoft Academic Search

Two strains of Pseudomonas MRS23 and CRP55b showed antagonistic activity towards the pathogenic fungi Aspergillus sp., Fusarium oxysporum f. sp. ciceri, Pythium aphanidermatum and Rhizoctonia solani under culture conditions. Larger growth inhibition zones were obtained on nutrient agar (NA) and King's B media in comparison to potato dextrose agar and pigment production media. Both the strains produced siderophore in agar

A. K. Goel; S. S. Sindhu; K. R. Dadarwal

2002-01-01

242

Transgenic tomato plants expressing a wheat endochitinase gene demonstrate enhanced resistance to Fusarium oxysporum f. sp. lycopersici  

Microsoft Academic Search

Various chitinases have been shown to inhibit the growth of fungal pathogens in in vitro as well as in planta conditions.\\u000a chi194, a wheat chitinases gene encoding a 33-kDa chitinase protein, was overexpressed in tomato plants (cv. Pusa Ruby) under the\\u000a control of maize ubiquitin 1 promoter. The integration of transgene in tomato plants was confirmed with polymerase chain reaction

P. V. Girhepuje; G. B. Shinde

2011-01-01

243

Commercial and improved germplasm evaluations for Fusarium wilt, FOV race 1 with root-knot nematodes and race 4  

Technology Transfer Automated Retrieval System (TEKTRAN)

Host plant resistance is the most economic and effective strategy for Fusarium wilt control. To implement steps to develop resistant germplasm to this pathogen, existing commercial Acala, non-Acala Upland (Gossypium hirsutum L.) and Pima (G. barbadense) cultivars, as well as improved germplasm were ...

244

Identification and biocontrol efficacy of Streptomyces miharaensis producing filipin III against Fusarium wilt.  

PubMed

A number of bacterial strains were isolated from the internal tissue of Trapa japonica. Of these, strain KPE62302H, which had a 16S rDNA sequence identical to that of Streptomyces miharaensis showed antifungal activity against several plant pathogens. Treatment of seeds with strain KPE62302H induced a significant reduction in the incidence of Fusarium wilt in tomato plants compared with untreated controls. An antifungal substance (FP-1) was purified from the culture extract of strain KPE62302H using C18 flash and Sephadex LH-20 column chromatography and reverse phase HPLC. Extensive spectrometric analysis using MS and NMR identified this as filipin III. FP-1 inhibited the mycelial growth of plant pathogenic fungi such as Alternaria mali, Aspergillus niger, Colletotrichum gloeosporioides, C. orbiculare, Cylindrocarpon destructans, Diaporthe citiri, Fusarium oxysporum at 1-10 ?g ml(-1) and also markedly inhibited the development of Fusarium wilt caused by F. oxysporum f.sp. lycopersici in tomato plants by treatment with 10 ?g ml(-1) under greenhouse conditions. The efficacy of FP-1 against Fusarium wilt was comparable to that of the synthetic fungicide benomyl. An egfp -tagged strain of KPE62302H confirmed its ability to colonize tomato plants. PMID:22460913

Kim, Jeong Do; Han, Jae Woo; Hwang, In Cheon; Lee, Dongho; Kim, Beom Seok

2011-07-21

245

On the trail of a cereal killer: recent advances in Fusarium graminearum pathogenomics and host resistance.  

PubMed

The ascomycete fungal pathogen Fusarium graminearum (sexual stage: Gibberella zeae) causes the devastating head blight or scab disease on wheat and barley, and cob or ear rot disease on maize. Fusarium graminearum infection causes significant crop and quality losses. In addition to roles as virulence factors during pathogenesis, trichothecene mycotoxins (e.g. deoxynivalenol) produced by this pathogen constitute a significant threat to human and animal health if consumed in respective food or feed products. In the last few years, significant progress has been made towards a better understanding of the processes involved in F. graminearum pathogenesis, toxin biosynthesis and host resistance mechanisms through the use of high-throughput genomic and phenomic technologies. In this article, we briefly review these new advances and also discuss how future research can contribute to the development of sustainable plant protection strategies against this important plant pathogen. PMID:22098555

Kazan, Kemal; Gardiner, Donald M; Manners, John M

2011-11-20

246

Simultaneous detection of Fusarium culmorum and F. graminearum in plant material by duplex PCR with melting curve analysis  

Microsoft Academic Search

BACKGROUND: Fusarium head blight (FHB) is a disease of cereal crops, which has a severe impact on wheat and barley production worldwide. Apart from reducing the yield and impairing grain quality, FHB leads to contamination of grain with toxic secondary metabolites (mycotoxins), which pose a health risk to humans and livestock. The Fusarium species primarily involved in FHB are F.

Christoph Brandfass; Petr Karlovsky

2006-01-01

247

EST Mining and Functional Expression Assays Identify Extracellular Effector Proteins From the Plant Pathogen Phytophthora  

Microsoft Academic Search

Plant pathogenic microbes have the remarkable ability to manipulate biochemical, physiological, and morphological processes in their host plants.These manipulations are ac hieved through a diverse array of effector molecules that can either promote infection or trigger defense responses.We describe a general functional genomics approach aimed at identifying extracellular effector proteins from plant pathogenic microorganisms by combining data mining of expressed

Trudy A. Torto; Shuang Li; Allison Styer; Edgar Huitema; Antonino Testa; Neil A. R. Gow; Pieter van West; Sophien Kamoun

2003-01-01

248

Induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.  

PubMed

Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina citri Kuwayama) vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of specific headspace volatiles and plant nutritional contents. Furthermore, we show in a laboratory setting that this apparent pathogen-mediated manipulation of vector behavior may facilitate pathogen spread. PMID:22457628

Mann, Rajinder S; Ali, Jared G; Hermann, Sara L; Tiwari, Siddharth; Pelz-Stelinski, Kirsten S; Alborn, Hans T; Stelinski, Lukasz L

2012-03-22

249

Similarity between the Rhizobium meliloti fliP gene and pathogenicity-associated genes from animal and plant pathogens.  

PubMed

The nucleotide sequence of the Rhizobium meliloti (Rm) fliP gene was determined. Rm strains carrying insertions within this gene were non-motile, lacked flagella and formed normal N2-fixing root nodules on alfalfa. The FliP protein showed similarity to several bacterial gene products involved in pathogenicity in both plant and animal pathogens. It is likely that all of these proteins share a common functional role in the secretion of specific proteins from bacterial cells. PMID:7828930

Finan, T M; Gough, C; Truchet, G

1995-01-11

250

The relative abundance of viable spores of Gibberella zeae in the planetary boundary layer suggests the role of long-distance transport in regional epidemics of Fusarium head blight  

Microsoft Academic Search

The long-distance transport of plant pathogens takes place primarily in the planetary boundary layer (PBL) of the atmosphere. The PBL extends from about 50m to nearly 1km above the surface of the earth. We used remote-piloted vehicles (RPVs) to measure the relative abundance of viable spores of Gibberella zeae (anamorph Fusarium graminearum), causal agent of Fusarium head blight of wheat,

Sandra Lee Maldonado-Ramirez; David G. Schmale; Elson J. Shields; Gary C. Bergstrom

2005-01-01

251

Antifungal Screening of Plants of the State of Morelos, Mexico Against Four Fungal Postharvest Pathogens of Fruits and Vegetables  

Microsoft Academic Search

To evaluate the fungicide properties of cultivated plant species from the State of Morelos, Mexico, aqueous extracts and powders from leaves of 20 different plant species were prepared to evaluate their in vitro effect on development of the postharvest phytopathogenic fungi: Alternaria spp., Fusarium spp., Pestalotiopsis spp. and Rhizopus spp. The parameters evaluated were mycelial growth, sporulation and mycelial dry

Silvia Bautista-Bańos; Mónica Hernández-López; Laura Leticia Barrera-Necha

2000-01-01

252

Detecting single nucleotide polymorphisms using DNA arrays for plant pathogen diagnosis  

Microsoft Academic Search

The lack of a rapid and reliable means for routine pathogen identification has been one of the main limitations in plant disease management, and has pushed the development of culture-independent, molecular approaches. Currently, DNA array technology is the most suitable technique for high-throughput detection and identification, as well as quantification, of multiple pathogens in a single assay. Closely related pathogens

Bart Lievens; Loes Claes; Alfons C. R. C. Vanachter; Bruno P. A. Cammue; Bart P. H. J. Thomma

2006-01-01

253

Indigenous arbuscular mycorrhizal fungal assemblages protect grassland host plants from pathogens.  

PubMed

Plant roots can establish associations with neutral, beneficial and pathogenic groups of soil organisms. Although it has been recognized from the study of individual isolates that these associations are individually important for plant growth, little is known about interactions of whole assemblages of beneficial and pathogenic microorganisms associating with plants.We investigated the influence of an interaction between local arbuscular mycorrhizal (AM) fungal and pathogenic/saprobic microbial assemblages on the growth of two different plant species from semi-arid grasslands in NE Germany (Mallnow near Berlin). In a greenhouse experiment each plant species was grown for six months in either sterile soil or in sterile soil with one of three different treatments: 1) an AM fungal spore fraction isolated from field soil from Mallnow; 2) a soil pathogen/saprobe fraction consisting of a microbial community prepared with field soil from Mallnow and; 3) the combined AM fungal and pathogen/saprobe fractions. While both plant species grew significantly larger in the presence of AM fungi, they responded negatively to the pathogen/saprobe treatment. For both plant species, we found evidence of pathogen protection effects provided by the AM fungal assemblages. These results indicate that interactions between assemblages of beneficial and pathogenic microorganisms can influence the growth of host plants, but that the magnitude of these effects is plant species-specific. PMID:22110635

Wehner, Jeannine; Antunes, Pedro M; Powell, Jeff R; Caruso, Tancredi; Rillig, Matthias C

2011-11-16

254

Salicylate degradation by the fungal plant pathogen Sclerotinia sclerotiorum.  

PubMed

The fungal plant pathogen Sclerotinia sclerotiorum was studied to determine its ability to degrade salicylate, an important defense-signaling molecule in plants. S. sclerotiorum D-E7 was grown at 25 °C in an undefined medium (50 ml) containing minerals, 0.1% soytone, 50 mM MES buffer (pH 6.5), 25 mM glucose, and 1 mM salicylate. Glucose, oxalate, and salicylate concentrations were monitored by HPLC. S. sclerotiorum D-E7 was found to be active in salicylate degradation. However, salicylate alone was not growth supportive and, at higher levels (10 mM), inhibited glucose-dependent growth. Biomass formation (130 mg [dry wt] of mycelium per 50 ml of undefined medium), oxalate concentrations (~10 mM), and culture acidification (final culture pH approximated 5) were essentially the same in cultures grown with or without salicylate (1 mM). Time-course analyses revealed that salicylate degradation and glucose consumption were complete after 7 days of incubation and was concomitant with growth. Trace amounts of catechol, a known intermediate of salicylate metabolism, were detected during salicylate degradation. Overall, these results indicated that S. sclerotiorum has the ability to degrade salicylate and that the presence of low levels of salicylate did not affect growth or oxalate production by S. sclerotiorum. PMID:23512122

Penn, Cory D; Daniel, Steven L

2013-03-20

255

Chitinolytic Enterobacter agglomerans Antagonistic to Fungal Plant Pathogens  

PubMed Central

Three Enterobacter agglomerans strains which produce and excrete proteins with chitinolytic activity were found while screening soil-borne bacteria antagonistic to fungal plant pathogens. The chitinolytic activity was induced when the strains were grown in the presence of colloidal chitin as the sole carbon source. It was quantitated by using assays with chromogenic p-nitrophenyl analogs of disaccharide, trisaccharide, and tetrasaccharide derivatives of N-acetylglucosamine. A set of three fluorescent substrates with a 4-methylumbelliferyl group linked by (beta)-1,4 linkage to N-acetylglucosamine mono- or oligosaccharides were used to identify the chitinolytic activities of proteins which had been renatured following their separation by electrophoresis. This study provides the most complete evidence for the presence of a complex of chitinolytic enzymes in Enterobacter strains. Four enzymes were detected: two N-acetyl-(beta)-d-glucosaminidases of 89 and 67 kDa, an endochitinase with an apparent molecular mass of 59 kDa, and a chitobiosidase of 50 kDa. The biocontrol ability of the chitinolytic strains was demonstrated under greenhouse conditions. The bacteria decreased the incidence of disease caused by Rhizoctonia solani in cotton by 64 to 86%. Two Tn5 mutants of one of the isolates, which were deficient in chitinolytic activity, were unable to protect plants against the disease.

Chernin, L.; Ismailov, Z.; Haran, S.; Chet, I.

1995-01-01

256

Deciphering the cryptic genome: Genome-wide analyses of the rice pathogen Fusarium fujikuroi reveal complex regulation of secondary metabolism and novel metabolites  

Technology Transfer Automated Retrieval System (TEKTRAN)

The fungus Fusarium fujikuroi is agriculturally important because it produces the phytohormones gibberellic acids (GAs) and causes bakanae (“foolish seedling”) disease of rice. The fungus also produces multiple other secondary metabolites, including pigments and mycotoxins. Here, we present a high-q...

257

Characterization of an Insertion Sequence Element Associated with Genetically Diverse Plant Pathogenic Streptomyces spp  

Microsoft Academic Search

Streptomycetes are common soil inhabitants, yet few described species are plant pathogens. While the patho- genicity mechanisms remain unclear, previous work identified a gene, nec1, which encodes a putative patho- genicity or virulence factor. nec1 and a neighboring transposase pseudogene, ORFtnp, are conserved among un- related plant pathogens and absent from nonpathogens. The atypical GC content of nec1 suggests that

FRANK G. HEALY; RAGHIDA A. BUKHALID; ROSEMARY LORIA

1999-01-01

258

Genome Sequence of the Plant-Pathogenic Bacterium Dickeya dadantii 3937?  

PubMed Central

Dickeya dadantii is a plant-pathogenic enterobacterium responsible for the soft rot disease of many plants of economic importance. We present here the sequence of strain 3937, a strain widely used as a model system for research on the molecular biology and pathogenicity of this group of bacteria.

Glasner, Jeremy D.; Yang, Ching-Hong; Reverchon, Sylvie; Hugouvieux-Cotte-Pattat, Nicole; Condemine, Guy; Bohin, Jean-Pierre; Van Gijsegem, Frederique; Yang, Shihui; Franza, Thierry; Expert, Dominique; Plunkett, Guy; San Francisco, Michael J.; Charkowski, Amy O.; Py, Beatrice; Bell, Kenneth; Rauscher, Lise; Rodriguez-Palenzuela, Pablo; Toussaint, Ariane; Holeva, Maria C.; He, Sheng Yang; Douet, Vanessa; Boccara, Martine; Blanco, Carlos; Toth, Ian; Anderson, Bradley D.; Biehl, Bryan S.; Mau, Bob; Flynn, Sarah M.; Barras, Frederic; Lindeberg, Magdalen; Birch, Paul R. J.; Tsuyumu, Shinji; Shi, Xiangyang; Hibbing, Michael; Yap, Mee-Ngan; Carpentier, Mathilde; Dassa, Elie; Umehara, Masahiro; Kim, Jihyun F.; Rusch, Michael; Soni, Pritin; Mayhew, George F.; Fouts, Derrick E.; Gill, Steven R.; Blattner, Frederick R.; Keen, Noel T.; Perna, Nicole T.

2011-01-01

259

Genome sequence of the plant-pathogenic bacterium Dickeya dadantii 3937.  

PubMed

Dickeya dadantii is a plant-pathogenic enterobacterium responsible for the soft rot disease of many plants of economic importance. We present here the sequence of strain 3937, a strain widely used as a model system for research on the molecular biology and pathogenicity of this group of bacteria. PMID:21217001

Glasner, Jeremy D; Yang, Ching-Hong; Reverchon, Sylvie; Hugouvieux-Cotte-Pattat, Nicole; Condemine, Guy; Bohin, Jean-Pierre; Van Gijsegem, Frédérique; Yang, Shihui; Franza, Thierry; Expert, Dominique; Plunkett, Guy; San Francisco, Michael J; Charkowski, Amy O; Py, Béatrice; Bell, Kenneth; Rauscher, Lise; Rodriguez-Palenzuela, Pablo; Toussaint, Ariane; Holeva, Maria C; He, Sheng Yang; Douet, Vanessa; Boccara, Martine; Blanco, Carlos; Toth, Ian; Anderson, Bradley D; Biehl, Bryan S; Mau, Bob; Flynn, Sarah M; Barras, Frédéric; Lindeberg, Magdalen; Birch, Paul R J; Tsuyumu, Shinji; Shi, Xiangyang; Hibbing, Michael; Yap, Mee-Ngan; Carpentier, Mathilde; Dassa, Elie; Umehara, Masahiro; Kim, Jihyun F; Rusch, Michael; Soni, Pritin; Mayhew, George F; Fouts, Derrick E; Gill, Steven R; Blattner, Frederick R; Keen, Noel T; Perna, Nicole T

2011-01-07

260

Plant chemical defense against herbivores and pathogens: generalized defense or trade-offs?  

Microsoft Academic Search

Plants are often attacked by multiple enemies, including pathogens and herbivores. While many plant secondary metabolites show specific effects toward either pathogens or herbivores, some can affect the performance of both these groups of natural enemies and are considered to be “generalized defense compounds”. We tested whether aucubin and catalpol, two iridoid glycosides present in ribwort plantain ( Plantago lanceolata),

Arjen Biere; Hamida B. Marak; Jos M. M. van Damme

2004-01-01

261

PARTICIPATION OF CHITIN SPECIFIC ISOFORMS OF PEROXIDASE IN PROTECTIVE REACTION OF PLANTS INFECTED BY PATHOGENS  

Technology Transfer Automated Retrieval System (TEKTRAN)

We are interested in how isoforms of peroxidases may influence the cotton plant's resistance to pathogens. Cotton is a member of the Malvaceae and we have been investigating the resistance of wild members of the Malvaceae to the plant pathogen Verticillium dahliae. Using electrophoresis, we have obs...

262

A METHOD TO SURVEY FOR CITRUS PATHOGENS WHEN BIOLOGICAL INDICATOR PLANTS ARE NOT AVAILABLE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Technical Abstract: The use of biological indicator plants for indexing for graft transmissible pathogens of citrus is absolutely essential. However in Guatemala there was an urgent need to conduct a survey to identify what citrus pathogens were present, and no indicator plants were available. We ...

263

NPS6, Encoding a Nonribosomal Peptide Synthetase Involved in Siderophore-Mediated Iron Metabolism, Is a Conserved Virulence Determinant of Plant Pathogenic Ascomycetes[W  

PubMed Central

NPS6, encoding a nonribosomal peptide synthetase, is a virulence determinant in the maize (Zea mays) pathogen Cochliobolus heterostrophus and is involved in tolerance to H2O2. Deletion of NPS6 orthologs in the rice (Oryza sativa) pathogen, Cochliobolus miyabeanus, the wheat (Triticum aestivum) pathogen, Fusarium graminearum, and the Arabidopsis thaliana pathogen, Alternaria brassicicola, resulted in reduced virulence and hypersensitivity to H2O2. Introduction of the NPS6 ortholog from the saprobe Neurospora crassa to the ?nps6 strain of C. heterostrophus restored wild-type virulence to maize and tolerance to H2O2, demonstrating functional conservation in filamentous ascomycete phytopathogens and saprobes. Increased sensitivity to iron depletion was identified as a conserved phenotype of ?nps6 strains. Exogenous application of iron enhanced the virulence of ?nps6 strains of C. heterostrophus, C. miyabeanus, F. graminearum, and A. brassicicola to each host. NPS6 is responsible for the biosynthesis of extracellular siderophores by C. heterostrophus, F. graminearum, and A. brassicicola. Application of the extracellular siderophore of A. brassicicola restored wild-type virulence of the ?Abnps6 strain to Arabidopsis. It is proposed that the role of extracellular siderophores in fungal virulence to plants is to supply an essential nutrient, iron, to their producers in planta and not to act as phytotoxins, depriving their hosts of iron.

Oide, Shinichi; Moeder, Wolfgang; Krasnoff, Stuart; Gibson, Donna; Haas, Hubertus; Yoshioka, Keiko; Turgeon, B. Gillian

2006-01-01

264

Diversity of polyketide synthases in Fusarium  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium can produce a structurally diverse array of secondary metabolites (SMs) with a range of biological activities, including pigmentation, plant growth regulation, and toxicity to humans and other animals. Contamination of grain-based food and feed with toxic SMs produced by Fusarium is associa...

265

Isolation and characterization of Leu[7]-Surfactin from the endophytic bacterium Bacillus mojavensis RRC 101, a biocontrol agent for Fusarium verticillioides  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacillus mojavensis is an endophytic bacterium patented for control of fungal diseases in maize and other plants. Culture extracts and filtrates from this bacterium were antagonistic to the pathogenic and mycotoxic fungus Fusarium verticillioides. However, the identity of the inhibitory substance ...

266

DETERMINING THE BIOSYNTHETIC SEQUENCE IN THE EARLY STEPS OF THE FUMONISIN PATHWAY BY USE OF THREE GENE-DISRUPTION MUTANTS OF FUSARIUM VERTICILLIOIDES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fumonisins are polyketide-derived mycotoxins produced by Fusarium verticillioides, a fungal pathogen of corn plants. Although a gene cluster for the biosynthesis of fumonisins has been cloned, the biosynthetic pathway is still not clear. We have used three gene-disrupted mutants, designated delta-...

267

Phylogenetic placement of plant pathogenic Sclerotium species among teleomorph genera.  

PubMed

Phylogenetic analyses and morphological characteristics were used to assess the taxonomic placement of eight plant-pathogenic Sclerotium species. Members of this genus produce only sclerotia and no fruiting bodies or spores, so Sclerotium species have been difficult to place taxonomically. Sequences of rDNA large subunit (LSU) and internal transcribed spacer (ITS) regions were determined for isolates of Sclerotium cepivorum, S. coffeicola, S. denigrans, S. hydrophilum, Ceratorhiza oryzae-sativae, S. perniciosum, S. rhizodes, S. rolfsii and S. rolfsii var. delphinii. Parsimony analysis grouped two species previously thought to be in the Basidiomycota, S. denigrans and S. perniciosum, within the Ascomycota; these species were found to have affinities with the teleomorph genera Sclerotinia and Stromatinia and the asexual Sclerotium cepivorum, which was known earlier to be related to Sclerotinia species. The other Sclerotium species were placed in one of two basidiomycetous groups, genera Athelia or Ceratobasidium. Based on rDNA analysis and morphology the basidiomycetous Sclerotium hydrophilum and S. rhizodes were transferred to genus Ceratorhiza, the anamorph of Ceratobasidium species. Sclerotium coffeicola was found to be close to S. rolfsii var. delphinii and S. rolfsii var. rolfsii, which was shown earlier to have an Athelia teleomorph. PMID:20361501

Xu, Zhihan; Harrington, Thomas C; Gleason, Mark L; Batzer, Jean C

268

Isolate Identity Determines Plant Tolerance to Pathogen Attack in Assembled Mycorrhizal Communities  

PubMed Central

Arbuscular mycorrhizal fungi (AMF) are widespread soil microorganisms that associate mutualistically with plant hosts. AMF receive photosynthates from the host in return for various benefits. One of such benefits is in the form of enhanced pathogen tolerance. However, this aspect of the symbiosis has been understudied compared to effects on plant growth and its ability to acquire nutrients. While it is known that increased AMF species richness positively correlates with plant productivity, the relationship between AMF diversity and host responses to pathogen attack remains obscure. The objective of this study was to test whether AMF isolates can differentially attenuate the deleterious effects of a root pathogen on plant growth, whether the richest assemblage of AMF isolates provides the most tolerance against the pathogen, and whether AMF-induced changes to root architecture serve as a mechanism for improved plant disease tolerance. In a growth chamber study, we exposed the plant oxeye daisy (Leucanthemum vulgare) to all combinations of three AMF isolates and to the plant root pathogen Rhizoctonia solani. We found that the pathogen caused an 81% reduction in shoot and a 70% reduction in root biomass. AMF significantly reduced the highly deleterious effect of the pathogen. Mycorrhizal plants infected with the pathogen produced 91% more dry shoot biomass and 72% more dry root biomass relative to plants solely infected with R. solani. AMF isolate identity was a better predictor of AMF-mediated host tolerance to the pathogen than AMF richness. However, the enhanced tolerance response did not result from AMF-mediated changes to root architecture. Our data indicate that AMF communities can play a major role in alleviating host pathogen attack but this depends primarily on the capacity of individual AMF isolates to provide this benefit.

Lewandowski, Thaddeus J.; Dunfield, Kari E.; Antunes, Pedro M.

2013-01-01

269

Arbuscular mycorrhizal fungal spores host bacteria that affect nutrient biodynamics and biocontrol of soil-borne plant pathogens  

PubMed Central

Summary The aim of this research was to isolate and characterize bacteria from spores of arbuscular mycorrhizal fungi (AMF). We designated these bacteria ‘probable endobacteria’ (PE). Three bacterial strains were isolated from approximately 500 spores of Gigaspora margarita (Becker and Hall) using a hypodermic needle (diameter, 200??m). The bacteria were identified by morphological methods and on the basis of ribosomal gene sequences as Bacillus sp. (KTCIGM01), Bacillus thuringiensis (KTCIGM02), and Paenibacillus rhizospherae (KTCIGM03). We evaluated the effect of these probable endobacteria on antagonistic activity to the soil-borne plant pathogens (SBPPs) Fusarium oxysporum f. sp. lactucae MAFF 744088, Rosellinia necatrix, Rhizoctonia solani MAFF 237426, and Pythium ultimum NBRC 100123. We also tested whether these probable endobacteria affected phosphorus solubilization, ethylene production, nitrogenase activity (NA), and stimulation of AMF hyphal growth. In addition, fresh samples of spores and hyphae were photographed using an in situ scanning electron microscope (SEM) (Quanta 250FEG; FEI Co., Japan). Bacterial aggregates (BAs), structures similar to biofilms, could be detected on the surface of hyphae and spores. We demonstrate that using extraction with an ultrathin needle, it is possible to isolate AMF-associated bacterial species that are likely derived from inside the fungal spores.

Cruz, Andre Freire; Ishii, Takaaki

2012-01-01

270

A second polycaprolactone depolymerase from Fusarium , a lipase distinct from cutinase  

Microsoft Academic Search

Polycaprolactone (PCL), a synthetic polyester with applications in biodegradable plastics, is degraded by a variety of microorganisms,\\u000a including fungal phytopathogens. These pathogens secrete cutinase, which hydrolyzes cutin, the polyester structural component\\u000a of plant cuticle, releasing ?-hydroxy fatty acids that induce cutinase synthesis. Our laboratory previously reported that\\u000a growth of Fusarium solani on PCL requires cutinase, which is active as a

C. A. Murphy; J. A. Cameron; S. J. Huang; R. T. Vinopal

1998-01-01

271

Responses of Fusarium oxysporum f. sp. niveum to exogenously added sinapic acid in vitro  

Microsoft Academic Search

To assess the influence of phenolic acids from plant root exudates on soil pathogens, we studied the effect of sinapic acid\\u000a added to chemically defined media on the growth and virulence factors of Fusarium oxysporum f. sp. niveum. Sinapic acid inhibited the growth and conidial formation and germination of F. oxysporum f. sp. niveum by 6.7–8.8% and 11.2–37.3%, respectively. Mycotoxin

Hong-sheng Wu; Yang Wang; Wei Bao; Dong-yang Liu; Waseem Raza; Qi-wei Huang; Ze-sheng Mao; Qi-rong Shen

2009-01-01

272

Isoflavonoid accumulation in soybean hairy roots upon treatment with Fusarium solani  

Microsoft Academic Search

Hairy roots were initiated from two soybean [Glycine max (L.) Merr.] genotypes with different susceptibility (susceptible ‘Spencer’ and partially resistant ‘PI567.374’) to the disease sudden death syndrome (SDS) caused by the soil-borne fungal pathogen Fusarium solani f. sp. glycines (FSG) to study the role of isoflavonoids in the plant response to FSG infection. Hairy root cultures obtained by transformation with

Vera V. Lozovaya; Anatoliy V. Lygin; Olga V. Zernova; Shuxian Li; Glen L. Hartman; Jack M. Widholm

2004-01-01

273

Three evolutionary lineages of tomato wilt pathogen, Fusarium oxysporum f. sp. lycopersici , based on sequences of IGS, MAT1 , and pg1 , are each composed of isolates of a single mating type and a single or closely related vegetative compatibility group  

Microsoft Academic Search

Three evolutionary lineages of the tomato wilt pathogen Fusarium oxysporum f. sp. lycopersici were found among a worldwide sample of isolates based on phylogenetic analysis of the ribosomal DNA intergenic spacer region. Each lineage consisted of isolates mainly belonging to a single or closely related vegetative compatibility group (VCG) and a single mating type (MAT). The first lineage (A1) was

Masato Kawabe; Yumiko Kobayashi; Gen Okada; Isamu Yamaguchi; Tohru Teraoka; Tsutomu Arie

2005-01-01

274

Endophytic fungal entomopathogens with activity against plant pathogens: ecology and evolution  

Microsoft Academic Search

Dual biological control, of both insect pests and plant pathogens, has been reported for the fungal entomopathogens, Beauveria bassiana (Bals.-Criv.) Vuill. (Ascomycota: Hypocreales) and Lecanicillium spp. (Ascomycota: Hypocreales). However, the primary mechanisms of plant disease suppression are different for these fungi.\\u000a Beauveria spp. produce an array of bioactive metabolites, and have been reported to limit growth of fungal plant pathogens

Bonnie H. OwnleyKimberly; Kimberly D. Gwinn; Fernando E. Vega

2010-01-01

275

Endophytic fungal entomopathogens with activity against plant pathogens: ecology and evolution  

Microsoft Academic Search

\\u000a Dual biological control, of both insect pests and plant pathogens, has been reported for the fungal entomopathogens, Beauveria bassiana (Bals.-Criv.) Vuill. (Ascomycota: Hypocreales) and Lecanicillium spp. (Ascomycota: Hypocreales). However, the primary mechanisms of plant disease suppression are different for these fungi.\\u000a Beauveria spp. produce an array of bioactive metabolites, and have been reported to limit growth of fungal plant pathogens

Bonnie H. OwnleyKimberly; Kimberly D. Gwinn; Fernando E. Vega

276

Diversity of effector genes in plant pathogenic bacteria of genus Xanthomonas  

Microsoft Academic Search

Gram-negative plant pathogenic bacteria are secreting into plant cell a special type of pathogeni city-related proteins called\\u000a effectors. They are capable of suppressing plant innate immunity or stimulating synthesis and export of metabolites desired\\u000a by the pathogen. We identified a number of effector-coding genes typical of xanthomonads analyzing 8 completely sequenced\\u000a genomes of genus Xanthomonas. Using representative collection provided by

M. V. Mokryakova; I. A. Abdeeva; E. S. Piruzyan; N. W. Schaad; A. N. Ignatov

2010-01-01

277

Contribution of the endogeic earthworm species Aporrectodea caliginosa to the degradation of deoxynivalenol and Fusarium biomass in wheat straw  

Microsoft Academic Search

In arable fields managed by conservation tillage combined with crop residue mulching, plant pathogen repression is an important\\u000a ecosystem service to prevent cultivated plants from fungal diseases and mycotoxin contamination. A laboratory microcosm study\\u000a was conducted to investigate the contribution of the endogeic, geophagous earthworm species Aporrectodea caliginosa as a secondary decomposer to the reduction of the phytopathogenic fungus Fusarium

Friederike Wolfarth; Stefan Schrader; Elisabeth Oldenburg; Joachim Weinert

278

Mycotoxigenic Fusarium and Deoxynivalenol Production Repress Chitinase Gene Expression in the Biocontrol Agent Trichoderma atroviride P1  

PubMed Central

Mycotoxin contamination associated with head blight of wheat and other grains caused by Fusarium culmorum and F. graminearum is a chronic threat to crop, human, and animal health throughout the world. One of the most important toxins in terms of human exposure is deoxynivalenol (DON) (formerly called vomitoxin), an inhibitor of protein synthesis with a broad spectrum of toxigenicity against animals. Certain Fusarium toxins have additional antimicrobial activity, and the phytotoxin fusaric acid has recently been shown to modulate fungus-bacterium interactions that affect plant health (Duffy and Défago, Phytopathology 87:1250-1257, 1997). The potential impact of DON on Fusarium competition with other microorganisms has not been described previously. Any competitive advantage conferred by DON would complicate efforts to control Fusarium during its saprophytic growth on crop residues that are left after harvest and constitute the primary inoculum reservoir for outbreaks in subsequent plantings. We examined the effect of the DON mycotoxin on ecological interactions between pathogenic Fusarium and Trichoderma atroviride strain P1, a competitor fungus with biocontrol activity against a wide range of plant diseases. Expression of the Trichoderma chitinase genes, ech42 and nag1, which contribute to biocontrol activity, was monitored in vitro and on crop residues of two maize cultivars by using goxA reporter gene fusions. We found that DON-producing F. culmorum and F. graminearum strains repressed expression of nag1-gox. DON-negative wild-type Fusarium strains and a DON-negative mutant with an insertional disruption in the tricothecene biosynthetic gene, tri5, had no effect on antagonist gene expression. The role of DON as the principal repressor above other pathogen factors was confirmed. Exposure of Trichoderma to synthetic DON or to a non-DON-producing Fusarium mutant resulted in the same level of nag1-gox repression as the level observed with DON-producing Fusarium. DON repression was specific for nag1-gox and had no effect, either positive or negative, on expression of another key chitinase gene, ech42. This is the first demonstration that a target pathogen down-regulates genes in a fungal biocontrol agent, and our results provide evidence that mycotoxins have a novel ecological function as factors in Fusarium competitiveness.

Lutz, Matthias P.; Feichtinger, Georg; Defago, Genevieve; Duffy, Brion

2003-01-01

279

Antibacterial activity of two plant extracts on eight burn pathogens  

Microsoft Academic Search

Antibacterial activity of crude alcoholic extract of Datura alba and Celosia argentea leaves were studied against pathogens isolated from infected burn patients. The disc-diffusion method showed significant zone of lysis against all the pathogens studied and the results are comparable to the conventional antibiotic cream namely Silver Sulphadiazine (SSD). On comparing the efficiency of the two extracts, extract of D.

A. Gnanamani; K. Shanmuga Priya; N. Radhakrishnan; Mary Babu

2003-01-01

280

Endophytic Fusarium verticillioides reduces disease severity caused by Ustilago maydis on maize.  

PubMed

Endophytic fungi represent diverse taxa that inhabit plant hosts without causing disease symptoms. We used endophytic isolates of Fusarium verticillioides (Sacc.) Nirenberg to understand how endophytic fungi interact with pathogens, in this case, the corn smut pathogen, Ustilago maydis DC (Corda). Endophytic F. verticillioides strains were inoculated onto maize seedlings before, simultaneously, or after inoculation with U. maydis, and the effects on smut disease severity and on plant growth were assessed. When F. verticillioides is simultaneously coinoculated with U. maydis, smut disease severity is significantly decreased and plant growth is increased, compared with other treatments. Controls show that F. verticillioides by itself does not have measurable effects on plant growth. Together, our results suggest that a commonly occurring fungal endophyte on maize, F. verticillioides, ameliorates the effects of a host-specific pathogen, U. maydis, by interfering with the early infection process and limiting disease development, resulting in increased plant growth. PMID:19694816

Lee, Keunsub; Pan, Jean J; May, Georgiana

2009-07-10

281

Transgenic tobacco plants with reduced capability to detoxify reactive oxygen intermediates are hyperresponsive to pathogen infection  

PubMed Central

Reactive oxygen intermediates (ROI) play a critical role in the defense of plants against invading pathogens. Produced during the “oxidative burst,” they are thought to activate programmed cell death (PCD) and induce antimicrobial defenses such as pathogenesis-related proteins. It was shown recently that during the interaction of plants with pathogens, the expression of ROI-detoxifying enzymes such as ascorbate peroxidase (APX) and catalase (CAT) is suppressed. It was suggested that this suppression, occurring upon pathogen recognition and coinciding with an enhanced rate of ROI production, plays a key role in elevating cellular ROI levels, thereby potentiating the induction of PCD and other defenses. To examine the relationship between the suppression of antioxidative mechanisms and the induction of PCD and other defenses during pathogen attack, we studied the interaction between transgenic antisense tobacco plants with reduced APX or CAT and a bacterial pathogen that triggers the hypersensitive response. Transgenic plants with reduced capability to detoxify ROI (i.e., antisense APX or CAT) were found to be hyperresponsive to pathogen attack. They activated PCD in response to low amounts of pathogens that did not trigger the activation of PCD in control plants. Our findings support the hypothesis that suppression of ROI-scavenging enzymes during the hypersensitive response plays an important role in enhancing pathogen-induced PCD.

Mittler, Ron; Herr, Elza Hallak; Orvar, Bjorn Larus; van Camp, Wim; Willekens, Hilde; Inze, Dirk; Ellis, Brian E.

1999-01-01

282

Modulating host homeostasis as a strategy in the plant-pathogen arms race.  

PubMed

In plant-pathogen interactions, pathogens aim to overcome host defense responses while plants employ a battery of responses to limit pathogen growth and thus disease. In this "arms race" between hosts and pathogens, horizontal gene transfer is a potent source of 'pathogenic innovation' for viruses and bacteria. However, bacteria rarely acquire 'eukaryotic-like' genes from their hosts, and where they appear to, evidence for a role of the acquired genes remains outstanding. We have recently reported experimental evidence that the citrus canker causing pathogen Xanthomonas axonopodis pv. citri contains a plant natriuretic peptide-like gene (XacPNP) that encodes a protein that modulates host homeostasis to its advantage. We argue that Xanthomonas PNP has been acquired in an ancient horizontal gene transfer, and given that plant and bacterial PNPs trigger a number of similar physiological responses, we make a case of molecular mimicry. Released XacPNP mimics host PNP and results in a suppressed host response, "improved" host tissue health and consequently better pathogen survival in the lesions. Finally, we propose that Xanthomonas axonopodis pv. citri host interactions can serve as model system to study the role of host homeostasis in plant defense against biotrophic pathogens. PMID:19704897

Gottig, Natalia; Garavaglia, Betiana S; Daurelio, Lucas D; Valentine, Alex; Gehring, Chris; Orellano, Elena G; Ottado, Jorgelina

2009-01-01

283

Phenotypic Variation in the Plant Pathogenic Bacterium Acidovorax citrulli.  

PubMed

Acidovorax citrulli causes bacterial fruit blotch (BFB) of cucurbits, a disease that threatens the cucurbit industry worldwide. Despite the economic importance of BFB, little is known about pathogenicity and fitness strategies of the bacterium. We have observed the phenomenon of phenotypic variation in A. citrulli. Here we report the characterization of phenotypic variants (PVs) of two strains, M6 and 7a1, isolated from melon and watermelon, respectively. Phenotypic variation was observed following growth in rich medium, as well as upon isolation of bacteria from inoculated plants or exposure to several stresses, including heat, salt and acidic conditions. When grown on nutrient agar, all PV colonies possessed a translucent appearance, in contrast to parental strain colonies that were opaque. After 72 h, PV colonies were bigger than parental colonies, and had a fuzzy appearance relative to parental strain colonies that are relatively smooth. A. citrulli colonies are generally surrounded by haloes detectable by the naked eye. These haloes are formed by type IV pilus (T4P)-mediated twitching motility that occurs at the edge of the colony. No twitching haloes could be detected around colonies of both M6 and 7a1 PVs, and microscopy observations confirmed that indeed the PVs did not perform twitching motility. In agreement with these results, transmission electron microscopy revealed that M6 and 7a1 PVs do not produce T4P under tested conditions. PVs also differed from their parental strain in swimming motility and biofilm formation, and interestingly, all assessed variants were less virulent than their corresponding parental strains in seed transmission assays. Slight alterations could be detected in some DNA fingerprinting profiles of 7a1 variants relative to the parental strain, while no differences at all could be seen among M6 variants and parental strain, suggesting that, at least in the latter, phenotypic variation is mediated by slight genetic and/or epigenetic alterations. PMID:24023830

Shrestha, Ram Kumar; Rosenberg, Tally; Makarovsky, Daria; Eckshtain-Levi, Noam; Zelinger, Einat; Kopelowitz, June; Sikorski, Johannes; Burdman, Saul

2013-09-02

284

Phenotypic Variation in the Plant Pathogenic Bacterium Acidovorax citrulli  

PubMed Central

Acidovorax citrulli causes bacterial fruit blotch (BFB) of cucurbits, a disease that threatens the cucurbit industry worldwide. Despite the economic importance of BFB, little is known about pathogenicity and fitness strategies of the bacterium. We have observed the phenomenon of phenotypic variation in A. citrulli. Here we report the characterization of phenotypic variants (PVs) of two strains, M6 and 7a1, isolated from melon and watermelon, respectively. Phenotypic variation was observed following growth in rich medium, as well as upon isolation of bacteria from inoculated plants or exposure to several stresses, including heat, salt and acidic conditions. When grown on nutrient agar, all PV colonies possessed a translucent appearance, in contrast to parental strain colonies that were opaque. After 72 h, PV colonies were bigger than parental colonies, and had a fuzzy appearance relative to parental strain colonies that are relatively smooth. A. citrulli colonies are generally surrounded by haloes detectable by the naked eye. These haloes are formed by type IV pilus (T4P)-mediated twitching motility that occurs at the edge of the colony. No twitching haloes could be detected around colonies of both M6 and 7a1 PVs, and microscopy observations confirmed that indeed the PVs did not perform twitching motility. In agreement with these results, transmission electron microscopy revealed that M6 and 7a1 PVs do not produce T4P under tested conditions. PVs also differed from their parental strain in swimming motility and biofilm formation, and interestingly, all assessed variants were less virulent than their corresponding parental strains in seed transmission assays. Slight alterations could be detected in some DNA fingerprinting profiles of 7a1 variants relative to the parental strain, while no differences at all could be seen among M6 variants and parental strain, suggesting that, at least in the latter, phenotypic variation is mediated by slight genetic and/or epigenetic alterations.

Shrestha, Ram Kumar; Rosenberg, Tally; Makarovsky, Daria; Eckshtain-Levi, Noam; Zelinger, Einat; Kopelowitz, June; Sikorski, Johannes; Burdman, Saul

2013-01-01

285

RNA silencing suppression by plant pathogens: defence, counter-defence and counter-counter-defence.  

PubMed

RNA silencing is a central regulator of gene expression in most eukaryotes and acts both at the transcriptional level through DNA methylation and at the post-transcriptional level through direct mRNA interference mediated by small RNAs. In plants and invertebrates, the same pathways also function directly in host defence against viruses by targeting viral RNA for degradation. Successful viruses have consequently evolved diverse mechanisms to avoid silencing, most notably through the expression of viral suppressors of RNA silencing. RNA silencing suppressors have also been recently identified in plant pathogenic bacteria and oomycetes, suggesting that disruption of host silencing is a general virulence strategy across several kingdoms of plant pathogens. There is also increasing evidence that plants have evolved specific defences against RNA-silencing suppression by pathogens, providing yet another illustration of the never-ending molecular arms race between plant pathogens and their hosts. PMID:24129510

Pumplin, Nathan; Voinnet, Olivier

2013-10-16

286

Control biológico del marchitamiento vascular causado por Fusarium oxysporum f. sp. phaseoli en fríjol Phaseolus vulgaris L., mediante la acción combinada de Entrophospora colombiana, Trichoderma sp .y Pseudomonas fluorescens Biological control of Phaseolus vulgaris bean vascular wilt caused by Fusarium oxysporum f. sp. phaseoli with combined Entrophospora colombiana, Trichoderma sp. and Pseudomonas fluorescens action  

Microsoft Academic Search

Entrophospora colombiana, Trichodermasp., Pseudomonas fluorescens and a combination of these organisms were evaluated as antagonists in biologi- cal control of Fusarium oxysporumf. sp.phaseoli on 'ICA Tundama' variety bean plants. The research was carried out in one of Corpoica's mesh-houses using a completely randomized design, with 5 treatments, an absolute control treatment (no microorganisms present) and an infected control treatment (pathogen

Camila Avendańo; Germán Arbeláez

287

Terrific Protein Traffic: The Mystery of Effector Protein Delivery by Filamentous Plant Pathogens  

PubMed Central

Many biotrophic fungal and oomycete plant pathogens deliver effector proteins directly into host cells during infection. Recent advances are revealing the extensive effector repertoires of these pathogens and are beginning to shed light on how they manipulate host cells to establish a parasitic relationship. Surprisingly, oomycete effectors seem to share a common uptake system with those from the human malaria pathogen. The current explosion of information is opening new research avenues in molecular plant pathology and is providing new opportunities to limit the impact of plant disease on food production.

Panstruga, Ralph; Dodds, Peter N.

2009-01-01

288

Heading for disaster: Fusarium graminearum on cereal crops.  

PubMed

SUMMARY The rapid global re-emergence of Fusarium head blight disease of wheat and barley in the last decade along with contamination of grains with mycotoxins attributable to the disease have spurred basic research on the fungal causal agent. As a result, Fusarium graminearum quickly has become one of the most intensively studied fungal plant pathogens. This review briefly summarizes current knowledge on the pathogenicity, population genetics, evolution and genomics of Fusarium graminearum. Taxonomy: Based on the sexual state Gibberella zeae (Schwein.) Petch: Superkingdom Eukaryota; Kingdom Fungi; Phylum Ascomycota; Subphylum Pezizomycotina; Class Sordariomycetidae; Subclass Hypocreomycetidae; Order Hypocreales; Family Nectriaceae; Genus Gibberella. Host range: The pathogen is capable of causing head blight or 'scab' on wheat (Triticum), barley (Hordeum), rice (Oryza), oats (Avena) and Gibberella stalk and ear rot disease on maize (Zea). The fungus also may infect other plant species without causing disease symptoms. Other host genera cited for Gibberella zeae or F. graminearum sensu lato (see below) are Agropyron, Agrostis, Bromus, Calamagrostis, Cenchrus, Cortaderia, Cucumis, Echinochloa, Glycine, Hierochloe, Lolium, Lycopersicon, Medicago, Phleum, Poa, Schizachyrium, Secale, Setaria, Sorghum, Spartina and Trifolium. Disease symptoms and signs: For wheat, brown, dark purple to black necrotic lesions form on the exterior surface of the florets and glume (Fig. 1). Although these lesion symptoms sometimes are referred to as scab, they are not formally related to the hyperplasia and hypertrophic epidermal growth associated with other scab diseases such as apple scab. Peduncles immediately below the inflorescence may become discoloured brown/purple. With time, tissue of the inflorescence often becomes blighted, appearing bleached and tan, while the grain within atrophies. Awns often become deformed, twisted and curved downward. In barley, infections are not always readily apparent in the field. Infected spikelets may show a browning or water-soaked appearance. Infected barley kernels show a tan to dark brown discolouration that can be similar to that caused by other kernel blighting organisms. During prolonged wet periods, pink to salmon-orange spore masses of the fungus are often seen on infected spikelets, glumes and kernels in both wheat and barley. For maize ear rot, infection occurs by way of colonizing silk and thus symptoms first appear at the ear apex. White mycelium, turning pink to red with time, colonizes kernels and may progress basipetally, covering the entire ear. Useful websites: http://www.broad.mit.edu/annotation/fungi/fusarium/mips.gsf.de/genre/proj/fusarium/ http://www.cdl.umn.edu/scab/gz-consort.html http://www.scabusa.org/ PMID:20565626

Goswami, Rubella S; Kistler, H Corby

2004-11-01

289

Other Fusarium - Associated Problems  

Technology Transfer Automated Retrieval System (TEKTRAN)

In addition to Fusarium yellows and Fusarium root rot, caused by Fusarium oxysporum, other species of Fusarium can infect sugar beet and cause foliar yellowing, root rot, or other symptoms. The importance of many of these problems is not well understood. This chapter discusses some of what is know...

290

Nicotiana plumbaginifolia plants silenced for the ATP-binding cassette transporter gene NpPDR1 show increased susceptibility to a group of fungal and oomycete pathogens.  

PubMed

SUMMARY The behaviour of Nicotiana plumbaginifolia plants silenced for the ATP-binding cassette transporter gene NpPDR1 was investigated in response to fungal and oomycete infections. The importance of NpPDR1 in plant defence was demonstrated for two organs in which NpPDR1 is constitutively expressed: the roots and the petal epidermis. The roots of the plantlets of two lines silenced for NpPDR1 expression were clearly more sensitive than those of controls to the fungal pathogens Botrytis cinerea, Fusarium oxysporum sp., F. oxysporum f. sp. nicotianae, F. oxysporum f. sp. melonis and Rhizoctonia solani, as well as to the oomycete pathogen Phytophthora nicotianae race 0. The Ph gene-linked resistance of N. plumbaginifolia to P. nicotianae race 0 was totally ineffective in NpPDR1-silenced lines. In addition, the petals of the NpPDR1-silenced lines were spotted 15%-20% more rapidly by B. cinerea than were the controls. The rapid induction (after 2-4 days) of NpPDR1 expression in N. plumbaginifolia and N. tabacum mature leaves in response to pathogen presence was demonstrated for the first time with fungi and one oomycete: R. solani, F. oxysporum and P. nicotianae. With B. cinerea, such rapid expression was not observed in healthy mature leaves. NpPDR1 expression was not observed during latent infections of B. cinerea in N. plumbaginifolia and N. tabacum, but was induced when conditions facilitated B. cinerea development in leaves, such as leaf ageing or an initial root infection. This work demonstrates the increased sensitivity of NpPDR1-silenced N. plumbaginifolia plants to all of the fungal and oomycete pathogens investigated. PMID:19694955

Bultreys, Alain; Trombik, Tomasz; Drozak, Anna; Boutry, Marc

2009-09-01

291

Complex interactions between a plant pathogen and insect parasitoid via the shared vector-host: consequences for host plant infection  

Microsoft Academic Search

Plant viruses modify the development of their aphid vectors by inducing physiological changes in the shared host plant. The\\u000a performance of hymenopterous parasitoids exploiting these aphids can also be modified by the presence of the plant pathogen.\\u000a We used laboratory and glasshouse microcosms containing beans (Vicia faba) as the host plant to examine the interactions between a plant virus (pea

Simon Hodge; Glen Powell

2008-01-01

292

Phenazine antibiotics produced by fluorescent pseudomonads contribute to natural soil suppressiveness to Fusarium wilt  

Microsoft Academic Search

Natural disease-suppressive soils provide an untapped resource for the discovery of novel beneficial microorganisms and traits. For most suppressive soils, however, the consortia of microorganisms and mechanisms involved in pathogen control are unknown. To date, soil suppressiveness to Fusarium wilt disease has been ascribed to carbon and iron competition between pathogenic Fusarium oxysporum and resident non-pathogenic F. oxysporum and fluorescent

Sylvie Mazurier; Thérčse Corberand; Philippe Lemanceau; Jos M Raaijmakers

2009-01-01

293

Evaluation of the Antibacterial Potential of Some Plants Against Human Pathogenic Bacteria  

Microsoft Academic Search

Plants are rich source of antibacterial agents, which could be exploited in human disease management. Aqueous extracts of leaves of 46 plants selected based on an ethnobotanical survey from Mysore region Karnataka (India) were subjected to in vitro antibacterial activity assay against 14 important human pathogenic bacteria employing cup diffusion method. Antibacterial activity of the twelve plants aqueous extracts was

S. Satish; M. P. Raghavendra; K. A. Raveesha

294

Antibacterial Activity of Important Medicinal Plants on Human Pathogenic Bacteria-a Comparative Analysis  

Microsoft Academic Search

The use of plants in treatment of burns, dermatophytes and infectious diseases is common in traditional medicine. Based on ethno pharmacological and taxonomic information, antibacterial activities of aqueous and methanol extracts of some medicinal plants were determined by in vitro by agar diffusion-method against some human pathogenic bacteria. The leaves of five different plants, belonging to the different family and

H. V. Girish; S. Satish

295

[Trichothecene mycotoxins of Fusarium poae from different habitats].  

PubMed

Comparative study of the ability of three strains of Fusarium poae for the synthesis of trichothecen mycotoxins has been carried out. Studied strains were isolated from different habitats: forest soil, wheat (plant pathogen) and cranberry root (endophytic strain). All three strains were able to synthesize T-2 toxin, HT-2 toxin and T-2 tetraol but they were in various amounts. The soil strain 50660 was characterized by high level of synthesis of both HT-2 toxin and T-2 tetraol; plant pathogenic 50674 and endophytic 50685 strains were characterized by high level of T-2 tetraol synthesis and lower level of HT-2 toxin synthesis. The main trichothecene mycotoxin of this group - T-2 toxin - was detected in trace amounts for all three strains of F. poae. PMID:24006781

Kurchenko, I N; Tsyganenko, E S

296

Roles of Arabidopsis WRKY3 and WRKY4 Transcription Factors in Plant Responses to Pathogens  

PubMed Central

Background Plant WRKY DNA-binding transcription factors are involved in plant responses to biotic and abiotic responses. It has been previously shown that Arabidopsis WRKY3 and WRKY4, which encode two structurally similar WRKY transcription factors, are induced by pathogen infection and salicylic acid (SA). However, the role of the two WRKY transcription factors in plant disease resistance has not been directly analyzed. Results Both WRKY3 and WRKY4 are nuclear-localized and specifically recognize the TTGACC W-box sequences in vitro. Expression of WRKY3 and WRKY4 was induced rapidly by stress conditions generated by liquid infiltration or spraying. Stress-induced expression of WRKY4 was further elevated by pathogen infection and SA treatment. To determine directly their role in plant disease resistance, we have isolated T-DNA insertion mutants and generated transgenic overexpression lines for WRKY3 and WRKY4. Both the loss-of-function mutants and transgenic overexpression lines were examined for responses to the biotrophic bacterial pathogen Pseudomonas syringae and the necrotrophic fungal pathogen Botrytis cinerea. The wrky3 and wrky4 single and double mutants exhibited more severe disease symptoms and support higher fungal growth than wild-type plants after Botrytis infection. Although disruption of WRKY3 and WRKY4 did not have a major effect on plant response to P. syringae, overexpression of WRKY4 greatly enhanced plant susceptibility to the bacterial pathogen and suppressed pathogen-induced PR1 gene expression. Conclusion The nuclear localization and sequence-specific DNA-binding activity support that WRKY3 and WRKY4 function as transcription factors. Functional analysis based on T-DNA insertion mutants and transgenic overexpression lines indicates that WRKY3 and WRKY4 have a positive role in plant resistance to necrotrophic pathogens and WRKY4 has a negative effect on plant resistance to biotrophic pathogens.

Lai, Zhibing; Vinod, KM; Zheng, Zuyu; Fan, Baofang; Chen, Zhixiang

2008-01-01

297

Paenibacillus polymyxa antagonizes oomycete plant pathogens Phytophthora palmivora and Pythium aphanidermatum  

Microsoft Academic Search

Aim: To find sustainable alternatives to the application of synthetic chemicals for oomycete pathogen suppression. Methods and Results: Here, we present experiments on an Arabidopsis thaliana model system in which we studied the antagonistic properties of rhizobacteri- um Paenibacillus polymyxa strains towards the oomycete plant pathogens Phy- tophthora palmivora and Pythium aphanidermatum. We carried out studies on agar plates, in

S. Timmusk; P. van West; N. A. R. Gow; R. Paul Huffstutler

2009-01-01

298

Biodiversity of emerging pathogenic and invasive fungi in plants, animals and humans in Italy  

Microsoft Academic Search

In the last 30 years the spread of emerging and invasive fungal pathogens has had a profound impact on plants, animals and humans, causing crop losses and damaging their health with economic and social impact. Awareness of the biodiversity of these pathogens is essential for their detection, identification, and control. In this paper their diversity in Italy is reviewed taking

A. M. Picco; P. Angelini; C. Ciccarone; A. Franceschini; A. Ragazzi; M. Rodolfi; G. C. Varese; M. Zotti

2011-01-01

299

Conserved virulence factor regulation and secretion systems in bacterial pathogens of plants and animals  

Microsoft Academic Search

Recent research has revealed the emergence of common themes in the molecular mechanisms of virulence in bacterial pathogens of plants and animals. In particular, the systems used for the global control of virulence factor synthesis and for the secretion of virulence determinants in diverse bacterial pathogens show strong conservation, implying evolutionary relatedness. Global control of virulence factor synthesis can be

Susan D. Wharam; Vincent Mulholland; George P. C. Salmond

1995-01-01

300

A theoretical framework for biological control of soil-borne plant pathogens: Identifying effective strategies  

Microsoft Academic Search

We develop and analyse a flexible compartmental model of the interaction between a plant host, a soil-borne pathogen and a microbial antagonist, for use in optimising biological control. By extracting invasion and persistence thresholds of host, pathogen and biological control agent, performing an equilibrium analysis, and numerical investigation of sensitivity to parameters and initial conditions, we determine criteria for successful

Nik J. Cunniffe; Christopher A. Gilligan

2011-01-01

301

Antibacterial activity of two plant extracts on eight burn pathogens.  

PubMed

Antibacterial activity of crude alcoholic extract of Datura alba and Celosia argentea leaves were studied against pathogens isolated from infected burn patients. The disc-diffusion method showed significant zone of lysis against all the pathogens studied and the results are comparable to the conventional antibiotic cream namely Silver Sulphadiazine (SSD). On comparing the efficiency of the two extracts, extract of D. alba exhibited more than 50% increase in antibacterial activity compared to C. argentea. PMID:12686442

Gnanamani, A; Priya, K Shanmuga; Radhakrishnan, N; Babu, Mary

2003-05-01

302

Molecular Tools to Study Epidemiology and Toxicology of Fusarium Head Blight of Cereals  

Microsoft Academic Search

Fusarium head blight (FHB) of cereals is a disease complex. Fusarium graminearum is the major pathogen worldwide, while F. culmorum, F. avenaceum and F. poae are also associated with this disease. In addition to the true Fusarium species, Microdochium nivale may also cause head blight and is particularly prevalent where cooler, wetter conditions prevail. Other species such as F. sporotrichioides,

Paul Nicholson; E. Chandler; R. C. Draeger; N. E. Gosman; D. R. Simpson; M. Thomsett; A. H. Wilson

2003-01-01

303

Glyphosate associations with cereal diseases caused by Fusarium spp. in the Canadian Prairies  

Microsoft Academic Search

Fusarium pathogens cause important diseases, such as root\\/crown rot and Fusarium head blight (FHB), in cereal crops. These diseases can be caused by similar Fusarium spp. Common root rot (CRR) is widespread in the western Canadian Prairies, whereas FHB has potential of becoming an important disease in this region. There are no commercially available cereal cultivars with good resistance to

M. R. Fernandez; R. P. Zentner; P. Basnyat; D. Gehl; F. Selles; D. Huber

2009-01-01

304

Life-style transitions in plant pathogenic Colletotrichum fungi deciphered by genome and transcriptome analyses  

Technology Transfer Automated Retrieval System (TEKTRAN)

Colletotrichum species are devastating fungal pathogens of major crop plants worldwide. Infection involves differentiation of specialized cell-types associated with host surface penetration, growth inside living host cells (biotrophy) and tissue destruction (necrotrophy). Here we report genome and t...

305

Aggressiveness of Fusarium species and impact of root infection on growth and yield of soybeans.  

PubMed

Fusarium spp. are commonly isolated from soybean roots but the pathogenic activity of most species is poorly documented. Aggressiveness and yield impact of nine species of Fusarium were determined on soybean in greenhouse (50 isolates) and field microplot (19 isolates) experiments. Root rot severity and shoot and root dry weights were compared at growth stages V3 or R1. Root systems were scanned and digital image analysis was conducted; yield was measured in microplots. Disease severity and root morphology impacts varied among and within species. Fusarium graminearum was highly aggressive (root rot severity >90%), followed by F. proliferatum and F. virguliforme. Significant variation in damping-off (20 to 75%) and root rot severity (<20 to >60%) was observed among F. oxysporum isolates. In artificially-infested microplots, root rot severity was low (<25%) and mean yield was not significantly reduced. However, there were significant linear relationships between yield and root symptoms for some isolates. Root morphological characteristics were more consistent indicators of yield loss than root rot severity. This study provides the first characterization of aggressiveness and yield impact of Fusarium root rot species on soybean at different plant stages and introduces root image analysis to assess the impact of root pathogens on soybean. PMID:23514263

Arias, María M Díaz; Leandro, Leonor F; Munkvold, Gary P

2013-08-01

306

Cytochemical Labeling for Fungal and Host Components in Plant Tissues Inoculated with Fungal Wilt Pathogens  

NASA Astrophysics Data System (ADS)

Antibodies to detect pectin in present investigations attached to distinct fibrils in vessel lumina. In carnation infected with an isolate of Fusarium oxysporum f.sp., labeling of pathogen cells also occurred; in a resistant cultivar (cv.), it was coincident with proximate pectin fibrils and linked to altered fungal walls, which was the opposite in the susceptible cv., indicating that hindrance of pathogen ability to degrade pectin may be related to resistance. Labeling of the fungus in culture was nil, except in media containing pectin, showing that pectin is not native to the pathogen. Labeling of fungal walls for cellulose in elm (inoculated with Ophiostoma novo-ulmi) and carnation also occurred, linked to adsorbed host wall components. The chitin probe often attached to dispersed matter, in vessel lumina, traceable to irregularly labeled fungal cells and host wall degradation products. With an anti-horseradish peroxidase probe, host and fungal walls were equally labeled, and with a glucosidase, differences of labeling between these walls were observed, depending on pH of the test solution. Fungal extracellular matter and filamentous structures, present in fungal walls, predominantly in another elm isolate (Phaeotheca dimorphospora), did not label with any of the probes used. However, in cultures of this fungus, extracellular material labeled, even at a distance from the colony margin, with an anti-fimbriae probe.

Ouellette, G. B.; Baayen, R. P.; Chamberland, H.; Simard, M.; Rioux, D.; Charest, P. M.

2004-08-01

307

Upscaled CTAB-Based DNA Extraction and Real-Time PCR Assays for Fusarium culmorum and F. graminearum DNA in Plant Material with Reduced Sampling Error  

PubMed Central

Fusarium graminearum Schwabe (Gibberella zeae Schwein. Petch.) and F. culmorum W.G. Smith are major mycotoxin producers in small-grain cereals afflicted with Fusarium head blight (FHB). Real-time PCR (qPCR) is the method of choice for species-specific, quantitative estimation of fungal biomass in plant tissue. We demonstrated that increasing the amount of plant material used for DNA extraction to 0.5–1.0 g considerably reduced sampling error and improved the reproducibility of DNA yield. The costs of DNA extraction at different scales and with different methods (commercial kits versus cetyltrimethylammonium bromide-based protocol) and qPCR systems (doubly labeled hybridization probes versus SYBR Green) were compared. A cost-effective protocol for the quantification of F. graminearum and F. culmorum DNA in wheat grain and maize stalk debris based on DNA extraction from 0.5–1.0 g material and real-time PCR with SYBR Green fluorescence detection was developed.

Brandfass, Christoph; Karlovsky, Petr

2008-01-01

308

Upscaled CTAB-based DNA extraction and real-time PCR assays for Fusarium culmorum and F. graminearum DNA in plant material with reduced sampling error.  

PubMed

Fusarium graminearum Schwabe (Gibberella zeae Schwein. Petch.) and F. culmorum W.G. Smith are major mycotoxin producers in small-grain cereals afflicted with Fusarium head blight (FHB). Real-time PCR (qPCR) is the method of choice for species-specific, quantitative estimation of fungal biomass in plant tissue. We demonstrated that increasing the amount of plant material used for DNA extraction to 0.5-1.0 g considerably reduced sampling error and improved the reproducibility of DNA yield. The costs of DNA extraction at different scales and with different methods (commercial kits versus cetyltrimethylammonium bromide-based protocol) and qPCR systems (doubly labeled hybridization probes versus SYBR Green) were compared. A cost-effective protocol for the quantification of F. graminearum and F. culmorum DNA in wheat grain and maize stalk debris based on DNA extraction from 0.5-1.0 g material and real-time PCR with SYBR Green fluorescence detection was developed. PMID:19330077

Brandfass, Christoph; Karlovsky, Petr

2008-11-25

309

Exploiting generic platform technologies for the detection and identification of plant pathogens  

Microsoft Academic Search

The detection and identification of plant pathogens currently relies upon a very diverse range of techniques and skills, from\\u000a traditional culturing and taxonomic skills to modern molecular-based methods. The wide range of methods employed reflects\\u000a the great diversity of plant pathogens and the hosts they infect. The well-documented decline in taxonomic expertise, along\\u000a with the need to develop ever more

Neil Boonham; Rachel Glover; Jenny Tomlinson; Rick Mumford

2008-01-01

310

Exploiting generic platform technologies for the detection and identification of plant pathogens  

Microsoft Academic Search

The detection and identification of plant pathogens currently relies upon a very diverse range of techniques and skills, from\\u000a traditional culturing and taxonomic skills to modern molecular-based methods. The wide range of methods employed reflects\\u000a the great diversity of plant pathogens and the hosts they infect. The well-documented decline in taxonomic expertise, along\\u000a with the need to develop ever more

Neil Boonham; Rachel Glover; Jenny Tomlinson; Rick Mumford

311

Enterococcus faecalis Mammalian Virulence-Related Factors Exhibit Potent Pathogenicity in the Arabidopsis thaliana Plant Model  

Microsoft Academic Search

Some pathogenic bacteria belong to a large, diverse group of species capable of infecting plants, animals, and humans. Enterococcus faecalis is an opportunistic human pathogen capable of infecting patients with a deficient immune system. Here we report that three E. faecalis strains (FA-2-2, V583, and OG1RF) are capable of infecting the leaves and roots of the model plant species Arabidopsis

Ajay K. Jha; Harsh P. Bais; Jorge M. Vivanco

2005-01-01

312

Pathogen virulence factors as molecular probes of basic plant cellular functions  

PubMed Central

Summary To successfully colonize plants, pathogens have evolved a myriad of virulence factors that allow them to manipulate host cellular pathways in order to gain entry into, multiply and move within, and eventually exit the host for a new infection cycle. In the past few years, substantial progress has been made in characterizing the host targets of viral and bacterial virulence factors, providing unique insights into basic plant cellular processes such as gene silencing, vesicle trafficking, hormone signaling, and innate immunity. Identification of the host targets of additional pathogen virulence factors promises to continue shedding light on fundamental cellular mechanisms in plants, thus enhancing our understanding of plant signaling, metabolism and cell biology.

Speth, Elena Bray; Lee, Young Nam; He, Sheng Yang

2007-01-01

313

Regulation of Pathogenic Spore Germination by CgRac1 in the Fungal Plant Pathogen Colletotrichum gloeosporioides ? ‡  

PubMed Central

Colletotrichum gloeosporioides is a facultative plant pathogen: it can live as a saprophyte on dead organic matter or as a pathogen on a host plant. Different patterns of conidial germination have been recognized under saprophytic and pathogenic conditions, which also determine later development. Here we describe the role of CgRac1 in regulating pathogenic germination. The hallmark of pathogenic germination is unilateral formation of a single germ tube following the first cell division. However, transgenic strains expressing a constitutively active CgRac1 (CA-CgRac1) displayed simultaneous formation of two germ tubes, with nuclei continuing to divide in both cells after the first cell division. CA-CgRac1 also caused various other abnormalities, including difficulties in establishing and maintaining cell polarity, reduced conidial and hyphal adhesion, and formation of immature appressoria. Consequently, CA-CgRac1 isolates were completely nonpathogenic. Localization studies with cyan fluorescent protein (CFP)-CgRac1 fusion protein showed that the CgRac1 protein is abundant in conidia and in hyphal tips. Although the CFP signal was equally distributed in both cells of a germinating conidium, reactive oxygen species accumulated only in the cell that produced a germ tube, indicating that CgRac1 was active only in the germinating cell. Collectively, our results show that CgRac1 is a major regulator of asymmetric development and that it is involved in the regulation of both morphogenesis and nuclear division. Modification of CgRac1 activity disrupts the morphogenetic program and prevents fungal infection.

Nesher, Iris; Minz, Anna; Kokkelink, Leonie; Tudzynski, Paul; Sharon, Amir

2011-01-01

314

The role of saprophytic microflora in the development of Fusarium ear blight of winter wheat caused by Fusarium culmorum  

Microsoft Academic Search

Saprophytic microflora may interact with ear blight pathogens of wheat and contribute to the poor performance of fungicides against this disease in vivo. A glasshouse experiment and in vitro experiments were conducted to determine the relationship between saprophytic microflora and Fusarium culmorum and to determine fungicide effects on Alternaria alternata, Botrytis cinerea, Cladosporium herbarum and Fusarium culmorum. Inoculation of winter

J. Liggitt; P. Jenkinson; D. W. Parry

1997-01-01

315

Peptidotriazoles with antimicrobial activity against bacterial and fungal plant pathogens.  

PubMed

We designed and prepared peptidotriazoles based on the antimicrobial peptide BP100 (LysLysLeuPheLysLysIleLeuLysTyrLeu-NH(2)) by introducing a triazole ring in the peptide backbone or onto the side chain of a selected residue. These compounds were screened for their in vitro growth inhibition of bacterial and fungal phytopathogens, and for their cytotoxic effects on eukaryotic cells and tobacco leaves. Their proteolytic susceptibility was also analyzed. The antibacterial activity and the hemolysis were influenced by the amino acid that was modified with the triazole as well as by the absence of presence of a substituent in this heterocyclic ring. We identified sequences active against the bacteria Xanthomonas axonopodis pv. vesicatoria, Erwinia amylovora, Pseudomonas syringae pv. syringae (MIC of 1.6-12.5 ?M), and against the fungi Fusarium oxysporum (MIC<6.2-12.5 ?M) with low hemolytic activity (0-23% at 50 ?M), high stability to protease digestion and no phytotoxicity. These peptidotriazoles constitute good candidates to design new antimicrobial agents. PMID:22198367

Güell, Imma; Micaló, Lluís; Cano, Laura; Badosa, Esther; Ferre, Rafael; Montesinos, Emilio; Bardají, Eduard; Feliu, Lidia; Planas, Marta

2011-12-16

316

The role of a dark septate endophytic fungus, Veronaeopsis simplex Y34, in Fusarium disease suppression in Chinese cabbage.  

PubMed

The soil-inhabiting fungal pathogen Fusarium oxysporum has been an increasing threat to Chinese cabbage (Brassica campestris L.). A dark septate endophytic fungus, Veronaeopsis simplex Y34, isolated from Yaku Island, Japan, was evaluated in vitro for the ability to suppress Fusarium disease. Seedlings grown in the presence of the endophyte showed a 71% reduction in Fusarium wilt disease and still had good growth. The disease control was achieved through a synergetic effect involving a mechanical resistance created by a dense network of V. simplex Y34 hyphae, which colonized the host root, and siderophore production acting indirectly to induce a resistance mechanism in the plant. Changes in the relative abundance of the fungal communities in the soil as determined by fluorescently labelled T-RFs (terminal restriction fragments), appeared 3 weeks after application of the fungus. Results showed the dominance of V. simplex Y34, which became established in the rhizosphere and out-competed F. oxysporum. PMID:22923110

Khastini, Rida O; Ohta, Hiroyuki; Narisawa, Kazuhiko

2012-08-25

317

A proteomic approach provides new insights into the control of soil-borne plant pathogens by Bacillus species.  

PubMed

Beneficial microorganisms (also known as biopesticides) are considered to be one of the most promising methods for more rational and safe crop management practices. We used Bacillus strains EU07, QST713 and FZB24, and investigated their inhibitory effect on Fusarium. Bacterial cell cultures, cell-free supernatants and volatiles displayed varying degrees of suppressive effect. Proteomic analysis of secreted proteins from EU07 and FZB24 revealed the presence of lytic enzymes, cellulases, proteases, 1,4-?-glucanase and hydrolases, all of which contribute to degradation of the pathogen cell wall. Further proteomic investigations showed that proteins involved in metabolism, protein folding, protein degradation, translation, recognition and signal transduction cascade play an important role in the control of Fusarium oxysporum. Our findings provide new knowledge on the mechanism of action of Bacillus species and insight into biocontrol mechanisms. PMID:23301041

Baysal, Omür; Lai, Duo; Xu, Han-Hong; Siragusa, Mirko; Cal??kan, Mikail; Carimi, Francesco; da Silva, Jaime A Teixeira; Tör, Mahmut

2013-01-03

318

A Proteomic Approach Provides New Insights into the Control of Soil-Borne Plant Pathogens by Bacillus Species  

PubMed Central

Beneficial microorganisms (also known as biopesticides) are considered to be one of the most promising methods for more rational and safe crop management practices. We used Bacillus strains EU07, QST713 and FZB24, and investigated their inhibitory effect on Fusarium. Bacterial cell cultures, cell-free supernatants and volatiles displayed varying degrees of suppressive effect. Proteomic analysis of secreted proteins from EU07 and FZB24 revealed the presence of lytic enzymes, cellulases, proteases, 1,4-?-glucanase and hydrolases, all of which contribute to degradation of the pathogen cell wall. Further proteomic investigations showed that proteins involved in metabolism, protein folding, protein degradation, translation, recognition and signal transduction cascade play an important role in the control of Fusarium oxysporum. Our findings provide new knowledge on the mechanism of action of Bacillus species and insight into biocontrol mechanisms.

Xu, Han-Hong; Siragusa, Mirko; Cal?skan, Mikail; Carimi, Francesco; da Silva, Jaime A. Teixeira.; Tor, Mahmut

2013-01-01

319

Computational models in plant-pathogen interactions: the case of Phytophthora infestans  

PubMed Central

Background Phytophthora infestans is a devastating oomycete pathogen of potato production worldwide. This review explores the use of computational models for studying the molecular interactions between P. infestans and one of its hosts, Solanum tuberosum. Modeling and conclusion Deterministic logistics models have been widely used to study pathogenicity mechanisms since the early 1950s, and have focused on processes at higher biological resolution levels. In recent years, owing to the availability of high throughput biological data and computational resources, interest in stochastic modeling of plant-pathogen interactions has grown. Stochastic models better reflect the behavior of biological systems. Most modern approaches to plant pathology modeling require molecular kinetics information. Unfortunately, this information is not available for many plant pathogens, including P. infestans. Boolean formalism has compensated for the lack of kinetics; this is especially the case where comparative genomics, protein-protein interactions and differential gene expression are the most common data resources.

2009-01-01

320

Ecology and Human Pathogenicity of Plant-Associated Bacteria  

Microsoft Academic Search

\\u000a Plant species and organs are colonised by diverse bacterial communities, which fulfil important functions for their host.\\u000a Plant-associated bacteria have a great potential in diverse areas of biotechnology, e.g. as biological control agents (BCAs)\\u000a in plant protection. Although many of them have a positive interaction with their host plants, they can interact with other\\u000a eukaryotic hosts like humans in a

Gabriele Berg; Christin Zachow; Massimiliano Cardinale; Henry Müller

321

Transmission rates and adaptive evolution of pathogens in sympatric heterogeneous plant populations.  

PubMed Central

Diversification in agricultural cropping patterns is widely practised to delay the build-up of virulent races that can overcome host resistance in pathogen populations. This can lead to balanced polymorphism, but the long-term consequences of this strategy for the evolution of crop pathogen populations are still unclear. The widespread occurrence of sibling species and reproductively isolated sub-species among fungal and oomycete plant pathogens suggests that evolutionary divergence is common. This paper develops a mathematical model of host-pathogen interactions using a simple framework of two hosts to analyse the influences of sympatric host heterogeneity on the long-term evolutionary behaviour of plant pathogens. Using adaptive dynamics, which assumes that sequential mutations induce small changes in pathogen fitness, we show that evolutionary outcomes strongly depend on the shape of the trade-off curve between pathogen transmission on sympatric hosts. In particular, we determine the conditions under which the evolutionary branching of a monomorphic into a dimorphic population occurs, as well as the conditions that lead to the evolution of specialist (single host range) or generalist (multiple host range) pathogen populations.

Gudelj, I; van den Bosch, F; Gilligan, C A

2004-01-01

322

Host and parasite population structure in a natural plant–pathogen system  

Microsoft Academic Search

We investigated the genetic population structure in a metapopulation of the plant Silene latifolia (Caryophyllaceae) and its fungal pathogen Microbotryum violaceum (Ustilaginales), a pollinator-borne disease. Population structure of the host plant was estimated using allozyme markers and that of the fungus by microsatellites. Both host and parasite showed significant differentiation, but parasite populations were 12 times more strongly differentiated than

François Delmotte; Erika Bucheli; JACQUI A. SHYKOFF

1999-01-01

323

RESPONSE OF GLYPHOSATE-TOLERANT SUGAR BEET TO FUNGAL PLANT PATHOGENS IN THE PRESENCE OF GLYPHOSATE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Recent efforts at improving crop plants have included the development of novel forms of herbicide resistance to enhance weed control efforts. One common type of herbicide resistance is to the herbicide glyphosate. Some herbicides can affect disease severity by direct effects on plant pathogens or ...

324

Functional analysis of Pcipg2 from the straminopilous plant Pathogen Phytophthora capsici  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phytophthora capsici is an oomycete plant pathogen that causes severe diseases in a wide variety of crops. Polygalacturonases (PGs) play a major role in the degradation pectin in plant cell walls. A genomic library was made from a highly virulent strain of P. capsici with high PGs activity. Seven pg...

325

The linear chromosome of the plant-pathogenic mycoplasma 'Candidatus Phytoplasma mali'  

Microsoft Academic Search

BACKGROUND: Phytoplasmas are insect-transmitted, uncultivable bacterial plant pathogens that cause diseases in hundreds of economically important plants. They represent a monophyletic group within the class Mollicutes (trivial name mycoplasmas) and are characterized by a small genome with a low GC content, and the lack of a firm cell wall. All mycoplasmas, including strains of 'Candidatus (Ca.) Phytoplasma asteris' and 'Ca.

Michael Kube; Bernd Schneider; Heiner Kuhl; Thomas Dandekar; Katja Heitmann; Alexander M Migdoll; Richard Reinhardt; Erich Seemüller

2008-01-01

326

Antimicrobial activities of extracts from tropical Atlantic marine plants against marine pathogens and saprophytes  

Microsoft Academic Search

Studies investigating disease resistance in marine plants have indicated that secondary metabolites may have important defensive functions against harmful marine microorganisms. The goal of this study was to systematically screen extracts from marine plants for antimicrobial effects against marine pathogens and saprophytes. Lipophilic and hydrophilic extracts from species of 49 marine algae and 3 seagrasses collected in the tropical Atlantic

Sebastian Engel; Melany P. Puglisi; Paul R. Jensen; William Fenical

2006-01-01

327

Disease induction by human microbial pathogens in plant-model systems: potential, problems and prospects  

Microsoft Academic Search

Relatively simple eukaryotic model organisms such as the genetic model weed plant Arabidopsis thaliana possess an innate immune system that shares important similarities with its mammalian counterpart. In fact, some human pathogens infect Arabidopsis and cause overt disease with human symptomology. In such cases, decisive elements of the plant's immune system are likely to be targeted by the same microbial

Peter van Baarlen; Alex van Belkum; Bart P. H. J. Thomma

2007-01-01

328

Harpins, multifunctional proteins secreted by gram-negative plant-pathogenic bacteria.  

PubMed

Harpins are glycine-rich and heat-stable proteins that are secreted through type III secretion system in gram-negative plant-pathogenic bacteria. Many studies show that these proteins are mostly targeted to the extracellular space of plant tissues, unlike bacterial effector proteins that act inside the plant cells. Over the two decades since the first harpin of pathogen origin, HrpN of Erwinia amylovora, was reported in 1992 as a cell-free elicitor of hypersensitive response (HR), diverse functional aspects of harpins have been determined. Some harpins were shown to have virulence activity, probably because of their involvement in the translocation of effector proteins into plant cytoplasm. Based on this function, harpins are now considered to be translocators. Their abilities of pore formation in the artificial membrane, binding to lipid components, and oligomerization are consistent with this idea. When harpins are applied to plants directly or expressed in plant cells, these proteins trigger diverse beneficial responses such as induction of defense responses against diverse pathogens and insects and enhancement of plant growth. Therefore, in this review, we will summarize the functions of harpins as virulence factors (or translocators) of bacterial pathogens, elicitors of HR and immune responses, and plant growth enhancers. PMID:23745678

Choi, Min-Seon; Kim, Wooki; Lee, Chanhui; Oh, Chang-Sik

2013-10-01

329

Fun Microbiology: Using a Plant Pathogenic Fungus To Demonstrate Koch's Postulates.  

ERIC Educational Resources Information Center

Describes an experiment using a plant pathogenic fungus in which students learn to follow aseptic techniques, grow and produce spores of a fungus, use a hemacytometer for enumerating spores, prepare serial dilutions, grow and inoculate plants, isolate a pure culture using agar streak plates, and demonstrate the four steps of Koch's postulates.…

Mitchell, James K.; Orsted, Kathy M.; Warnes, Carl E.

1997-01-01

330

Plant-in-chip: Microfluidic system for studying root growth and pathogenic interactions in Arabidopsis  

NASA Astrophysics Data System (ADS)

We report a microfluidic platform for the hydroponic growth of Arabidopsis plants with high-resolution visualization of root development and root-pathogen interactions. The platform comprises a set of parallel microchannels with individual input/output ports where 1-day old germinated seedlings are initially placed. Under optimum conditions, a root system grows in each microchannel and its images are recorded over a 198-h period. Different concentrations of plant growth media show different root growth characteristics. Later, the developed roots are inoculated with two plant pathogens (nematodes and zoospores) and their physicochemical interactions with the live root systems are observed.

Parashar, Archana; Pandey, Santosh

2011-06-01

331

Terrific Protein Traffic: The Mystery of Effector Protein Delivery by Filamentous Plant Pathogens  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Many biotrophic fungal and oomycete plant pathogens deliver effector proteins directly into host cells during infection. Recent advances are revealing the extensive effector repertoires of these pathogens and are beginning to shed light on how they manipulate host cells to establish a parasitic relationship. The current explosion of information is opening new research avenues in molecular plant pathology and is providing new opportunities to limit the impact of plant disease on food production.

Ralph Panstruga (Max-Planck Institute for Plant Breeding Research;Department of Plant-Microbe Interactions); Peter N. Dodds (Commonwealth Scientific and Industrial Research Organization Plant Industry;)

2009-05-08

332

Bacterial Pathogens in Plants: Life up against the Wall  

Microsoft Academic Search

of transposon mutagenesis, broad-host-range cosmid vectors, and marker-exchange mutagenesis to identify and manipulate bacterial genes that have a readily scored phenotype when mutated, conjugated into a related strain, or expressed in Esch- erichia coli. These approaches have yielded a large inventory of hrp (hypersensitive (esponse and pathogenicity) and avr (eirulence) genes that directly relate to the HR puzzle as we!l

James R. Alfano; Alan Collmer

1996-01-01

333

Fusarium polycaprolactone depolymerase is cutinase.  

PubMed Central

Polycaprolactone (PCL), a synthetic polyester, is degraded by a variety of microorganisms, including some phytopathogens. Many phytopathogens secrete cutinase, a serine hydrolase that degrades cutin, the structural polymer of the plant cuticle. We compared wild-type strains and a cutinase-negative gene replacement mutant strain of Fusarium solani f. sp. pisi (D. J. Stahl and W. Schäfer, Plant Cell 4:621-629, 1992) and a wild-type strain of Fusarium moniliforme to show that Fusarium cutinase is a PCL depolymerase. The wild-type strains, but not the mutant strain, (i) degraded PCL and used it as a source of carbon and energy, (ii) showed induction of secreted PCL depolymerase and an esterase activity of cutinase when grown in the presence of cutin, and (iii) showed induction of PCL depolymerase and an esterase activity of cutinase when grown in the presence of a hydrolysate of PCL, which contains PCL oligomers that are structurally similar to the natural inducers of cutinase. These results together with other details of regulation and conditions for optimal enzyme activity indicate that the Fusarium PCL depolymerase, required for degradation and utilization of PCL, is cutinase.

Murphy, C A; Cameron, J A; Huang, S J; Vinopal, R T

1996-01-01

334

Plant immunity: a lesson from pathogenic bacterial effector proteins  

Microsoft Academic Search

Summary Phytopathogenic bacteria inject an array of effec- tor proteins into host cells to alter host physiology and assist the infection process. Some of these effectors can also trigger disease resistance as a result of recognition in the plant cell by cyto- plasmic immune receptors. In addition to effector- triggered immunity, plants immunity can be triggered upon the detection of

Haitao Cui; Tingting Xiang; Jian-Min Zhou

2009-01-01

335

Genes from mycoparasitic fungi as a source for improving plant resistance to fungal pathogens  

PubMed Central

Disease resistance in transgenic plants has been improved, for the first time, by the insertion of a gene from a biocontrol fungus. The gene encoding a strongly antifungal endochitinase from the mycoparasitic fungus Trichoderma harzianum was transferred to tobacco and potato. High expression levels of the fungal gene were obtained in different plant tissues, which had no visible effect on plant growth and development. Substantial differences in endochitinase activity were detected among transformants. Selected transgenic lines were highly tolerant or completely resistant to the foliar pathogens Alternaria alternata, A. solani, Botrytis cinerea, and the soilborne pathogen Rhizoctonia solani. The high level and the broad spectrum of resistance obtained with a single chitinase gene from Trichoderma overcome the limited efficacy of transgenic expression in plants of chitinase genes from plants and bacteria. These results demonstrate a rich source of genes from biocontrol fungi that can be used to control diseases in plants.

Lorito, Matteo; Woo, Sheridan L.; Fernandez, Irene Garcia; Colucci, Gabriella; Harman, Gary E.; Pintor-Toro, Jose A.; Filippone, Edgardo; Muccifora, Simona; Lawrence, Christopher B.; Zoina, Astolfo; Tuzun, Sadik; Scala, Felice

1998-01-01

336

The Ascomycete Verticillium longisporum Is a Hybrid and a Plant Pathogen with an Expanded Host Range  

PubMed Central

Hybridization plays a central role in plant evolution, but its overall importance in fungi is unknown. New plant pathogens are thought to arise by hybridization between formerly separated fungal species. Evolution of hybrid plant pathogens from non-pathogenic ancestors in the fungal-like protist Phytophthora has been demonstrated, but in fungi, the most important group of plant pathogens, there are few well-characterized examples of hybrids. We focused our attention on the hybrid and plant pathogen Verticillium longisporum, the causal agent of the Verticillium wilt disease in crucifer crops. In order to address questions related to the evolutionary origin of V. longisporum, we used phylogenetic analyses of seven nuclear loci and a dataset of 203 isolates of V. longisporum, V. dahliae and related species. We confirmed that V. longisporum was diploid, and originated three different times, involving four different lineages and three different parental species. All hybrids shared a common parent, species A1, that hybridized respectively with species D1, V. dahliae lineage D2 and V. dahliae lineage D3, to give rise to three different lineages of V. longisporum. Species A1 and species D1 constituted as yet unknown taxa. Verticillium longisporum likely originated recently, as each V. longisporum lineage was genetically homogenous, and comprised species A1 alleles that were identical across lineages.

Inderbitzin, Patrik; Davis, R. Michael; Bostock, Richard M.; Subbarao, Krishna V.

2011-01-01

337

In vitro screening of some tropical ash samples against seedborne pathogens of wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Eleven ash samples obtained from nine tropical plants were screened in vitro for their potential to reduce the mycelial growth of the seedborne pathogens Helminthosporium sativum, Curvularia lunata and Fusarium graminearum. All ash samples inhibited the mycelial growth of these pathogens. Delonix regia wood ash induced up to 77.8, 80.7 and 88.8% reduction in the mycelial growth of H. sativum,

O. A. Enikuomehin; I. A. Kehinde

2007-01-01

338

Migratory moths as dispersal vectors of an introduced plant-pathogenic fungus in Japan  

Microsoft Academic Search

The plant-pathogenic fungus Claviceps paspali infects florets of the dallisgrass Paspalum dilatatum and induces the plant to produce honeydew (containing massive amounts of conidia), which in turn attracts insects for dispersal\\u000a of the fungal spores. In Japan, the association between C. paspali and its host plant is common, although both P. dilatatum and C. paspali are introduced species. To determine

Shinji Sugiura; Kazuo Yamazaki

2007-01-01

339

Reaction of glucosinolate-myrosinase defence system in Brassica plants to pathogenicity factor of Sclerotinia sclerotiorum  

Microsoft Academic Search

The glucosinolate-myrosinase defence system, specific to Brassicales plants, produces toxic volatile compounds during mechanical\\u000a injury or pathogen attack. The reaction of this system to oxalic acid, known as a pathogenicity factor of Sclerotinia sclerotiorum, is not fully understood. The hydrolysis of glucosinolates was studied at varying conditions in the presence of oxalic acid\\u000a in the substrate. In a bioassay, colonies

Siamak Rahmanpour; David Backhouse; Heather M. Nonhebel

2010-01-01

340

Coevolution and Life Cycle Specialization of Plant Cell Wall Degrading Enzymes in a Hemibiotrophic Pathogen  

PubMed Central

Zymoseptoria tritici is an important fungal pathogen on wheat that originated in the Fertile Crescent. Its closely related sister species Z. pseudotritici and Z. ardabiliae infect wild grasses in the same region. This recently emerged host–pathogen system provides a rare opportunity to investigate the evolutionary processes shaping the genome of an emerging pathogen. Here, we investigate genetic signatures in plant cell wall degrading enzymes (PCWDEs) that are likely affected by or driving coevolution in plant-pathogen systems. We hypothesize four main evolutionary scenarios and combine comparative genomics, transcriptomics, and selection analyses to assign the majority of PCWDEs in Z. tritici to one of these scenarios. We found widespread differential transcription among different members of the same gene family, challenging the idea of functional redundancy and suggesting instead that specialized enzymatic activity occurs during different stages of the pathogen life cycle. We also find that natural selection has significantly affected at least 19 of the 48 identified PCWDEs. The majority of genes showed signatures of purifying selection, typical for the scenario of conserved substrate optimization. However, six genes showed diversifying selection that could be attributed to either host adaptation or host evasion. This study provides a powerful framework to better understand the roles played by different members of multigene families and to determine which genes are the most appropriate targets for wet laboratory experimentation, for example, to elucidate enzymatic function during relevant phases of a pathogen’s life cycle.

Brunner, Patrick C.; Torriani, Stefano F.F.; Croll, Daniel; Stukenbrock, Eva H.; McDonald, Bruce A.

2013-01-01

341

Experimental Evolution of a Plant Pathogen into a Legume Symbiont  

PubMed Central

Rhizobia are phylogenetically disparate ?- and ?-proteobacteria that have achieved the environmentally essential function of fixing atmospheric nitrogen in symbiosis with legumes. Ample evidence indicates that horizontal transfer of symbiotic plasmids/islands has played a crucial role in rhizobia evolution. However, adaptive mechanisms that allow the recipient genomes to express symbiotic traits are unknown. Here, we report on the experimental evolution of a pathogenic Ralstonia solanacearum chimera carrying the symbiotic plasmid of the rhizobium Cupriavidus taiwanensis into Mimosa nodulating and infecting symbionts. Two types of adaptive mutations in the hrpG-controlled virulence pathway of R. solanacearum were identified that are crucial for the transition from pathogenicity towards mutualism. Inactivation of the hrcV structural gene of the type III secretion system allowed nodulation and early infection to take place, whereas inactivation of the master virulence regulator hrpG allowed intracellular infection of nodule cells. Our findings predict that natural selection of adaptive changes in the legume environment following horizontal transfer has been a major driving force in rhizobia evolution and diversification and show the potential of experimental evolution to decipher the mechanisms leading to symbiosis.

Cruveiller, Stephane; Chane-Woon-Ming, Beatrice; Gris, Carine; Timmers, Ton; Poinsot, Verena; Gilbert, Luz B.; Heeb, Philipp; Medigue, Claudine; Batut, Jacques; Masson-Boivin, Catherine

2010-01-01

342

Brachypodium distachyon: a new pathosystem to study Fusarium head blight and other Fusarium diseases of wheat  

PubMed Central

Background Fusarium species cause Fusarium head blight (FHB) and other important diseases of cereals. The causal agents produce trichothecene mycotoxins such as deoxynivalenol (DON). The dicotyledonous model species Arabidopsis thaliana has been used to study Fusarium-host interactions but it is not ideal for model-to-crop translation. Brachypodium distachyon (Bd) has been proposed as a new monocotyledonous model species for functional genomic studies in grass species. This study aims to assess the interaction between the most prevalent FHB-causing Fusarium species and Bd in order to develop and exploit Bd as a genetic model for FHB and other Fusarium diseases of wheat. Results The ability of Fusarium graminearum and Fusarium culmorum to infect a range of Bd tissues was examined in various bioassays which showed that both species can infect all Bd tissues examined, including intact foliar tissues. DON accumulated in infected spike tissues at levels similar to those of infected wheat spikes. Histological studies revealed details of infection, colonisation and host response and indicate that hair cells are important sites of infection. Susceptibility to Fusarium and DON was assessed in two Bd ecotypes and revealed variation in resistance between ecotypes. Conclusions Bd exhibits characteristics of susceptibility highly similar to those of wheat, including susceptibility to spread of disease in the spikelets. Bd is the first reported plant species to allow successful infection on intact foliar tissues by FHB-causing Fusarium species. DON appears to function as a virulence factor in Bd as it does in wheat. Bd is proposed as a valuable model for undertaking studies of Fusarium head blight and other Fusarium diseases of wheat.

2011-01-01

343

Genetic Elucidation of Nitric Oxide Signaling in Incompatible Plant-Pathogen Interactions[w  

PubMed Central

Recent experiments indicate that nitric oxide (NO) plays a pivotal role in disease resistance and several other physiological processes in plants. However, most of the current information about the function of NO in plants is based on pharmacological studies, and additional approaches are therefore required to ascertain the role of NO as an important signaling molecule in plants. We have expressed a bacterial nitric oxide dioxygenase (NOD) in Arabidopsis plants and/or avirulent Pseudomonas syringae pv tomato to study incompatible plant-pathogen interactions impaired in NO signaling. NOD expression in transgenic Arabidopsis resulted in decreased NO levels in planta and attenuated a pathogen-induced NO burst. Moreover, NOD expression in plant cells had very similar effects on plant defenses compared to NOD expression in avirulent Pseudomonas. The defense responses most affected by NO reduction during the incompatible interaction were decreased H2O2 levels during the oxidative burst and a blockage of Phe ammonia lyase expression, the key enzyme in the general phenylpropanoid pathway. Expression of the NOD furthermore blocked UV light-induced Phe ammonia lyase and chalcone synthase gene expression, indicating a general signaling function of NO in the activation of the phenylpropanoid pathway. NO possibly functions in incompatible plant-pathogen interactions by inhibiting the plant antioxidative machinery, and thereby ensuring locally prolonged H2O2 levels. Additionally, albeit to a lesser extent, we observed decreases in salicylic acid production, a diminished development of hypersensitive cell death, and a delay in pathogenesis-related protein 1 expression during these NO-deficient plant-pathogen interactions. Therefore, this genetic approach confirms that NO is an important regulatory component in the signaling network of plant defense responses.

Zeier, Jurgen; Delledonne, Massimo; Mishina, Tatiana; Severi, Emmanuele; Sonoda, Masatoshi; Lamb, Chris

2004-01-01

344

Fusarium Race 4: Management Recommendations for Growers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Over the past five to seven years, race 4 of the fungal pathogen Fusarium oxysporum spp. vasinfectum (race 4 FOV) has been widely studied and has increasingly impacted cotton fields in California’s San Joaquin Valley. Findings from field and greenhouse research and observations can be summarized as:...

345

FUSARIUM BULB ROT OF ONION AND GARLIC  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium proliferatum is a hyphomycetous fungal pathogen with a wide host range, including onion and garlic. In garlic, invasion by the fungus results in water-soaked lesions, then a progressive tan-brown rot of the cloves. In onion, the fungus may be confined to the outer layers of the bulb, wher...

346

FUMONISIN MYCOTOXIN BIOSYNTHESIS IN FUSARIUM VERTICILLIOIDES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fumonsins are mycotoxins produced by the maize pathogen Fusarium verticillioides. These toxins are of concern because of their association with cancer in experimental rodents and the epidemiological correlation between consumption of fumonisin-contaminated maize and human esophageal cancer. We hav...

347

Methylobacterium-Induced Endophyte Community Changes Correspond with Protection of Plants against Pathogen Attack  

PubMed Central

Plant inoculation with endophytic bacteria that normally live inside the plant without harming the host is a highly promising approach for biological disease control. The mechanism of resistance induction by beneficial bacteria is poorly understood, because pathways are only partly known and systemic responses are typically not seen. The innate endophytic community structures change in response to external factors such as inoculation, and bacterial endophytes can exhibit direct or indirect antagonism towards pathogens. Earlier we showed that resistance induction by an endophytic Methylobacterium sp. in potato towards Pectobacterium atrosepticum was dependent on the density of the inoculum, whereas the bacterium itself had no antagonistic activity. To elucidate the role of innate endophyte communities in plant responses, we studied community changes in both in vitro and greenhouse experiments using various combinations of plants, endophyte inoculants, and pathogens. Induction of resistance was studied in several potato (Solanum tuberosum L.) cultivars by Methylobacterium sp. IMBG290 against the pathogens P. atrosepticum, Phytophthora infestans and Pseudomonas syringae pv. tomato DC3000, and in pine (Pinus sylvestris L.) by M. extorquens DSM13060 against Gremmeniella abietina. The capacities of the inoculated endophytic Methylobacterium spp. strains to induce resistance were dependent on the plant cultivar, pathogen, and on the density of Methylobacterium spp. inoculum. Composition of the endophyte community changed in response to inoculation in shoot tissues and correlated with resistance or susceptibility to the disease. Our results demonstrate that endophytic Methylobacterium spp. strains have varying effects on plant disease resistance, which can be modulated through the endophyte community of the host.

Ardanov, Pavlo; Sessitsch, Angela; Haggman, Hely; Kozyrovska, Natalia; Pirttila, Anna Maria

2012-01-01

348

Modified Primers for the Identification of Nonpathogenic Fusarium oxysporum Isolates That Have Biological Control Potential against Fusarium Wilt of Cucumber in Taiwan  

PubMed Central

Previous investigations demonstrated that Fusarium oxysporum (Fo), which is not pathogenic to cucumbers, could serve as a biological control agent for managing Fusarium wilt of cucumber caused by Fo f. sp. cucumerinum (Foc) in Taiwan. However, thus far it has not been possible to separate the populations of pathogenic Fo from the nonpathogenic isolates that have biological control potential through their morphological characteristics. Although these two populations can be distinguished from one another using a bioassay, the work is laborious and time-consuming. In this study, a fragment of the intergenic spacer (IGS) region of ribosomal DNA from an Fo biological control agent, Fo366, was PCR-amplified with published general primers, FIGS11/FIGS12 and sequenced. A new primer, NPIGS-R, which was designed based on the IGS sequence, was paired with the FIGS11 primer. These primers were then evaluated for their specificity to amplify DNA from nonpathogenic Fo isolates that have biological control potential. The results showed that the modified primer pair, FIGS11/NPIGS-R, amplified a 500-bp DNA fragment from five of seven nonpathogenic Fo isolates. These five Fo isolates delayed symptom development of cucumber Fusarium wilt in greenhouse bioassay tests. Seventy-seven Fo isolates were obtained from the soil and plant tissues and then subjected to amplification using the modified primer pair; six samples showed positive amplification. These six isolates did not cause symptoms on cucumber seedlings when grown in peat moss infested with the isolates and delayed disease development when the same plants were subsequently inoculated with a virulent isolate of Foc. Therefore, the modified primer pair may prove useful for the identification of Fo isolates that are nonpathogenic to cucumber which can potentially act as biocontrol agents for Fusarium wilt of cucumber.

Wang, Chaojen; Lin, Yisheng; Lin, Yinghong; Chung, Wenhsin

2013-01-01

349

Utility of the phylotoxigenic relationships among trichothecene-producing Fusarium species for predicting their mycotoxin-producing potential.  

PubMed

Species of the genus Fusarium are well-known plant pathogens and mycotoxigenic fusaria are associated with health hazards to humans and animals. There is a need to understand the mechanisms of mycotoxin production by Fusarium species and to predict which produce mycotoxins. In this study, the Fusarium phylogenetic tree was first inferred among trichothecene producers and related species. We reconstructed the maximum likelihood (ML) tree based on the combined data from nucleotide sequences of rDNA cluster regions, the ?-tubulin gene (?-tub) and the elongation factor 1? gene (EF-1?). Second, based on this tree topology, the ancestral states of the producing potential of type A and B trichothecenes (TriA and TriB), zearalenone (ZEN), moniliformin (MON), beauvericin (BEA) and enniatins (ENN) were reconstructed using the maximum parsimony (MP) method based on the observed production by extant species as reported in the literature. Finally, the species having the potential to produce each of these six mycotoxins was predicted on the basis of the parsimonious analysis. The ML tree indicated that the Fusarium species analysed in this study could be divided into two major clades. Clade I was divided into four distinct subclades: I-a, I-b, I-c and I-d. Furthermore, the parsimony reconstruction suggested that the potential for producing MON and ZEN was gained or lost only once, and that the producing potential for TriA and TriB, BEA and ENN was repeatedly gained and lost during the evolutionary history of the Fusarium species analysed in this study. Interestingly, the results showed the possibility that several species, about which reports were scarce with regard to mycotoxin production, have the potential to produce one or more of the six evaluated in this study. The phylogenetic information therefore helps one to predict the mycotoxin-producing potential by Fusarium species, and these "phylotoxigenic relationships" may be useful for predicting the pathogenicity of fungi. PMID:23731171

Watanabe, M; Yonezawa, T; Sugita-Konishi, Y; Kamata, Y

2013-06-03

350

The impact of plant-pathogen studies on medicinal drug discovery.  

PubMed

The pharmaceutical industry is reliant on a constant supply of new chemical entities and molecular targets for disease intervention. In this tutorial review, we want to illustrate that basic research studies on the biological function of natural products involved in plant-pathogen interactions can serve as an inspiring source for the identification of new bioactive entities as well as of strategies on how to achieve small molecule manipulation of biological systems. An application of findings from plant-pathogen interaction studies might therefore display a significant impact on drug discovery. PMID:22293617

Ottmann, Christian; van der Hoorn, Renier A L; Kaiser, Markus

2012-02-01

351

Volatile induction of infected and neighbouring uninfected plants potentially influence attraction/repellence of a cereal herbivore  

Technology Transfer Automated Retrieval System (TEKTRAN)

Plant infection by pathogens can induce volatile organic compounds (VOCs). We infected ‘McNeal’ wheat and ‘Harrington’ barley with a Fusarium spp. blend (graminearum, avenaceum, and culmorum). Both cereals had highest VOC induction 14 d after pathogen introduction, significantly slightly lower induc...

352

Characterization of Fusarium species section Liseola by restriction analysis of the IGS region.  

PubMed

Fusarium species section Liseola namely F. fujikuroi, F. proliferatum, F. andiyazi, F. verticillioides, and F. sacchari are well-known plant pathogens on rice, sugarcane and maize. In the present study, restriction analysis of the intergenic spacer regions (IGS) was used to characterize the five Fusarium species isolated from rice, sugarcane and maize collected from various locations in Peninsular Malaysia. From the analysis, and based on restriction patterns generated by the six restriction enzymes, Bsu151, BsuRI, EcoRI, Hin6I, HinfI, and MspI, 53 haplotypes were recorded among 74 isolates. HinfI showed the most variable restriction patterns (with 11 patterns), while EcoRI showed only three patterns. Although a high level of variation was observed, it was possible to characterize closely related species and isolates from different species. UPGMA cluster analysis showed that the isolates of Fusarium from the same species were grouped together regardless of the hosts. We conclude that restriction analysis of the IGS regions can be used to characterize Fusarium species section Liseola and to discriminate closely related species as well as to clarify their taxonomic position. PMID:22370941

Heng, M H; Baharuddin, S; Latiffah, Z

2012-02-16

353

SGT1 positively regulates the process of plant cell death during both compatible and incompatible plant-pathogen interactions.  

PubMed

SGT1 (suppressor of G2 allele of Skp1), an interactor of SCF (Skp1-Cullin-F-box) ubiquitin ligase complexes that mediate protein degradation, plays an important role at both G1-S and G2-M cell cycle transitions in yeast, and is highly conserved throughout eukaryotes. Plant SGT1 is required for both resistance (R) gene-mediated disease resistance and nonhost resistance to certain pathogens. Using virus-induced gene silencing (VIGS) in Nicotiana benthamiana, we demonstrate that SGT1 positively regulates the process of cell death during both host and nonhost interactions with various pathovars of Pseudomonas syringae. Silencing of NbSGT1 in N. benthamiana plants delays the induction of hypersensitive response (HR)-mediated cell death against nonhost pathogens and the development of disease-associated cell death caused by the host pathogen P. syringae pv. tabaci. Our results further demonstrate that NbSGT1 is required for Erwinia carotovora- and Sclerotinia sclerotiorum-induced disease-associated cell death. Overexpression of NbSGT1 in N. benthamiana accelerates the development of HR during R gene-mediated disease resistance and nonhost resistance. Our data also indicate that SGT1 is required for pathogen-induced cell death, but is not always necessary for the restriction of bacterial multiplication in planta. Therefore, we conclude that SGT1 is an essential component affecting the process of cell death during both compatible and incompatible plant-pathogen interactions. PMID:20695999

Wang, Keri; Uppalapati, Srinivasa Rao; Zhu, Xiaohong; Dinesh-Kumar, Savithramma P; Mysore, Kirankumar S

2010-09-01

354

Rapid in vivo analysis of synthetic promoters for plant pathogen phytosensing  

PubMed Central

Background We aimed to engineer transgenic plants for the purpose of early detection of plant pathogen infection, which was accomplished by employing synthetic pathogen inducible promoters fused to reporter genes for altered phenotypes in response to the pathogen infection. Toward this end, a number of synthetic promoters consisting of inducible regulatory elements fused to a red fluorescent protein (RFP) reporter were constructed for use in phytosensing. Results For rapid analysis, an Agrobacterium-mediated transient expression assay was evaluated, then utilized to assess the inducibility of each synthetic promoter construct in vivo. Tobacco (Nicotiana tabacum cv. Xanthi) leaves were infiltrated with Agrobacterium harboring the individual synthetic promoter-reporter constructs. The infiltrated tobacco leaves were re-infiltrated with biotic (bacterial pathogens) or abiotic (plant defense signal molecules salicylic acid, ethylene and methyl jasmonate) agents 24 and 48 hours after initial agroinfiltration, followed by RFP measurements at relevant time points after treatment. These analyses indicated that the synthetic promoter constructs were capable of conferring the inducibility of the RFP reporter in response to appropriate phytohormones and bacterial pathogens, accordingly. Conclusions These observations demonstrate that the Agrobacterium-mediated transient expression is an efficient method for in vivo assays of promoter constructs in less than one week. Our results provide the opportunity to gain further insights into the versatility of the expression system as a potential tool for high-throughput in planta expression screening prior to generating stably transgenic plants for pathogen phytosensing. This system could also be utilized for temporary phytosensing; e.g., not requiring stably transgenic plants.

2011-01-01

355

Coevolution and life cycle specialization of plant cell wall degrading enzymes in a hemibiotrophic pathogen.  

PubMed

Zymoseptoria tritici is an important fungal pathogen on wheat that originated in the Fertile Crescent. Its closely related sister species Z. pseudotritici and Z. ardabiliae infect wild grasses in the same region. This recently emerged host-pathogen system provides a rare opportunity to investigate the evolutionary processes shaping the genome of an emerging pathogen. Here, we investigate genetic signatures in plant cell wall degrading enzymes (PCWDEs) that are likely affected by or driving coevolution in plant-pathogen systems. We hypothesize four main evolutionary scenarios and combine comparative genomics, transcriptomics, and selection analyses to assign the majority of PCWDEs in Z. tritici to one of these scenarios. We found widespread differential transcription among different members of the same gene family, challenging the idea of functional redundancy and suggesting instead that specialized enzymatic activity occurs during different stages of the pathogen life cycle. We also find that natural selection has significantly affected at least 19 of the 48 identified PCWDEs. The majority of genes showed signatures of purifying selection, typical for the scenario of conserved substrate optimization. However, six genes showed diversifying selection that could be attributed to either host adaptation or host evasion. This study provides a powerful framework to better understand the roles played by different members of multigene families and to determine which genes are the most appropriate targets for wet laboratory experimentation, for example, to elucidate enzymatic function during relevant phases of a pathogen's life cycle. PMID:23515261

Brunner, Patrick C; Torriani, Stefano F F; Croll, Daniel; Stukenbrock, Eva H; McDonald, Bruce A

2013-03-20

356

The arbuscular mycorrhizal fungus, Glomus irregulare, controls the mycotoxin production of Fusarium sambucinum in the pathogenesis of potato.  

PubMed

Trichothecenes are an important family of mycotoxins produced by several species of the genus Fusarium. These fungi cause serious disease on infected plants and postharvest storage of crops, and the toxins can cause health problems for humans and animals. Unfortunately, there are few methods for controlling mycotoxin production by fungal pathogens, and most rely on chemicals, creating therefore subsequent problems of chemical resistance. We tested the impact of the symbiotic arbuscular mycorrhizal fungus Glomus irregulare on a trichothecene-producing strain of Fusarium sambucinum isolated from naturally infected potato plants. Using dual in vitro cultures, we showed that G. irregulare inhibited the growth of F. sambucinum and significantly reduced the production of the trichothecene 4, 15-diacetoxyscirpenol (DAS). Furthermore, using G. irregulare-colonized potato plants infected with F. sambucinum, we found that the G. irregulare treatment inhibited the production of DAS in roots and tubers. Thus, in addition to the known beneficial effect of mycorrhizal symbiosis on plant growth, we found that G. irregulare controlled the growth of a virulent fungal pathogen and reduced production of a mycotoxin. This previously undescribed, biological control of Fusarium mycotoxin production by G. irregulare has potential implications for improved potato crop production and food safety. PMID:23964970

Ismail, Youssef; McCormick, Susan; Hijri, Mohamed

2013-09-10

357

Pest Risk Analysis as Applied to Plant Pathogens  

Microsoft Academic Search

\\u000a The European and Mediterranean Plant Protection Organization (EPPO) is a regional standard-setting organization created in\\u000a 1951. One of EPPO’s main priorities is to prevent the introduction of dangerous pests from other parts of the world, and to\\u000a limit their spread within the region should they be introduced. In recent years, trade networks have expanded and diversified,\\u000a increasing the risks of

Françoise Petter; Sarah Brunel; Muriel Suffert

358

Type III protein secretion mechanism in mammalian and plant pathogens  

Microsoft Academic Search

The type III protein secretion system (TTSS) is a complex organelle in the envelope of many Gram-negative bacteria; it delivers potentially hundreds of structurally diverse bacterial virulence proteins into plant and animal cells to modulate host cellular functions. Recent studies have revealed several basic features of this secretion system, including assembly of needle\\/pilus-like secretion structures, formation of putative translocation pores

Sheng Yang He; Kinya Nomura; Thomas S. Whittam

2004-01-01

359

Belowground effects of organic and conventional farming on aboveground plant–herbivore and plant–pathogen interactions  

Microsoft Academic Search

Soil organisms may significantly affect the aboveground system. However, the influence of farming practices in modifying the effects of soil organisms on aboveground systems is poorly understood. The aim of our study was to investigate: (1) How important are soil organisms for plant growth and the development of herbivores and pathogens above the ground? (2) How do agricultural management practices

Katja Poveda; Ingolf Steffan-Dewenter; Stefan Scheu; Teja Tscharntke

2006-01-01

360

The endophytic strain Fusarium oxysporum Fo47: a good candidate for priming the defense responses in tomato roots.  

PubMed

The protective Fusarium oxysporum strain Fo47 is effective in controlling Fusarium wilt in tomato. Previous studies have demonstrated the role of direct antagonism and involvement of induced resistance. The aim of the present study was to investigate whether priming of plant defense responses is a mechanism by which Fo47 controls Fusarium wilt. An in vitro design enabled inoculation of the tap root with Fo47 and the pathogenic strain (Fol8) at different locations and different times. The expression levels of six genes known to be involved in tomato defense responses were quantified using reverse-transcription quantitative polymerase chain reaction (qPCR). Three genes-CHI3, GLUA, and PR-1a-were overexpressed in the root preinoculated with Fo47, and then challenged with Fol8. The genes GLUA and PR-1a were upregulated in cotyledons after inoculation of Fo47. Fungal growth in the root was assessed by qPCR, using specific markers for Fo47 and Fol8. Results showed a reduction of the pathogen growth in the root of the tomato plant preinoculated with Fo47. This study demonstrated that priming of tomato defense responses is one of the mechanisms of action of Fo47, which induces a reduced colonization of the root by the pathogen. PMID:23617416

Aimé, Sébastien; Alabouvette, Claude; Steinberg, Christian; Olivain, Chantal

2013-08-01

361

Advanced backcross QTL mapping of resistance to Fusarium head blight and plant morphological traits in a Triticum macha × T. aestivum population.  

PubMed

While many reports on genetic analysis of Fusarium head blight (FHB) resistance in bread wheat have been published during the past decade, only limited information is available on FHB resistance derived from wheat relatives. In this contribution, we report on the genetic analysis of FHB resistance derived from Triticum macha (Georgian spelt wheat). As the origin of T. macha is in the Caucasian region, it is supposed that its FHB resistance differs from other well-investigated resistance sources. To introduce valuable alleles from the landrace T. macha into a modern genetic background, we adopted an advanced backcross QTL mapping scheme. A backcross-derived recombinant-inbred line population of 321 BC(2)F(3) lines was developed from a cross of T. macha with the Austrian winter wheat cultivar Furore. The population was evaluated for Fusarium resistance in seven field experiments during four seasons using artificial inoculations. A total of 300 lines of the population were genetically fingerprinted using SSR and AFLP markers. The resulting linkage map covered 33 linkage groups with 560 markers. Five novel FHB-resistance QTL, all descending from T. macha, were found on four chromosomes (2A, 2B, 5A, 5B). Several QTL for morphological and developmental traits were mapped in the same population, which partly overlapped with FHB-resistance QTL. Only the 2BL FHB-resistance QTL co-located with a plant height QTL. The largest-effect FHB-resistance QTL in this population mapped at the spelt-type locus on chromosome 5A and was associated with the wild-type allele q, but it is unclear whether q has a pleiotropic effect on FHB resistance or is closely linked to a nearby resistance QTL. PMID:21479934

Buerstmayr, Maria; Lemmens, Marc; Steiner, Barbara; Buerstmayr, Hermann

2011-04-11

362

A plant pathogen reduces the enemy-free space of an insect herbivore on a shared host plant.  

PubMed

An important mechanism in stabilizing tightly linked host-parasitoid and prey-predator interactions is the presence of refuges that protect organisms from their natural enemies. However, the presence and quality of refuges can be strongly affected by the environment. We show that infection of the host plant Silene latifolia by its specialist fungal plant pathogen Microbotryum violaceum dramatically alters the enemy-free space of a herbivore, the specialist noctuid seed predator Hadena bicruris, on their shared host plant. The pathogen arrests the development of seed capsules that serve as refuges for the herbivore's offspring against the specialist parasitoid Microplitis tristis, a major source of mortality of H. bicruris in the field. Pathogen infection resulted both in lower host-plant food quality, causing reduced adult emergence, and in twofold higher rates of parasitism of the herbivore. We interpret the strong oviposition preference of H. bicruris for uninfected plants in the field as an adaptive response, positioning offspring on refuge-rich, high-quality hosts. To our knowledge, this is the first demonstration that plant-inhabiting micro-organisms can affect higher trophic interactions through alteration of host refuge quality. We speculate that such interference can potentially destabilize tightly linked multitrophic interactions. PMID:12427312

Biere, Arjen; Elzinga, Jelmer A; Honders, Sonja C; Harvey, Jeffrey A

2002-11-01

363

A Domain-Centric Analysis of Oomycete Plant Pathogen Genomes Reveals Unique Protein Organization1[W][OA  

PubMed Central

Oomycetes comprise a diverse group of organisms that morphologically resemble fungi but belong to the stramenopile lineage within the supergroup of chromalveolates. Recent studies have shown that plant pathogenic oomycetes have expanded gene families that are possibly linked to their pathogenic lifestyle. We analyzed the protein domain organization of 67 eukaryotic species including four oomycete and five fungal plant pathogens. We detected 246 expanded domains in fungal and oomycete plant pathogens. The analysis of genes differentially expressed during infection revealed a significant enrichment of genes encoding expanded domains as well as signal peptides linking a substantial part of these genes to pathogenicity. Overrepresentation and clustering of domain abundance profiles revealed domains that might have important roles in host-pathogen interactions but, as yet, have not been linked to pathogenicity. The number of distinct domain combinations (bigrams) in oomycetes was significantly higher than in fungi. We identified 773 oomycete-specific bigrams, with the majority composed of domains common to eukaryotes. The analyses enabled us to link domain content to biological processes such as host-pathogen interaction, nutrient uptake, or suppression and elicitation of plant immune responses. Taken together, this study represents a comprehensive overview of the domain repertoire of fungal and oomycete plant pathogens and points to novel features like domain expansion and species-specific bigram types that could, at least partially, explain why oomycetes are such remarkable plant pathogens.

Seidl, Michael F.; Van den Ackerveken, Guido; Govers, Francine; Snel, Berend

2011-01-01

364

The effects of fungicides on non-target mites can be mediated by plant pathogens.  

PubMed

Field tests are useful for the evaluation of the pesticides' impact in realistic use situations. However, the distinction between the direct and indirect effects of a pesticide is not always possible in field, with consequences on the conclusions about pesticides toxicity. Generalist predatory mites belonging to the Phytoseiidae family are widely considered as non-target organisms in pesticide side-effect evaluations. Plant pathogens of several cultivated plants can be of importance as food resources for various phytoseiids. Pesticides with fungicidal activity may have a direct impact on phytoseiids, but they can also have an indirect effect reducing food availability for predatory mites. Here, we present the results of field experiments performed on grapevine, where we investigate whether the availability of the plant pathogen grape downy mildew has an effect on fungicides impact on the predatory mites Typhlodromus pyri Scheuten and Amblyseius andersoni (Chant). In these experiments we used fungicides characterized by differential selectivity to predatory mites in laboratory: copper compounds, folpet, and mancozeb. Results indicated that the abundance of predatory mites was associated with the plant pathogen foliar symptoms presence. The presence of predatory mites was different among treatments in response of the toxicological traits of a pesticide (direct effects), but also as consequences of differential plant pathogen availability induced by fungicide applications (indirect effects). During the investigation, the variable plant pathogen spread on untreated control determined contrasting results on pesticides effect. We segregated the direct effects from the indirect food resource-mediated effects including a non-toxic reference in the experimental protocols. PMID:20172588

Pozzebon, Alberto; Borgo, Michele; Duso, Carlo

2010-02-20

365

Complete genome sequence of the fire blight pathogen Erwinia pyrifoliae DSM 12163T and comparative genomic insights into plant pathogenicity  

PubMed Central

Background Erwinia pyrifoliae is a newly described necrotrophic pathogen, which causes fire blight on Asian (Nashi) pear and is geographically restricted to Eastern Asia. Relatively little is known about its genetics compared to the closely related main fire blight pathogen E. amylovora. Results The genome of the type strain of E. pyrifoliae strain DSM 12163T, was sequenced using both 454 and Solexa pyrosequencing and annotated. The genome contains a circular chromosome of 4.026 Mb and four small plasmids. Based on their respective role in virulence in E. amylovora or related organisms, we identified several putative virulence factors, including type III and type VI secretion systems and their effectors, flagellar genes, sorbitol metabolism, iron uptake determinants, and quorum-sensing components. A deletion in the rpoS gene covering the most conserved region of the protein was identified which may contribute to the difference in virulence/host-range compared to E. amylovora. Comparative genomics with the pome fruit epiphyte Erwinia tasmaniensis Et1/99 showed that both species are overall highly similar, although specific differences were identified, for example the presence of some phage gene-containing regions and a high number of putative genomic islands containing transposases in the E. pyrifoliae DSM 12163T genome. Conclusions The E. pyrifoliae genome is an important addition to the published genome of E. tasmaniensis and the unfinished genome of E. amylovora providing a foundation for re-sequencing additional strains that may shed light on the evolution of the host-range and virulence/pathogenicity of this important group of plant-associated bacteria.

2010-01-01

366

Exploiting pathogens' tricks of the trade for engineering of plant disease resistance: challenges and opportunities.  

PubMed

With expansion of our understanding of pathogen effector strategies and the multiplicity of their host targets, it is becoming evident that novel approaches to engineering broad-spectrum resistance need to be deployed. The increasing availability of high temporal gene expression data of a range of plant-microbe interactions enables the judicious choices of promoters to fine-tune timing and magnitude of expression under specified stress conditions. We can therefore contemplate engineering a range of transgenic lines designed to interfere with pathogen virulence strategies that target plant hormone signalling or deploy specific disease resistance genes. An advantage of such an approach is that hormonal signalling is generic so if this strategy is effective, it can be easily implemented in a range of crop species. Additionally, multiple re-wired lines can be crossed to develop more effective responses to pathogens. PMID:23279915

Grant, Murray R; Kazan, Kemal; Manners, John M

2013-01-02

367

Evaluating plant pathogens for biological control of weeds: an alternative view of pest risk assessment  

Microsoft Academic Search

Biological control of weeds is still a relatively new field in plant pathology, in which, instead of trying to keep out exotic\\u000a plant pathogens or to contain indigenous ones, they are actively being exploited in weed management, particularly for alien\\u000a invasives. Two broad approaches can be distinguished, although these are not necessarily mutually exclusive: classical or\\u000a inoculative biological control, involving

Harry C. Evans

2000-01-01

368

LysM receptor-like kinases to improve plant defense response against fungal pathogens  

Microsoft Academic Search

Perception of chitin fragments (chitooligosaccharides) is an important first step in plant defense response against fungal pathogen. LysM receptor-like kinases (LysM RLKs) are instrumental in this perception process. LysM RLKs also play a role in activating transcription of chitin-responsive genes (CRGs) in plants. Mutations in the LysM kinase receptor genes or the downstream CRGs may affect the fungal susceptibility of

Jinrong Wan; Gary Stacey; Minviluz Stacey; Xuecheng Zhang

2012-01-01

369

The Use of Bioluminescence for Monitoring in planta Growth Dynamics of a Pseudomonas syringae Plant Pathogen  

Microsoft Academic Search

The use of bioluminescence was evaluated as a tool to study Pseudomonas syringae population dynamics in susceptible and resistant plant environments. Plasmid pGLITE, containing the luxCDABE genes from Photorhabdus luminescens, was introduced into Pseudomonas syringae pv. phaseolicola race 7 strain 1449B, a Gram-negative pathogen of bean (Phaseolus vulgaris). Bacteria recovered from plant tissue over a five-day period were enumerated by

Christopher D. Paynter; Vyvyan C. Salisbury; Dawn L. Arnold; Robert W. Jackson

2006-01-01

370

Antibacterial activity of plant extracts from Brazil against fish pathogenic bacteria.  

PubMed

The aim of this work was to evaluate the antibacterial activity of Brazilian plants extracts against fish pathogenic bacteria. Forty six methanolic extracts were screened to identify their antibacterial properties against Streptococcus agalactiae, Flavobacterium columnare and Aeromonas hydrophila. Thirty one extracts showed antibacterial activity. PMID:24031303

Castro, S B R; Leal, C A G; Freire, F R; Carvalho, D A; Oliveira, D F; Figueiredo, H C P

2008-12-01

371

A Pathogenic Fungi Diphenyl Ether Phytotoxin Targets Plant Enoyl (Acyl Carrier Protein) Reductase  

Microsoft Academic Search

Cyperin is a natural diphenyl ether phytotoxin produced by several fungal plant pathogens. At high concentrations, this metabolite inhibits protoporphyrinogen oxidase, a key enzyme in porphyrin synthesis. However, unlike its herbicide structural analogs, the mode of action of cyperin is not light dependent, causing loss of membrane integrity in the dark. We report that this natural diphenyl ether inhibits Arabidopsis

Franck E. Dayan; Daneel Ferreira; Yan-Hong Wang; Ikhlas A. Khan; John A. McInroy; Zhiqiang Pan

2008-01-01

372

Meiosis Drives Extraordinary Genome Plasticity in the Haploid Fungal Plant Pathogen Mycosphaerella graminicola  

Microsoft Academic Search

Meiosis in the haploid plant-pathogenic fungus Mycosphaerella graminicola results in eight ascospores due to a mitotic division following the two meiotic divisions. The transient diploid phase allows for recombination among homologous chromosomes. However, some chromosomes of M. graminicola lack homologs and do not pair during meiosis. Because these chromosomes are not present universally in the genome of the organism they

Alexander H. J. Wittenberg; Sarrah Ben M'barek; Sarah B. Ware; Stephen B. Goodwin; Andrzej Kilian; Richard G. F. Visser; Gert H. J. Kema; Henk J. Schouten; Jason E. Stajich

2009-01-01

373

Insights from the genome of the biotrophic fungal plant pathogen Ustilago maydis  

Microsoft Academic Search

Ustilago maydis is a ubiquitous pathogen of maize and a well-established model organism for the study of plant-microbe interactions. This basidiomycete fungus does not use aggressive virulence strategies to kill its host. U. maydis belongs to the group of biotrophic parasites (the smuts) that depend on living tissue for proliferation and development. Here we report the genome sequence for a

Jörg Kämper; Regine Kahmann; Michael Bölker; Li-Jun Ma; Thomas Brefort; Barry J. Saville; Flora Banuett; James W. Kronstad; Scott E. Gold; Olaf Müller; Michael H. Perlin; Han A. B. Wösten; Ronald de Vries; José Ruiz-Herrera; Cristina G. Reynaga-Peńa; Karen Snetselaar; Michael McCann; José Pérez-Martín; Michael Feldbrügge; Christoph W. Basse; Gero Steinberg; Jose I. Ibeas; William Holloman; Plinio Guzman; Mark Farman; Jason E. Stajich; Rafael Sentandreu; Juan M. González-Prieto; John C. Kennell; Lazaro Molina; Jan Schirawski; Artemio Mendoza-Mendoza; Doris Greilinger; Karin Münch; Nicole Rössel; Mario Scherer; Miroslav Vranes; Oliver Ladendorf; Volker Vincon; Uta Fuchs; Björn Sandrock; Shaowu Meng; Eric C. H. Ho; Matt J. Cahill; Kylie J. Boyce; Jana Klose; Steven J. Klosterman; Heine J. Deelstra; Lucila Ortiz-Castellanos; Weixi Li; Patricia Sanchez-Alonso; Peter H. Schreier; Isolde Häuser-Hahn; Martin Vaupel; Edda Koopmann; Gabi Friedrich; Hartmut Voss; Thomas Schlüter; Jonathan Margolis; Darren Platt; Candace Swimmer; Andreas Gnirke; Feng Chen; Valentina Vysotskaia; Gertrud Mannhaupt; Ulrich Güldener; Martin Münsterkötter; Dirk Haase; Matthias Oesterheld; Hans-Werner Mewes; Evan W. Mauceli; David Decaprio; Claire M. Wade; Jonathan Butler; Sarah Young; David B. Jaffe; Sarah Calvo; Chad Nusbaum; James Galagan; Bruce W. Birren

2006-01-01

374

Antibacterial activity of plant extracts from Brazil against fish pathogenic bacteria  

PubMed Central

The aim of this work was to evaluate the antibacterial activity of Brazilian plants extracts against fish pathogenic bacteria. Forty six methanolic extracts were screened to identify their antibacterial properties against Streptococcus agalactiae, Flavobacterium columnare and Aeromonas hydrophila. Thirty one extracts showed antibacterial activity.

Castro, S.B.R.; Leal, C.A.G.; Freire, F.R.; Carvalho, D.A.; Oliveira, D.F.; Figueiredo, H.C.P.

2008-01-01

375

Antibacterial Evaluation of Some Plant Extracts Against Some Human Pathogenic Bacteria  

Microsoft Academic Search

The aqueous, different solvent extracts and isolated constituents of eight higher medicinal plants viz., Argemone mexicana, Caesalpinia coriaria, Decalepis hamiltonii, Euphorbia tirucalli, Leucas aspera, Phyllanthus amarus, Phyllanthus niruri, Tinospora cordifolia and Tribulus terrestris were screened in vitro for antibacterial activity by cup diffusion method against eleven human pathogenic bacteria. Caesalpinia coriaria (Jacq.) Willd. (Caesalpinaceae) recorded significant antibacterial activity against all

D. C. Mohan; S. Satish; K. A. Raveesha

376

Fungal Control of Pathogenic Fungi Isolated From Some Wild Plants in Taif Governorate, Saudi Arabia  

Microsoft Academic Search

Twenty two plants were collected from Taif Governorate and identified as: Aerva lanata, Arnebia hispidissima, Artemisia judaica, Artemisia monosperma, Asphodelus aestives, Avena barbata, Capparis dcidua, Eucalyptus globulus, Euphorbia glomerifera, Foeniculum vulgare, Forsskaolea tenacissima, Juniperus procera, Launaea mucronata, Launaea sonchoides, Medicago sativa, Opuntia ficus, Phagnalon sinaicum, Prunus persica, Pulicaria crispa, Punica granatum, Rumex dentatus and Trichodesma calathiforme. Pathogenic fungi were isolated

Abd El-Fattah

377

Effects of fungal pathogens on seeds of native and exotic plants: a test using congeneric pairs  

Microsoft Academic Search

Summary 1. It has previously been hypothesized that low rates of attack by natural enemies may contribute to the invasiveness of exotic plants. 2. We tested this hypothesis by investigating the influence of pathogens on survival dur- ing a critical life-history stage: the seed bank. We used fungicide treatments to estimate the impacts of soil fungi on buried seeds of

C. S. BLANEY; P. M. KOTANEN

2001-01-01

378

Non-oak native plants are main hosts for sudden oak death pathogen in California  

Microsoft Academic Search

The finding of Phytophthora ramorum — the pathogen that causes sudden oak death in four California native trees — on rhododendron in Europe led us to hypothesize that its host range in California's natural forests was much greater than previously suspected. In addition to the affected oak species, we have now identified an additional 13 species from 10 plant families

Matteo Garbelotto; Jennifer M. Davidson; Kelly Ivors; Patricia E. Maloney; Daniel Hüberli; Steven T. Koike; David M. Rizzo

2002-01-01

379

Molecular variability among isolates of Fusarium oxysporum associated with root rot disease of Agave tequilana.  

PubMed

In this study, 115 isolates of Fusarium oxysporum from roots of Agave tequilana Weber cv azul plants and soil in commercial plantations in western Mexico were characterized using morphological and molecular methods. Genetic analyses of monosporic isolates included restriction enzyme analysis of rDNA (ARDRA) using HaeIII and HinfI, and genetic diversity was determined using Box-PCR molecular markers. Box-PCR analysis generated 14 groups. The groups correlated highly with the geographic location of the isolate and sample type. These results demonstrate the usefulness of ARDRA and Box-PCR techniques in the molecular characterization of the Fusarium genus for the discrimination of pathogenic isolates. PMID:23315087

Vega-Ramos, Karla L; Uvalle-Bueno, J Xavier; Gómez-Leyva, Juan F

2013-01-12

380

Biological control of the potato dry rot caused by Fusarium species using PGPR strains  

Microsoft Academic Search

In this study, a total of 17 Plant Growth Promoting Rhizobacteria (PGPR) strains, consisting of eight different species (Bacillus subtilis, Bacillus pumilus, Burkholderia cepacia, Pseudomonas putida, Bacillus amyloliquefaciens, Bacillus atrophaeus, Bacillus macerans and Flavobacter balastinium), were tested for antifungal activity in in vitro (on Petri plate) and in vivo (on potato tuber) conditions against Fusarium sambucinum, Fusarium oxysporum and Fusarium

Kotan Recep; Sahin Fikrettin; Demirci Erkol; Eken Cafer

2009-01-01

381

Elite-upland cotton germplasm-pool assessment of fusarium wilt (FOV) resistance in California  

Technology Transfer Automated Retrieval System (TEKTRAN)

Host-plant resistance is currently the most economic and effective strategy for managing Fusarium wilt [Fusarium oxysporum f. sp. vasinfectum (FOV)] disease. Over the past nine years, a new race of Fusarium (FOV race 4) has increasingly impacted cotton (Gossypium spp.) in production fields in the Sa...

382

Soil and Rhizosphere Populations of Fusarium and Fluorescent Pseudomonas spp. Associated with Field-Grown Plants are Affected by Sorghum Genotype  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sorghum [Sorghum bicolor (L.) Moench] is valued for bioenergy, feed and food. Potential of sorghum genotypes to support differing populations of root- and soil-associated fluorescent Pseudomonas spp. or Fusarium spp., in two soils, was assessed. Pseudomonad and Fusarium numbers were assessed from ro...

383

Antifungal activity of essential oil and its constituents from Calocedrus macrolepis var. formosana Florin leaf against plant pathogenic fungi  

Microsoft Academic Search

Resistance to conventional fungicides causes the poor disease control of agriculture. Natural products from plants have great potential as novel fungicide sources for controlling pathogenic fungi. In this study antipathogenic activity of the leaf essential oil and its constituents from Calocedrus macrolepis var. formosana Florin were evaluated in vitro against six plant pathogenic fungi. Chemical analysis of leaf oil by

Hui-Ting Chang; Ying-Hung Cheng; Chi-Lin Wu; Shang-Tzen Chang; Tun-Tschu Chang; Yu-Chang Su

2008-01-01

384

Stepwise screening of microorganisms for commercial use in biological control of plant pathogenic fungi and bacteria. Biological Control  

Microsoft Academic Search

The development of new biocontrol products against plant diseases requires screening of high numbers of candidate antagonists. Antagonists for commercial use have to fulfill many different requirements. Besides being active against the specific targeted plant pathogens they must be safe and cost-effective. Important criteria besides pathogenic efficacy are market size, ecological characteristics, production costs, safety, environmental risks, and possibilities for

J. Köhl; J. Postma; P. Nicot; M. Ruocco

2011-01-01

385

Comparative genomics reveals insight into virulence strategies of plant pathogenic oomycetes.  

PubMed

The kingdom Stramenopile includes diatoms, brown algae, and oomycetes. Plant pathogenic oomycetes, including Phytophthora, Pythium and downy mildew species, cause devastating diseases on a wide range of host species and have a significant impact on agriculture. Here, we report comparative analyses on the genomes of thirteen straminipilous species, including eleven plant pathogenic oomycetes, to explore common features linked to their pathogenic lifestyle. We report the sequencing, assembly, and annotation of six Pythium genomes and comparison with other stramenopiles including photosynthetic diatoms, and other plant pathogenic oomycetes such as Phytophthora species, Hyaloperonospora arabidopsidis, and Pythium ultimum var. ultimum. Novel features of the oomycete genomes include an expansion of genes encoding secreted effectors and plant cell wall degrading enzymes in Phytophthora species and an over-representation of genes involved in proteolytic degradation and signal transduction in Pythium species. A complete lack of classical RxLR effectors was observed in the seven surveyed Pythium genomes along with an overall reduction of pathogenesis-related gene families in H. arabidopsidis. Comparative analyses revealed fewer genes encoding enzymes involved in carbohydrate metabolism in Pythium species and H. arabidopsidis as compared to Phytophthora species, suggesting variation in virulence mechanisms within plant pathogenic oomycete species. Shared features between the oomycetes and diatoms revealed common mechanisms of intracellular signaling and transportation. Our analyses demonstrate the value of comparative genome analyses for exploring the evolution of pathogenesis and survival mechanisms in the oomycetes. The comparative analyses of seven Pythium species with the closely related oomycetes, Phytophthora species and H. arabidopsidis, and distantly related diatoms provide insight into genes that underlie virulence. PMID:24124466

Adhikari, Bishwo N; Hamilton, John P; Zerillo, Marcelo M; Tisserat, Ned; Lévesque, C André; Buell, C Robin

2013-10-04

386

Comparative Genomics Reveals Insight into Virulence Strategies of Plant Pathogenic Oomycetes  

PubMed Central

The kingdom Stramenopile includes diatoms, brown algae, and oomycetes. Plant pathogenic oomycetes, including Phytophthora, Pythium and downy mildew species, cause devastating diseases on a wide range of host species and have a significant impact on agriculture. Here, we report comparative analyses on the genomes of thirteen straminipilous species, including eleven plant pathogenic oomycetes, to explore common features linked to their pathogenic lifestyle. We report the sequencing, assembly, and annotation of six Pythium genomes and comparison with other stramenopiles including photosynthetic diatoms, and other plant pathogenic oomycetes such as Phytophthora species, Hyaloperonospora arabidopsidis, and Pythium ultimum var. ultimum. Novel features of the oomycete genomes include an expansion of genes encoding secreted effectors and plant cell wall degrading enzymes in Phytophthora species and an over-representation of genes involved in proteolytic degradation and signal transduction in Pythium species. A complete lack of classical RxLR effectors was observed in the seven surveyed Pythium genomes along with an overall reduction of pathogenesis-related gene families in H. arabidopsidis. Comparative analyses revealed fewer genes encoding enzymes involved in carbohydrate metabolism in Pythium species and H. arabidopsidis as compared to Phytophthora species, suggesting variation in virulence mechanisms within plant pathogenic oomycete species. Shared features between the oomycetes and diatoms revealed common mechanisms of intracellular signaling and transportation. Our analyses demonstrate the value of comparative genome analyses for exploring the evolution of pathogenesis and survival mechanisms in the oomycetes. The comparative analyses of seven Pythium species with the closely related oomycetes, Phytophthora species and H. arabidopsidis, and distantly related diatoms provide insight into genes that underlie virulence.

Adhikari, Bishwo N.; Hamilton, John P.; Zerillo, Marcelo M.; Tisserat, Ned; Levesque, C. Andre; Buell, C. Robin

2013-01-01

387

Green Leaf Volatiles: A Plant's Multifunctional Weapon against Herbivores and Pathogens  

PubMed Central

Plants cannot avoid being attacked by an almost infinite number of microorganisms and insects. Consequently, they arm themselves with molecular weapons against their attackers. Plant defense responses are the result of a complex signaling network, in which the hormones jasmonic acid (JA), salicylic acid (SA) and ethylene (ET) are the usual suspects under the magnifying glass when researchers investigate host-pest interactions. However, Green Leaf Volatiles (GLVs), C6 molecules, which are very quickly produced and/or emitted upon herbivory or pathogen infection by almost every green plant, also play an important role in plant defenses. GLVs are semiochemicals used by insects to find their food or their conspecifics. They have also been reported to be fundamental in indirect defenses and to have a direct effect on pests, but these are not the only roles of GLVs. These volatiles, being probably one of the fastest weapons exploited, are also able to directly elicit or prime plant defense responses. Moreover, GLVs, via crosstalk with phytohormones, mostly JA, can influence the outcome of the plant’s defense response against pathogens. For all these reasons GLVs should be considered as co-protagonists in the play between plants and their attackers.

Scala, Alessandra; Allmann, Silke; Mirabella, Rossana; Haring, Michel A.; Schuurink, Robert C.

2013-01-01

388

Chemical Diversity and Defence Metabolism: How Plants Cope with Pathogens and Ozone Pollution  

PubMed Central

Chemical defences represent a main trait of the plant innate immune system. Besides regulating the relationship between plants and their ecosystems, phytochemicals are involved both in resistance against pathogens and in tolerance towards abiotic stresses, such as atmospheric pollution. Plant defence metabolites arise from the main secondary metabolic routes, the phenylpropanoid, the isoprenoid and the alkaloid pathways. In plants, antibiotic compounds can be both preformed (phytoanticipins) and inducible (phytoalexins), the former including saponins, cyanogenic glycosides and glucosinolates. Chronic exposure to tropospheric ozone (O3) stimulates the carbon fluxes from the primary to the secondary metabolic pathways to a great extent, inducing a shift of the available resources in favour of the synthesis of secondary products. In some cases, the plant defence responses against pathogens and environmental pollutants may overlap, leading to the unspecific synthesis of similar molecules, such as phenylpropanoids. Exposure to ozone can also modify the pattern of biogenic volatile organic compounds (BVOC), emitted from plant in response to herbivore feeding, thus altering the tritrophic interaction among plant, phytophagy and their natural enemies. Finally, the synthesis of ethylene and polyamines can be regulated by ozone at level of S-adenosylmethionine (SAM), the biosynthetic precursor of both classes of hormones, which can, therefore, mutually inhibit their own biosynthesis with consequence on plant phenotype.

Iriti, Marcello; Faoro, Franco

2009-01-01

389

Biological control of plant pathogens: advantages and limitations seen through the case study of Pythium oligandrum.  

PubMed

The management of certain plant beneficial microorganisms [biological control agents (BCAs)] seems to be a promising and environmental friendly method to control plant pathogens. However, applications are still limited because of the lack of consistency of BCAs when they are applied in the field. In the present paper, the advantages and limitations of BCAs are seen through the example of Pythium oligandrum, an oomycete that has received much attention in the last decade. The biological control exerted by P. oligandrum is the result of a complex process, which includes direct effects through the control of pathogens and/or indirect effects mediated by P. oligandrum, i.e. induction of resistance and growth promotion. P. oligandrum antagonism is a multifaceted and target fungus-dependent process. Interestingly, it does not seem to disrupt microflora biodiversity on the roots. P. oligandrum has an atypical relationship with the plant because it rapidly penetrates into the root tissues but it cannot stay alive in planta. After root colonisation, because of the elicitation by P. oligandrum of the plant-defence system, plants are protected from a range of pathogens. The management of BCAs, here P. oligandrum, is discussed with regard to its interactions with the incredibly complex agrosystems. PMID:23695856

Gerbore, J; Benhamou, N; Vallance, J; Le Floch, G; Grizard, D; Regnault-Roger, C; Rey, P

2013-05-22

390

Effect of artificial reconstitution of the interaction between the plant Camptotheca acuminata and the fungal endophyte Fusarium solani on camptothecin biosynthesis.  

PubMed

Fungal endophytes inhabit healthy tissues of all terrestrial plant taxa studied and occasionally produce host-specific compounds. We recently isolated an endophytic fungus, Fusarium solani, from Camptotheca acuminata, capable of biosynthesizing camptothecin (CPT, 1), but this capability substantially decreased on repeated subculturing. The endophyte with an impaired 1 biosynthetic capability was artificially inoculated into the living host plants and then recovered after colonization. Although the host-endophyte interaction could be reconstituted, biosynthesis of 1 could not be restored. Using a homology-based approach and high-precision isotope-ratio mass spectrometry (HP-IRMS), a cross-species biosynthetic pathway is proposed where the endophyte utilizes indigenous G10H (geraniol 10-hydroxylase), SLS (secologanin synthase), and TDC (tryptophan decarboxylase) to biosynthesize precursors of 1. However, the endophyte requires host STR (strictosidine synthase) in order to condense the nitrogen-containing moiety (tryptamine, 2) with the carbon-containing moiety (secologanin, 3) to form strictosidine (4) and complete the biosynthesis of 1. Biosynthetic genes of 1 in the seventh subculture generation of the endophyte revealed random and unpredictable nonsynonymous mutations. These random base substitutions led to dysfunction at the amino acid level. The controls, Top1 gene and rDNA, remained intact over subculturing, revealing that instability of biosynthetic genes of 1 was not reflected in the primary metabolic processes and functioning of the housekeeping genes. The present results reveal the causes of decreased production of 1 on subculturing, which could not be reversed by host-endophyte reassociation. PMID:21348469

Kusari, Souvik; Zühlke, Sebastian; Spiteller, Michael

2011-02-24

391

Host-selective toxins produced by the plant pathogenic fungus Alternaria alternata.  

PubMed

Host-selective toxins (HSTs) produced by fungal plant pathogens are generally low-molecular-weight secondary metabolites with a diverse range of structures that function as effectors controlling pathogenicity or virulence in certain plant-pathogen interactions. There are now seven known diseases caused by Alternaria alternata in which HSTs are responsible for fungal pathogenesis. The pathogens have been defined as pathotypes of A. alternata because of morphological similarity but pathological differences. Chemical structures of HSTs from six pathotypes have been determined. The role of A. alternata HSTs in pathogenesis has been studied extensively, and discovery of the release of HSTs from germinating conidia prior to penetration aids in understanding the early participation of HSTs to induce susceptibility of host cells by suppressing their defence reactions. Many attempts have been made to find the target sites of A. alternata HSTs, and four cellular components, plasma membrane, mitochondrion, chloroplast and a metabolically important enzyme, have been identified as the primary sites of each HST action, leading to elucidation of the molecular mechanisms of HST sensitivity in host plants. Studies of the molecular genetics of HST production have identified supernumerary chromosomes encoding HST gene clusters and have provided new insights into the evolution of A. alternata pathotypes. PMID:22846083

Tsuge, Takashi; Harimoto, Yoshiaki; Akimitsu, Kazuya; Ohtani, Kouhei; Kodama, Motoichiro; Akagi, Yasunori; Egusa, Mayumi; Yamamoto, Mikihiro; Otani, Hiroshi

2012-08-24

392

Tools to kill: Genome of one of the most destructive plant pathogenic fungi Macrophomina phaseolina  

PubMed Central

Background Macrophomina phaseolina is one of the most destructive necrotrophic fungal pathogens that infect more than 500 plant species throughout the world. It can grow rapidly in infected plants and subsequently produces a large amount of sclerotia that plugs the vessels, resulting in wilting of the plant. Results We sequenced and assembled ~49?Mb into 15 super-scaffolds covering 92.83% of the M. phaseolina genome. We predict 14,249 open reading frames (ORFs) of which 9,934 are validated by the transcriptome. This phytopathogen has an abundance of secreted oxidases, peroxidases, and hydrolytic enzymes for degrading cell wall polysaccharides and lignocelluloses to penetrate into the host tissue. To overcome the host plant defense response, M. phaseolina encodes a significant number of P450s, MFS type membrane transporters, glycosidases, transposases, and secondary metabolites in comparison to all sequenced ascomycete species. A strikingly distinct set of carbohydrate esterases (CE) are present in M. phaseolina, with the CE9 and CE10 families remarkably higher than any other fungi. The phenotypic microarray data indicates that M. phaseolina can adapt to a wide range of osmotic and pH environments. As a broad host range pathogen, M. phaseolina possesses a large number of pathogen-host interaction genes including those for adhesion, signal transduction, cell wall breakdown, purine biosynthesis, and potent mycotoxin patulin. Conclusions The M. phaseolina genome provides a framework of the infection process at the cytological and molecular level which uses a diverse arsenal of enzymatic and toxin tools to destroy the host plants. Further understanding of the M. phaseolina genome-based plant-pathogen interactions will be instrumental in designing rational strategies for disease control, essential to ensuring global agricultural crop production and security.

2012-01-01

393

Fusarium Infection in Lung Transplant Patients  

PubMed Central

Fusarium is a fungal pathogen of immunosuppressed lung transplant patients associated with a high mortality in those with severe and persistent neutropenia. The principle portal of entry for Fusarium species is the airways, and lung involvement almost always occurs among lung transplant patients with disseminated infection. In these patients, the immunoprotective mechanisms of the transplanted lungs are impaired, and they are, therefore, more vulnerable to Fusarium infection. As a result, fusariosis occurs in up to 32% of lung transplant patients. We studied fusariosis in 6 patients following lung transplantation who were treated at Massachusetts General Hospital during an 8-year period and reviewed 3 published cases in the literature. Cases were identified by the microbiology laboratory and through discharge summaries. Patients presented with dyspnea, fever, nonproductive cough, hemoptysis, and headache. Blood tests showed elevated white blood cell counts with granulocytosis and elevated inflammatory markers. Cultures of Fusarium were isolated from bronchoalveolar lavage, blood, and sputum specimens. Treatments included amphotericin B, liposomal amphotericin B, caspofungin, voriconazole, and posaconazole, either alone or in combination. Lung involvement occurred in all patients with disseminated disease and it was associated with a poor outcome. The mortality rate in this group of patients was high (67%), and of those who survived, 1 patient was treated with a combination of amphotericin B and voriconazole, 1 patient with amphotericin B, and 1 patient with posaconazole. Recommended empirical treatment includes voriconazole, amphotericin B or liposomal amphotericin B first-line, and posaconazole for refractory disease. High-dose amphotericin B is recommended for treatment of most cases of fusariosis. The echinocandins (for example, caspofungin, micafungin, anidulafungin) are generally avoided because Fusarium species have intrinsic resistance to them. Treatment should ideally be based on the Fusarium isolate, susceptibility testing, and host-specific factors. Prognosis of fusariosis in the immunocompromised is directly related to a patient’s immune status. Prevention of Fusarium infection is recommended with aerosolized amphotericin B deoxycholate, which also has activity against other important fungi.

Carneiro, Herman A.; Coleman, Jeffrey J.; Restrepo, Alejandro; Mylonakis, Eleftherios

2013-01-01

394

Molecular and biochemical detection of fengycin- and bacillomycin D-producing Bacillus spp., antagonistic to fungal pathogens of canola and wheat  

Microsoft Academic Search

Bacillus species are well known for their ability to control plant diseases through various mechanisms, including the production of secondary metabolites. Bacillus subtilis DFH08, an antagonist of Fusarium graminearum, and other Ba- cillus spp. that are antagonists of common fungal pathogens of canola were screened for peptide synthetase biosynthetic genes of fengycin and bacillomycin D. Specific polymerase chain reaction (PCR)

Rajesh Ramarathnam; Shen Bo; Yu Chen; W. G. Dilantha Fernando; Gao Xuewen; Teresa de Kievit

2007-01-01

395

Presence of pathogenic amoebae in power plant cooling waters. Final report, October 15, 1977-September 30, 1979. [Naegleria fowleri  

SciTech Connect

Cooling-water-associated algae and sediments from five northern and five southern or western electric power plants were tested for the presence of pathogenic amoebae. In addition, water algae and sediments from five northern and five southern/western sites not associated with power plants were tested. There was a significant correlation at northern power plants between the presence of thermophilic, pathogenic amoebae in cooling waters and thermal additions. Presence of the pathogenic did not correlate with salinity, pH, conductivity, or a variety of various chemical components of the cooling waters. Selected pathogenic isolates were tested serologically and were classified as Naegleria fowleri. Although thermal additions were shown to be contributing factor in predisposing cooling waters to the growth of pathogenic amoebae, the data suggest the involvement of other currently undefined parameters associated with the presence of the pathogenic amoebae. 35 refs., 21 tabs.

Tyndall, R.L.; Willaert, E.; Stevens, A.R.

1981-03-01

396

Green Leaf Volatiles: A Plant's Multifunctional Weapon against Herbivores and Pathogens.  

PubMed

Plants cannot avoid being attacked by an almost infinite number of microorganisms and insects. Consequently, they arm themselves with molecular weapons against their attackers. Plant defense responses are the result of a complex signaling network, in which the hormones jasmonic acid (JA), salicylic acid (SA) and ethylene (ET) are the usual suspects under the magnifying glass when researchers investigate host-pest interactions. However, Green Leaf Volatiles (GLVs), C6 molecules, which are very quickly produced and/or emitted upon herbivory or pathogen infection by almost every green plant, also play an important role in plant defenses. GLVs are semiochemicals used by insects to find their food or their conspecifics. They have also been reported to be fundamental in indirect defenses and to have a direct effect on pests, but these are not the only roles of GLVs. These volatiles, being probably one of the fastest weapons exploited, are also able to directly elicit or prime plant defense responses. Moreover, GLVs, via crosstalk with phytohormones, mostly JA, can influence the outcome of the plant's defense response against pathogens. For all these reasons GLVs should be considered as co-protagonists in the play between plants and their attackers. PMID:23999587

Scala, Alessandra; Allmann, Silke; Mirabella, Rossana; Haring, Michel A; Schuurink, Robert C

2013-08-30

397

Ctf1, a transcriptional activator of cutinase and lipase genes in Fusarium oxysporum is dispensable for virulence.  

PubMed

Cutinolytic enzymes are secreted by fungal pathogens attacking the aerial parts of the plant, to facilitate penetration of the outermost cuticular barrier of the host. The role of cutinases in soil-borne root pathogens has not been studied thus far. Here we report the characterization of the zinc finger transcription factor Ctf1 from the vascular wilt fungus Fusarium oxysporum, a functional orthologue of CTF1alpha that controls expression of cutinase genes and virulence in the pea stem pathogen Fusarium solani f. sp. pisi. Mutants carrying a Deltactf1 loss-of-function allele grown on inducing substrates failed to activate extracellular cutinolytic activity and expression of the cut1 and lip1 genes, encoding a putative cutinase and lipase, respectively, whereas strains harbouring a ctf1(C) allele in which the ctf1 coding region was fused to the strong constitutive Aspergillus nidulans gpdA promoter showed increased induction of cutinase activity and gene expression. These results suggest that F. oxysporum Ctf1 mediates expression of genes involved in fatty acid hydrolysis. However, expression of lip1 during root infection was not dependent on Ctf1, and virulence of the ctf1 mutants on tomato plants and fruits was indistinguishable from that of the wild-type. Thus, in contrast to the stem pathogen F. solani, Ctf1 is not essential for virulence in the root pathogen F. oxysporum. PMID:18705871

Rocha, Ana Lilia Martínez; Di Pietro, Antonio; Ruiz-Roldán, Carmen; Roncero, M Isabel G

2008-05-01

398

Environmental conditions that contribute to development and severity of Sugar Beet Fusarium Yellows caused by Fusarium oxysporum f. sp. betae: temperature  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium yellows in sugar beet, caused by Fusarium oxysporum f. sp. betae, continues to cause significant problems to sugar beet production by causing considerable reductions in root yield, sucrose percentage, and juice purity in affected sugar beets. Environment plays a critical role in pathogen i...

399

Making a Protein Extract from Plant Pathogenic Fungi for Gel- and LC-Based Proteomics.  

PubMed

Proteomic technologies have become a successful tool to provide relevant information on fungal biology. In the case of plant pathogenic fungi, this approach would allow a deeper knowledge of the interaction and the biological cycle of the pathogen, as well as the identification of pathogenicity and virulence factors. These two elements open up new possibilities for crop disease diagnosis and environment-friendly crop protection. Phytopathogenic fungi, due to its particular cellular characteristics, can be considered as a recalcitrant biological material, which makes it difficult to obtain quality protein samples for proteomic analysis. This chapter focuses on protein extraction for gel- and LC-based proteomics with specific protocols of our current research with Botrytis cinerea. PMID:24136517

Fernández, Raquel González; Redondo, Inmaculada; Jorrin-Novo, Jesus V

2014-01-01

400

Characterization of disease resistance gene candidates of the nucleotide binding site (NBS) type from banana and correlation of a transcriptional polymorphism with resistance to Fusarium oxysporum f.sp. cubense race 4  

Microsoft Academic Search

Most plant disease resistance (R) genes encode proteins with a nucleotide binding site and leucine-rich repeat structure (NBS-LRR).\\u000a In this study, degenerate primers were used to amplify genomic NBS-type sequences from wild banana (Musa acuminata ssp. malaccensis) plants resistant to the fungal pathogen Fusarium oxysporum formae specialis (f. sp.) cubense (FOC) race 4. Five different classes of NBS-type sequences were

Santy Peraza-Echeverria; James L. Dale; Rob M. Harding; Mike K. Smith; Chris Collet

2008-01-01

401

Functional characterization and gene expression profiling of superoxide dismutase from plant pathogenic phytoplasma.  

PubMed

The rapid production of huge amounts of reactive oxygen species (ROS) is one of the responses of animal and plant cells induced under stress conditions, such as pathogenic bacterial infection. To protect against the cytotoxic ROS, it is important for pathogenic bacteria to inactivate ROS by employing their antioxidant enzymes like superoxide dismutase (SOD). Here, we cloned and characterized the sodA gene from the plant pathogenic bacterium, 'Candidatus Phytoplasma asteris' OY-W strain. This is the first description of gene expression and antioxidant enzymatic activity of SOD from a phytoplasma. We also demonstrated the sodA gene product (OY-SOD) functions as Mn-type SOD. Since other Mollicutes bacteria such as mycoplasmas do not possess sodA probably due to reductive evolution, it is intriguing that phytoplasmas possess sodA despite their lack of many metabolic genes, suggesting that OY-SOD may play an important role in the phytoplasma colonization of plants and insects. Moreover, Western blot analysis and real-time PCR revealed that OY-SOD is expressed when the phytoplasma is grown in both plant and insect hosts, suggesting it is functioning in both hosts. Possible role of SOD in protection against damage by host-derived ROS is discussed. PMID:22982017

Miura, Chihiro; Sugawara, Kyoko; Neriya, Yutaro; Minato, Nami; Keima, Takuya; Himeno, Misako; Maejima, Kensaku; Komatsu, Ken; Yamaji, Yasuyuki; Oshima, Kenro; Namba, Shigetou

2012-09-08

402

The life history of the plant pathogen Pseudomonas syringae is linked to the water cycle.  

PubMed

Pseudomonas syringae is a plant pathogen well known for its capacity to grow epiphytically on diverse plants and for its ice-nucleation activity. The ensemble of its known biology and ecology led us to postulate that this bacterium is also present in non-agricultural habitats, particularly those associated with water. Here, we report the abundance of P. syringae in rain, snow, alpine streams and lakes and in wild plants, in addition to the previously reported abundance in epilithic biofilms. Each of these substrates harbored strains that corresponded to P. syringae in terms of biochemical traits, pathogenicity and pathogenicity-related factors and that were ice-nucleation active. Phylogenetic comparisons of sequences of four housekeeping genes of the non-agricultural strains with strains of P. syringae from disease epidemics confirmed their identity as P. syringae. Moreover, strains belonging to the same clonal lineage were isolated from snow, irrigation water and a diseased crop plant. Our data suggest that the different substrates harboring P. syringae modify the structure of the associated populations. Here, we propose a comprehensive life cycle for P. syringae--in agricultural and non-agricultural habitats--driven by the environmental cycle of water. This cycle opens the opportunity to evaluate the importance of non-agricultural habitats in the evolution of a plant pathogen and the emergence of virulence. The ice-nucleation activity of all strains from snow, unlike from other substrates, strongly suggests that P. syringae plays an active role in the water cycle as an ice nucleus in clouds. PMID:18185595

Morris, Cindy E; Sands, David C; Vinatzer, Boris A; Glaux, Catherine; Guilbaud, Caroline; Buffičre, Alain; Yan, Shuangchun; Dominguez, Hélčne; Thompson, Brian M

2008-01-10

403

Biological control of alligatorweed ( Alternanthera philoxeroides ) with a Fusarium sp  

Microsoft Academic Search

Alligatorweed (Alternanthera philoxeroidesG.) has become a serious weed in different crops in China. A fungal pathogen was found in Chongqing and Sichuan Provinces and was identified as a species in the Fusarium genus. The fungus produced macroconidia and chlamydospores abundantly on potato sucrose agar (PSA) plates. The bestconidial production and germination and colonygrowth of Fusarium sp. were at 23–31°C and

W. Z. Tan; Q. J. Li; L. Qing

2002-01-01

404

New species of Fusarium associated with dieback of Spartina alterniflora in Atlantic salt marshes.  

PubMed

Sudden vegetation dieback (SVD) is the loss of smooth cordgrass (Spartina alterniflora) along intertidal creeks in salt marshes of the Atlantic and Gulf states. The underlying cause of SVD remains unclear, but earlier work suggested a contributing role for Fusarium spp. in Louisiana. This report investigated whether these or other Fusarium species were associated with S. alterniflora dieback in mid- to north-Atlantic states. Isolations from seven SVD sites yielded 192 isolates of Fusarium spp., with more than 75% isolated from aboveground tissue. Most isolates (88%) fell into two undescribed morphospecies (MS) distinguished from each other by macroconidial shape, phialide ontogeny and growth rates. Pathogenicity tests on wound-inoculated S. alterniflora stems and seedling roots revealed that isolates in MS1 were more virulent than those in MS2 but no single isolate caused plant mortality. No matches to known species of Fusarium were revealed by DNA sequence queries of translation elongation factor 1-? (tef1) sequences. A phylogenetic analysis of partial sequences of three genes, ?-tubulin (?-tub), calmodulin (cal) and tef1, was conducted on representative isolates from MS1 (n = 20) and MS2 (n = 18); it provided strong evidence that the MS1 isolates form a clade that represents a heretofore undescribed species, which we designate Fusarium palustre sp. nov. Isolates from the more variable MS2 clustered with the F. incarnatum-equiseti species complex as F. cf. incarnatum. Although a strong association exists between both species and declining S. alterniflora in SVD sites, neither appears to play a primary causal role in SVD. However, our findings suggest that F. palustre might play an important secondary role in the ecological disruption of the salt marshes. PMID:21471289

Elmer, Wade H; Marra, Robert E

2011-04-06

405

Presence of pathogenic amoebae in power plant cooling waters. Final report, October 15, 1977September 30, 1979. [Naegleria fowleri  

Microsoft Academic Search

Cooling-water-associated algae and sediments from five northern and five southern or western electric power plants were tested for the presence of pathogenic amoebae. In addition, water algae and sediments from five northern and five southern\\/western sites not associated with power plants were tested. There was a significant correlation at northern power plants between the presence of thermophilic, pathogenic amoebae in

R. L. Tyndall; E. Willaert; A. R. Stevens

1981-01-01

406

Functional identification of high-affinity iron permeases from Fusarium graminearum  

Microsoft Academic Search

The ScFTR1 gene encodes an iron permease in Saccharomyces cerevisiae. Its homologues, FgFtr1 and FgFtr2, were identified from filamentous pathogenic plant fungus, Fusarium graminearum. Homologies between the deduced amino acid sequences of ScFtr1p and FgFtr1 and FgFtr2 were 56 and 54%, respectively, and both had REXXE sequences, which form the conserved amino acid sequence of ScFtr1p. FgFtr1 expression increased under

Yong-Sung Park; Il-Dong Choi; Chang-Min Kang; Mun-Sik Ham; Ji-Hyun Kim; Tae-Hyoung Kim; Sung-Hwan Yun; Yin-Won Lee; Hyo-Ihl Chang; Ha-Chin Sung; Cheol-Won Yun

2006-01-01

407

A Conserved Homeobox Transcription Factor Htf1 Is Required for Phialide Development and Conidiogenesis in Fusarium Species  

PubMed Central

Conidia are primary means of asexual reproduction and dispersal in a variety of pathogenic fungi, and it is widely recognized that they play a critical role in animal and plant disease epidemics. However, genetic mechanisms associated with conidiogenesis are complex and remain largely undefined in numerous pathogenic fungi. We previously showed that Htf1, a homeobox transcription factor, is required for conidiogenesis in the rice pathogen Magnaporthe oryzae. In this study, our aim was to characterize how Htf1 homolog regulates common and also distinctive conidiogenesis in three key Fusarium pathogens: F. graminearm, F. verticillioides, and F. oxysporum. When compared to wild-type progenitors, the gene-deletion mutants in Fusarium species failed to form conventional phialides. Rather, they formed clusters of aberrant phialides that resembled elongated hyphae segments, and it is conceivable that this led to the obstruction of conidiation in phialides. We also observed that mutants, as well as wild-type Fusaria, can initiate alternative macroconidia production directly from hyphae through budding-like mechanism albeit at low frequencies. Microscopic observations led us to conclude that proper basal cell division and subsequent foot cell development of macroconidia were negatively impacted in the mutants. In F. verticillioides and F. oxysporum, mutants exhibited a 2- to 5- microconidia complex at the apex of monophialides resulting in a floral petal-like shape. Also, prototypical microconidia chains were absent in F. verticillioides mutants. F. graminearum and F. verticillioides mutants were complemented by introducing its native HTF1 gene or homologs from other Fusarium species. These results suggest that Fusarium Htf1 is functionally conserved homeobox transcription factor that regulates phialide development and conidiogenesis via distinct signaling pathways yet to be characterized in fungi.

Zheng, Wenhui; Zhao, Xu; Xie, Qiurong; Huang, Qingping; Zhang, Chengkang; Zhai, Huanchen; Xu, Liping; Lu, Guodong; Shim, Won-Bo; Wang, Zonghua

2012-01-01

408

Disseminated Fusarium originating from toenail paronychia in a neutropenic patient  

PubMed Central

Fusarium is a saprophytic organism that is found widely distributed in soil, subterranean and aerial plants, plant debris and other organic substrates. The organism can cause local tissue infections in immunocompetent patients such as onychomycosis, bone and joint infections, or sinusitis. Since the first case of disseminated Fusarium was described, the incidence of disseminated disease has increased significantly, particularly affecting those immunocompromised with hematological malignancies. We report here a 38 year-old hospitalized male with newly diagnosed acute myelogenous leukemia (AML) who developed disseminated Fusarium infection, originating from a toenail paronychia, in the setting of neutropenia. Pathological diagnosis of Fusarium is difficult because the septate hyphae of Fusarium are difficult to distinguish from Aspergillus, which has a more favorable outcome. Cultures of potential sources of infection, as well as tissue cultures, are essential in identifying the organism and initiating early aggressive therapy.

Bourgeois, Greg P.; Cafardi, Jennifer A.; Sellheyer, Klaus; Andea, Aleodor A.

2010-01-01

409

The effects of microgravity and clinorotation on the interaction of plant cells with fungal pathogen  

NASA Astrophysics Data System (ADS)

The influence of microgravity and slow horizontal clinorotation (2 rev/min), which partly mimics microgravity, on the interaction of plant cells of soybean roots to Phytophthora sojae and of potato minitubers to Phytophthora infestans was studied during the Space Shuttle Mission STS-87 and during clinorotation. Seedlings of soybean cultivar Williams 82 grown in spaceflight and at 1 g were untreated or inoculated with pathogen P. sojae; minitubers of potato (cv Adreta) grown at horizontal clinorotation and the vertical control also were untreated or inoculated with pathogen P. infestans. The methods of light microscopy, scanning and transmission electron microscopy, confocal microscopy and also cytochemistry for the determination of callose content and peroxydase activity were used in the experiments. Post-landing analysis of the meristem cells of soybean roots infected with P. sojae and post-clinorotation analysis of the parenchyma cells of potato minitubers cells infected with P. infestans showed more destroying symptoms in cells of plant-host, which were more extensive colonized relative to the controls exposed to the pathogen fungus. Infected cells of plants-host were divided in two types: cells of first type were completely destroyed and hyphae of pathogen fungus were into these cells or in intercellular spaces; cells of second type characterized by partly changed ultrastructure and a calcium sites were contained above in mentioned cells. These data suggest that root cells of soybean seedlings grown in microgravity and cells of potato minitubers grown at slow horizontal clinorotation are more susceptible to penetration of a fungal pathogen in comparison with the corresponding controls.

Nedukha, O.; Kordyum, E.; Leach, J.; Martyn, G.; Ryba-White, M.

410

Regeneration of flax ( Linum usitatissimum L.) plants from anther culture and somatic tissue with increased resistance to Fusarium oxysporum  

Microsoft Academic Search

The aim of this study was to establish a protocol for the efficient production of flax plants of microspore origin. The results were compared to those obtained for plants regenerated from somatic explants from hypocotyls, cotyledons, leaves, stems and roots. All the plants obtained during the experiments were regenerated from callus that was grown for periods from a few weeks

I. Rutkowska-Krause; G. Mankowska; M. Lukaszewicz; J. Szopa

2003-01-01

411

Insights from the genome of the biotrophic fungal plant pathogen Ustilago maydis.  

PubMed

Ustilago maydis is a ubiquitous pathogen of maize and a well-established model organism for the study of plant-microbe interactions. This basidiomycete fungus does not use aggressive virulence strategies to kill its host. U. maydis belongs to the group of biotrophic parasites (the smuts) that depend on living tissue for proliferation and development. Here we report the genome sequence for a member of this economically important group of biotrophic fungi. The 20.5-million-base U. maydis genome assembly contains 6,902 predicted protein-encoding genes and lacks pathogenicity signatures found in the genomes of aggressive pathogenic fungi, for example a battery of cell-wall-degrading enzymes. However, we detected unexpected genomic features responsible for the pathogenicity of this organism. Specifically, we found 12 clusters of genes encoding small secreted proteins with unknown function. A significant fraction of these genes exists in small gene families. Expression analysis showed that most of the genes contained in these clusters are regulated together and induced in infected tissue. Deletion of individual clusters altered the virulence of U. maydis in five cases, ranging from a complete lack of symptoms to hypervirulence. Despite years of research into the mechanism of pathogenicity in U. maydis, no 'true' virulence factors had been previously identified. Thus, the discovery of the secreted protein gene clusters and the functional demonstration of their decisive role in the infection process illuminate previously unknown mechanisms of pathogenicity operating in biotrophic fungi. Genomic analysis is, similarly, likely to open up new avenues for the discovery of virulence determinants in other pathogens. PMID:17080091

Kämper, Jörg; Kahmann, Regine; Bölker, Michael; Ma, Li-Jun; Brefort, Thomas; Saville, Barry J; Banuett, Flora; Kronstad, James W; Gold, Scott E; Müller, Olaf; Perlin, Michael H; Wösten, Han A B; de Vries, Ronald; Ruiz-Herrera, José; Reynaga-Peńa, Cristina G; Snetselaar, Karen; McCann, Michael; Pérez-Martín, José; Feldbrügge, Michael; Basse, Christoph W; Steinberg, Gero; Ibeas, Jose I; Holloman, William; Guzman, Plinio; Farman, Mark; Stajich, Jason E; Sentandreu, Rafael; González-Prieto, Juan M; Kennell, John C; Molina, Lazaro; Schirawski, Jan; Mendoza-Mendoza, Artemio; Greilinger, Doris; Münch, Karin; Rössel, Nicole; Scherer, Mario; Vranes, Miroslav; Ladendorf, Oliver; Vincon, Volker; Fuchs, Uta; Sandrock, Björn; Meng, Shaowu; Ho, Eric C H; Cahill, Matt J; Boyce, Kylie J; Klose, Jana; Klosterman, Steven J; Deelstra, Heine J; Ortiz-Castellanos, Lucila; Li, Weixi; Sanchez-Alonso, Patricia; Schreier, Peter H; Häuser-Hahn, Isolde; Vaupel, Martin; Koopmann, Edda; Friedrich, Gabi; Voss, Hartmut; Schlüter, Thomas; Margolis, Jonathan; Platt, Darren; Swimmer, Candace; Gnirke, Andreas; Chen, Feng; Vysotskaia, Valentina; Mannhaupt, Gertrud; Güldener, Ulrich; Münsterkötter, Martin; Haase, Dirk; Oesterheld, Matthias; Mewes, Hans-Werner; Mauceli, Evan W; DeCaprio, David; Wade, Claire M; Butler, Jonathan; Young, Sarah; Jaffe, David B; Calvo, Sarah; Nusbaum, Chad; Galagan, James; Birren, Bruce W

2006-11-01

412

A soybean cyst nematode resistance gene points to a new mechanism of plant resistance to pathogens.  

PubMed

Soybean (Glycine max (L.) Merr.) is an important crop that provides a sustainable source of protein and oil worldwide. Soybean cyst nematode (Heterodera glycines Ichinohe) is a microscopic roundworm that feeds on the roots of soybean and is a major constraint to soybean production. This nematode causes more than US$1 billion in yield losses annually in the United States alone, making it the most economically important pathogen on soybean. Although planting of resistant cultivars forms the core management strategy for this pathogen, nothing is known about the nature of resistance. Moreover, the increase in virulent populations of this parasite on most known resistance sources necessitates the development of novel approaches for control. Here we report the map-based cloning of a gene at the Rhg4 (for resistance to Heterodera glycines 4) locus, a major quantitative trait locus contributing to resistance to this pathogen. Mutation analysis, gene silencing and transgenic complementation confirm that the gene confers resistance. The gene encodes a serine hydroxymethyltransferase, an enzyme that is ubiquitous in nature and structurally conserved across kingdoms. The enzyme is responsible for interconversion of serine and glycine and is essential for cellular one-carbon metabolism. Alleles of Rhg4 conferring resistance or susceptibility differ by two genetic polymorphisms that alter a key regulatory property of the enzyme. Our discovery reveals an unprecedented plant resistance mechanism against a pathogen. The mechanistic knowledge of the resistance gene can be readily exploited to improve nematode resistance of soybean, an increasingly important global crop. PMID:23235880

Liu, Shiming; Kandoth, Pramod K; Warren, Samantha D; Yeckel, Greg; Heinz, Robert; Alden, John; Yang, Chunling; Jamai, Aziz; El-Mellouki, Tarik; Juvale, Parijat S; Hill, John; Baum, Thomas J; Cianzio, Silvia; Whitham, Steven A; Korkin, Dmitry; Mitchum, Melissa G; Meksem, Khalid

2012-10-15

413

GENETIC DIVERSITY OF HUMAN PATHOGENIC MEMBERS OF THE FUSARIUM OXYSPORUM COMPLEX INFERRED FROM GENE GENALOGIES & AFLP ANALYSES: EVIDENCE FOR THE RECENT DISPERSION OF A GEOGRAPHICALLY WIDESPREAD CLONAL LINEAGE & NOSOCOMIAL ORIG  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium oxysporum is a phylogenetically diverse monophyletic complex of filamentous ascomycetous fungi responsible for localized and systemic life-threatening opportunistic infections, respectively, in immunocompetent and severely neutropenic patients. Although members of this complex were isolate...

414

Note : In vitro antagonism of actinomycetes isolated from fungus-growing ants against plant pathogenic fungi  

Microsoft Academic Search

Fungus-growing ants have been found recently to be symbiotic with actinomycetes living on the ant’s cuticle; these bacteria\\u000a are inhibitory to soil fungi that are detrimental to the ants’ fungus gardens. In order to investigate whether actinomycetes\\u000a found on the cuticle of attine ants also had inhibitory properties against plant pathogenic fungi, we isolated 32 strains\\u000a of actinomycetes from fungus-growing

S. R. Sánchez-Peńa; M. R. Sánchez-Ovalle; Gabriel Gallegos-Morales; Abiel Sánchez-Arizpe

2008-01-01

415

Antimicrobial activities of extracts from Indo-Pacific marine plants against marine pathogens and saprophytes  

Microsoft Academic Search

This study is the second of two surveys designed to systematically screen extracts from marine plants for antimicrobial effects\\u000a against ecologically relevant marine microorganisms, and to compare results on a geographical basis. In the preceding survey,\\u000a extracts from tropical Atlantic marine algae and seagrasses were screened in growth inhibition assays against the pathogenic\\u000a fungus Lindra thalassiae, the saprophytic fungus Dendryphiella

Melany P. Puglisi; Sebastian Engel; Paul R. Jensen; William Fenical

2007-01-01

416

Agrobacterium tumefaciens -mediated transformation of the plant pathogenic fungus Rosellinia necatrix  

Microsoft Academic Search

Rosellinia necatrix is a soil-borne root pathogen affecting a wide range of commercially important plant species. The mycelium of R. necatrix was transformed to hygromycin B resistance by an Agrobacterium tumefaciens-mediated transformation system using a binary plasmid vector containing the hygromycin B phosphotransferase (hph) gene controlled by the heterologous fungal Aspergillus nidulans P-gpd (glyceraldehyde 3-phosphate dehydrogenase) promoter and the trpC

Sanae Kano; Takuma Kurita; Satoko Kanematsu; Tsutomu Morinaga

2011-01-01

417

Development and evaluation of a TaqMan Real-Time PCR assay for Fusarium oxysporum f. sp. spinaciae  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium oxysporum f. sp. spinaciae, causal agent of spinach Fusarium wilt, is an important soilborne pathogen in many areas of the world where spinach is grown. The pathogen is persistent in acid soils of maritime western Oregon and Washington, the only region of the USA suitable for commercial spi...

418

The threat of plant pathogens as weapons against U.S. crops.  

PubMed

The U.S. National Research Council (NRC) concluded in 2002 that U.S. agriculture is vulnerable to attack and that the country has inadequate plans for dealing with agricultural bioterrorism. This article addresses the vulnerability of U.S. crops to attack from biological weapons by reviewing the costs and impact of plant diseases on crops, pointing out the difficulty in preventing deliberate introduction of pathogens and discovering new disease outbreaks quickly, and discussing why a plant pathogen might be chosen as a biological weapon. To put the threat into context, a brief historical review of anti-crop biological weapons programs is given. The argument is made that the country can become much better prepared to counter bioterrorism by developing a list of likely anti-crop threat agents, or categories of agents, that is based on a formal risk analysis; making structural changes to the plant protection system, such as expanding diagnostic laboratories, networking the laboratories in a national system, and educating first responders; and by increasing our understanding of the molecular biology and epidemiology of threat agents, which could lead to improved disease control, faster and more sensitive diagnostic methods, and predictions of disease invasion, persistence, and spread following pathogen introduction. PMID:12730385

Madden, L V; Wheelis, M

2003-04-18

419

A bacterial sensor of plant cell contact controls the transcriptional induction of Ralstonia solanacearum pathogenicity genes  

PubMed Central

The hrp genes of the plant pathogen Ralstonia solanacearum are key pathogenicity determinants; they encode a type III protein secretion machinery involved in the secretion of mediators of the bacterium–plant interaction. These hrp genes are under the genetic control of the hrpB regulatory gene, expression of which is induced when bacteria are co-cultivated with plant cell suspensions. In this study, we used hrp–gfp transcriptional fusions to demonstrate that the expression of the hrpB and type III secretion genes is specifically induced in response to the bacterium–plant cell contact. This contact-dependent induction of hrpB gene expression requires the outer membrane protein PrhA, but not a functional type III secretion apparatus. Genetic evidence indicates that PrhA constitutes the first example of a bacterial receptor for a non-diffusible signal present in the plant cell wall and which triggers the transcriptional activation of bacterial virulence genes.

Aldon, Didier; Brito, Belen; Boucher, Christian; Genin, Stephane

2000-01-01

420

The Plant Pathogen Pseudomonas syringae pv. tomato Is Genetically Monomorphic and under Strong Selection to Evade Tomato Immunity  

Microsoft Academic Search

Recently, genome sequencing of many isolates of genetically monomorphic bacterial human pathogens has given new insights into pathogen microevolution and phylogeography. Here, we report a genome-based micro-evolutionary study of a bacterial plant pathogen, Pseudomonas syringae pv. tomato. Only 267 mutations were identified between five sequenced isolates in 3,543,009 nt of analyzed genome sequence, which suggests a recent evolutionary origin of

Rongman Cai; James Lewis; Shuangchun Yan; Haijie Liu; Christopher R. Clarke; Francesco Campanile; Nalvo F. Almeida; David J. Studholme; Magdalen Lindeberg; David Schneider; Massimo Zaccardelli; Joao C. Setubal; Nadia P. Morales-Lizcano; Adriana Bernal; Gitta Coaker; Christy Baker; Carol L. Bender; Scotland Leman; Boris A. Vinatzer

2011-01-01