Dataset Information

The NADPH oxidase Cpnox1 is required for full pathogenicity of the ergot fungus Claviceps purpurea.

ABSTRACT: The role of reactive oxygen species (ROS) in interactions between phytopathogenic fungi and their hosts is well established. An oxidative burst mainly caused by superoxide formation by membrane-associated NADPH oxidases is an essential element of plant defence reactions. Apart from primary effects, ROS play a major role as a second messenger in host response. Recently, NADPH oxidase (nox)-encoding genes have been identified in filamentous fungi. Functional analyses have shown that these fungal enzymes are involved in sexual differentiation, and there is growing evidence that they also affect developmental programmes involved in fungus-plant interactions. Here we show that in the biotrophic plant pathogen Claviceps purpurea deletion of the cpnox1 gene, probably encoding an NADPH oxidase, has impact on germination of conidia and pathogenicity: Deltacpnox1 mutants can penetrate the host epidermis, but they are impaired in colonization of the plant ovarian tissue. In the few cases where macroscopic signs of infection (honeydew) appear, they are extremely delayed and fully developed sclerotia have never been observed. C. purpurea Nox1 is important for the interaction with its host, probably by directly affecting pathogenic differentiation of the fungus.

SUBMITTER: Giesbert S

PROVIDER: S-EPMC6640299 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The NADPH oxidase Cpnox1 is required for full pathogenicity of the ergot fungus Claviceps purpurea.

Giesbert Sabine S Schürg Timo T Scheele Sandra S Tudzynski Paul P

Molecular plant pathology 20080501 3

The role of reactive oxygen species (ROS) in interactions between phytopathogenic fungi and their hosts is well established. An oxidative burst mainly caused by superoxide formation by membrane-associated NADPH oxidases is an essential element of plant defence reactions. Apart from primary effects, ROS play a major role as a second messenger in host response. Recently, NADPH oxidase (nox)-encoding genes have been identified in filamentous fungi. Functional analyses have shown that these fungal e ...[more]

PMID: 18705873

Similar Datasets

Project description:Abstract The ergot diseases of agricultural and nonagricultural grasses are caused by the infection of Claviceps spp. (Hypocreales, Ascomycota) on florets, producing dark spur?like sclerotia on spikes that are toxic to humans and animals, leading to detrimental impacts on agriculture and economy due to the downgrading of cereal grains, import–export barriers, reduced yield, and ecological concerns. At least seven phylogenetic lineages (phylogenetic species) were identified within the premolecular concept of C. purpurea s.l. (sensu lato) in agricultural areas and vicinities in Canada and the Western United States. Claviceps purpurea s.s (sensu stricto) remained as the most prevalent species with a wide host range, including cereal crops, native, invasive, and weedy grasses. The knowledge on genetic diversity and distribution of C. purpurea s.s. in North America is lacking. The objective of the present study was to shed light on genetic differentiation and evolution of the natural populations of C. purpurea s.s. Multilocus DNA sequences of samples from Canada and the Western USA were analyzed using a phylogenetic network approach, and population demographic parameters were investigated. Results showed that three distinct genetically subdivided populations exist, and the subdivision is not correlated with geographic or host differentiations. Potential intrinsic mechanisms that might play roles in leading to the cessation of gene flows among the subpopulations, that is, mating and/or vegetative incompatibility, genomic adaptation, were discussed. The neutrality of two house?keeping genes that are widely used for DNA barcoding, that is, translation elongation factor 1?? (TEF1??) and RNA polymerase II second largest subunit (RPB2), was challenged and discussed. Regardless of the frequent sexuality and multiple modes of dispersal, the population of the toxigenic plant pathogen, Claviceps purpurea, that infects wide range of agricultural and nonagricultural grasses, was subdivided in nature. The population structure shed light on the underline mechanisms that might have led to the cessation of gene flow among subdivided populations. House?keeping gene markers were not neutral in certain circumstances.

Project description:BackgroundErgot, caused by the fungal pathogen Claviceps purpurea, infects the female flowers of a range of cereal crops, including wheat. To understand the interaction between C. purpurea and hexaploid wheat we undertook an extensive examination of the reprogramming of the wheat transcriptome in response to C. purpurea infection through floral tissues (i.e. the stigma, transmitting and base ovule tissues of the ovary) and over time.ResultsC. purpurea hyphae were observed to have grown into and down the stigma at 24 h (H) after inoculation. By 48H hyphae had grown through the transmitting tissue into the base, while by 72H hyphae had surrounded the ovule. By 5 days (D) the ovule had been replaced by fungal tissue. Differential gene expression was first observed at 1H in the stigma tissue. Many of the wheat genes differentially transcribed in response to C. purpurea infection were associated with plant hormones and included the ethylene (ET), auxin, cytokinin, gibberellic acid (GA), salicylic acid and jasmonic acid (JA) biosynthetic and signaling pathways. Hormone-associated genes were first detected in the stigma and base tissues at 24H, but not in the transmitting tissue. Genes associated with GA and JA pathways were seen in the stigma at 24H, while JA and ET-associated genes were identified in the base at 24H. In addition, several defence-related genes were differential expressed in response to C. purpurea infection, including antifungal proteins, endocytosis/exocytosis-related proteins, NBS-LRR class proteins, genes involved in programmed cell death, receptor protein kinases and transcription factors. Of particular interest was the identification of differential expression of wheat genes in the base tissue well before the appearance of fungal hyphae, suggesting that a mobile signal, either pathogen or plant-derived, is delivered to the base prior to colonisation.ConclusionsMultiple host hormone biosynthesis and signalling pathways were significantly perturbed from an early stage in the wheat - C. purpurea interaction. Differential gene expression at the base of the ovary, ahead of arrival of the pathogen, indicated the potential presence of a long-distance signal modifying host gene expression.

Dataset Information

The NADPH oxidase Cpnox1 is required for full pathogenicity of the ergot fungus Claviceps purpurea.

Publications

The NADPH oxidase Cpnox1 is required for full pathogenicity of the ergot fungus Claviceps purpurea.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets