Mechanisms in Growth-Promoting of Cucumber by the Endophytic Fungus Strain ND35.

Endophytic fungi are effective in plant growth and development by secreting various kinds of plant hormones and nutrients. However, the cellular and molecular interactions between the endophytic fungi and plant growth-promoting have remained less explored. The present study was designed to explore the effects of the infection and colonization events of strain ND35 on cucumber growth and the expression pattern of some metabolically important genes in development of the cucumber radicle.

Small One-Helix Proteins Are Essential for Photosynthesis in Arabidopsis.

The extended superfamily of chlorophyll binding proteins comprises the Light-Harvesting Complex Proteins (LHCs), the Early Light-Induced Proteins (ELIPs) and the Photosystem II Subunit S (PSBS). The proteins of the ELIP family were proposed to function in photoprotection or assembly of thylakoid pigment-protein complexes and are further divided into subgroups with one to three transmembrane helices. Two small One-Helix Proteins (OHPs) are expressed constitutively in green plant tissues and their levels increase in response to light stress.

Altered levels of LIL3 isoforms in Arabidopsis lead to disturbed pigment-protein assembly and chlorophyll synthesis, chlorotic phenotype and impaired photosynthetic performance.

Light-harvesting complex (LHC)-like (LIL) proteins contain two transmembrane helices of which the first bears a chlorophyll (Chl)-binding motif. They are widespread in photosynthetic organisms, but almost nothing is known about their expression and physiological functions. We show that two LIL3 paralogues (LIL3:1 and LIL3:2) in Arabidopsis thaliana are expressed in photosynthetically active tissues and their expression is differentially influenced by light stress.

The haustorial transcriptomes of Uromyces appendiculatus and Phakopsora pachyrhizi and their candidate effector families.

Haustoria of biotrophic rust fungi are responsible for the uptake of nutrients from their hosts and for the production of secreted proteins, known as effectors, which modulate the host immune system. The identification of the transcriptome of haustoria and an understanding of the functions of expressed genes therefore hold essential keys for the elucidation of fungus-plant interactions and the development of novel fungal control strategies. Here, we purified haustoria from infected leaves and used 454 sequencing to examine the haustorial transcriptomes of Phakopsora pachyrhizi and Uromyces appendiculatus, the causal agents of soybean rust and common bean rust, respectively.

A novel structural effector from rust fungi is capable of fibril formation.

It has been reported that filament-forming surface proteins such as hydrophobins are important virulence determinants in fungi and are secreted during pathogenesis. Such proteins have not yet been identified in obligate biotrophic pathogens such as rust fungi. Rust transferred protein 1 (RTP1p), a rust protein that is transferred into the host cytoplasm, accumulates around the haustorial complex.

The rust transferred proteins-a new family of effector proteins exhibiting protease inhibitor function.

Only few fungal effectors have been described to be delivered into the host cell during obligate biotrophic interactions. RTP1p, from the rust fungi Uromyces fabae and U. striatus, was the first fungal protein for which localization within the host cytoplasm could be demonstrated directly.

Niche differentiation of two sympatric species of Microdochium colonizing the roots of common reed.

Background: Fungal endophyte communities are often comprised of many species colonizing the same host. However, little is known about the causes of this diversity. On the one hand, the apparent coexistence of closely related species may be explained by the traditional niche differentiation hypothesis, which suggests that abiotic and/or biotic factors mediate partitioning.

Immunolocalization of pathogen effectors.

The use of polyclonal antibodies enables the detection of proteins on a cellular and even subcellular level. Immunolocalization can be used on all pathosystems even if one or both partners of the interaction are unamenable to molecular tools like transformation. This chapter provides detailed information about how to obtain high quality antibodies, how to prepare samples, and finally how to detect the proteins.

Lack of evidence for a role of hydrophobins in conferring surface hydrophobicity to conidia and hyphae of Botrytis cinerea.

Background: Hydrophobins are small, cysteine rich, surface active proteins secreted by filamentous fungi, forming hydrophobic layers on the walls of aerial mycelia and spores. Hydrophobin mutants in a variety of fungi have been described to show 'easily wettable' phenotypes, indicating that hydrophobins play a general role in conferring surface hydrophobicity to aerial hyphae and spores.

Results: In the genome of the grey mould fungus Botrytis cinerea, genes encoding three hydrophobins and six hydrophobin-like proteins were identified.

The role of mitogen-activated protein (MAP) kinase signalling components and the Ste12 transcription factor in germination and pathogenicity of Botrytis cinerea.

In all fungi studied so far, mitogen-activated protein (MAP) kinase cascades serve as central signalling complexes that are involved in various aspects of growth, stress response and infection. In this work, putative components of the yeast Fus3/Kss1-type MAP kinase cascade and the putative downstream transcription factor Ste12 were analysed in the grey mould fungus Botrytis cinerea. Deletion mutants of the MAP triple kinase Ste11, the MAP kinase kinase Ste7 and the MAP kinase adaptor protein Ste50 all resulted in phenotypes similar to that of the previously described BMP1 MAP kinase mutant, namely defects in germination, delayed vegetative growth, reduced size of conidia, lack of sclerotia formation and loss of pathogenicity.

Host plant development, water level and water parameters shape Phragmites australis-associated oomycete communities and determine reed pathogen dynamics in a large lake.

In a 3-year-study, we analysed the population dynamics of the reed pathogen Pythium phragmitis and other reed-associated oomycetes colonizing fresh and dried reed leaves in the littoral zone of a large lake. Oomycete communities derived from internal transcribed spacer clone libraries were clearly differentiated according to substrate and seasonal influences. In fresh leaves, diverse communities consisting of P.

Different Resistance Mechanisms of Medicago truncatula Ecotypes Against the Rust Fungus Uromyces striatus.

ABSTRACT A pathosystem consisting of the model plant Medicago truncatula and the rust fungus Uromyces striatus was characterized. From a collection of 113 mostly European accessions of M. truncatula, the vast majority were found to be susceptible to U.

Colonization of barley roots by endophytic fungi and their reduction of take-all caused by Gaeumannomyces graminis var. tritici.

Fungal root endophytes obtained from natural vegetation were tested for antifungal activity in dual culture tests against the root pathogen Gaeumannomyces graminis var. tritici. Fifteen isolates, including Acremonium blochii, Acremonium furcatum, Aspergillus fumigatus, Cylindrocarpon sp.

Diversity, host, and habitat specificity of oomycete communities in declining reed stands (Phragmites australis) of a large freshwater lake.

We studied the diversity of oomycetes in a declining reed belt (Phragmites australis) of Lake Constance, Germany, using conventional baiting with specific reed and standard oak baits, accompanied by molecular techniques. Apart from an Aphanomyces sp. and a Phytophthora sp.

Cloning and characterization of a novel invertase from the obligate biotroph Uromyces fabae and analysis of expression patterns of host and pathogen invertases in the course of infection.

Invertases are key enzymes in carbon partitioning in higher plants. They gain additional importance in the distribution of carbohydrates in the event of wounding or pathogen attack. Although many researchers have found an increase in invertase activity upon infection, only a few studies were able to determine whether the source of this activity was host or parasite.

Volatiles modulate the development of plant pathogenic rust fungi.

Rust fungi are obligate biotrophic pathogens that differentiate a series of specialized cells to establish infection. One of these cells, the haustorium, which serves to absorb nutrients from living host cells, normally develops only in planta. Here, we show that the rust fungus Uromyces fabae (Pers.

Only a few fungal species dominate highly diverse mycofloras associated with the common reed.

Plants are naturally colonized by many fungal species that produce effects ranging from beneficial to pathogenic. However, how many of these fungi are linked with a single host plant has not been determined. Furthermore, the composition of plant-associated fungal communities has not been rigorously determined.

Pythium litorale sp. nov., a new species from the littoral of Lake Constance, Germany.

A description is given of Pythium litorale sp. nov., a new species from reed stands in Germany.

Pythium phragmitis sp. nov., a new species close to P. arrhenomanes as a pathogen of common reed (Phragmites australis).

During a study on the occurrence and pathogenicity of oomycetes in the reed-belt (Phragmites australis) of Lake Constance (Germany), a new Pythium resembling the important cereal pathogen species complex P. arrhenomanes/P. graminicola was consistently isolated from necrotic mature reed leaves and reed rhizosphere samples.

Identification of a protein from rust fungi transferred from haustoria into infected plant cells.

The formation of haustoria is one of the hallmarks of the interaction of obligate biotrophic fungi with their host plants. In addition to their role in nutrient uptake, it is hypothesized that haustoria are actively involved in establishing and maintaining the biotrophic relationship. We have identified a 24.

Microarray analysis of expressed sequence tags from haustoria of the rust fungus Uromyces fabae.

Rust fungi are plant parasites which colonise host tissue with an intercellular mycelium that forms haustoria within living plant cells. To identify genes expressed during biotrophic growth, EST sequencing was performed with a haustorium-specific cDNA library from Uromyces fabae. One thousand seventeen ESTs were generated, which assembled into 530 contigs.

Characterization of a novel NADP(+)-dependent D-arabitol dehydrogenase from the plant pathogen Uromyces fabae.

We have identified and characterized a novel NADP(+)-dependent D-arabitol dehydrogenase and the corresponding gene from the rust fungus Uromyces fabae, a biotrophic plant pathogen on broad bean (Vicia faba). The new enzyme was termed ARD1p (D-arabitol dehydrogenase 1). It recognizes D-arabitol and mannitol as substrates in the forward reaction, and D-xylulose, D-ribulose and D-fructose as substrates in the reverse reaction.

Possible roles for mannitol and mannitol dehydrogenase in the biotrophic plant pathogen Uromyces fabae.

Levels of the C6-polyol mannitol were observed to rise dramatically in the biotrophic interaction of the rust fungus Uromyces fabae and its host plant Vicia faba. Mannitol was found in millimolar concentrations in extracts and apoplastic fluids of infected leaves and also in extracts of spores. We suggest that this polyol might have at least a dual function: first, as a carbohydrate storage compound, and second, as a scavenger of reactive oxygen species.