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Plant pathogenic fungi colonizing living plant tissue secrete a cocktail of effector proteins to suppress plant immunity and reprogramme host cells. Although many of these effectors function inside host cells, delivery systems used by pathogenic bacteria to translocate effectors into host cells have not been detected in fungi. Here, we show that five unrelated effectors and two membrane proteins from Ustilago maydis, a biotrophic fungus causing smut disease in corn, form a stable protein complex. All seven genes appear co-regulated and are only expressed during colonization. Single mutants arrest in the epidermal layer, fail to suppress host defence responses and fail to induce non-host resistance, two reactions that likely depend on translocated effectors. The complex is anchored in the fungal membrane, protrudes into host cells and likely contacts channel-forming plant plasma membrane proteins. Constitutive expression of all seven complex members resulted in a surface-exposed form in cultured U. maydis cells. As orthologues of the complex-forming proteins are conserved in smut fungi, the complex may become an interesting fungicide target., This study reports that five effectors and two transmembrane proteins from the plant pathogenic fungus Ustilago maydis form a stable cell surface-exposed protein complex required for virulence.

Plastic pollution has become a serious issue on Earth. Although efficient industrial recycling processes exist, a significant fraction of plastic waste still ends up in nature, where it can endure for centuries. Slow mechanical and chemical decay lead to the formation of micro- and nanoplastics, which are washed from land into rivers and finally end up in the oceans. As such particles cannot be efficiently removed from the environment, biological degradation mechanisms are highly desirable. Several enzymes have been described that are capable of degrading certain plastic materials such as polyethylene terephthalate (PET). Such enzymes have a huge potential for future biotechnology applications. However, they require model systems that can be efficiently adapted to very specific conditions. Here, we present detailed instructions, how to convert the model diatom Phaeodactylum into a solar-fueled microbial cell factory for PETase expression, resulting in a whole cell catalyst for PET degradation at moderate temperatures under saltwater conditions.

The present paper analyses the community structure of ectomycorrhiza (ECM) and arbuscular mycorrhiza (AM) fungi associated with seven different poplar clone types growing in a patch system on soil from four different former land use types, originating from spruce forest, poplar stand, grassland and cornfield. We determined the extent to which ECM and AM play a role on the studied factors (genotype, former land use type and host growth). The diversity of ECM and AM fungal communities was estimated by morphological and molecular analyses of the 18S and ITS of the rDNA genes. Fifteen ECM fungal taxa and four AM groups were distinguished in the roots of the poplars grown for 18 months on soil originating from the respective land use types. The poplar clones showed significantly different rates of shoot length and AM colonization, especially concerning the occurrence of Glomus intraradices and Scutellospora sp. Populus deltoides had significantly higher Scutellospora sp. abundance. Although ECM abundance and diversity was high, no significant differences between the different land use types was found. However, some ECM fungi like Paxillus involutus, Laccaria proxima and Laccaria tortilis showed significant preferences for specific land use types. Our findings suggest that both factors, former land use type and poplar genotype, are important determinants of mycorrhizal colonization of the host plants.

Tomato (Solanum lycopersicum L.) roots from four different crop sites in Colombia were surface sterilized and 51 fungal isolates were obtained and conserved for further analysis. Based on microscopical observations and growth characteristics, 20 fungal isolates corresponded to genus Fusarium, six presented asexual conidia different from Fusarium, eight were sterile mycelia, seven of which had dark septate hyphae and 17 did not continue to grow on plates after being recovered from conservation. Growth on different media, detailed morphological characterization and ITS region sequencing of the six sporulating and eight sterile isolates revealed that they belonged to different orders of Ascomycota and that the sterile dark septate endophytes did not correspond to the well known Phialocephala group. Interactions of nine isolates with tomato plantlets were assessed in vitro. No effect on shoot development was revealed, but three isolates caused brown spots in roots. Colonization patterns as analyzed by confocal microscopy differed among the isolates and ranged from epidermal to cortical penetration. Altogether 11 new isolates from root endophytic fungi were obtained, seven of which showed features of dark septate endophytes. Four known morphotypes were represented by five isolates, while six isolates belonged to five morphotypes of putative new unknown species.

Phylogenetic mid-point rooted tree of the GRs based on protein sequences. Outer rings represent the expression in body, mouthparts (T. castaneum: palps, mandible, labrum, and labium; D. melanogaster: palp and proboscis; An. gambiae: maxillary palp) and antenna as a percentage compared to the highest expressed gene according to the scale in the left upper corner. Note that the methods used to obtain the different expression data (RNAseq and microarray) are not directly comparable. This figure can, thus, only give an impression of the tissue-specific abundance of the transcripts. The scale bars within the trees represent 1 amino acid substitution per site. Potential sugar and fructose receptors are labeled and highlighted in yellow and in grey, and CO2 receptors are highlighted in orange. (PDF 1733 kb)

Sequences of primers and template plasmid used to generate pSLfa1180[2.5kbOrcoUp_GAL4delta]. (PDF 111 kb)

Primary and secondary antibodies and dyes used with additional information such as source and specificity. n/a not available. (PDF 118 kb)

Metamorphosis is a fundamental developmental process and has been intensively studied for various neuron types of Drosophila melanogaster. However, detailed accounts of the fate of identified peptidergic neurons are rare. We have performed a detailed study of the larval morphology and pupal remodelling of identified peptidergic neurons, the CAPA-expressing Va neurons of D. melanogaster. In the larva, Va neurons innervate abdominal median and transverse nerves that are typically associated with perisympathetic organs (PSOs), major neurohaemal release sites in insects. Since median and transverse nerves are lacking in the adult, Va neurites have to undergo substantial remodelling during metamorphosis. We have examined the hitherto uncharacterised gross morphology of the thoracic PSOs and the abdominal median and transverse nerves by scanning electron microscopy and found that the complete reduction of these structures during metamorphosis starts around pupal stage P7 and is completed at P9. Concomitantly, neurite pruning of the Va neurons begins at P6 and is preceded by the high expression of the ecdysone receptor (EcR) subtype B1 in late L3 larvae and the first pupal stages. New neuritic outgrowth mainly occurs from P7-P9 and coincides with the expression of EcR-A, indicating that the remodelling of the Va neurons is under ecdysteroid control. Immunogold-labelling has located the CAPA peptides to large translucent vesicles, which are released from the transverse nerves, as suggested by fusion profiles. Hence, the transverse nerves may serve a neurohaemal function in D. melanogaster.

The ontogeny of the fruit bodies of Mycena stylobates was studied by light microscopy and scanning electron microscopy (SEM). The ontogeny was divided into two phases: first the primordium with all the structures of the mature fruit body was established, then the primordial stipe elongated rapidly and the exposed hymenium started producing spores immediately. The first detected stage of fruit body formation was an irregularly arranged hyphal structure within the substrate colonized. After the rupture of the surface of the substrate, the primordium established on the surface. Soon a layer of wrapping hyphae was differentiated, which covered the complete primordium. The structures of the stipe and the cap developed synchronously. The developing stipe, cap and basal disc together formed a secondary ring-like cavity, in which the development of the hymenophore took place. The lower side of the cap was covered by a layer of degenerated hyphae. The development of the hymenophore started with a number of small alveolae on the lower side of the cap, which were covered with a hymenophoral palisade. The margins of these alveolae formed the primary lamellae, which in the first stage of their development were covered by a layer of degenerated hyphae. The hymenophoral palisade spread from the developing alveolae to the lamellar edge; the edge of the primary lamellae was forked in the early stages. Secondary lamellae were formed by the down folding of ridges from the lower side of the cap. In contrast to the primary lamellae, they were covered with hymenophoral palisade from the beginning. Spore production started immediately after the elongation of the stipe. These results were compared with other known modes of ontogeny within the Agaricales and some comments on the terminology used for the description of basidiome morphogenesis are made.

A review is given about the morphological and ultrastructural characters of Piriformospora indica. The morphology of hyphal cells, mycelial, and chlamydospores are described in detail. Piriformospora is able to form different types of interactions with plant groups mosses, ferns, and gymno- and angiosperms. A survey of the tested host plants is given. The morphology of interacting hyphae and root cells depends on the plant species. Besides the mutualistic mode of life, Piriformospora indica is able to live as an endophytic fungus; under specific conditions, this species can behave as a necrotrophic fungus. All these different characters of the plant growth-promoting fungus, Piriformospora indica, indicate that this species is very valuable for basic research and a wide spectrum of applications in agriculture and horticulture.

The arbuscular mycorrhiza (AM) is characterized by specific morphological structures of the fungus and the plant and by physiological adaptations which are mostly beneficial for both partners of the symbiosis. This review describes approaches to study the molecular basis of the interaction. RNA accumulation patterns have been monitored in Pisum sativum to analyse the plant response to arbuscule development. In a direct approach, the Mtha1 gene from Medicago truncatula was cloned which is expressed in arbusculated cells of M. truncatula. The gene putatively encodes an H(+)-ATPase involved in the improved plant nutrition during mycorrhization. Finally, a tripartite system between M. truncatula, Glomus mosseae and Aphanomyces euteiches was established, in order to study bioprotection. Analysis of the transcriptome has been started to analyse the interaction between the plant, the pathogen and the AM fungus.

Piriformospora indica (Sebacinaceae, Basidiomycota) is an axenically cultivable, plant growth promoting root endophyte with a wide host range, including Populus. Rooting of Populus Esch5 explants started within 6 days after transfer to WPM medium. If such plantlets with roots were inoculated with P. indica, there was an increase in root biomass, and the number of 2nd order roots was increased significantly. A totally different observation was recorded when the explants were placed into WPM with pre-grown P. indica. The interaction led to complete blocking of root production and severely inhibited plant growth. Additionally, branched aerial roots appeared which did not penetrate the medium. On contact with the fungal colony or the medium, the ends of the aerial roots became inflated. Prolonged incubation stimulated the fungus to colonize aerial parts of the plant (stem and leaves). Mycelium not only spread on the surface of the aerial parts, but also invaded the cortical tissues inter- and intracellularly. Detached Populus leaves remained vital for 4 - 5 weeks on sterile agar media or on AspM medium with pre-grown P. indica. When the fungus was pre-grown on culture media such as WPM, containing ammonium as the main source of nitrogen, leaves in contact with the cultures turned brownish within 4 - 12 h. Thereafter, the leaves bleached, and about one day later had become whitish. Thus, cultural conditions could alter the behaviour of the fungus drastically: the outcome of the interaction between plant and fungus can be directed from mutualistic to antagonistic, characterized by fungal toxin formation and extension of the colonization to Populus shoots.

Soil microflora influence plant growth and health both beneficially and adversely. The microorganisms used as biofertilisers stimulate plant growth response by providing necessary nutrients as a result of their colonisation of the rhizosphere (Azotob acter, Azospirillum, phosphate-solubilising bacteria and cyanobacteria) or by symbiotic association (Rhizobium, mycorrhizae fungi and Frankia). They may also regulate the physiological processes in the ecosystems by involvement in the decomposition of organic matter, fixation of atmospheric nitrogen, secretion of growth-promoting substances, increase in the availability of mineral nutrients, immobilisation of these assimilable nutrients and protection of plants from pathogens (Mukerji et al. 1998). Thus, rhizosphere effects through microbial activities, modify the plants by providing plant growth substances and increasing the availability of nutrients at the root zone. Plant root anatomy and tissue articulation play a significant role in the symbiotic processes (Lynch 1995).

The larvae of the cabbage root fly induce serious damage to cultivated crops of the family Brassicaceae. We here report the biochemical characterisation of neuropeptides from the central nervous system and neurohemal organs, as well as regulatory peptides from enteroendocrine midgut cells of the cabbage maggot. By LC-MALDI-TOF/TOF and chemical labelling with 4-sulfophenyl isothiocyanate, 38 peptides could be identified, representing major insect peptide families: allatostatin A, allatostatin C, FMRFamide-like peptides, kinin, CAPA peptides, pyrokinins, sNPF, myosuppressin, corazonin, SIFamide, sulfakinins, tachykinins, NPLP1-peptides, adipokinetic hormone and CCHamide 1. We also report a new peptide (Yamide) which appears to be homolog to an amidated eclosion hormone-associated peptide in several Drosophila species. Immunocytochemical characterisation of the distribution of several classes of peptide-immunoreactive neurons and enteroendocrine cells shows a very similar but not identical peptide distribution to Drosophila. Since peptides regulate many vital physiological and behavioural processes such as moulting or feeding, our data may initiate the pharmacological testing and development of new specific peptide-based protection methods against the cabbage root fly and its larva.

A new fungus isolate was discovered in an arbuscular mycorrhizal fungal spore from a desert soil in India. It could easily be cultivated on various synthetic media, and formed pear-shaped chlamydos...