Cells possess stress-activated protein kinase (SAPK) signalling pathways, which are activated practically in response to any cellular insult, regulating responses for survival and adaptation to harmful environmental changes. To understand the function of SAPK pathways in T. atroviride, mutants lacking the MAPKK Pbs2 and the MAPK Tmk3 were analysed under several cellular stresses, and in their response to light. All mutants were highly sensitive to cellular insults such as osmotic and oxidative stress, cell wall damage, high temperature, cadmium, and UV irradiation. Under oxidative stress, the Tmk3 pathway showed specific roles during development, which in conidia are essential for tolerance to oxidant agents and appear to play a minor role in mycelia. The function of this pathway was more evident in Δpbs2 and Δtmk3 mutant strains when combining oxidative stress or cell wall damage with light. Light stimulates tolerance to osmotic stress through Tmk3 independently of the photoreceptor Blr1. Strikingly, photoconidiation and expression of blue light regulated genes was severally affected in Δtmk3 and Δpbs2 strains, indicating that this pathway regulates light responses. Furthermore, Tmk3 was rapidly phosphorylated upon light exposure. Thus, our data indicate that Tmk3 signalling cooperates with the Blr photoreceptor complex in the activation of gene expression.

Phylogenetic relationships in the genus Helvella were investigated using both LSU rDNA sequences and morphological features. The latter were coded and included in the analyses, resulting in better-supported clades. Helvella is monophyletic and Wynnella is its sister genus. Aporhynchous vs. pleurorhynchous asci are the synapomorphies for the 2 subgenera, Leucomelaenae and Helvella, which were confirmed as natural groups. Other recovered supported clades were section Leucomelaenae in the subgenus Leucomelaenae, and sections Elasticae, Helvella, and Lacunosae within the subgenus Helvella. Generic description, comments on taxonomically informative features, species complexes, and species that need typification are presented.

Based on morphology, fungal species have been considered widespread and as a result names of species from Europe or eastern North America were applied to species in western North America. However, DNA sequences have shown that many western taxa are different from their European counterparts; one such case is presented here. Comparisons of ITS and LSU rDNA sequences from ectomycorrhizal root tips and ascomata of specimens identified as Helvella lacunosa from North America, Europe and Asia revealed that the taxa from western North America and Mexico formed a well supported clade different from the eastern North American, European and Asian taxa. Within this western North American clade there are at least four taxa. Here we describe two of these western taxa as new species: Helvella vespertina and Helvella dryophila. Helvella vespertina is a bigger version of H. lacunosa, is variable in hymenial color and shape and forms ectomycorrhizae with conifers; it fruits typically Oct-Jan. Helvella dryophila is characterized by a dark almost black, squat pileus, a light stipe when young, medium size and forms ectomycorrhizae with Quercus species; it fruits Jan-Jun. Due to insufficient material, the two other Helvella taxa are discussed but not formally described here. We also examined the Hypomyces and other mycoparasites associated with the ascomata of Helvella species and discuss misleadingly labeled sequences in public databases.

Sixteen type and some additional specimens representing fifteen species assigned to Helvella were studied with the aim of providing new data for their improved delimitation and recognition. Specimens were received on loan from DAOM, FH, H, K, MA, MICH, S and UPS. A synoptic key to the studied species is provided to contribute to a better understanding of the genus and the taxonomy of the morphospecies. Original descriptions are emended to include data on the anatomy of the apothecial excipulum and stipe layers, apothecium and stipe reactivity to Melzer's reagent, and ascospore ornamentation. Reasons are given for maintaining H. subglabra, H. atra, H. griseoalba, and H. costifera as independent taxa and for considering Helvella hyperborea a synonym of H. costifera. Previously imprecise descriptive terms are clarified.

BackgroundFungi have multiple uses in temperate areas of México, but an important decrease in the traditional knowledge of uses and customs of mushrooms becomes a fundamental issue for fungi conservation. However, only few studies quantify the traditional ethnomycological knowledge in México, and this study is the first quantitative report for Querétaro, a central state with both Otomí and Mestizo communities and a high fungi diversity.MethodsThe present study was conducted registering traditional knowledge on the use and consumption of mushrooms in three Hñähñu (Otomí) communities (Tesquedó, Xajay, and Tenasdá) in Amealco de Bonfil, Querétaro, México, between August 2013 and November 2014. We conducted a stratified sampling, where uses common Hñähñu and Spanish names, and eight quantitative variables that conform the “Edible Mushrooms Cultural Significant Index” (EMCI) were recorded from 100 informants. For the classification and ordination analysis of species and uses, we used multivariate techniques such as cluster, multidimensional scaling, and principal components (PC).ResultsThirty-three mushrooms species were registered, most of them used for consumption by households, few aimed for commercial purposes, one species is medicinal, another has veterinary, and other ludic uses (as a toy). The three species with the highest EMCSI were Amanita basii, Fistulinella wolfeana, and Lactarius indigo. Edibility was the main use detected in the survey, and people harvested mushrooms provided by the forest mainly during the rainy season. We observed that mushroom searching and collection are activities that strengthen the family ties and are crucial for the transfer of this knowledge through generations. Cluster analysis separates groups according to different values in EMCSI variables, and principal components ordinate the species by frequencies (PC1) and traditions (PC2).ConclusionsThe current state of knowledge in the studied communities is strong, especially among women, but with a tendency to disappear due to migration and lack of interest among new generations. Future quantitative studies are important to analyze tendencies of the traditional ethnomycological knowledge transferred to new generations.

No abstract

Trehalose is an important disaccharide that can be found in bacteria, fungi, invertebrates and plants. In some Ascomycota fungal plant pathogens, the role of trehalose was recently studied and shown to be important for conferring protection against several environmental stresses and for virulence. In most of the fungi studied, two enzymes are involved in the synthesis of trehalose: trehalose-6-phosphate synthase (Tps1) and trehalose-6-phosphate phosphatase (Tps2). To study the role of trehalose in virulence and stress response in the Basidiomycota maize pathogen Ustilago maydis, Δtps2 deletion mutants were constructed. These mutants did not produce trehalose as confirmed by HPLC analysis, showing that the single gene disruption impaired its biosynthesis. The mutants displayed increased sensitivity to oxidative, heat, acid, ionic and osmotic stresses as compared to the wild-type strains. Virulence of Δtps2 mutants to maize plants was extremely reduced compared to wild-type strains, possibly due to reduced capability to deal with the hostile host environment. The phenotypic traits displayed by Δtps2 strains were fully restored to wild-type levels when complemented with the endogenous UmTPS2 gene, or a chimeric construct having the Saccharomyces cerevisiae TPS2 ORF. This report demonstrates the presence of a single biosynthetic pathway for trehalose, and its importance for virulence in this model Basidiomycota plant pathogen.

With the worldwide development of anthelmintic resistance, new alternative approaches for controlling gastrointestinal nematodes in sheep are urgently required. In this work, we identified and characterized native nematode-trapping fungi. We collected seven isolates of fungi with the capacity to form adhesive, three-dimensional networks as the main mechanism to capture, kill, and consume nematodes. The nematode-trapping fungi were classified into two groups; the first group includes the R2-13 strain, showing faster growth, abundant aerial hyphae, scarce conidia production, bigger conidia, and it formed a clade with Arthrobotrys oligospora sensu stricto. The second comprises the A6, A12, A13, R2-1, R2-6, and R2-14 strains, showing a growth adhering to the culture medium, forming little aerial hyphae, smaller conidia, and these formed a sister clade to A. oligospora. Except for the R2-6 strain, conidia production was induced by light. In all the strains, the predatory capacity against the sheep gastrointestinal nematode Haemonchus contortus was greater than 58% compared with the control group. The A6 and A13 strains were the most active against the infective H. contortus third instar (L3) larvae, with an average capture capacity of 91%. Altogether, our results support evidence for a novel A. oligospora variety with high nematode-trapping activity and promissory in helminthic control.