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Fungi are among the most diverse and ecologically important kingdoms in life. However, the distributional ranges of fungi remain largely unknown as do the ecological mechanisms that shape their distributions1,2. To provide an integrated view of the spatial and seasonal dynamics of fungi, we implemented a globally distributed standardized aerial sampling of fungal spores3. The vast majority of operational taxonomic units were detected within only one climatic zone, and the spatiotemporal patterns of species richness and community composition were mostly explained by annual mean air temperature. Tropical regions hosted the highest fungal diversity except for lichenized, ericoid mycorrhizal and ectomycorrhizal fungi, which reached their peak diversity in temperate regions. The sensitivity in climatic responses was associated with phylogenetic relatedness, suggesting that large-scale distributions of some fungal groups are partially constrained by their ancestral niche. There was a strong phylogenetic signal in seasonal sensitivity, suggesting that some groups of fungi have retained their ancestral trait of sporulating for only a short period. Overall, our results show that the hyperdiverse kingdom of fungi follows globally highly predictable spatial and temporal dynamics, with seasonality in both species richness and community composition increasing with latitude. Our study reports patterns resembling those described for other major groups of organisms, thus making a major contribution to the long-standing debate on whether organisms with a microbial lifestyle follow the global biodiversity paradigms known for macroorganisms4,5.

Novel methods for sampling and characterizing biodiversity hold great promise for re-evaluating patterns of life across the planet. The sampling of airborne spores with a cyclone sampler, and the sequencing of their DNA, have been suggested as an efficient and well-calibrated tool for surveying fungal diversity across various environments. Here we present data originating from the Global Spore Sampling Project, comprising 2,768 samples collected during two years at 47 outdoor locations across the world. Each sample represents fungal DNA extracted from 24 m3 of air. We applied a conservative bioinformatics pipeline that filtered out sequences that did not show strong evidence of representing a fungal species. The pipeline yielded 27,954 species-level operational taxonomic units (OTUs). Each OTU is accompanied by a probabilistic taxonomic classification, validated through comparison with expert evaluations. To examine the potential of the data for ecological analyses, we partitioned the variation in species distributions into spatial and seasonal components, showing a strong effect of the annual mean temperature on community composition.

As a first line of defense against insect herbivores many plants store high concentrations of toxic and deterrent secondary metabolites in glandular trichomes. Plant Pleiotropic Drug Resistance (PDR)-type ABC transporters are known secondary metabolite transporters, and several have been implicated in pathogen or herbivore defense. Here, we report on Petunia hybrida PhPDR2 as a major contributor to trichome-related chemical defense. PhPDR2 was found to localize to the plasma membrane and be predominantly expressed in multicellular glandular trichomes of leaves and stems. Down-regulation of PhPDR2 via RNA interference (pdr2) resulted in a markedly higher susceptibility of the transgenic plants to the generalist foliage feeder Spodoptera littoralis. Untargeted screening of pdr2 trichome metabolite contents showed a significant decrease in petuniasterone and petuniolide content, compounds, which had previously been shown to act as potent toxins against various insects. Our findings suggest that PhPDR2 plays a leading role in controlling petuniasterone levels in leaves and trichomes of petunia, thus contributing to herbivory resistance.

Strigolactones were originally identified as stimulators of the germination of root-parasitic weeds (1) that pose a serious threat to resource-limited agriculture (2). They are mostly exuded from roots and function as signalling compounds in the initiation of arbuscular mycorrhizae (3), which are plant-fungus symbionts with a global effect on carbon and phosphate cycling (4). Recently, strigolactones were established to be phytohormones that regulate plant shoot architecture by inhibiting the outgrowth of axillary buds (5,6). Despite their importance, it is not known how strigolactones are transported. ATP-binding cassette (ABC) transporters, however, are known to have functions in phytohormone translocation (7-9). Here we show that the Petunia hybrida ABC transporter PDR1 has a key role in regulating the development of arbuscular mycorrhizae and axillary branches, by functioning as a cellular strigolactone exporter. P. hybrida pdrl mutants are defective in strigolactone exudation from their roots, resulting in reduced symbiotic interactions. Above ground, pdrl mutants have an enhanced branching phenotype, which is indicative of impaired strigolactone allocation. Overexpression of Petunia axillaris PDR1 in Arabidopsis thaliana results in increased tolerance to high concentrations of a synthetic strigolactone, consistent with increased export of strigolactones from the roots. PDRl is the first known component in strigolactone transport, providing new opportunities for investigating and manipulating strigolactone-dependent processes., Strigolactones are a new class of carotenoid-derived (10) phytohormone in land plants. In addition to their role in shoot branching, strigolactones are exuded into the rhizosphere under phosphorus-limiting conditions (5) [...]

Recently, different reproductive modes were proposed between the emerging forest pathogen Hymenoscyphus fraxineus and its closely related avirulent sister species, Hymenoscyphus albidus . In the present study, inter- and intraspecific crosses were performed to experimentally assess the reproduction barriers between the two species and to verify H. albidus ’ putative haploid-selfing reproductive mode. By means of H. fraxineus -specific microsatellite markers, no hybridization was observed in 29 apothecia that emerged from inter-specific crosses, suggesting reproduction barriers are well-established. In a similar experimental setup, we used two newly developed polymorphic H. albidus -specific microsatellites to show that haploid-selfing is H. albidus ’ only reproductive mode ( N = 17 apothecia). Further to this, the reproductive modes of both species were investigated under natural conditions. Microsatellite allele-segregation studies of H. fraxineus ’ single-spore progeny of apothecia ( N = 31) from field samples suggest that often more than two paternal nuclei are involved in mating. In contrast, analysis of single-spore progeny of field-collected H. albidus apothecia ( N = 21) confirmed the solely haploid-selfing reproductive mode detected in vitro . Furthermore, we present the complete mating type 1-1 locus of H. fraxineus and report the finding of three additional genes within this region; the as yet unobserved typical mating type gene MAT1-1-1 , a DNA polymerase zeta catalytic subunit -like gene and a pre-mRNA-splicing factor SLU7 -like gene. The same genes were also detected in the homothallic mating type locus of H. albidus . Further analysis confirmed the expression of all typical mating type genes ( MAT1-2-1 , MAT1-1-3 , MAT1-1-1 ) in both species. Interestingly, the MAT1-1-3 gene of homothallic H. albidus is expressed despite three stop codons interrupting the coding sequence. Overall, our findings highlight vital differences in the reproduction systems of the two species and suggest that interspecific hybridization is not possible. [ABSTRACT FROM AUTHOR]

Background: Whereas an increasing number of pathogenic and mutualistic ascomycetous species were sequenced in the past decade, species showing a seemingly neutral association such as root endophytes received less attention. In the present study, the genome of Phialocephala subalpina, the most frequent species of the Phialocephala fortinii s.l. - Acephala applanata species complex, was sequenced for insight in the genome structure and gene inventory of these wide-spread root endophytes., Results: The genome of P. subalpina was sequenced using Roche/454 GS FLX technology and a whole genome shotgun strategy. The assembly resulted in 205 scaffolds and a genome size of 69.7 Mb. The expanded genome size in P. subalpina was not due to the proliferation of transposable elements or other repeats, as is the case with other ascomycetous genomes. Instead, P. subalpina revealed an expanded gene inventory that includes 20,173 gene models. Comparative genome analysis of P. subalpina with 13 ascomycetes shows that P. subalpina uses a versatile gene inventory including genes specific for pathogens and saprophytes. Moreover, the gene inventory for carbohydrate active enzymes (CAZymes) was expanded including genes involved in degradation of biopolymers, such as pectin, hemicellulose, cellulose and lignin., Conclusions: The analysis of a globally distributed root endophyte allowed detailed insights in the gene inventory and genome organization of a yet largely neglected group of organisms. We showed that the ubiquitous root endophyte P. subalpina has a broad gene inventory that links pathogenic and saprophytic lifestyles.