CAG RNAs induce DNA damage and apoptosis by silencing NUDT16 expression in polyglutamine degeneration.

DNA damage plays a central role in the cellular pathogenesis of polyglutamine (polyQ) diseases, including Huntington's disease (HD). In this study, we showed that the expression of untranslatable expanded CAG RNA per se induced the cellular DNA damage response pathway. By means of RNA sequencing (RNA-seq), we found that expression of the Nudix hydrolase 16 (NUDT16) gene was down-regulated in mutant CAG RNA-expressing cells. The loss of NUDT16 function results in a misincorporation of damaging nucleotides into DNAs and leads to DNA damage. We showed that small CAG (sCAG) RNAs, species generated from expanded CAG transcripts, hybridize with CUG-containing NUDT16 mRNA and form a CAG-CUG RNA heteroduplex, resulting in gene silencing of NUDT16 and leading to the DNA damage and cellular apoptosis. These results were further validated using expanded CAG RNA-expressing mouse primary neurons and in vivo R6/2 HD transgenic mice. Moreover, we identified a bisamidinium compound, DB213, that interacts specifically with the major groove of the CAG RNA homoduplex and disfavors the CAG-CUG heteroduplex formation. This action subsequently mitigated RNA-induced silencing complex (RISC)-dependent NUDT16 silencing in both in vitro cell and in vivo mouse disease models. After DB213 treatment, DNA damage, apoptosis, and locomotor defects were rescued in HD mice. This work establishes NUDT16 deficiency by CAG repeat RNAs as a pathogenic mechanism of polyQ diseases and as a potential therapeutic direction for HD and other polyQ diseases.

An Experimental and Computational Approach to Development of Mixing Processes for Miscible Liquids in Unbaffled Tanks.

PURPOSE: Mixing of liquids is a critical unit operation in the biopharmaceutical drug product manufacturing. It commonly consists of mixing miscible liquids to dilute bulk drug substance (DS) or pool multiple lots of drug substance. In the past, at-scale mixing studies have been conducted to determine the mixing parameters, namely mixing speed, and mixing time. At-scale studies have historically been utilized to overcome the challenges associated with geometric dissimilarity of mixing systems found when scaling up. In addition, such studies are quite costly, as they often use actual DS to overcome a lack of representativeness associated with simple salt trace models often employed. As a result, there is a significant need for alternative cost-effective methods that can predict mixing parameters with close agreement to actual experiments and operations. METHOD: At-scale mixing experiments were conducted using full-sized tanks and surrogate solutions. Several computational fluid dynamic (CFD) simulation methods were conducted and compared with the experiments to determine the most reliable computational techniques. RESULTS: The experiments demonstrate that surrogate solutions can be used reliably to determine mixing parameters in at-scale studies instead of the valuable drug products. Studying different CFD methods also showed that transient simulations that use a large eddy simulation (LES) viscous model and a sliding mesh can correctly predict the mixing parameters. CONCLUSION: Results of this study establish a practical and reliable methodology to perform mixing studies for miscible liquids with different kinematic viscosities. The methods discussed herein greatly reduce the routine mixing study costs in the biopharmaceutical industry and increase efficiency and accuracy of the results, allowing proactive scale-up of mixing operations.

Acetylsalicylic acid inhibits intravascular coagulation during Staphylococcus aureus-induced sepsis in mice.

Antiplatelet therapies have been proposed for the treatment of sepsis, a syndrome resulting from a dysregulated immune response and inappropriate activation of coagulation. Acetylsalicylic acid (ASA) may serve as a potential therapeutic strategy to prevent infection-induced coagulopathy and associated tissue damage. Using intravital microscopy, we found that Staphylococcus aureus infection induced neutrophil recruitment, platelet aggregation, and neutrophil extracellular trap (NET) release in the liver. Mice pretreated with ASA, or animals receiving ASA 3 hours postinfection, had significantly reduced platelet aggregation and NET release. Additionally, ASA-treated mice had reduced intravascular thrombin activity and microvascular occlusion as compared with untreated S aureus-infected mice. This inhibition of coagulation was accompanied by decreased levels of alanine aminotransferase and aspartate aminotransferase in the plasma, indicating less liver damage. Finally, bacterial loads (colony-forming units per milliliter) in liver, lung, and spleen were not different between groups, and the phagocytic capacity of Kupffer cells was preserved following ASA treatment. These results suggest that ASA may serve as a therapeutic approach to sepsis through its ability to reduce the deleterious action of immunothrombi while maintaining innate immune functions.

AQAMAN, a bisamidine-based inhibitor of toxic protein inclusions in neurons, ameliorates cytotoxicity in polyglutamine disease models.

Polyglutamine (polyQ) diseases are a group of dominantly inherited neurodegenerative disorders caused by the expansion of an unstable CAG repeat in the coding region of the affected genes. Hallmarks of polyQ diseases include the accumulation of misfolded protein aggregates, leading to neuronal degeneration and cell death. PolyQ diseases are currently incurable, highlighting the urgent need for approaches that inhibit the formation of disaggregate cytotoxic polyQ protein inclusions. Here, we screened for bisamidine-based inhibitors that can inhibit neuronal polyQ protein inclusions. We demonstrated that one inhibitor, AQAMAN, prevents polyQ protein aggregation and promotes de-aggregation of self-assembled polyQ proteins in several models of polyQ diseases. Using immunocytochemistry, we found that AQAMAN significantly reduces polyQ protein aggregation and specifically suppresses polyQ protein-induced cell death. Using a recombinant and purified polyQ protein (thioredoxin-Huntingtin-Q46), we further demonstrated that AQAMAN interferes with polyQ self-assembly, preventing polyQ aggregation, and dissociates preformed polyQ aggregates in a cell-free system. Remarkably, AQAMAN feeding of Drosophila expressing expanded polyQ disease protein suppresses polyQ-induced neurodegeneration in vivo In addition, using inhibitors and activators of the autophagy pathway, we demonstrated that AQAMAN's cytoprotective effect against polyQ toxicity is autophagy-dependent. In summary, we have identified AQAMAN as a potential therapeutic for combating polyQ protein toxicity in polyQ diseases. Our findings further highlight the importance of the autophagy pathway in clearing harmful polyQ proteins.

Multi-omics tools for studying microbial biofilms: current perspectives and future directions.

The advent of omics technologies has greatly improved our understanding of microbial biology, particularly in the last two decades. The field of microbial biofilms is, however, relatively new, consolidated in the 1980s. The morphogenic switching by microbes from planktonic to biofilm phenotype confers numerous survival advantages such as resistance to desiccation, antibiotics, biocides, ultraviolet radiation, and host immune responses, thereby complicating treatment strategies for pathogenic microorganisms. Hence, understanding the mechanisms governing the biofilm phenotype can result in efficient treatment strategies directed specifically against molecular markers mediating this process. The application of omics technologies for studying microbial biofilms is relatively less explored and holds great promise in furthering our understanding of biofilm biology. In this review, we provide an overview of the application of omics tools such as transcriptomics, proteomics, and metabolomics as well as multi-omics approaches for studying microbial biofilms in the current literature. We also highlight how the use of omics tools directed at various stages of the biological information flow, from genes to metabolites, can be integrated via multi-omics platforms to provide a holistic view of biofilm biology. Following this, we propose a future artificial intelligence-based multi-omics platform that can predict the pathways associated with different biofilm phenotypes.

A divalent cation-dependent variant of the glmS ribozyme with stringent Ca2+ selectivity co-opts a preexisting nonspecific metal ion-binding site.

Ribozymes use divalent cations for structural stabilization, as catalytic cofactors, or both. Because of the prominent role of Ca2+ in intracellular signaling, engineered ribozymes with stringent Ca2+ selectivity would be important in biotechnology. The wild-type glmS ribozyme (glmSWT) requires glucosamine-6-phosphate (GlcN6P) as a catalytic cofactor. Previously, a glmS ribozyme variant with three adenosine mutations (glmSAAA) was identified, which dispenses with GlcN6P and instead uses, with little selectivity, divalent cations as cofactors for site-specific RNA cleavage. We now report a Ca2+-specific ribozyme (glmSCa) evolved from glmSAAA that is >10,000 times more active in Ca2+ than Mg2+, is inactive in even 100 mM Mg2+, and is not responsive to GlcN6P. This stringent selectivity, reminiscent of the protein nuclease from Staphylococcus, allows rapid and selective ribozyme inactivation using a Ca2+ chelator such as EGTA. Because glmSCa functions in physiologically relevant Ca2+ concentrations, it can form the basis for intracellular sensors that couple Ca2+ levels to RNA cleavage. Biochemical analysis of glmSCa reveals that it has co-opted for selective Ca2+ binding a nonspecific cation-binding site responsible for structural stabilization in glmSWT and glmSAAA Fine-tuning of the selectivity of the cation site allows repurposing of this preexisting molecular feature.

Structural basis for high-affinity fluorophore binding and activation by RNA Mango.

Genetically encoded fluorescent protein tags have revolutionized proteome studies, whereas the lack of intrinsically fluorescent RNAs has hindered transcriptome exploration. Among several RNA-fluorophore complexes that potentially address this problem, RNA Mango has an exceptionally high affinity for its thiazole orange (TO)-derived fluorophore, TO1-Biotin (Kd ∼3 nM), and, in complex with related ligands, it is one of the most redshifted fluorescent macromolecular tags known. To elucidate how this small aptamer exhibits such properties, which make it well suited for studying low-copy cellular RNAs, we determined its 1.7-Å-resolution co-crystal structure. Unexpectedly, the entire ligand, including TO, biotin and the linker connecting them, abuts one of the near-planar faces of the three-tiered G-quadruplex. The two heterocycles of TO are held in place by two loop adenines and form a 45° angle with respect to each other. Minimizing this angle would increase quantum yield and further improve this tool for in vivo RNA visualization.

Effect of subacute and prenatal DINCH plasticizer exposure on rat dams and male offspring hepatic function: The role of PPAR-α.

Plasticizers are compounds added to plastics to modify their physical proprieties. The most well-known class of plasticizers, the phthalates, has been shown to possess antiandrogenic and tumor promoting activities. 1,2-Cyclohexane dicarboxylic acid diisononyl ester (DINCH) was approved for use in food contact containers in 2006 and has been used as a replacement for phthalates in toys and children products. However, we reported previously that the DINCH metabolite MINCH acts on primary rat adipocytes through the peroxisome proliferator activated receptor (PPAR)-α pathway in a manner similar to phthalates. Evidence from our studies, as well as from the current bibliography on DINCH, suggests that the liver might be one of its target organs. In the present study, we collected tissues from dams exposed subacutely and progeny at postnatal day (PND) 3 and 60 exposed in utero to DINCH (1, 10 and 100 mg/kg bw/day). Exposure to DINCH drastically affected liver gene expression in all 3 age groups tested and in particular at the dose of 1 mg/kg bw/day. The PPAR-α pathway along with other metabolic and DNA replication pathways were affected by DINCH. Modifications in PPAR-α and superoxide dismutase (SOD)-1 protein levels were observed in dams at PND21, as well as male progeny at PND3 and 60. No sign of fibrosis or direct liver toxicity was observed after 8 days of stimulus with low doses of DINCH. This study provides evidence that DINCH is not a biologically inert molecule in the rat, and in the liver its actions are mediated, at least in part, by PPAR-α.

Genetics-based interactions of foundation species affect community diversity, stability and network structure.

We examined the hypothesis that genetics-based interactions between strongly interacting foundation species, the tree Populus angustifolia and the aphid Pemphigus betae, affect arthropod community diversity, stability and species interaction networks of which little is known. In a 2-year experimental manipulation of the tree and its aphid herbivore four major findings emerged: (i) the interactions of these two species determined the composition of an arthropod community of 139 species; (ii) both tree genotype and aphid presence significantly predicted community diversity; (iii) the presence of aphids on genetically susceptible trees increased the stability of arthropod communities across years; and (iv) the experimental removal of aphids affected community network structure (network degree, modularity and tree genotype contribution to modularity). These findings demonstrate that the interactions of foundation species are genetically based, which in turn significantly contributes to community diversity, stability and species interaction networks. These experiments provide an important step in understanding the evolution of Darwin's 'entangled bank', a metaphor that characterizes the complexity and interconnectedness of communities in the wild.

Genetically informed ecological niche models improve climate change predictions.

We examined the hypothesis that ecological niche models (ENMs) more accurately predict species distributions when they incorporate information on population genetic structure, and concomitantly, local adaptation. Local adaptation is common in species that span a range of environmental gradients (e.g., soils and climate). Moreover, common garden studies have demonstrated a covariance between neutral markers and functional traits associated with a species' ability to adapt to environmental change. We therefore predicted that genetically distinct populations would respond differently to climate change, resulting in predicted distributions with little overlap. To test whether genetic information improves our ability to predict a species' niche space, we created genetically informed ecological niche models (gENMs) using Populus fremontii (Salicaceae), a widespread tree species in which prior common garden experiments demonstrate strong evidence for local adaptation. Four major findings emerged: (i) gENMs predicted population occurrences with up to 12-fold greater accuracy than models without genetic information; (ii) tests of niche similarity revealed that three ecotypes, identified on the basis of neutral genetic markers and locally adapted populations, are associated with differences in climate; (iii) our forecasts indicate that ongoing climate change will likely shift these ecotypes further apart in geographic space, resulting in greater niche divergence; (iv) ecotypes that currently exhibit the largest geographic distribution and niche breadth appear to be buffered the most from climate change. As diverse agents of selection shape genetic variability and structure within species, we argue that gENMs will lead to more accurate predictions of species distributions under climate change.

In vitro evolution of coenzyme-independent variants from the glmS ribozyme structural scaffold.

Uniquely among known natural ribozymes that cleave RNA sequence-specifically, the glmS ribozyme-riboswitch employs a small molecule, glucosamine-6-phosphate (GlcN6P) as a catalytic cofactor. In vitro selection was employed to search for coenzyme-independent variants of this ribozyme. In addition to shedding light on the catalytic mechanism of the ribozyme, such variants could resemble the evolutionary ancestors of the modern, GlcN6P-regulated ribozyme-riboswitch. A mutant pool was constructed such that the secondary structure elements, which define the triply-pseudoknotted global fold of the ribozyme, was preserved. A stringent selection scheme that relies on thiol-mercury affinity chromatography for separating active and inactive sequences ultimately yielded a triple mutant with a cleavage rate exceeding 3min(-1) that only requires divalent cations for activity. Mutational analysis demonstrated that a point reversion of the variant toward the wild-type sequence was sufficient to partially restore GlcN6P-dependence, suggesting that coenzyme dependence can be readily be acquired by RNAs that adopt the glmS ribozyme fold. The methods employed to perform this selection experiment are described in detail in this review.

Plant-herbivore interactions in a trispecific hybrid swarm of Populus: assessing support for hypotheses of hybrid bridges, evolutionary novelty and genetic similarity.

UNLABELLED: Natural systems of hybridizing plants are powerful tools with which to assess evolutionary processes between parental species and their associated arthropods. Here we report on these processes in a trispecific hybrid swarm of Populus trees. Using field observations, common garden experiments and genetic markers, we tested the hypothesis that genetic similarities among hosts underlie the distributions of 10 species of gall-forming arthropods and their ability to adapt to new host genotypes. KEY FINDINGS: the degree of genetic relatedness among parental species determines whether hybridization is primarily bidirectional or unidirectional; host genotype and genetic similarity strongly affect the distributions of gall-forming species, individually and as a community. These effects were detected observationally in the wild and experimentally in common gardens; correlations between the diversity of host genotypes and their associated arthropods identify hybrid zones as centres of biodiversity and potential species interactions with important ecological and evolutionary consequences. These findings support both hybrid bridge and evolutionary novelty hypotheses. However, the lack of parallel genetic studies on gall-forming arthropods limits our ability to define the host of origin with their subsequent shift to other host species or their evolution on hybrids as their final destination.

Genotypic variation in foundation species generates network structure that may drive community dynamics and evolution.

Although genetics in a single species is known to impact whole communities, little is known about how genetic variation influences species interaction networks in complex ecosystems. Here, we examine the interactions in a community of arthropod species on replicated genotypes (clones) of a foundation tree species, Populus angustifolia James (narrowleaf cottonwood), in a long-term, common garden experiment using a bipartite "genotype-species" network perspective. We combine this empirical work with a simulation experiment designed to further investigate how variation among individual tree genotypes can impact network structure. Three findings emerged: (1) the empirical "genotype-species network" exhibited significant network structure with modularity being greater than the highly conservative null model; (2) as would be expected given a modular network structure, the empirical network displayed significant positive arthropod co-occurrence patterns; and (3) furthermore, the simulations of "genotype-species" networks displayed variation in network structure, with modularity in particular clearly increasing, as genotypic variation increased. These results support the conclusion that genetic variation in a single species contributes to the structure of ecological interaction networks, which could influence eco-ogical dynamics (e.g., assembly and stability) and evolution in a community context.

Many Activities, One Structure: Functional Plasticity of Ribozyme Folds.

Catalytic RNAs, or ribozymes, are involved in a number of essential biological processes, such as replication of RNA genomes and mobile genetic elements, RNA splicing, translation, and RNA degradation. The function of ribozymes requires the formation of active sites decorated with RNA functional groups within defined three-dimensional (3D) structures. The genotype (sequence) of RNAs ultimately determines what 3D structures they adopt (as a function of their environmental conditions). These 3D structures, in turn, give rise to biochemical activity, which can further elaborate them by catalytic rearrangements or association with other molecules. The fitness landscape of a non-periodic linear polymer, such as RNA, relates its primary structure to a phenotype. Two major challenges in the analysis of ribozymes is to map all possible genotypes to their corresponding catalytic activity (that is, to determine their fitness landscape experimentally), and to understand whether their genotypes and three-dimensional structures can support multiple different catalytic functions. Recently, the combined results of experiments that employ in vitro evolution methods, high-throughput sequencing and crystallographic structure determination have hinted at answers to these two questions: while the fitness landscape of ribozymes is rugged, meaning that their catalytic activity cannot be optimized by a smooth trajectory in sequence space, once an RNA achieves a stable three-dimensional fold, it can be endowed with distinctly different biochemical activities through small changes in genotype. This functional plasticity of highly structured RNAs may be particularly advantageous for the adaptation of organisms to drastic changes in selective pressure, or for the development of new biotechnological tools.

An in vitro evolved glmS ribozyme has the wild-type fold but loses coenzyme dependence.

Uniquely among known ribozymes, the glmS ribozyme-riboswitch requires a small-molecule coenzyme, glucosamine-6-phosphate (GlcN6P). Although consistent with its gene-regulatory function, the use of GlcN6P is unexpected because all of the other characterized self-cleaving ribozymes use RNA functional groups or divalent cations for catalysis. To determine what active site features make this ribozyme reliant on GlcN6P and to evaluate whether it might have evolved from a coenzyme-independent ancestor, we isolated a GlcN6P-independent variant through in vitro selection. Three active site mutations suffice to generate a highly reactive RNA that adopts the wild-type fold but uses divalent cations for catalysis and is insensitive to GlcN6P. Biochemical and crystallographic comparisons of wild-type and mutant ribozymes show that a handful of functional groups fine-tune the RNA to be either coenzyme or cation dependent. These results indicate that a few mutations can confer new biochemical activities on structured RNAs. Thus, families of structurally related ribozymes with divergent function may exist.

Rapid plant evolution in the presence of an introduced species alters community composition.

Because introduced species may strongly interact with native species and thus affect their fitness, it is important to examine how these interactions can cascade to have ecological and evolutionary consequences for whole communities. Here, we examine the interactions among introduced Rocky Mountain elk, Cervus canadensis nelsoni, a common native plant, Solidago velutina, and the diverse plant-associated community of arthropods. While introduced species are recognized as one of the biggest threats to native ecosystems, relatively few studies have investigated an evolutionary mechanism by which introduced species alter native communities. Here, we use a common garden design that addresses and supports two hypotheses. First, native S. velutina has rapidly evolved in the presence of introduced elk. We found that plants originating from sites with introduced elk flowered nearly 3 weeks before plants originating from sites without elk. Second, evolution of S. velutina results in a change to the plant-associated arthropod community. We found that plants originating from sites with introduced elk supported an arthropod community that had ~35 % fewer total individuals and a different species composition. Our results show that the impacts of introduced species can have both ecological and evolutionary consequences for strongly interacting species that subsequently cascade to affect a much larger community. Such evolutionary consequences are likely to be long-term and difficult to remediate.

GnRH agonist trigger and ovarian hyperstimulation syndrome: relook at 'freeze-all strategy'.

A case is reported of early onset ovarian hyperstimulation syndrome (OHSS) after gonadotrophin-releasing hormone agonist (GnRHa) trigger for final oocyte maturation in a GnRH antagonist protocol. The use of GnRHa in place of HCG as a trigger for final oocyte maturation in an antagonist IVF cycle has been proposed as a method for preventing OHSS in predicted high-responders. This approach, however, did not prevent the occurrence of OHSS in our case despite a freeze-all strategy. To the best of our knowledge, this is a possible index case of severe OHSS with GnRHa trigger for oocyte maturation without any luteal HCG rescue for a high responder, despite IVF cycle segmentation.

Tree genotype and genetically based growth traits structure twig endophyte communities.

PREMISE OF THE STUDY: Fungal endophytes asymptomatically inhabit plant tissues where they have mutualistic, parasitic, or commensal relationships with their hosts. Although plant-fungal interactions at the genotype scale have broad ecological and evolutionary implications, the sensitivity of endophytes in woody tissues to differences among plant genotypes is poorly understood. We hypothesize that (1) endophyte communities in Populus angustifolia (Salicaceae) twigs vary among tree genotypes, (2) endophyte variation is linked to quantitative tree traits, and (3) tree genotype influences interspecific fungal interactions. METHODS: Endophytes were isolated from twigs of replicated P. angustifolia genotypes in a common garden and characterized with PCR-RFLP and DNA sequencing. Twig length and diameter, aboveground tree biomass, and condensed tannins were also quantified. KEY RESULTS: (1) Aspects of fungal community structure, including composition and total isolation frequency (i.e., abundance), varied among genotypes. (2) Aboveground biomass and twig diameter were positively associated with isolation frequency and covaried with composition, whereas twig length and condensed tannin concentration were not significantly correlated to endophytes. (3) Fungal co-occurrence patterns suggested negative species interactions, but the presence of significant co-occurrences was genotype dependent. CONCLUSIONS: The species is often assumed to be the most important ecological unit; however, these results indicate that genetically based trait variation within a species can influence an important community of associated organisms. Given the dominance of plants as primary producers and the ubiquity of endophytes, the effect of host genetic variation on endophytes has fundamental implications for our understanding of terrestrial ecosystems.

Social oocyte freezing: a survey among Singaporean female medical students.

AIM: Social oocyte freezing has gained increasing interest worldwide. We conducted a cross-sectional survey on 129 female medical students in Singapore to assess their mindset and attitudes toward fertility and social oocyte freezing. METHODS: An anonymous online survey was conducted among female medical students in Singapore. The desired sample size was 100 participants. Their awareness of the existence of social oocyte freezing was first assessed. An information leaflet was provided subsequently, followed by a more detailed questionnaire. The questions focused on their awareness of age-related fertility decline and their intentions for social oocyte freezing if made available. RESULTS: One hundred and twenty-nine female students participated in the electronic survey, of whom 36.4% had heard of social oocyte freezing. Of these, 70% had personally considered taking up this option. However, after reading the information leaflet, only 48.9% would still consider this option. Of the total, 89.9% considered themselves too old for pregnancy after the age of 35 years, 37.2% would delay family planning for their career, 45.7% would consider social oocyte freezing to postpone family planning for their career, 46.5% would consider oocyte freezing if they had no suitable partners yet, 50.4% may consider freezing their eggs after the age of 30 years and 71.3% may be more amenable to oocyte freezing if government subsidy is available. CONCLUSION: We hypothesize that social oocyte freezing may be a viable option for single young women who wish to delay child-bearing for 'reproductive insurance', so long as this is done with appropriate informed consent with non-directive counseling.

An elusive ectomycorrhizal fungus reveals itself: a new species of Geopora (Pyronemataceae) associated with Pinus edulis.

Species of the genus Geopora are important ectomycorrhizal associates that can dominate the communities of some plant taxa, such as pinyon pine (Pinus edulis), a widespread tree of the western United States. Several members of the genus Geopora are known only from ectomycorrhizal root tips and thus have not been described formally. The sporocarps of some Geopora species occur infrequently because they depend on wet years for sporulation. In addition, Geopora sporocarps can be small and may be hypogeous at some developmental stage, limiting the opportunities for describing their morphology. Using molecular and morphological data, we have described a new species of fungus, Geopora pinyonensis, which produced ascocarps after unusually high precipitation at a northern Arizona site in summer 2012. Based on analysis of the ITS and nuLSU regions of the rDNA, G pinyonensis is a new species of Geopora. It has small sporocarps and ascospores relative to other members of the genus; however, these morphological features overlap with other species. Using rDNA data from sporocarps and ectomycorrhizal root tips, we show that the sporocarps correspond to an abundant species of ectomycorrhizal fungus associated with pinyon pines that is increasing in abundance in drought-affected landscapes and may promote drought tolerance.