Horizontal and vertical distribution of Clarireedia spp., in asymptomatic and symptomatic creeping bentgrass cultivars.

Dollar spot is an important disease of both cool- and warm-season turfgrasses caused by six fungal species in the genus Clarireedia, yet the ecology and epidemiology of these pathogens remains poorly understood. The goal of this study was to determine the distribution of Clarireedia in asymptomatic and symptomatic creeping bentgrass (Agrostis stolonifera) in the field using a previously developed qPCR assay. To determine the horizontal distribution of the pathogen, the abundance of Clarireedia spp. was measured in leaf and crown tissue from 90, 1-cm diameter cores spaced 10-cm apart in May 2019 and 2020 (asymptomatic tissue) and August 2019 and July 2020 (symptomatic tissue). Thirty-seven to 69% of cores sampled from asymptomatic turfgrass and 77 to 95% of cores taken from symptomatic turfgrass yielded positive detections for Clarireedia. Spatial analysis indicated that Clarireedia was randomly distributed in the field in both asymptomatic and symptomatic turfgrass. To assess the vertical distribution of the pathogen, the abundance of Clarireedia was measured in the foliar, crown, and thatch layers of 39, 1-cm dia. x 2.5-cm deep cores of creeping bentgrass maintained at fairway height (9.5 mm) during 2019 and 2020. Clarireedia was most abundant in foliar tissue, followed by crown tissue, and thatch (lowest abundance) throughout the two-year study. Both studies provide evidence that Clarireedia is widely distributed in turfgrass swards prior to symptom development and that it can persist within turfgrass as an endophyte. These findings will improve our understanding of Clarireedia epidemiology and may lead to more sustainable dollar spot management.

First Report of Phialocephala bamuru Causing Root Rot on Hard Fescue (Festuca brevipila) in the United States.

Turfgrasses are susceptible to a wide variety of ectotrophic root-infecting (ERI) fungi that cause root rot (Tredway et al., 2023). Among the root rot diseases, fairway patch, caused by Phialocephala bamuru P.T.W. Wong & C. Dong sp. nov., was recently identified and characterized in Australia infecting bermudagrass (Cynodon dactylon) and kikuyu (Pennisetum clandestinum) grass (Wong et al., 2015). Symptoms begin as small, 5-10 cm diameter patches of yellowed turf that may coalesce into larger areas of diseased grass. A characteristic sign of fairway patch is roots colonized by dark brown to black, ectotrophic mycelium. In June 2020, many tan colored, irregular-shaped patches ranging from 10-30 cm in diameter developed on a hard fescue (Festuca brevipila) cultivar 'Beacon' turfgrass field in North Brunswick, New Jersey, USA. The centers of these patches later died and became sunken or filled in partially by recovering hard fescue. The patches grew into tan irregular-shaped rings with diameters up to 3 m by Aug 2023. Symptoms were indicative of a root disease. Five 'Beacon' hard fescue soil cores at the interface of the symptomatic and non-symptomatic area were sampled in Aug 2023. Root and crown samples were observed under a dissecting microscope and dark ectotrophic hyphae were observed on both. Roots with visible ectotrophic mycelium were removed, rinsed in sterile water three times, cut into 5 mm pieces, and plated onto 10% potato dextrose agar amended with streptomycin and gentamicin at 100 mg/L (PDA+). The plates were incubated at 25°C in the dark for 5 days. The most abundant colonies being characteristic long, septate hyphae that were hyaline at the edge and dark brown to black in the center and resembled the fungus described in Wong et al., 2015. These colonies were subcultured onto PDA+ medium and selected for molecular identification. Other less abundant colonies could be identified using morphology after subcultured and had no record being pathogenic to turfgrass. To confirm the isolate's identity, its internal transcribed spacer (ITS) region was amplified in PCR using the ITS1F/ITS4 primers (Bellemain et al., 2010). The amplicon was then sequenced with both ITS1 and ITS4 primers by Sanger sequencing. Sequences were assembled (GenBank #PP000819). The consensus sequence was then BLASTn analyzed with default settings, and the result showed 99.64% sequence identity with P. bamuru (GenBank #MG195534.1). Koch's postulate was conducted in an environmentally controlled growth chamber. Six healthy 'Beacon' hard fescue plugs were sampled from the field. Three of the six plugs (treatment) were each inoculated with P. bamuru by placing 20 g of P. bamuru colonized millets beneath and around the plug before filling the pots with sand. The other three plugs (control) received the same treatment except the P. bamuru colonized millets were autoclaved. The pots were incubated in the growth chamber with a 16 h light period and 25/20°C day/night temperatures. Symptoms resembling those observed in the field appeared on the treatment pots after 21 days of incubation while the control pots remained healthy. The roots from the treatment pots were examined under the dissecting microscope to confirm the colonization of P. bamuru on the roots, and P. bamuru was reisolated and confirmed using the aforementioned morphological traits and molecular assays (GenBank #PP000820). This is the first report of a turfgrass root rot disease caused by P. bamuru in the United States. Further epidemiological, disease ecological, and pathogen biological studies are required to clarify the importance of this disease in the United States and establish proper disease containment or control measures.

The Epichloë festucae Antifungal Protein Efe-AfpA Has Activity against Numerous Plant Pathogens.

Fungal plant pathogens can present major problems for most crop species. Currently, control of fungal diseases relies heavily on the use of fungicides. However, there are problems associated with fungicide use, including potential toxicity to non-target organisms and the development of resistance in the target fungus. New strategies are being sought to reduce fungicide use. One area of active research is the potential use of antifungal proteins from various fungal species as alternatives or complements to traditional fungicides. An antifungal protein, Efe-AfpA, from the fungal endophyte Epichloë festucae was previously found to protect plants from the pathogen Clarireedia jacksonii, the causal agent of dollar spot disease. Here we report that Efe-AfpA also has inhibitory activity against other important plant pathogens. These results suggest that it may be possible to develop Efe-AfpA as a biofungicide to target a broad range of destructive plant pathogens.

The Epichloë festucae Antifungal Protein Efe-AfpA Protects Creeping Bentgrass (Agrostis stolonifera) from the Plant Pathogen Clarireedia jacksonii, the Causal Agent of Dollar Spot Disease.

Dollar spot disease, caused by the fungal pathogen Clarireedia jacksonii, is a major problem in many turfgrass species, particularly creeping bentgrass (Agrostis stolonifera). It is well-established that strong creeping red fescue (Festuca rubra subsp. rubra) exhibits good dollar spot resistance when infected by the fungal endophyte Epichloë festucae. This endophyte-mediated disease resistance is unique to the fine fescues and has not been observed in other grass species infected with other Epichloë spp. The mechanism underlying the unique endophyte-mediated disease resistance in strong creeping red fescue has not yet been established. We pursued the possibility that it may be due to the presence of an abundant secreted antifungal protein produced by E. festucae. Here, we compare the activity of the antifungal protein expressed in Escherichia coli, Pichia pastoris, and Penicillium chrysogenum. Active protein was recovered from all systems, with the best activity being from Pe. chrysogenum. In greenhouse assays, topical application of the purified antifungal protein to creeping bentgrass and endophyte-free strong creeping red fescue protected the plants from developing severe symptoms caused by C. jacksonii. These results support the hypothesis that Efe-AfpA is a major contributor to the dollar spot resistance observed with E. festucae-infected strong creeping red fescue in the field, and that this protein could be developed as an alternative or complement to fungicides for the management of this disease on turfgrasses.

Rapid Detection of the Recently Identified Turfgrass Pathogen Magnaporthiopsis meyeri-festucae Using Recombinase Polymerase Amplification.

Magnaporthiopsis meyeri-festucae is a recently identified root-infecting pathogen of fine fescue (Festuca spp.) turfgrasses. Although it is phylogenetically similar to other root-infecting turfgrass pathogens such as M. poae, management of M. meyeri-festucae is distinct and highlights the need for fast and accurate identification. The objective of this study was to develop a rapid detection method for M. meyeri-festucae using recombinase polymerase amplification (RPA) to assist turfgrass managers in identifying the disease in the field and facilitate further epidemiological research on the pathogen. Three isolates of M. meyeri-festucae and eight isolates from four related Magnaporthiopsis species were used to test the specificity of the RPA assay targeting M. meyeri-festucae. Rapid visualization of the RPA assay results using a mixture of purified amplicon and SYBR-Safe fluorescence emitting asymmetrical cyanine dye showed that the assay was effective at detecting M. meyeri-festucae on turfgrass roots with no observed incidence of false positives or false negatives. The assay also differentiated between M. meyeri-festucae and other Magnaporthiopsis species, although overall sensitivity was lower compared with a PCR-based method. The RPA assay successfully detected M. meyeri-festucae following inoculation onto and grinding of turfgrass roots, indicating possible use as a rapid field diagnostic tool for turfgrass managers. The fast and accurate RPA M. meyeri-festucae detection method presented here will be used for additional field and laboratory applications that will help improve the management of this emerging pathogen.

Patient Perspectives on a Digital Mobile Health Application for RA.

BACKGROUND: Emerging evidence suggests that patients are increasingly willing to use digital mobile health applications for rheumatoid arthritis (RA apps). The development and diffusion of RA apps open the possibility of improved management of the disease and better physician-patient interactions. However, adoption rates among apps have been lower than hoped, and research shows that many available RA apps lack key features. There is little research exploring patient preferences for RA apps or patients' habits and preferences for app payment, which are likely key factors affecting adoption of this technology. This study seeks to understand characteristics of RA patients who have adopted RA apps, their preferences for app features, and their willingness to pay for, and experiences with app payment. METHODS: Data for this study come from a 33-question online survey of patients with RA in Canada and the United States (N=30). Information on demographics, diagnosis and management of RA, current use and desired features of RA apps, and prior experience with and willingness to pay for an app was collected. Descriptive statistics are reported, and bivariate analyses (chi-square, point-biserial correlation, and ANOVA) were performed to understand relationships between variables. RESULTS: Respondents showed a clear preference for certain app features, namely symptom tracking, scheduling appointments, and reminders. Physician recommendation for an app and patient tracking of symptoms with an app were significantly related to patient adoption of an RA app. Years since diagnosis with RA, physician recommendation for an RA app, and current use of a non-RA health tracking app were significantly related to patients' willingness to pay a subscription for an RA app. CONCLUSION: RA patients appear to prefer task support features in an RA app, notably symptom tracking, appointment scheduling, and reminders, over other features such as those related to dialogue support and social support. The choice of whether an RA app will be free or based on a subscription, pay-per-service, or one-time purchase model may also play a role in eventual adoption. Similarly, physician recommendation appears to influence patients' decision to use an RA app as well as their willingness to pay a subscription for an app.

The Epichloë festucae Antifungal Protein Efe-AfpA Is also a Possible Effector Protein Required for the Interaction of the Fungus with Its Host Grass Festuca rubra subsp. rubra.

Strong creeping red fescue (Festuca rubra subsp. rubra) is a commercially important low-maintenance turfgrass and is often naturally infected with the fungal endophyte Epichloë festucae. Epichloë spp. are endophytes of several cool-season grass species, often conferring insect resistance to the grass hosts due to the production of toxic alkaloids. In addition to insect resistance, a unique feature of the strong creeping red fescue/E. festucae symbiosis is the endophyte-mediated disease resistance to the fungal pathogen Clarireedia jacksonii, the causal agent of dollar spot disease. Such disease resistance is not a general feature of other grass/ Epichloë interactions. E. festucae isolates infecting red fescue have an antifungal protein gene Efe-afpA, whereas most other Epichloë spp. do not have a similar gene. The uniqueness of this gene suggests it may, therefore, be a component of the unique disease resistance seen in endophyte-infected red fescue. Here, we report the generation of CRISPR-Cas9 Efe-afpA gene knockouts with the goal of determining if absence of the protein in endophyte-infected Festuca rubra leads to disease susceptibility. However, it was not possible to infect plants with the knockout isolates, although infection was possible with the wild type E. festucae and with complemented isolates. This raises the interesting possibility that, in addition to having antifungal activity, the protein is required for the symbiotic interaction. The antifungal protein is a small secreted protein with high expression in planta relative to its expression in culture, all characteristics consistent with effector proteins. If Efe-AfpA is an effector protein it must be specific to certain interactions, since most Epichloë spp. do not have such a gene in their genomes.

Genome Resources for Seven Fungal Isolates That Cause Dollar Spot Disease in Turfgrass, Including Clarireedia jacksonii and C. monteithiana.

Fungi in the genus Clarireedia are widespread and destructive pathogens of grasses worldwide, and are best known as the causal agents of dollar spot disease in turfgrass. Here, we report genome assemblies of seven Clarireedia isolates, including ex-types of the two most widespread species, Clarireedia jacksonii and C. monteithiana. These datasets provide a valuable resource for ongoing studies of the dollar spot pathogens that include population diversity, host-pathogen interactions, marker development, and disease control.

Real-Time PCR Detection of Clarireedia spp., the Causal Agents of Dollar Spot in Turfgrasses.

Dollar spot is one of the most economically important diseases of turfgrasses. Recent taxonomic revisions have placed the dollar spot fungal pathogens in the new genus Clarireedia, with five species described. The main goal of this study was to develop a quantitative real-time PCR (qPCR) molecular detection assay based on the internal transcribed spacer (ITS) of the ribosomal RNA genes to quantify the abundance of Clarireedia spp. from environmental (field) samples. The qPCR assay was able to detect isolates of the four tested Clarireedia spp. but did not cross react with nontarget fungi, including closely related taxa, other turfgrass pathogens, or other fungal species commonly isolated from turfgrass. The assay is capable of detecting as little as 38.0 fg (3.8 × 10-14 g) of Clarireedia genomic DNA in 3 h. The qPCR assay detected Clarireedia spp. in both symptomatic and asymptomatic creeping bentgrass (Agrostis stolonifera) foliar tissue. Clarireedia spp. were rarely detected in the thatch or soil, indicating that these pathogens are not widely distributed in these areas of the environment. The fact that the pathogen was detected in asymptomatic tissue suggests that creeping bentgrass may be able to tolerate a certain quantity of the pathogens in leaves before disease symptoms appear; however, further research is needed to validate this hypothesis.

Transcriptome Analysis of Choke Stroma and Asymptomatic Inflorescence Tissues Reveals Changes in Gene Expression in Both Epichloë festucae and Its Host Plant Festuca rubra subsp. rubra.

Many cool-season grasses have symbiotic relationships with Epichloë (Ascomycota, Clavicipitaceae) fungal endophytes that inhabit the intercellular spaces of the above-ground parts of the host plants. The presence of the Epichloë endophytes is generally beneficial to the hosts due to enhanced tolerance to biotic and abiotic stresses conferred by the endophytes. Many Epichloë spp. are asexual, and those infections always remain asymptomatic. However, some Epichloë spp. have a sexual stage and produce a macroscopic fruiting body, a stroma, that envelops the developing inflorescence causing a syndrome termed "choke disease". Here, we report a fungal and plant gene expression analysis of choke stroma tissue and asymptomatic inflorescence tissue of Epichloë festucae-infected strong creeping red fescue (Festuca rubra subsp. rubra). Hundreds of fungal genes and over 10% of the plant genes were differentially expressed when comparing the two tissue types. The differentially expressed fungal genes in the choke stroma tissue indicated a change in carbohydrate and lipid metabolism, as well as a change in expression of numerous genes for candidate effector proteins. Plant stress-related genes were up-regulated in the stroma tissue, suggesting the plant host was responding to the epiphytic stage of E. festucae as a pathogen.

Clarireedia: A new fungal genus comprising four pathogenic species responsible for dollar spot disease of turfgrass.

Dollar spot is one of the most destructive and economically important fungal diseases of amenity turfgrasses. The causal agent was first described in 1937 as the ascomycete Sclerotinia homoeocarpa. However, the genus-level taxonomic placement of this fungus has been the subject of an ongoing debate for over 75 y. Existing morphological and rDNA sequence evidence indicates that this organism is more appropriately placed in the family Rutstroemiaceae rather than the Sclerotiniaceae. Here we use DNA sequence data from samples of the dollar spot fungus and other members of the Rutstroemiaceae (e.g. Rutstroemia, Lanzia, Lambertella) collected throughout the world to determine the generic identity of the turfgrass dollar spot pathogen. Phylogenetic evidence from three nucleotide sequence markers (CaM, ITS and Mcm7; 1810-bp) confirmed that S. homoeocarpa is not a species of Sclerotinia; nor is it a member of any known genus in the Rutstroemiaceae. These data support the establishment of a new genus, which we describe here as Clarireedia gen. nov. The type species for the genus, Clarireedia homoeocarpa comb. nov., is described to accommodate the dollar spot fungus, and a neotype is designated. Three new species in this clade, Clarireedia bennettii sp. nov., Clarireedia jacksonii sp. nov., and Clarireedia monteithiana sp. nov. that also cause dollar spot disease are described. Clarireedia homoeocarpa and C. bennettii occur primarily on Festuca rubra (C3 grass) hosts and appear to be restricted to the United Kingdom. Clarireedia jacksonii and C. monteithiana occur on a variety of C3 and C4 grass hosts, respectively, and appear to be globally distributed. This resolved taxonomy puts to rest a major controversy amongst plant pathologists and provides a foundation for better understanding the nature and biology of these destructive pathogens.

PLANETARY CANDIDATES OBSERVED BY Kepler. VIII. A FULLY AUTOMATED CATALOG WITH MEASURED COMPLETENESS AND RELIABILITY BASED ON DATA RELEASE 25.

We present the Kepler Object of Interest (KOI) catalog of transiting exoplanets based on searching four years of Kepler time series photometry (Data Release 25, Q1-Q17). The catalog contains 8054 KOIs of which 4034 are planet candidates with periods between 0.25 and 632 days. Of these candidates, 219 are new in this catalog and include two new candidates in multi-planet systems (KOI-82.06 and KOI-2926.05), and ten new high-reliability, terrestrial-size, habitable zone candidates. This catalog was created using a tool called the Robovetter which automatically vets the DR25 Threshold Crossing Events (TCEs) found by the Kepler Pipeline (Twicken et al. 2016). Because of this automation, we were also able to vet simulated data sets and therefore measure how well the Robovetter separates those TCEs caused by noise from those caused by low signal-to-noise transits. Because of these measurements we fully expect that this catalog can be used to accurately calculate the frequency of planets out to Kepler's detection limit, which includes temperate, super-Earth size planets around GK dwarf stars in our Galaxy. This paper discusses the Robovetter and the metrics it uses to decide which TCEs are called planet candidates in the DR25 KOI catalog. We also discuss the simulated transits, simulated systematic noise, and simulated astrophysical false positives created in order to characterize the properties of the final catalog. For orbital periods less than 100 d the Robovetter completeness (the fraction of simulated transits that are determined to be planet candidates) across all observed stars is greater than 85%. For the same period range, the catalog reliability (the fraction of candidates that are not due to instrumental or stellar noise) is greater than 98%. However, for low signal-to-noise candidates found between 200 and 500 days, our measurements indicate that the Robovetter is 73.5% complete and 37.2% reliable across all searched stars (or 76.7% complete and 50.5% reliable when considering just the FGK dwarf stars). We describe how the measured completeness and reliability varies with period, signal-to-noise, number of transits, and stellar type. Also, we discuss a value called the disposition score which provides an easy way to select a more reliable, albeit less complete, sample of candidates. The entire KOI catalog, the transit fits using Markov chain Monte Carlo methods, and all of the simulated data used to characterize this catalog are available at the NASA Exoplanet Archive.

The Epichloë festucae antifungal protein has activity against the plant pathogen Sclerotinia homoeocarpa, the causal agent of dollar spot disease.

Epichloë spp. are naturally occurring fungal endophytic symbionts of many cool-season grasses. Infection by the fungal endophytes often confers biotic and abiotic stress tolerance to their hosts. Endophyte-mediated disease resistance is well-established in the fine fescue grass Festuca rubra subsp. rubra (strong creeping red fescue) infected with E. festucae. Resistance to fungal pathogens is not an established effect of endophyte infection of other grass species, and may therefore be unique to the fine fescues. The underlying mechanism of the disease resistance is unknown. E. festucae produces a secreted antifungal protein that is highly expressed in the infected plant tissues and may therefore be involved in the disease resistance. Most Epichloë spp. do not have a gene for a similar antifungal protein. Here we report the characterization of the E. festucae antifungal protein, designated Efe-AfpA. The antifungal protein partially purified from the apoplastic proteins of endophyte-infected plant tissue and the recombinant protein expressed in the yeast Pichia pastoris was found to have activity against the important plant pathogen Sclerotinia homoeocarpa. Efe-AfpA may therefore be a component of the disease resistance seen in endophyte-infected strong creeping red fescue.

Magnaporthiopsis meyeri-festucae, sp. nov., associated with a summer patch-like disease of fine fescue turfgrasses.

Summer patch is a common and destructive root disease of turfgrasses. In this study, a new Magnaporthiopsis species, M. meyeri-festucae, was identified from the roots of fine fescue (Festuca spp.) turfgrasses with summer patch-like symptoms. It is described and illustrated on the basis of phenotypic characteristics and partial sequences of rDNA 18S, internal transcribed spacer (ITS), and 28S regions, and of MCM7, RPB1, and TEF1 genes. A key for all seven described species in the genus Magnaporthiopsis is provided. Distinctions between the new species and related species are discussed. Fulfillment of Koch's postulates confirmed Magnaporthiopsis meyeri-festucae as a pathogen causing summer patch-like symptoms of fine fescue turfgrasses. This work is the basis for future studies on biogeography, host range, and impact of summer patch pathogens on a broader scale.

Development of a greenhouse-based inoculation protocol for the fungus Colletotrichum cereale pathogenic to annual bluegrass (Poa annua).

The fungus Colletotrichum cereale incites anthracnose disease on Poa annua (annual bluegrass) turfgrass. Anthracnose disease is geographically widespread throughout the world and highly destructive to cool-season turfgrasses, with infections by C. cereale resulting in extensive turf loss. Comprehensive research aimed at controlling turfgrass anthracnose has been performed in the field, but knowledge of the causal organism and its basic biology is still needed. In particular, the lack of a reliable greenhouse-based inoculation protocol performed under controlled environmental conditions is an obstacle to the study of C. cereale and anthracnose disease. Our objective was to develop a consistent and reproducible inoculation protocol for the two major genetic lineages of C. cereale. By adapting previously successful field-based protocols and combining with components of existing inoculation procedures, the method we developed consistently produced C. cereale infection on two susceptible P. annua biotypes. Approximately 7 to 10 days post-inoculation, plants exhibited chlorosis and thinning consistent with anthracnose disease symptomology. Morphological inspection of inoculated plants revealed visual signs of the fungus (appressoria and acervuli), although acervuli were not always present. After stringent surface sterilization of inoculated host tissue, C. cereale was consistently re-isolated from symptomatic tissue. Real-time PCR detection analysis based on the Apn2 marker confirmed the presence of the pathogen in host tissue, with both lineages of C. cereale detected from all inoculated plants. When a humidifier was not used, no infection developed for any biotypes or fungal isolates tested. The inoculation protocol described here marks significant progress for in planta studies of C. cereale, and will enable scientifically reproducible investigations of the biology, infectivity and lifestyle of this important grass pathogen.

Influence of host and geographic locale on the distribution of Colletotrichum cereale lineages.

Colletotrichum cereale is an ascomycete inhabitant of cool-season Pooideae grasses. The fungus has increased in frequency over the past decade as a destructive pathogen of Poa annua and Agrostis stolonifera turfgrass. Colletotrichum cereale exists as two lineages, designated clades A and B, but little is known about the distribution of these clades in natural environments, or what role these subdivisions may play in the trajectory of disease outbreaks. In this study, our objective was to determine the frequency of C. cereale clades A and B. To rapidly discriminate between the two C. cereale clades, a real-time PCR assay was developed based on the Apn2 gene. A collection of 700 C. cereale pathogens and endophytes from twenty Pooideae grass genera were genotyped. 87% of the collection was identifed as part of clade A, 11.7% as part of clade B, and 1.3% was a mixture. Colletotrichum cereale from turfgrass hosts in North America were most commonly members of clade A (78%). The overabundance of clade A in turfgrass isolates was directly attributable to the dominance of this lineage from southern sampling sites, irrespective of host. In contrast, 111 C. cereale turfgrass isolates collected from northern sampling sites were evenly distributed between clades A and B. Only 28% of C. cereale from A. stolonifera at northern sampling sites were part of clade A. These data show that environmental factors such as geographic location and host identity likely played a role in the distribution of the major C. cereale clades in North American turfgrass.

Kepler-47: a transiting circumbinary multiplanet system.

We report the detection of Kepler-47, a system consisting of two planets orbiting around an eclipsing pair of stars. The inner and outer planets have radii 3.0 and 4.6 times that of Earth, respectively. The binary star consists of a Sun-like star and a companion roughly one-third its size, orbiting each other every 7.45 days. With an orbital period of 49.5 days, 18 transits of the inner planet have been observed, allowing a detailed characterization of its orbit and those of the stars. The outer planet's orbital period is 303.2 days, and although the planet is not Earth-like, it resides within the classical "habitable zone," where liquid water could exist on an Earth-like planet. With its two known planets, Kepler-47 establishes that close binary stars can host complete planetary systems.

Alignment of the stellar spin with the orbits of a three-planet system.

The Sun's equator and the planets' orbital planes are nearly aligned, which is presumably a consequence of their formation from a single spinning gaseous disk. For exoplanetary systems this well-aligned configuration is not guaranteed: dynamical interactions may tilt planetary orbits, or stars may be misaligned with the protoplanetary disk through chaotic accretion , magnetic interactions or torques from neighbouring stars. Indeed, isolated 'hot Jupiters' are often misaligned and even orbiting retrograde. Here we report an analysis of transits of planets over starspots on the Sun-like star Kepler-30 (ref. 8), and show that the orbits of its three planets are aligned with the stellar equator. Furthermore, the orbits are aligned with one another to within a few degrees. This configuration is similar to that of our Solar System, and contrasts with the isolated hot Jupiters. The orderly alignment seen in the Kepler-30 system suggests that high obliquities are confined to systems that experienced disruptive dynamical interactions. Should this be corroborated by observations of other coplanar multi-planet systems, then star-disk misalignments would be ruled out as the explanation for the high obliquities of hot Jupiters, and dynamical interactions would be implicated as the origin of hot Jupiters.

Development and application of a TaqMan real-time PCR assay for rapid detection of Magnaporthe poae.

In North America, one of the most important root diseases of Poa and Festuca turf is summer patch, caused by Magnaporthe poae. Detection and identification of M. poae in infected roots by conventional culture-based methods is difficult and time consuming, typically taking 3 wk or longer to accomplish. In this study, a culture-independent, TaqMan real-time PCR assay was developed for the detection of M. poae from the roots of fungicide treated and non-treated Kentucky bluegrass (Poa pratensis) turf. The assay was validated with the target pathogen, closely related fungal species and a number of other microorganisms that inhabit the same host and soil environment. This assay was more sensitive (could detect as little as 3.88 pg genomic DNA of M. poae), rapid and accurate compared to direct microscopic observation and isolation on a selective medium. The real-time PCR detection results corresponded closely to visual assessments of disease severity in the field. Utilization of this assay in diagnostic laboratories will enable turfgrass managers to more quickly and effectively detect and potentially reduce fungicide usage through early and accurate identification of the pathogen.

Dimeric oligonucleotide probes enhance diagnostic macroarray performance.

Disease management can be improved with rapid and accurate pathogen detection and identification techniques. Here we describe the development of a macroarray diagnostic technique with enhanced detection sensitivity and only small reduction in specificity. With probes designed based on the internal transcribed spacer sequences of the rRNA genes of fungal and oomycete strains, we produced a macroarray, which included five types of oligonucleotide probes: monomers (20-24nt), dimers (40-48nt), dimers with a poly-A spacer of 10 bases between the two repeats (50-58nt), monomers with a poly-A tail of 10 (30-34nt) and 20 (40-44nt) bases. The use of repeat sequence probes (dimers) greatly improved the sensitivity of the macroarray. The dimeric probes could reliably detect 0.01fg target genomic DNA, which is lower than the detection limits of most currently available molecular diagnostic methods, such as the conventional PCR and real-time PCR. Dimer probes also had lower signal variability, thereby increasing the macroarray signal uniformity. However, in a few cases, specificity was reduced in the dimer probes. Cross-hybridization occurred in highly similar sequences where the mismatched base was located near the end or in a chain of the same base, but this should be prevented in future array probe design.