24 research outputs found

    'Candidatus Phytoplasma phoenicium’ associated with almond witches’-broom disease: from draft genome to genetic diversity among strain populations

    Get PDF
    BACKGROUND: Almond witches'-broom (AlmWB), a devastating disease of almond, peach and nectarine in Lebanon, is associated with 'Candidatus Phytoplasma phoenicium'. In the present study, we generated a draft genome sequence of 'Ca. P. phoenicium' strain SA213, representative of phytoplasma strain populations from different host plants, and determined the genetic diversity among phytoplasma strain populations by phylogenetic analyses of 16S rRNA, groEL, tufB and inmp gene sequences. RESULTS: Sequence-based typing and phylogenetic analysis of the gene inmp, coding an integral membrane protein, distinguished AlmWB-associated phytoplasma strains originating from diverse host plants, whereas their 16S rRNA, tufB and groEL genes shared 100 % sequence identity. Moreover, dN/dS analysis indicated positive selection acting on inmp gene. Additionally, the analysis of 'Ca. P. phoenicium' draft genome revealed the presence of integral membrane proteins and effector-like proteins and potential candidates for interaction with hosts. One of the integral membrane proteins was predicted as BI-1, an inhibitor of apoptosis-promoting Bax factor. Bioinformatics analyses revealed the presence of putative BI-1 in draft and complete genomes of other 'Ca. Phytoplasma' species. CONCLUSION: The genetic diversity within 'Ca. P. phoenicium' strain populations in Lebanon suggested that AlmWB disease could be associated with phytoplasma strains derived from the adaptation of an original strain to diverse hosts. Moreover, the identification of a putative inhibitor of apoptosis-promoting Bax factor (BI-1) in 'Ca. P. phoenicium' draft genome and within genomes of other 'Ca. Phytoplasma' species suggested its potential role as a phytoplasma fitness-increasing factor by modification of the host-defense response

    Identification of new 16SrIX subgroups, -F and -G, among ‘Candidatus Phytoplasma phoenicium’ strains infecting almond, peach and nectarine in Lebanon

    Get PDF
    Almond witches’-broom is a lethal almond disease associated with ‘Candidatus Phytoplasma phoenicium’, subgroups 16SrIX-B and -D. In Lebanon, where the disease was first reported, analogous diseases affecting peach and nectarine were recently associated with presence of ‘Ca. P. phoenicium’. In the present study, genetic diversity among 24 ‘Ca. P. phoenicium’ strains infecting almond, peach and nectarine plants in diverse geographic regions of Lebanon was investigated by virtual restriction fragment length polymorphism (RFLP) analysis of 16S rDNA nucleotide sequences. Calculation of virtual restriction similarity coefficients revealed the presence of two new subgroups, -F and -G, in group 16SrIX that were confirmed by real RFLP analyses. Obtained results open new opportunities for in-depth studies of the distribution of ‘Ca. P. phoenicium’ strains in plant hosts and insect vector populations from different geographic areas of Lebanon

    Multi-messenger observations of a binary neutron star merger

    Get PDF
    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Proceedings of the 3rd Biennial Conference of the Society for Implementation Research Collaboration (SIRC) 2015: advancing efficient methodologies through community partnerships and team science

    Get PDF
    It is well documented that the majority of adults, children and families in need of evidence-based behavioral health interventionsi do not receive them [1, 2] and that few robust empirically supported methods for implementing evidence-based practices (EBPs) exist. The Society for Implementation Research Collaboration (SIRC) represents a burgeoning effort to advance the innovation and rigor of implementation research and is uniquely focused on bringing together researchers and stakeholders committed to evaluating the implementation of complex evidence-based behavioral health interventions. Through its diverse activities and membership, SIRC aims to foster the promise of implementation research to better serve the behavioral health needs of the population by identifying rigorous, relevant, and efficient strategies that successfully transfer scientific evidence to clinical knowledge for use in real world settings [3]. SIRC began as a National Institute of Mental Health (NIMH)-funded conference series in 2010 (previously titled the “Seattle Implementation Research Conference”; $150,000 USD for 3 conferences in 2011, 2013, and 2015) with the recognition that there were multiple researchers and stakeholdersi working in parallel on innovative implementation science projects in behavioral health, but that formal channels for communicating and collaborating with one another were relatively unavailable. There was a significant need for a forum within which implementation researchers and stakeholders could learn from one another, refine approaches to science and practice, and develop an implementation research agenda using common measures, methods, and research principles to improve both the frequency and quality with which behavioral health treatment implementation is evaluated. SIRC’s membership growth is a testament to this identified need with more than 1000 members from 2011 to the present.ii SIRC’s primary objectives are to: (1) foster communication and collaboration across diverse groups, including implementation researchers, intermediariesi, as well as community stakeholders (SIRC uses the term “EBP champions” for these groups) – and to do so across multiple career levels (e.g., students, early career faculty, established investigators); and (2) enhance and disseminate rigorous measures and methodologies for implementing EBPs and evaluating EBP implementation efforts. These objectives are well aligned with Glasgow and colleagues’ [4] five core tenets deemed critical for advancing implementation science: collaboration, efficiency and speed, rigor and relevance, improved capacity, and cumulative knowledge. SIRC advances these objectives and tenets through in-person conferences, which bring together multidisciplinary implementation researchers and those implementing evidence-based behavioral health interventions in the community to share their work and create professional connections and collaborations

    Identification of new 16SrIX subgroups, -F and -G, among ‘<I>Candidatus Phytoplasma phoenicium</I>’ strains infecting almond, peach and nectarine in Lebanon

    No full text
    Almond witches’-broom is a lethal almond disease associated with ‘Candidatus Phytoplasma phoenicium’, subgroups 16SrIX-B and -D. In Lebanon, where the disease was first reported, analogous diseases affecting peach and nectarine were recently associated with presence of ‘Ca. P. phoenicium’. In the present study, genetic diversity among 24 ‘Ca. P. phoenicium’ strains infecting almond, peach and nectarine plants in diverse geographic regions of Lebanon was investigated by virtual restriction fragment length polymorphism (RFLP) analysis of 16S rDNA nucleotide sequences. Calculation of virtual restriction similarity coefficients revealed the presence of two new subgroups, -F and -G, in group 16SrIX that were confirmed by real RFLP analyses. Obtained results open new opportunities for in-depth studies of the distribution of ‘Ca. P. phoenicium’ strains in plant hosts and insect vector populations from different geographic areas of Lebanon

    Asymmetrasca decedens (Cicadellidae, Typhlocybinae), a natural vector of &apos;Candidatus Phytoplasma phoenicium&apos;

    No full text
    'Candidatus Phytoplasma phoenicium' is associated with a lethal disease of almond, peach and nectarine named almond witches'-broom disease (AlmWB). The disease spread rapidly in Lebanon from coastal areas to elevations exceeding 1200 m, killing over 150,000 trees in a span of two decades. The mode of spread suggested the involvement of efficient vector(s) and Asymmetrasca decedens (Hemiptera, Cicadellidae) was suspected as it is the most abundant leafhopper species present in Lebanese stone fruit orchards. Living A. decedens specimens were collected from fields heavily infested by AlmWB and used in transmission trials on healthy peach almond hybrid GF-677 and peach GF-305 seedlings with an inoculation-access period of 30 days. PCR analysis supported by sequencing showed that A. decedens is a carrier of the phytoplasma, and that the phytoplasma was detected in insect salivary glands and in some inoculated GF-677 and GF-305 seedlings. One year post-inoculation, 'Ca. P. phoenicium' was detected in newly emergent leaves of inoculated seedlings. However, the characteristic symptoms of witches'-broom were not observed. PCR amplified fragments from phytoplasma-positive seedlings and from A. decedens samples showed 99.9% nucleotide identity in their 16S RNA region and phylogenetic analysis using a neighbour jointing tree confirmed that the phytoplasmas detected in both insects and inoculated seedlings belonged to 16SrIX-B (D). The present manuscript is the first known report for a leafhopper vector of 'Ca. P. phoenicium' and shows that the incubation period of the disease in plants may be longer than 1 year. The importance of phytosanitary control measures, the adoption of a national strategy and regional cooperation in order to contain the further spread of the disease are discussed
    corecore