Tracking the global dispersal of a cosmopolitan insect pest, the peach potato aphid

<p>Abstract</p> <p>Background</p> <p>Global commerce and human transportation are responsible for the range expansion of various insect pests such as the plant sucking aphids. High resolution DNA markers provide the opportunity to examine the genetic structure of aphid populations, identify aphid genotypes and infer their evolutionary history and routes of expansion which is of value in developing management strategies. One of the most widespread aphid species is the peach-potato aphid <it>Myzus persicae</it>, which is considered as a serious pest on various crops in many parts of the world. The present study examined the genetic variation of this aphid at a world scale and then related this to distribution patterns. In particular, 197 aphid parthenogenetic lineages from around the world were analysed with six microsatellite loci.</p> <p>Results</p> <p>Bayesian clustering and admixture analysis split the aphid genotypes into three genetic clusters: European <it>M. persicae persicae</it>, New Zealand <it>M. persicae persicae </it>and Global <it>M. persicae nicotianae</it>. This partition was supported by <it>F</it>_STand genetic distance analyses. The results showed two further points, a possible connection between genotypes found in the UK and New Zealand and globalization of <it>nicotianae </it>associated with colonisation of regions where tobacco is not cultivated. In addition, we report the presence of geographically widespread clones and for the first time the presence of a <it>nicotianae </it>genotype in the Old and New World. Lastly, heterozygote deficiency was detected in some sexual and asexual populations.</p> <p>Conclusion</p> <p>The study revealed important genetic variation among the aphid populations we examined and this was partitioned according to region and host-plant. Clonal selection and gene flow between sexual and asexual lineages are important factors shaping the genetic structure of the aphid populations. In addition, the results reflected the globalization of two subspecies of <it>M. persicae </it>with successful clones being spread at various scales throughout the world. A subspecies appears to result from direct selection on tobacco plants. This information highlights the ultimate ability of a polyphagous aphid species to generate and maintain ecologically successful gene combinations through clonal propagation and the role of human transportation and global commerce for expanding their range.</p

New records of aphid species (Hemiptera: Aphididae) in Greece

Τις τελευταίες δυο δεκαετίες έχουν δημοσιευθεί αρκετές εργασίες σχετικές με την αφιδοπανίδα της Ελλάδας. Ωστόσο, ο αριθμός των καταγεγραμμένων ειδών αφίδων είναι αρκετά μικρότερος από άλλες Ευρωπαϊκές χώρες, συμπεριλαμβανομένων αυτών στη λεκάνη της Μεσογείου. Στην παρούσα εργασία συλλέξαμε δείγματα αφίδων από διάφορους ξενιστές και περιοχές της νότιας, κεντρικής και βόρειας Ελλάδας. Συνολικά συλλέχθηκαν 128 είδη αφίδων, που ανήκουν σε 55 γένη και έξι υποοικογένειες, από 200 είδη φυτών-ξενιστών. Τα περισσότερα είδη αφίδων ανήκαν στην υποοικογένεια Aphidinae (ειδικά στις φυλές Macrosiphini και Aphidini). Δεκαοκτώ από τα συλλεχθέντα είδη είναι νέες αναφορές για την Ελλάδα. Τα αποτελέσματα της παρούσας εργασίας αυξάνουν τη γνώση μας σχετικά με την αφιδοπανίδα της Ελλάδας και δείχνουν ότι ο αριθμός των καταγεγραμμένων ειδών στην Ελλάδα μπορεί να αυξηθεί σημαντικά αν πραγματοποιηθούν επιπλέον σχετικές μελέτες. Several papers have been published on aphid fauna in Greece during the last two decades, but the number of recorded species is still low compared to other European countries, including some from the Mediterranean basin. In this context, we collected aphids from various host-plants and regions in southern, central and northern Greece characterized by diverse flora, climatic conditions and ecological habitats. In total, 128 aphid species belonging to 55 genera and six subfamilies were collected on 200 host-species. Most of the species dominated the subfamily Aphidinae (especially tribes Macrosiphini and Aphidini). Among the species collected, 18 were new records in Greece. The present work improves our knowledge regarding the aphid fauna of Greece and suggests that the number of recorded species could increase further if additional studies were undertaken

Morphometric Relationship, Phylogenetic Correlation, and Character Evolution in the Species-Rich Genus Aphis (Hemiptera: Aphididae)

The species-rich genus Aphis consists of more than 500 species, many of them host-specific on a wide range of plants, yet very similar in general appearance due to convergence toward particular morphological types. Most species have been historically clustered into four main phenotypic groups (gossypii, craccivora, fabae, and spiraecola groups). To confirm the morphological hypotheses between these groups and to examine the characteristics that determine them, multivariate morphometric analyses were performed using 28 characters measured/counted from 40 species. To infer whether the morphological relationships are correlated with the genetic relationships, we compared the morphometric dataset with a phylogeny reconstructed from the combined dataset of three mtDNA and one nuclear DNA regions.Based on a comparison of morphological and molecular datasets, we confirmed morphological reduction or regression in the gossypii group unlike in related groups. Most morphological characteristics of the gossypii group were less variable than for the other groups. Due to these, the gossypii group could be morphologically well separated from the craccivora, fabae, and spiraecola groups. In addition, the correlation of the rates of evolution between morphological and DNA datasets was highly significant in their diversification.The morphological separation between the gossypii group and the other species-groups are congruent with their phylogenetic relationships. Analysis of trait evolution revealed that the morphological traits found to be significant based on the morphometric analyses were confidently correlated with the phylogeny. The dominant patterns of trait evolution resulting in increased rates of short branches and temporally later evolution are likely suitable for the modality of Aphis speciation because they have adapted species-specifically, rapidly, and more recently on many different host plants

Predicting outcomes in rheumatoid arthritis related interstitial lung disease

Aims: To compare radiology-based prediction models in rheumatoid arthritis-related interstitial lung disease (RA-ILD) to identify patients with a progressive fibrosis phenotype.Methods: RAILD patients had CTs scored visually and by CALIPER and forced vital capacity (FVC) measurements. Outcomes were evaluated using three techniques: 1.Scleroderma system evaluating visual ILD extent and FVC values; 2.Fleischer Society IPF diagnostic guidelines applied to RAILD; 3.CALIPER scores of vessel-related structures (VRS). Outcomes were compared to IPF patients.Results: On univariable Cox analysis, all three staging systems strongly predicted outcome: Scleroderma System:HR=3.78, p=9×10-5; Fleischner System:HR=1.98, p=2×10-3; 4.4% VRS threshold:HR=3.10, p=4×10-4 When the Scleroderma and Fleischner Systems were combined, termed the Progressive Fibrotic System (C-statistic=0.71), they identified a patient subset (n=36) with a progressive fibrotic phenotype and similar 4-year survival to IPF.On multivariable analysis, with adjustment for patient age, gender and smoking status, when analysed alongside the Progressive Fibrotic System, the VRS threshold of 4.4% independently predicted outcome (Model C-statistic=0.77).Conclusions: The combination of two visual CT-based staging systems identified 23% of an RAILD cohort with an IPF-like progressive fibrotic phenotype. The addition of a computer-derived VRS threshold further improved outcome prediction and model fit, beyond that encompassed by RAILD measures of disease severity and extent

Global patterns in genomic diversity underpinning the evolution of insecticide resistance in the aphid crop pest Myzus persicae

Abstract: The aphid Myzus persicae is a destructive agricultural pest that displays an exceptional ability to develop resistance to both natural and synthetic insecticides. To investigate the evolution of resistance in this species we generated a chromosome-scale genome assembly and living panel of >110 fully sequenced globally sampled clonal lines. Our analyses reveal a remarkable diversity of resistance mutations segregating in global populations of M. persicae. We show that the emergence and spread of these mechanisms is influenced by host–plant associations, uncovering the widespread co‐option of a host-plant adaptation that also offers resistance against synthetic insecticides. We identify both the repeated evolution of independent resistance mutations at the same locus, and multiple instances of the evolution of novel resistance mechanisms against key insecticides. Our findings provide fundamental insights into the genomic responses of global insect populations to strong selective forces, and hold practical relevance for the control of pests and parasites.Peer reviewedFinal Published versio

Age-dependent and sex-dependent disparity in mortality in patients with adrenal incidentalomas and autonomous cortisol secretion: an international, retrospective, cohort study

Background: The association between cortisol secretion and mortality in patients with adrenal incidentalomas is controversial. We aimed to assess all-cause mortality, prevalence of comorbidities, and occurrence of cardiovascular events in uniformly stratified patients with adrenal incidentalomas and cortisol autonomy (defined as non-suppressible serum cortisol on dexamethasone suppression testing). Methods: We conducted an international, retrospective, cohort study (NAPACA Outcome) at 30 centres in 16 countries. Eligible patients were aged 18 years or older with an adrenal incidentaloma (diameter ≥1 cm) detected between Jan 1, 1996, and Dec 31, 2015, and availability of a 1 mg dexamethasone suppression test result from the time of the initial diagnosis. Patients with clinically apparent hormone excess, active malignancy, or follow-up of less than 36 months were excluded. Patients were stratified according to the 0800–0900 h serum cortisol values after an overnight 1 mg dexamethasone suppression test; less than 50 nmol/L was classed as non-functioning adenoma, 50–138 nmol/L as possible autonomous cortisol secretion, and greater than 138 nmol/L as autonomous cortisol secretion. The primary endpoint was all-cause mortality. Secondary endpoints were the prevalence of cardiometabolic comorbidities, cardiovascular events, and cause-specific mortality. The primary and secondary endpoints were assessed in all study participants. Findings: Of 4374 potentially eligible patients, 3656 (2089 [57·1%] with non-functioning adenoma, 1320 [36·1%] with possible autonomous cortisol secretion, and 247 [6·8%] with autonomous cortisol secretion) were included in the study cohort for mortality analysis (2350 [64·3%] women and 1306 [35·7%] men; median age 61 years [IQR 53–68]; median follow-up 7·0 years [IQR 4·7–10·2]). During follow-up, 352 (9·6%) patients died. All-cause mortality (adjusted for age, sex, comorbidities, and previous cardiovascular events) was significantly increased in patients with possible autonomous cortisol secretion (HR 1·52, 95% CI 1·19–1·94) and autonomous cortisol secretion (1·77, 1·20–2·62) compared with patients with non-functioning adenoma. In women younger than 65 years, autonomous cortisol secretion was associated with higher all-cause mortality than non-functioning adenoma (HR 4·39, 95% CI 1·93–9·96), although this was not observed in men. Cardiometabolic comorbidities were significantly less frequent with non-functioning adenoma than with possible autonomous cortisol secretion and autonomous cortisol secretion (hypertension occurred in 1186 [58·6%] of 2024 patients with non-functioning adenoma, 944 [74·0%] of 1275 with possible autonomous cortisol secretion, and 179 [75·2%] of 238 with autonomous cortisol secretion; dyslipidaemia occurred in 724 [36·2%] of 1999 patients, 547 [43·8%] of 1250, and 123 [51·9%] of 237; and any diabetes occurred in 365 [18·2%] of 2002, 288 [23·0%] of 1250, and 62 [26·7%] of 232; all p values &lt;0·001). Interpretation: Cortisol autonomy is associated with increased all-cause mortality, particularly in women younger than 65 years. However, until results from randomised interventional trials are available, a conservative therapeutic approach seems to be justified in most patients with adrenal incidentaloma. Funding: Deutsche Forschungsgemeinschaft, Associazione Italiana per la Ricerca sul Cancro, Università di Torino

The evolution of insecticide resistance in the peach-potato aphid, Myzus persicae

© 2014 The Authors. Published by Elsevier Ltd. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence e (http://creativecommons.org/licenses/by-nc-nd/3.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.The peach potato aphid, Myzus persicae is a globally distributed crop pest with a host range of over 400 species including many economically important crop plants. The intensive use of insecticides to control this species over many years has led to populations that are now resistant to several classes of insecticide. Work spanning over 40 years has shown that M. persicae has a remarkable ability to evolve mechanisms that avoid or overcome the toxic effect of insecticides with at least seven independent mechanisms of resistance described in this species to date. The array of novel resistance mechanisms, including several ‘first examples’, that have evolved in this species represents an important case study for the evolution of insecticide resistance and also rapid adaptive change in insects more generally. In this review we summarise the biochemical and molecular mechanisms underlying resistance in M. persicae and the insights study of this topic has provided on how resistance evolves, the selectivity of insecticides, and the link between resistance and host plant adaptation.Peer reviewedFinal Published versio