Hybridization and introgression between Helicoverpa armigera and H. zea: an adaptational bridge.

BACKGROUND: Invasion of organisms into new ecosystems is increasingly common, due to the global trade in commodities. One of the most complex post-invasion scenarios occurs when an invasive species is related to a native pest, and even more so when they can hybridize and produce fertile progeny. The global pest Helicoverpa armigera was first detected in Brazil in 2013 and generated a wave of speculations about the possibility of hybridization with the native sister taxon Helicoverpa zea. In the present study, we used genome-wide single nucleotide polymorphisms from field-collected individuals to estimate hybridization between H. armigera and H. zea in different Brazilian agricultural landscapes. RESULTS: The frequency of hybridization varied from 15 to 30% depending on the statistical analyses. These methods showed more congruence in estimating that hybrids contained approximately 10% mixed ancestry (i.e. introgression) from either species. Hybridization also varied considerably depending on the geographic locations where the sample was collected, forming a 'mosaic' hybrid zone where introgression may be facilitated by environmental and landscape variables. Both landscape composition and bioclimatic variables indicated that maize and soybean cropland are the main factors responsible for high levels of introgression in agricultural landscapes. The impact of multiple H. armigera incursions is reflected in the structured and inbred pattern of genetic diversity. CONCLUSIONS: Our data showed that the landscape composition and bioclimatic variables influence the introgression rate between H. armigera and H. zea in agricultural areas. Continuous monitoring of the hybridization process in the field is necessary, since agricultural expansion, climatic fluctuations, changing composition of crop species and varieties, and dynamic planting seasons are some factors in South America that could cause a sudden alteration in the introgression rate between Helicoverpa species. Introgression between invasive and native pests can dramatically impact the evolution of host ranges and resistance management.

Thiamethoxam Differentially Impacts the Survival of the Generalist Predators, Orius insidiosus (Hemiptera: Anthocoridae) and Hippodamia convergens (Coleoptera: Coccinellidae), When Exposed via the Food Chain.

Insect predators are seldom considered during toxicological trophic assessments for insecticide product development. As a result, the ecological impact of novel insecticides on predators is not well understood, especially via the food chain, i.e., when their prey is exposed to insecticides. Neonicotinoids are systemic insecticides widely used in agriculture to control herbivorous insects, but their effects on predatory insects via the food chain have not been well characterized. In this study, we documented the time-course effects of the neonicotinoid thiamethoxam on the survival of two predators, the insidiosus flower bug Orius insidiosus (Say) and the convergent lady beetle Hippodamia convergens Guérin-Méneville, when preying upon the aphids Aphis glycines Matsumura (Hemiptera: Aphididae), Aphis gossypii Glover (Hemiptera: Aphididae), and Myzus persicae (Sulzer) (Hemiptera: Aphididae). Aphids were exposed to thiamethoxam-treated or untreated plants every week over the course of 5 wk. After transferring aphids to Petri dishes, predators were allowed to feed on aphids. We found that the survival of the insidiosus flower bug, but not the convergent lady beetle, was reduced after consuming aphids reared on thiamethoxam-treated plants compared to untreated plants. Survival reduction of the insidiosus flower bug was observed only during the first weeks after thiamethoxam application; no reduction occurred 28 d after treatment or beyond. These results demonstrate that a systemic application of thiamethoxam could be compatible with convergent lady beetles and insidiosus flower bugs, if the time of predator release does not coincide with thiamethoxam activity. These findings are critical for the development of future pest control programs that integrate biological and chemical control.

Performance of Field-Collected Spodoptera frugiperda (Lepidoptera: Noctuidae) Strains Exposed to Different Transgenic and Refuge Maize Hybrids in Argentina.

Spodoptera frugiperda (J. E. Smith) is one of the major pests of maize in Argentina. The main tool for its control is the use of genetically modified maize hybrids expressing Bacillus thuringiensis (Bt) insecticidal proteins. Maize growers in Argentina initially controlled this pest with Bt maize that expressed a single Bt protein (Cry1Ab or Cry1F). Currently it is necessary to plant maize cultivars that produce two Bt proteins to achieve the satisfactory control. Recently, Cry1F field-evolved resistant populations of this species were confirmed in Argentina. The objective of this study was to evaluate the performance of S. frugiperda field-collected strains on different Bt and non-Bt maize hybrids. Strains were collected from non-Bt maize (T1), Agrisure TDMax (T2), Agrisure Viptera (T3), Agrisure Viptera 3110 (T4), Genuity VT Triple Pro (T5), and Power Core (T6). Three experiments were performed to 1) determine the survivorship and reproduction of field-collected larvae (F0) from Bt maize hybrids, 2) evaluate Cry1F resistance using an F1 screen, and 3) assess the performance of F1 strains on different maize hybrids. In the F0, the survivorship from larva to adult ranged from 0 to 63%. We obtained adults from only the T1, T2, T5, and T6 strains with no significant differences in the reproductive parameters. Continuously rearing F1 larvae on their collected hosts affected larval duration, which was significantly shorter for a known-laboratory Bt-susceptible strain than the field-collected strains. Our results support the existence of Cry1F-resistance alleles in S. frugiperda field populations in Argentina.

Influence of historical land use and modern agricultural expansion on the spatial and ecological divergence of sugarcane borer, Diatraea saccharalis (Lepidoptera: Crambidae) in Brazil.

Human-mediated changes in landscapes can facilitate niche expansion and accelerate the adaptation of insect species. The interaction between the evolutionary history of the sugarcane borer, Diatraea saccharalis Fabricius, and historical and modern agricultural activity in Brazil shaped its spatial genetic structure, facilitating ecological divergence and incipient host shifting. Based on microsatellite data, STRUCTURE analyses identified two (K = 2) and three (K = 3) significant genetic clusters that corresponded to: (a) a strong signal of spatial genetic structure and, (b) a cryptic signal of host differentiation. We inferred that K = 2 reflects the footprint of agricultural activity, such as expansion of crop production (sugarcane and maize), unintentional dispersion of pests, and management practices. In contrast, K = 3 indicated incipient host differentiation between larvae collected from sugarcane or maize. Our estimates of population size changes indicated that a historical bottleneck was associated with a reduction of sugarcane production ≈200 years ago. However, a more recent population expansion was detected (>1950s), associated with agricultural expansion of large crop production into previously unfarmed land. Partial Mantel tests supported our hypothesis of incipient host adaptation, and identified isolation-by-environment (e.g., host plant) in São Paulo and Minas Gerais states, where sugarcane has been traditionally produced in Brazil. The impact of agricultural production on D. saccharalis may continue, as the current population structure may hinder the efficacy of refuge plants in delaying insect resistance evolution to Bt toxin.

Transcriptomic dynamics in soybean near-isogenic lines differing in alleles for an aphid resistance gene, following infestation by soybean aphid biotype 2.

BACKGROUND: Genetic resistance of soybean [Glycine max (L.) Merr] against Aphis glycines provides effective management of this invasive pest, though the underlying molecular mechanisms are largely unknown. This study aimed to investigate genome-wide changes in gene expressions of soybean near-isogenic lines (NILs) either with the Rag5 allele for resistance or the rag5 allele for susceptibility to the aphid following infestation with soybean aphid biotype 2. RESULTS: The resistant (R)-NIL responded more rapidly to aphid infestation than the susceptible (S)-NIL, with differential expressions of 2496 genes during first 12 h of infestation (hai), compared to the aphid-free control. Although the majority of the differentially expressed genes (DEGs) in the R-NIL also responded to aphid infestation in S-NIL, overall the response time was longer and/or the magnitude of change was smaller in the S-NIL. In addition, 915 DEGs in R-NIL continued to be regulated at all time points (0, 6, 12, and 48 hai), while only 20 DEGs did so in S-NIL. Enriched gene ontology of the 2496 DEGs involved in plant defense responses including primary metabolite catalysis, oxidative stress reduction, and phytohormone-related signaling. By comparing R- vs. S-NIL, a total of 556 DEGs were identified. Of the 13 genes annotated in a 120-kb window of the Rag5 locus, two genes (Glyma.13 g190200 and Glyma.13 g190600) were differentially expressed (upregulated in S- or R-NIL), and another gene (Glyma.13 g190500) was induced up to 4-fold in the R-NIL at 6 and 12 h following aphid infestation. CONCLUSIONS: This study strengthens our understanding of the defense dynamics in compatible and incompatible interactions of soybean and soybean aphid biotype 2. Several DEGs (e.g., Glyma.13 g190200, Glyma.13 g190500, and Glyma.13 g190600) near the Rag5 locus are strong candidate genes for further investigations.

Shifts in Buchnera aphidicola density in soybean aphids (Aphis glycines) feeding on virus-infected soybean.

Vertically transmitted bacterial symbionts are common in arthropods. Aphids undergo an obligate symbiosis with Buchnera aphidicola, which provides essential amino acids to its host and contributes directly to nymph growth and reproduction. We previously found that newly adult Aphis glycines feeding on soybean infected with the beetle-transmitted Bean pod mottle virus (BPMV) had significantly reduced fecundity. We hypothesized that the reduced fecundity was attributable to detrimental impacts of the virus on the aphid microbiome, namely Buchnera. To test this, mRNA sequencing and quantitative real-time PCR were used to assay Buchnera transcript abundance and titre in A. glycines feeding on Soybean mosaic virus-infected, BPMV-infected, and healthy soybean for up to 14 days. Our results indicated that Buchnera density was lower and ultimately suppressed in aphids feeding on virus-infected soybean. While the decreased Buchnera titre may be associated with reduced aphid fecundity, additional mechanisms are probably involved. The present report begins to describe how interactions among insects, plants, and plant pathogens influence endosymbiont population dynamics.

Identification and mapping of quantitative trait loci (QTL) conferring resistance to Fusarium graminearum from soybean PI 567301B.

KEY MESSAGE: A major novel QTL was identified in a recombinant inbred line population derived from a cross of 'Wyandot' × PI 567301B for Fusarium graminearum, a seed and seedling pathogen of soybean. Fusarium graminearum is now recognized as a primary pathogen of soybean, causing root, seed rot and seedling damping-off in North America. In a preliminary screen, 'Wyandot' and PI 567301B were identified with medium and high levels of partial resistance to F. graminearum, respectively. The objective of this study was to characterise resistance towards F. graminearum using 184 recombinant inbred lines (RILs) derived from a cross of 'Wyandot' × PI 567301B. The parents and the RILs of the mapping population were evaluated for resistance towards F. graminearum using the rolled towel assay in a randomized incomplete block design. A genetic map was constructed from 2545 SNP markers and 2 SSR markers by composite interval mapping. One major and one minor QTL were identified on chromosomes 8 and 6, respectively, which explained 38.5 and 8.1 % of the phenotypic variance. The major QTL on chromosome 8 was mapped to a 300 kb size genomic region of the Williams 82 sequence. Annotation of this region indicates that there are 39 genes including the Rhg4 locus for soybean cyst nematode (SCN) resistance. Based on previous screens, PI 567301B is susceptible to SCN. Fine mapping of this locus will assist in cloning these candidate genes as well as identifying DNA markers flanking the QTL that can be used in marker-assisted breeding to develop cultivars with high levels of resistance to F. graminearum.

Nanoparticles Containing High Loads of Paclitaxel-Silicate Prodrugs: Formulation, Drug Release, and Anticancer Efficacy.

We have investigated particle size, interior structure, drug release kinetics, and anticancer efficacy of PEG-b-PLGA-based nanoparticles loaded with a series of paclitaxel (PTX)-silicate prodrugs [PTX-Si(OR)3]. Silicate derivatization enabled us to adjust the hydrophobicity and hydrolytic lability of the prodrugs by the choice of the alkyl group (R) in the silicate derivatives. The greater hydrophobicity of these prodrugs allows for the preparation of nanoparticles that are stable in aqueous dispersion even when loaded with up to ca. 75 wt % of the prodrug. The hydrolytic lability of silicates allows for facile conversion of prodrugs back to the parent drug, PTX. A suite of eight PTX-silicate prodrugs was investigated; nanoparticles were made by flash nanoprecipitation (FNP) using a confined impingement jet mixer with a dilution step (CIJ-D). The resulting nanoparticles were 80-150 nm in size with a loading level of 47-74 wt % (wt %) of a PTX-silicate, which corresponds to 36-59 effective wt % of free PTX. Cryogenic transmission electron microscopy images show that particles are typically spherical with a core-shell structure. Prodrug/drug release profiles were measured. Release tended to be slower for prodrugs having greater hydrophobicity and slower hydrolysis rate. Nanoparticles loaded with PTX-silicate prodrugs that hydrolyze most rapidly showed in vitro cytotoxicity similar to that of the parent PTX. Nanoparticles loaded with more labile silicates also tended to show greater in vivo efficacy.

Virus-independent and common transcriptome responses of leafhopper vectors feeding on maize infected with semi-persistently and persistent propagatively transmitted viruses.

BACKGROUND: Insects are the most important epidemiological factors for plant virus disease spread, with >75% of viruses being dependent on insects for transmission to new hosts. The black-faced leafhopper (Graminella nigrifrons Forbes) transmits two viruses that use different strategies for transmission: Maize chlorotic dwarf virus (MCDV) which is semi-persistently transmitted and Maize fine streak virus (MFSV) which is persistently and propagatively transmitted. To date, little is known regarding the molecular and cellular mechanisms in insects that regulate the process and efficiency of transmission, or how these mechanisms differ based on virus transmission strategy. RESULTS: RNA-Seq was used to examine transcript changes in leafhoppers after feeding on MCDV-infected, MFSV-infected and healthy maize for 4 h and 7 d. After sequencing cDNA libraries constructed from whole individuals using Illumina next generation sequencing, the Rnnotator pipeline in Galaxy was used to reassemble the G. nigrifrons transcriptome. Using differential expression analyses, we identified significant changes in transcript abundance in G. nigrifrons. In particular, transcripts implicated in the innate immune response and energy production were more highly expressed in insects fed on virus-infected maize. Leafhoppers fed on MFSV-infected maize also showed an induction of transcripts involved in hemocoel and cell-membrane linked immune responses within four hours of feeding. Patterns of transcript expression were validated for a subset of transcripts by quantitative real-time reverse transcription polymerase chain reaction using RNA samples collected from insects fed on healthy or virus-infected maize for between a 4 h and seven week period. CONCLUSIONS: We expected, and found, changes in transcript expression in G. nigrifrons feeding of maize infected with a virus (MFSV) that also infects the leafhopper, including induction of immune responses in the hemocoel and at the cell membrane. The significant induction of the innate immune system in G. nigrifrons fed on a foregut-borne virus (MCDV) that does not infect leafhoppers was less expected. The changes in transcript accumulation that occur independent of the mode of pathogen transmission could be key for identifying insect factors that disrupt vector-mediated plant virus transmission.

Flash nanoprecipitation: particle structure and stability.

Flash nanoprecipitation (FNP) is a process that, through rapid mixing, stabilizes an insoluble low molecular weight compound in a nanosized, polymer-stabilized delivery vehicle. The polymeric components are typically amphiphilic diblock copolymers (BCPs). In order to fully exploit the potential of FNP, factors affecting particle structure, size, and stability must be understood. Here we show that polymer type, hydrophobicity and crystallinity of the small molecule, and small molecule loading levels all affect particle size and stability. Of the four block copolymers (BCP) that we have studied here, poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) (PEG-b-PLGA) was most suitable for potential drug delivery applications due to its ability to give rise to stable nanoparticles, its biocompatibility, and its degradability. We found little difference in particle size when using PLGA block sizes over the range of 5 to 15 kDa. The choice of hydrophobic small molecule was important, as molecules with a calculated water-octanol partition coefficient (clogP) below 6 gave rise to particles that were unstable and underwent rapid Ostwald ripening. Studies probing the internal structure of nanoparticles were also performed. Analysis of differential scanning calorimetry (DSC), cryogenic transmission electron microscopy (cryo-TEM), and (1)H NMR experiments support a three-layer core-shell-corona nanoparticle structure.

Population genetic structure and genetic diversity of soybean aphid collections from the USA, South Korea, and Japan.

Following its recent invasion of North America, the soybean aphid (Aphis glycines Matsumura) has become the number one insect pest of soybean (Glycine max L. Merr.) in the north central states of the USA. A few studies have been conducted on the population genetic structure and genetic diversity of the soybean aphid and the source of its invasion in North America. Molecular markers, such as simple sequence repeats (SSRs) are very useful in the evaluation of population structure and genetic diversity. We used 18 SSR markers to assess the genetic diversity of soybean aphid collections from the USA, South Korea, and Japan. The aphids were collected from two sites in the USA (Indiana and South Dakota), two sites in South Korea (Yeonggwang district and Cheonan city), and one site in Japan (Utsunomiya). The SSR markers were highly effective in differentiating among aphid collections from different countries. The level of differentiation within each population and among populations from the same country was limited, even in the case of the USA where the two collection sites were more than 1200 km apart.

Widespread genomic divergence during sympatric speciation.

Speciation with gene flow is expected to generate a heterogeneous pattern of genomic differentiation. The few genes under or physically linked to loci experiencing strong disruptive selection can diverge, whereas gene flow will homogenize the remainder of the genome, resulting in isolated "genomic islands of speciation." We conducted an experimental test of this hypothesis in Rhagoletis pomonella, a model for sympatric ecological speciation. Contrary to expectations, we found widespread divergence throughout the Rhagoletis genome, with the majority of loci displaying host differences, latitudinal clines, associations with adult eclosion time, and within-generation responses to selection in a manipulative overwintering experiment. The latter two results, coupled with linkage disequilibrium analyses, provide experimental evidence that divergence was driven by selection on numerous independent genomic regions rather than by genome-wide genetic drift. "Continents" of multiple differentiated loci, rather than isolated islands of divergence, may characterize even the early stages of speciation. Our results also illustrate how these continents can exhibit variable topography, depending on selection strength, availability of preexisting genetic variation, linkage relationships, and genomic features that reduce recombination. For example, the divergence observed throughout the Rhagoletis genome was clearly accentuated in some regions, such as those harboring chromosomal inversions. These results highlight how the individual genes driving speciation can be embedded within an actively diverging genome.

Optimizing a rapid LAMP assay for discrimination of Drosophila suzukii (Diptera: Drosophilidae) from common drosophilids captured in monitoring traps from the Midwest, United States.

Spotted-wing Drosophila, Drosophila suzukii, is an economically important pest of small fruits worldwide. Currently, the timing of management strategies relies on detection of adult flies captured in baited monitoring traps; however, identifying D. suzukii in trap catch based on morphology can be challenging for growers. DNA-based diagnostic methods such as loop-mediated isothermal amplification (LAMP) have the potential to improve D. suzukii detection. This study evaluated a LAMP assay as a diagnostic tool to discriminate between D. suzukii and closely related drosophilid species found commonly in monitoring traps in the Midwestern United States. Targeting the mitochondrial cytochrome oxidase I (COI) gene, we found the LAMP assay accurately detected D. suzukii with as little as 0.1 ng/µl of DNA at 63 °C for 50 min. Under these optimal incubation conditions, D. suzukii could be discriminated from D. affinis and D. simulans consistently, when specimens collected from liquid monitoring traps were tested independently. Compared to other DNA-based diagnostic tools for D. suzukii, LAMP offers unique benefits: DNA extraction is not required, testing occurs at one temperature in less than 1 h, and positive results are visible as a colorimetric change from pink to yellow. The LAMP assay for D. suzukii can reduce reliance on morphological identification, enhance the adoption of monitoring tools, and improve accuracy of detection. Further optimization can be conducted to evaluate the accuracy and sensitivity of results when a mixture of DNA from both D. suzukii and congener flies are tested in a single LAMP reaction.

Genetic mutations linked to field-evolved Cry1Fa-resistance in the European corn borer, Ostrinia nubilalis.

Transgenic corn, Zea mays (L.), expressing insecticidal toxins such as Cry1Fa, from Bacillus thuringiensis (Bt corn) targeting Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) resulted in over 20 years of management success. The first case of practical field-evolved resistance by O. nubilalis to a Bt corn toxin, Cry1Fa, was discovered in Nova Scotia, Canada, in 2018. Laboratory-derived Cry1Fa-resistance by O. nubilalis was linked to a genome region encoding the ATP Binding Cassette subfamily C2 (ABCC2) gene; however, the involvement of ABCC2 and specific mutations in the gene leading to resistance remain unknown. Using a classical candidate gene approach, we report on O. nubilalis ABCC2 gene mutations linked to laboratory-derived and field-evolved Cry1Fa-resistance. Using these mutations, a DNA-based genotyping assay was developed to test for the presence of the Cry1Fa-resistance alleles in O. nubilalis strains collected in Canada. Screening data provide strong evidence that field-evolved Cry1Fa-resistance in O. nubilalis maps to the ABCC2 gene and demonstrates the utility of this assay for detecting the Cry1Fa resistance allele in O. nubilalis. This study is the first to describe mutations linked to Bt resistance in O. nubilalis and provides a DNA-based detection method that can be used for monitoring.

Distribution of SUN, OVATE, LC, and FAS in the tomato germplasm and the relationship to fruit shape diversity.

Phenotypic diversity within cultivated tomato (Solanum lycopersicum) is particularly evident for fruit shape and size. Four genes that control tomato fruit shape have been cloned. SUN and OVATE control elongated shape whereas FASCIATED (FAS) and LOCULE NUMBER (LC) control fruit locule number and flat shape. We investigated the distribution of the fruit shape alleles in the tomato germplasm and evaluated their contribution to morphology in a diverse collection of 368 predominantly tomato and tomato var. cerasiforme accessions. Fruits were visually classified into eight shape categories that were supported by objective measurements obtained from image analysis using the Tomato Analyzer software. The allele distribution of SUN, OVATE, LC, and FAS in all accessions was strongly associated with fruit shape classification. We also genotyped 116 representative accessions with additional 25 markers distributed evenly across the genome. Through a model-based clustering we demonstrated that shape categories, germplasm classes, and the shape genes were nonrandomly distributed among five genetic clusters (P < 0.001), implying that selection for fruit shape genes was critical to subpopulation differentiation within cultivated tomato. Our data suggested that the LC, FAS, and SUN mutations arose in the same ancestral population while the OVATE mutation arose in a separate lineage. Furthermore, LC, OVATE, and FAS mutations may have arisen prior to domestication or early during the selection of cultivated tomato whereas the SUN mutation appeared to be a postdomestication event arising in Europe.

Genetic mapping revealed two loci for soybean aphid resistance in PI 567301B.

The soybean aphid (Aphis glycines Matsumura) is the most damaging insect pest of soybean [Glycine max (L.) Merr.] in North America. New soybean aphid biotypes have been evolving quickly and at least three confirmed biotypes have been reported in USA. These biotypes are capable of defeating most known aphid resistant soybean genes indicating the need for identification of new genes. Plant Introduction (PI) 567301B was earlier identified to have antixenosis resistance against biotype 1 and 2 of the soybean aphid. Two hundred and three F(7:9) recombinant inbred lines (RILs) developed from a cross of soybean aphid susceptible cultivar Wyandot and resistant PI 567301B were used for mapping aphid resistance genes using the quantitative trait loci (QTL) mapping approach. A subset of 94 RILs and 516 polymorphic SNP makers were used to construct a genome-wide molecular linkage map. Two candidate QTL regions for aphid resistance were identified on this linkage map. Fine mapping of the QTL regions was conducted with SSR markers using all 203 RILs. A major gene on chromosome 13 was mapped near the previously identified Rag2 gene. However, an earlier study revealed that the detached leaves of PI 567301B had no resistance against the soybean aphids while the detached leaves of PI 243540 (source of Rag2) maintained aphid resistance. These results and the earlier finding that PI 243540 showed antibiosis resistance and PI 567301B showed antixenosis type resistance, indicating that the aphid resistances in the two PIs are not controlled by the same gene. Thus, we have mapped a new gene near the Rag2 locus for soybean aphid resistance that should be useful in breeding for new aphid-resistant soybean cultivars. Molecular markers closely linked to this gene are available for marker-assisted breeding. Also, the minor locus found on chromosome 8 represents the first reported soybean aphid-resistant locus on this chromosome.

Genetic mapping of the powdery mildew resistance gene in soybean PI 567301B.

Powdery mildew (PMD) of soybean [Glycine max (L.) Merr.] is caused by the fungus Microsphaera diffusa. Severe infection of PMD on susceptible varieties often causes premature defoliation and chlorosis of the leaves, which can result in considerable yield losses under favorable environmental conditions for disease development in the field. A total of 334 F(7)-derived recombinant inbred lines (RILs) from a cross of a PMD susceptible soybean cultivar Wyandot and PMD-resistant PI 567301B were used for genetic mapping of PMD resistance in PI 567301B and for development of molecular markers tightly linked to the gene. The result of the PMD screening for each line in the field was in agreement with that in the greenhouse test. The genetic map containing the PMD resistance gene was constructed in a 3.3 cM interval flanked by two simple sequence repeat (SSR) markers on chromosome 16. The PMD resistance gene was mapped at the same location with SSR marker BARCSOYSSR_16_1291, indicating that there was no recombination between the 334 RILs and this marker. In addition, a single nucleotide polymorphism (SNP) marker developed by high-resolution melting curve analysis and a cleaved amplified polymorphic sequence (CAPS) marker with Rsa1 recognition site were used for the genetic mapping. These two markers were also mapped to the same genomic location with the PMD resistance gene. We validated three tightly linked markers to the PMD resistance gene using 38 BC(6)F(2) lines and corresponding BC(6)F(2:3) families. The three marker genotypes of the backcross lines predicted the observed PMD phenotypes of the lines with complete accuracy. We have mapped a putatively novel single dominant PMD resistance gene in PI 567301B and developed three new molecular markers closely linked to the gene. Molecular markers developed from this study may be used for high-throughput marker-assisted breeding for PMD resistance with the gene from PI 567301B.

Development of soybean aphid genomic SSR markers using next generation sequencing.

Simple sequence repeats (SSRs) or microsatellites are very useful molecular markers, owing to their locus-specific codominant and multiallelic nature, high abundance in the genome, and high rates of transferability across species. The soybean aphid (Aphis glycines Matsumura) has become the most damaging insect pest of soybean (Glycine max (L.) Merr.) in North America, since it was first found in the Midwest of the United States in 2000. Biotypes of the soybean aphid capable of colonizing newly developed aphid-resistant soybean cultivars have been recently discovered. Genetic resources, including molecular markers, to study soybean aphids are severely lacking. Recently developed next generation sequencing platforms offer opportunities for high-throughput and inexpensive genome sequencing and rapid marker development. The objectives of this study were (i) to develop and characterize genomic SSR markers from soybean aphid genomic sequences generated by next generation sequencing technology and (ii) to evaluate the utility of the SSRs for genetic diversity or relationship analyses. In total 128 SSR primer pairs were designed from sequences generated by Illumina GAII from a reduced representation library of A. glycines. Nearly 94% (120) of the primer pairs amplified SSR alleles of expected size and 24 SSR loci were polymorphic among three aphid samples from three populations. The polymorphic SSRs were successfully used to differentiate among 24 soybean aphids from Ohio and South Dakota. Sequencing of PCR products of two SSR markers from four aphid samples revealed that the allelic polymorphism was due to variation in the SSR repeats among the aphids. These markers should be particularly useful for genetic differentiation among aphids collected from soybean fields at different localities and regions. These SSR markers provide the soybean aphid research community with the first set of PCR-based codominant markers developed from the genomic sequences of A. glycines.

Psychiatry after virtue: a modern practice in the ruins.

Contemporary psychiatry maintains the myth that it is value neutral by appeal to modern medical science for both its diagnostic categories and its therapeutic interventions, leaving the impression that it relies on reason--that is to say, reason divorced from tradition--to master human nature. Such a practice has a certain way of characterizing and defining humanity's lapses from acceptable human behavior--a lapse from human being. The modern practice of psychiatry applies a particular notion (largely influenced by Enlightenment ideals) of scientific instrumentation to the human person in order to diagnose the ailment and manufacture a corresponding treatment in keeping with a hidden conception of human biological flourishing. This covert vision is an impoverished (and possibly dangerous) one. As much as the practice of psychiatry is constrained by the goals of the dominant moral tradition of our day, it becomes a tool (or technique) for achieving the transient and partial ends of modern individualism. Given this truncated view of human nature and human end, modern psychiatry fails to attend comprehensively to the unity of a life, missing altogether the essential relevance of character formation, and thereby forfeiting excellence in human flourishing.

Presence-Absence Sampling Plans for Stink Bugs (Hemiptera: Pentatomidae) in the Midwest Region of the United States.

Stink bugs represent an increasing risk to soybean production in the Midwest region of the United States. The current sampling protocol for stink bugs in this region is tailored for population density estimation and thus is more relevant to research purposes. A practical decision-making framework with more efficient sampling effort for management of herbivorous stink bugs is needed. Therefore, a binomial sequential sampling plan was developed for herbivorous stink bugs in the Midwest region. A total of 146 soybean fields were sampled across 11 states using sweep nets in 2016, 2017, and 2018. The binomial sequential sampling plans were developed using combinations of five tally thresholds at two proportion infested action thresholds to identify those that provided the best sampling outcomes. Final assessment of the operating characteristic curves for each plan indicated that a tally threshold of 3 stink bugs per 25 sweeps, and proportion infested action thresholds of 0.75 and 0.95 corresponding to the action thresholds of 5 and 10 stink bugs per 25 sweeps, provided the optimal balance between highest probability of correct decisions (≥ 99%) and lowest probability of incorrect decisions (≤ 1%). In addition, the average sample size for both plans (18 and 12 sets of 25 sweeps, respectively) was lower than that for the other proposed plans. The binomial sequential sampling plan can reduce the number of sample units required to achieve a management decision, which is important because it can potentially reduce risk/cost of management for stink bugs in soybean in this region.