A Plant Stress-Responsive Bioreporter Coupled With Transcriptomic Analysis Allows Rapid Screening for Biocontrols of Necrotrophic Fungal Pathogens.

Streptomyces are soil-borne Actinobacteria known to produce a wide range of enzymes, phytohormones, and metabolites including antifungal compounds, making these microbes fitting for use as biocontrol agents in agriculture. In this study, a plant reporter gene construct comprising the biotic stress-responsive glutathione S-transferase promoter GSTF7 linked to a luciferase output (GSTF7:luc) was used to screen a collection of Actinobacteria candidates for manipulation of plant biotic stress responses and their potential as biocontrol agents. We identified a Streptomyces isolate (KB001) as a strong candidate and demonstrated successful protection against two necrotrophic fungal pathogens, Sclerotinia sclerotiorum and Rhizoctonia solani, but not against a bacterial pathogen (Pseudomonas syringe). Treatment of Arabidopsis plants with either KB001 microbial culture or its secreted compounds induced a range of stress and defense response-related genes like pathogenesis-related (PR) and hormone signaling pathways. Global transcriptomic analysis showed that both treatments shared highly induced expression of reactive oxygen species and auxin signaling pathways at 6 and 24 h posttreatment, while some other responses were treatment specific. This study demonstrates that GSTF7 is a suitable marker for the rapid and preliminary screening of beneficial bacteria and selection of candidates with potential for application as biocontrols in agriculture, including the Streptomyces KB001 that was characterized here, and could provide protection against necrotrophic fungal pathogens.

Developing Actinobacterial Endophytes as Biocontrol Products for Fusarium pseudograminearum in Wheat.

Crown rot of wheat, caused by Fusarium pseudograminearum, results in millions of dollars of yield losses globally each year. Management strategies to control crown rot are limited and there are concerns about development of fungicide resistance so novel treatment strategies are desirable. A collection of endophytic Actinobacteria was screened for their ability to suppress the growth of F. pseudograminearum and the development of crown rot symptoms in wheat with the aim of identifying candidates that can be developed into biocontrol products. The ability of the Actinobacteria isolates to suppress the growth of three different F. pseudograminearum strains in vitro was assessed using agar-plate competition assays. Soil-free seedling assays were used to screen for suppression of development of early disease symptoms in the susceptible wheat (Triticum aestivum) cv. Tamaroi. Four of the isolates were tested in a glasshouse pot experiment to assess their ability to decrease disease symptoms and prevent yield losses in wheat cv. Tamaroi grown to maturity in an unsterilized soil. The screening of 53 isolates identified two Streptomyces isolates, MH71 and MH243, with very strong antifungal activity against F. pseudograminearum strains in agar-plate competition and seedling assays. In the glasshouse pot trial, plants treated with seed coatings of either MH71 or MH243 had > 24% lower disease severity than control plants infected with F. pseudograminearum. These two cultures show potential for development as biocontrol products because they are easy to culture, grow on relatively inexpensive media, produce highly durable spores and can be delivered to plants as a seed coat.

Draft Genome Sequences of Streptomyces sp. Strains MH60 and 111WW2.

We report here the draft genome sequences, annotations, and predictions of secondary metabolite gene clusters of two endophytic Streptomyces species isolated from wheat plants growing in the Western Australian wheat belt. These strains, Streptomyces sp. strains MH60 and 111WW2, possess antifungal and/or plant growth-promoting activities.

Draft Genome Sequence of Rhodococcus sp. Strain 66b.

We report here the draft genome sequence and annotation of Rhodococcus sp. strain 66b isolated from the soil of southwest Western Australia. This strain exhibits a range of bioactivities, including plant growth promotion, biosurfactant production, and wax degradation. Whole-genome sequencing was conducted to uncover the underlying mechanisms.

Dimethylarsenate (DMA) exposure influences germination rates, arsenic uptake and arsenic species formation in wheat.

The contamination of cereals with arsenic (As) is a global health and agronomic concern. This study compared the physiological response, As uptake and As speciation in the grains and above ground tissues of 20 wheat cultivars exposed to 5 mg As kg-1 soil as either arsenate (AsV) or dimethylarsenate (DMA) under glasshouse conditions. Germination rates for the majority of cultivars exceeded 80% for the majority of cultivars when exposed to AsV, but fell significantly to 20-40% when exposed to DMA. For a number of cultivars, grain yields were 20-50% lower when plants were exposed to DMA compared to AsV. Grain As concentrations were between 0.6 and 1.6 µg As g-1 grain across the twenty cultivars when exposed to AsV, whereas grain As concentrations were much higher (2.2-4.6 µg As g-1 grain) when exposed to DMA. When plants were exposed to AsV, 100% of the As present in the grain was found as inorganic As while in plants exposed to DMA, 70-90% of As was present as DMA with the remainder found as inorganic As. DMA is believed to be incorporated by plants via silica (Si) acid channels and assessment of grain Si concentrations demonstrated that up to 40% less Si was accumulated in grains when plants were exposed to DMA. The decreased germination rates and grain yields in the presence of DMA is similar to the symptoms described for straight head disease in rice, which has been linked to DMA exposure. The results presented here indicate some analogous processes occur in wheat to those described in rice. We hypothesise that exposure to DMA may have inhibited Si-metabolism and translocation which resulted in both developmental impairment and possibly an increased susceptibility to soil pathogens.

Selenium speciation in wheat grain varies in the presence of nitrogen and sulphur fertilisers.

This study investigated whether selenium species in wheat grains could be altered by exposure to different combinations of nitrogen (N) and sulphur (S) fertilisers in an agronomic biofortification experiment. Four Australian wheat cultivars (Mace, Janz, Emu Rock and Magenta) were grown in a glasshouse experiment and exposed to 3 mg Se kg-1 soil as selenate (SeVI). Plants were also exposed to 60 mg N kg-1 soil as urea and 20 mg S kg-1 soil as gypsum in a factorial design (N + S + Se; N + Se; S + Se; Se only). Plants were grown to maturity with grain analysed for total Se concentrations via ICP-MS and Se species determined via HPLC-ICP-MS. Grain Se concentrations ranged from 22 to 70 µg Se g-1 grain (dry mass). Selenomethionine (SeMet), Se-methylselenocystine (MeSeCys), selenohomolanthionine (SeHLan), plus a large concentration of uncharacterised Se species were found in the extracts from grains. SeMet was the major Se species identified accounting for between 9 and 24 µg Se g-1 grain. Exposure to different N and S fertiliser combinations altered the SeMet content of Mace, Janz and Emu Rock grain, but not that of Magenta. MeSeCys and SeHLan were found in far lower concentrations (<4 µg Se g-1 grain). A large component of the total grain Se was uncharacterisable (>30 % of total grain Se) in all samples. When N fertiliser was applied (with or without S), the proportion of uncharacterisable Se increased between 60 and 70 % of the total grain Se. The data presented here indicate that it is possible to alter the content of individual Se species in wheat grains via biofortification combined with manipulation of N and S fertiliser regimes. This has potential significance in alleviating or combating both Se deficiency and Se toxicity effects in humans.

A composite guanyl thiourea (GTU), dicyandiamide (DCD) inhibitor improves the efficacy of nitrification inhibition in soil.

This study investigated whether applying dicyandiamide (DCD) and guanyl thiourea (GTU) in conjunction with urea improves the efficacy of nitrification inhibition relative to traditional fertiliser application of urea or urea + DCD. Urea at a rate of 100 mg N kg(-1) soil was applied to soil microcosms (high nutrient tenosol and low nutrient hydrosol) which were treated with either no inhibitor (urea-only); 15 mg DCD kg(-1) soil or 15 mg DCD kg(-1) soil plus 21 mg GTU kg soil(-1). Mineral N (NH4(+) & NO3(-)) concentrations, potential nitrification rates (PNR) and abundances of ammonia oxidising bacteria (AOB) were measured over time. After 100-days incubation, ∼73 mg N kg(-1) soil was found as NH4(+) when urea + DCD + GTU were applied to the tenosol. NH4(+) concentrations were lower (11-32 mg N kg(-1) soil) when urea or urea + DCD were applied. This suggests that the application of GTU in conjunction with DCD elongated the effects of nitrification inhibition. In both soils, PNRs were faster and AOB abundances (gene copies g(-1) soil) were higher when urea was applied without nitrification inhibitors. There were, however, no differences in PNR or AOB abundances in either soil type when 'urea + DCD' or 'urea + DCD + GTU' were applied. The results indicate that the application of GTU with DCD may extend nitrification inhibition in certain soil types. This finding has the potential to improve the efficacy of commercially available and widely used inhibitors such as DCD.

The services for children and adolescents-parent interview: development and performance characteristics.

OBJECTIVE: To date, no instrument has been developed that captures children's services use across primary care, specialty mental health, and other settings, including setting, treatment type, provider discipline, and length and intensity of specific interventions over varying follow-up periods. The authors developed a highly structured services assessment measure [Services for Children and Adolescents-Parent Interview (SCAPI)] for use in the National Institute of Mental Health Multimodal Treatment Study of Children With Attention Deficit Hyperactivity Disorder (MTA). METHOD: After successfully piloting and refining the SCAPI during initial phases of the MTA, the authors used this measure at 24 months post-randomization to ascertain the previous 6 months of services use for all participating (516 of 579) MTA children and families and 285 age- and gender-matched classroom control children. RESULTS: Findings revealed meaningful, face-valid differences between MTA and control children in levels and types of services used during the previous 6-month period. Services use data reported by parents was substantially in accord with data independently gathered by the research data center. Site variations were found in the level and use of several specific services, such as individual child psychotherapy (sites ranged from 0% to 6.8% among classroom controls compared with 9.7% to 46.1% among MTA participants) and special education services (0% to 14.6% among classroom controls, 27.5% to 34.8% among MTA participants), consistent with differences reported in other studies. CONCLUSIONS: These data support the descriptive validity of SCAPI-ascertained services use data and indicate that the SCAPI can provide investigators and policymakers a valid means of assessing services type, intensity, onset and offset, provider type, and content.

Reliability of the services for children and adolescents-parent interview.

OBJECTIVE: To describe the psychometric properties and test the reliability of a new instrument designed to measure mental health services use within pediatric clinical samples, the Services for Children and Adolescents-Parent Interview (SCAPI), which was developed by the National Institute of Mental Health Multimodal Treatment Study of Children With Attention Deficit Hyperactivity Disorder (MTA). METHOD: Similarities and differences with other measures of services use are described. Ten types of services are measured by the SCAPI. Formal test-retest reliability testing was carried out in 104 subjects with a mean time between tests of 18 days. RESULTS: Test-retest kappa values ranged from 0.49 to 1.00, with an overall kappa value for all services of 0.97. Seven of the 10 service types had kappa values of 0.75 or higher, indicating excellent reliability. In addition, matched responses on specific questions about reasons for seeking services, starting and ending dates, number and length of visits, and type of provider seen were more than 75% for most service categories, consistently so for reporting of medications and school services. CONCLUSIONS: The SCAPI is a reliable instrument for assessing mental health and related services use and may be an especially valuable adjunct in studies involving clinical samples, especially clinical trials.

Prevalence of mood disorders in a national sample of young American adults.

BACKGROUND: Availability of nationally representative mood disorder prevalence estimates in the United States, based on structured psychiatric interviews is limited. This report estimates overall lifetime prevalence of major depressive episode, dysthymia, and bipolar disorder using the Third National Health and Nutrition Examination Survey (NHANES III) and compares these estimates to the Epidemiologic Catchment Area Study (ECA) conducted 10 years earlier. Additionally, prevalence estimate breakdowns by selected sociodemographic and health characteristics are investigated. METHODS: NHANES III, conducted from 1988 to 1994, is a large nationally representative cross-sectional sample of the United States. A population-based sample of 8,602 men and women 17-39 years of age were eligible to participate, of whom 7,667 (89.1 %) completed interviews. Mood disorder assessments came from the Diagnostic Interview Schedule (DIS) administered as one component of the NHANES III. RESULTS: Lifetime prevalence estimates were assessed for six mood measures: 1) major depressive episode (MDE) 8.6%, 2) major depressive episode with severity (MDE-s) 7.7%, 3) dysthymia 6.2%, 4) MDE-s with dysthymia 3.4%, 5) any bipolar disorder 1.6%, and 6) any mood disorder 11.5%. All estimates except for MDE and MDE-s were significantly higher than comparable ECA estimates. CONCLUSIONS: These data provide recent national prevalence estimates. Based on their overall magnitudes, subgroup excesses, and observed increases compared to the ECA, continued monitoring of these estimates is warranted.

Searching for moderators and mediators of pharmacological treatment effects in children and adolescents with anxiety disorders.

OBJECTIVE: To examine whether age, gender, ethnicity, type of anxiety disorder, severity of illness, comorbidity, intellectual level, family income, or parental education may function as moderators and whether treatment adherence, medication dose, adverse events, or blinded rater's guess of treatment assignment may function as mediators of pharmacological treatment effect in children and adolescents with anxiety disorders. METHOD: The database of a recently reported double-blind placebo-controlled trial of fluvoxamine in 128 youths was analyzed. With a mixed-model random-effects regression analysis of the Pediatric Anxiety Rating Scale total score, moderators and mediators were searched by testing for a three-way interaction (strata by treatment by time). A two-way interaction (strata by time) identified predictors of treatment outcome. RESULTS: No significant moderators of efficacy were identified, except for lower baseline depression scores, based on parent's (but not child's) report, being associated with greater improvement (p < .001). Patients with social phobia (p < .05) and greater severity of illness (p < .001) were less likely to improve, independently of treatment assignment. Blinded rater's guess of treatment assignment acted as a possible mediator (p < .001), but improvement was attributed to fluvoxamine, regardless of actual treatment assignment. Treatment adherence tended to be associated (p = .05) with improvement. CONCLUSIONS: In this exploratory study, patient demographics, illness characteristics, family income, and parental education did not function as moderators of treatment effect. Social phobia and severity of illness predicted less favorable outcome. Attribution analyses indicated that study blindness remained intact. The presence of concomitant depressive symptoms deserves attention in future treatment studies of anxious children.

Treatment of pediatric anxiety disorders: an open-label extension of the research units on pediatric psychopharmacology anxiety study.

BACKGROUND: An 8-week placebo-controlled study, the Research Units on Pediatric Psychopharmacology Anxiety Study, documented beneficial effects of fluvoxamine in the treatment of pediatric social anxiety, separation anxiety, or generalized anxiety disorders. Following completion of this study, participants were invited to enter a 6-month open-label treatment phase designed to examine three issues: (a) long-term maintenance of response in fluvoxamine responders, (b) acute response to fluoxetine in fluvoxamine nonresponders, and (c) acute response to fluvoxamine in placebo nonresponders. METHODS: Participants aged 6-17 years meeting criteria for social anxiety, separation anxiety, or generalized anxiety disorders previously treated in an 8-week placebo-controlled trial (n = 128) were offered open treatment. Changes in symptoms of anxiety during open treatment were assessed in three groups: (a) fluvoxamine responders maintained on fluvoxamine, (b) fluvoxamine nonresponders changed to fluoxetine, and (c) placebo nonresponders changed to fluvoxamine. Response was defined based on Clinical Global Impression criteria. RESULTS: During 6 months of continued open treatment, anxiety symptoms remained low in 33 of 35 (94%) subjects who initially responded to fluvoxamine. Among 14 fluvoxamine nonresponders switched to fluoxetine, anxiety symptoms appeared significantly improved in 10 (71%) subjects. Finally, among 48 placebo nonresponders, 27 (56%) showed clinically significant improvement in anxiety on fluvoxamine. CONCLUSION: The current findings concerning extended treatment of pediatric anxiety disorders are only preliminary, because treatment was uncontrolled. Results suggest that an initial fluvoxamine response is likely to be retained with continued treatment, that some fluvoxamine nonresponders may respond to fluoxetine, and that some placebo nonresponders may respond to fluvoxamine.