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Aim: COVID-19 has had significant mental health impacts internationally and anxiety rates are estimated to have tripled during the pandemic, but the specific causes remain underexplored. This study's purpose was to investigate the associations of sociodemographic factors, COVID-19-related policies, and COVID-19 case/mortality rates with levels of anxiety among Canadians during the pandemic., Methods: This study used linear regression models populated with three integrated sources of data: a repeated cross-sectional survey (n = 7008), Oxford COVID-19 Government Response Tracker data, and COVID-19 case/mortality rates. Sociodemographic factors included were age, gender, race, province, income, education, rurality, household composition, and factors related to employment., Results: Local COVID-19 case and mortality rates and stay-at-home orders were positively associated with anxiety symptom severity. Anxiety was most severe among those who: were female, Indigenous, or Middle Eastern; had postsecondary education; lived with others; and became unemployed or had working hours altered during the pandemic. Anxiety was less severe among: older adults; male, Caucasians, and black individuals; those with high incomes, and; those for whom employment did not change during the pandemic., Conclusion: Anxiety was primarily driven by socioeconomic factors among Canadians during the COVID-19 pandemic. Policies that alleviate socioeconomic uncertainty for groups that are most vulnerable may reduce the long-term harm of the pandemic and associated lockdown policies., (© 2022 The Authors. Psychiatry and Clinical Neurosciences © 2022 Japanese Society of Psychiatry and Neurology.)

Objectives: The incidence of type 1 diabetes mellitus is increasing every year requiring substantial expenditure on treatment and complications. A systematic review was conducted on the cost-effectiveness of insulin formulations, including ultralong-, long-, or intermediate-acting insulin, and their biosimilar insulin equivalents., Methods: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, HTA, and NHS EED were searched from inception to June 11, 2021. Cost-effectiveness and cost-utility analyses were included if insulin formulations in adults (≥ 16 years) with type 1 diabetes mellitus were evaluated. Two reviewers independently screened titles, abstracts, and full-text articles, extracted study data, and appraised their quality using the Drummond 10-item checklist. Costs were converted to 2020 US dollars adjusting for inflation and purchasing power parity across currencies., Results: A total of 27 studies were included. Incremental cost-effectiveness ratios ranged widely across the studies. All pairwise comparisons (11 of 11, 100%) found that ultralong-acting insulin was cost-effective compared with other long-acting insulins, including a long-acting biosimilar. Most pairwise comparisons (24 of 27, 89%) concluded that long-acting insulin was cost-effective compared with intermediate-acting insulin. Few studies compared long-acting insulins with one another., Conclusions: Long-acting insulin may be cost-effective compared with intermediate-acting insulin. Future studies should directly compare biosimilar options and long-acting insulin options and evaluate the long-term consequences of ultralong-acting insulins., (Copyright © 2022. Published by Elsevier Inc.)

Background: Older adults experience a high risk of adverse events during hospital-to-home transitions. Implementation barriers have prevented widespread clinical uptake of the various digital health technologies that aim to support hospital-to-home transitions., Objective: To guide the development of a digital health intervention to support transitions from hospital to home (the Digital Bridge intervention), the specific objectives of this review were to describe the various roles and functions of health care providers supporting hospital-to-home transitions for older adults, allowing future technologies to be more targeted to support their work; describe the types of digital health interventions used to facilitate the transition from hospital to home for older adults and elucidate how these interventions support the roles and functions of providers; describe the lessons learned from the design and implementation of these interventions; and identify opportunities to improve the fit between technology and provider functions within the Digital Bridge intervention and other transition-focused digital health interventions., Methods: This 2-phase rapid review involved a selective review of providers' roles and their functions during hospital-to-home transitions (phase 1) and a structured literature review on digital health interventions used to support older adults' hospital-to-home transitions (phase 2). During the analysis, the technology functions identified in phase 2 were linked to the provider roles and functions identified in phase 1., Results: In phase 1, various provider roles were identified that facilitated hospital-to-home transitions, including navigation-specific roles and the roles of nurses and physicians. The key transition functions performed by providers were related to the 3 categories of continuity of care (ie, informational, management, and relational continuity). Phase 2, included articles (n=142) that reported digital health interventions targeting various medical conditions or groups. Most digital health interventions supported management continuity (eg, follow-up, assessment, and monitoring of patients' status after hospital discharge), whereas informational and relational continuity were the least supported. The lessons learned from the interventions were categorized into technology- and research-related challenges and opportunities and informed several recommendations to guide the design of transition-focused digital health interventions., Conclusions: This review highlights the need for Digital Bridge and other digital health interventions to align the design and delivery of digital health interventions with provider functions, design and test interventions with older adults, and examine multilevel outcomes., International Registered Report Identifier (irrid): RR2-10.1136/bmjopen-2020-045596., (©Hardeep Singh, Terence Tang, Carolyn Steele Gray, Kristina Kokorelias, Rachel Thombs, Donna Plett, Matthew Heffernan, Carlotta M Jarach, Alana Armas, Susan Law, Heather V Cunningham, Jason Xin Nie, Moriah E Ellen, Kednapa Thavorn, Michelle LA Nelson. Originally published in JMIR Aging (https://aging.jmir.org), 19.05.2022.)

Background: Digital health technologies have been proposed to support hospital-to-home transition for older adults. The COVID-19 pandemic and the associated physical distancing guidelines have propelled a shift toward digital health technologies. However, the characteristics of older adults who participated in digital health research interventions to support hospital-to-home transitions remain unclear. This information is needed to assess whether current digital health interventions are generalizable to the needs of the broader older adult population., Objective: This rapid review of the existing literature aimed to identify the characteristics of the populations targeted by studies testing the implementation of digital health interventions designed to support hospital-to-home transitions, identify the characteristics of the samples included in studies testing digital health interventions used to support hospital-to-home transitions, and create recommendations for enhancing the diversity of samples within future hospital-to-home digital health interventions., Methods: A rapid review methodology based on scoping review guidelines by Arksey and O'Malley was developed. A search for peer-reviewed literature published between 2010 and 2021 on digital health solutions that support hospital-to-home transitions for older adults was conducted using MEDLINE, Embase, and CINAHL databases. The data were analyzed using descriptive statistics and qualitative content analysis. The Sex- and Gender-Based Analysis Plus lens theoretically guided the study design, analysis, and interpretation., Results: A total of 34 studies met the inclusion criteria. Our findings indicate that many groups of older adults were excluded from these interventions and remain understudied. Specifically, the oldest old and those living with cognitive impairments were excluded from the studies included in this review. In addition, very few studies have described the characteristics related to gender diversity, education, race, ethnicity, and culture. None of the studies commented on the sexual orientation of the participants., Conclusions: This is the first review, to our knowledge, that has mapped the literature focusing on the inclusion of older adults in digital hospital-to-home interventions. The findings suggest that the literature on digital health interventions tends to operationalize older adults as a homogenous group, ignoring the heterogeneity in older age definitions. Inconsistency in the literature surrounding the characteristics of the included participants suggests a need for further study to better understand how digital technologies to support hospital-to-home transitions can be inclusive., (©Kristina Marie Kokorelias, Michelle LA Nelson, Terence Tang, Carolyn Steele Gray, Moriah Ellen, Donna Plett, Carlotta Micaela Jarach, Jason Xin Nie, Kednapa Thavorn, Hardeep Singh. Originally published in JMIR Aging (https://aging.jmir.org), 27.04.2022.)

Plant pathogens cause yield losses in crops worldwide. Breeding for improved disease resistance and management by precision agriculture are two approaches to limit such yield losses. Both rely on detecting and quantifying signs and symptoms of plant disease. To achieve this, the field of plant phenotyping makes use of non-invasive sensor technology. Compared to invasive methods, this can offer improved throughput and allow for repeated measurements on living plants. Abiotic stress responses and yield components have been successfully measured with phenotyping technologies, whereas phenotyping methods for biotic stresses are less developed, despite the relevance of plant disease in crop production. The interactions between plants and pathogens can lead to a variety of signs (when the pathogen itself can be detected) and diverse symptoms (detectable responses of the plant). Here, we review the strengths and weaknesses of a broad range of sensor technologies that are being used for sensing of signs and symptoms on plant shoots, including monochrome, RGB, hyperspectral, fluorescence, chlorophyll fluorescence and thermal sensors, as well as Raman spectroscopy, X-ray computed tomography, and optical coherence tomography. We argue that choosing and combining appropriate sensors for each plant-pathosystem and measuring with sufficient spatial resolution can enable specific and accurate measurements of above-ground signs and symptoms of plant disease., (© 2022. The Author(s).)

Perinatal mental health issues are a global public health challenge. Worldwide, it is estimated that 10% of pregnant women, and 13% of women who have just given birth, experience a mental disorder. Yet, for many reasons - including stigma, limited access to services, patients' lack of awareness about symptoms, and inadequate professional intervention - actual rates of clinical and subclinical perinatal mental health issues are likely higher. Studies have explored experiences such as postpartum depression, but few involve a wider-ranging exploration of a variety of self-reported perinatal mental health issues through personal narrative. We conducted 21 narrative interviews with women, in two Canadian provinces, about their experiences of perinatal mental health issues. Our aim was to deepen understanding of how individual and cultural narratives of motherhood and perinatal mental health can be sources of shame, guilt, and suffering, but also spaces for healing and recovery. We identified four predominant themes in women's narrative: feeling like a failed mother; societal silencing of negative experiences of motherhood; coming to terms with a new sense of self; and finding solace in shared experiences. These findings are consistent with other studies that highlight the personal challenges associated with perinatal mental health issues, particularly the dread of facing societal norms of the 'good mother'. We also highlight the positive potential for healing and self-care through sharing experiences, and the power of narratives to help shape feelings of self-worth and a new identity. This study adheres to the expectations for conducting and reporting qualitative research., (© 2021 The Authors. International Journal of Mental Health Nursing published by John Wiley & Sons Australia, Ltd.)

Introduction: Older adults may experience challenges during the hospital to home transitions that could be mitigated by digital health solutions. However, to promote adoption in practice and realise benefits, there is a need to specify how digital health solutions contribute to hospital to home transitions, particularly pertinent in this era of social distancing. This rapid review will: (1) elucidate the various roles and functions that have been developed to support hospital to home transitions of care, (2) identify existing digital health solutions that support hospital to home transitions of care, (3) identify gaps and new opportunities where digital health solutions can support these roles and functions and (4) create recommendations that will inform the design and structure of future digital health interventions that support hospital to home transitions for older adults (eg, the pre-trial results of the Digital Bridge intervention; ClinicalTrials.gov Identifier: NCT04287192)., Methods and Analysis: A two-phase rapid review will be conducted to meet identified aims. In phase 1, a selective literature review will be used to generate a conceptual map of the roles and functions of individuals that support hospital to home transitions for older adults. In phase 2, a search on MEDLINE, EMBASE and CINAHL will identify literature on digital health solutions that support hospital to home transitions. The ways in which digital health solutions can support the roles and functions that facilitate these transitions will then be mapped in the analysis and generation of findings., Ethics and Dissemination: This protocol is a review of the literature and does not involve human subjects, and therefore, does not require ethics approval. This review will permit the identification of gaps and new opportunities for digital processes and platforms that enable care transitions and can help inform the design and implementation of future digital health interventions. Review findings will be disseminated through publications and presentations to key stakeholders., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Roots vary their permeability to aid radial transport of solutes towards xylem vessels in response to nutritional cues. Nitrogen (N) depletion was previously shown to induce early suberization of endodermal cell walls and reduce hydraulic conductivity of barley roots suggesting reduced apoplastic transport of ions (Armand et al., 2019). Suberization may also limit transcellular ion movement by blocking access to transporters (Barberon et al., 2016). The aim of this study was to confirm that N depletion induced suberization in the roots of barley and demonstrate that this was a specific effect in response to NO 3 - depletion. Furthermore, in roots with early and enhanced suberization, we assessed their ability for transporter-mediated NO 3 - influx. N depletion induced lateral root elongation and early and enhanced endodermal suberization of the seminal root of each genotype. Both root to shoot NO 3 - translocation and net N uptake was half that of plants supplied with steady-state NO 3 - . Genes with predicted functions in suberin synthesis (HvHORST) and NO 3 - transport (HvNRT2.2) were induced under N-deplete conditions. N-deplete roots had a higher capacity for high-affinity NO 3 - influx in early suberized roots than under optimal NO 3 - . In conclusion, NO 3 - depletion induced early and enhanced suberization in the roots of barley, however, suberization did not restrict transcellular NO 3 - transport., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

A fundamental factor to improve crop productivity involves the optimization of reduced carbon translocation from source to sink tissues. Here, we present data consistent with the positive effect that the expression of the Arabidopsis thaliana H + -PPase ( AVP1 ) has on reduced carbon partitioning and yield increases in wheat. Immunohistochemical localization of H + -PPases (TaVP) in spring wheat Bobwhite L. revealed the presence of this conserved enzyme in wheat vasculature and sink tissues. Of note, immunogold imaging showed a plasma membrane localization of TaVP in sieve element- companion cell complexes of Bobwhite source leaves. These data together with the distribution patterns of a fluorescent tracer and [U 14 C]-sucrose are consistent with an apoplasmic phloem-loading model in wheat. Interestingly, 14 C-labeling experiments provided evidence for enhanced carbon partitioning between shoots and roots, and between flag leaves and milk stage kernels in AVP1 expressing Bobwhite lines. In keeping, there is a significant yield improvement triggered by the expression of AVP1 in these lines. Green house and field grown transgenic wheat expressing AVP1 also produced higher grain yield and number of seeds per plant, and exhibited an increase in root biomass when compared to null segregants. Another agriculturally desirable phenotype showed by AVP1 Bobwhite plants is a robust establishment of seedlings., (Copyright © 2020 Regmi, Yogendra, Gomes Farias, Li, Kandel, Yadav, Sha, Trittermann, Short, George, Evers, Plett, Ayre, Roy and Gaxiola.)

Objectives: To evaluate the cost-effectiveness of repetitive transcranial magnetic stimulation (rTMS) and electroconvulsive therapy (ECT), and combining both treatments in a stepped care pathway for patients with treatment-resistant depression (TRD) in Ontario., Methods: A cost-utility analysis evaluated the lifetime costs and benefits to society of rTMS and ECT as first-line treatments for TRD using a Markov model, which simulates the costs and health benefits of patients over their lifetime. Health states included acute treatment, maintenance treatment, remission, and severe depression. Treatment efficacy and health utility data were extracted and synthesized from randomized controlled trials and meta-analyses evaluating these techniques. Direct costing data were obtained from national and provincial costing databases. Indirect costs were derived from government records. Scenario, threshold, and probabilistic sensitivity analyses were performed to test robustness of the results., Results: rTMS dominated ECT, as it was less costly and produced better health outcomes, measured in quality-adjusted life years (QALYs), in the base case scenario. rTMS patients gained an average of 0.96 additional QALYs (equivalent to approximately 1 year in perfect health) over their lifetime with costs that were $46,094 less than ECT. rTMS remained dominant in the majority of scenario and threshold analyses. However, results from scenarios in which the model's maximum lifetime allowance of rTMS treatment courses was substantially limited, the dominance of rTMS over ECT was attenuated. The scenario that showed the highest QALY gain (1.19) and the greatest cost-savings ($46,614) was when rTMS nonresponders switched to ECT., Conclusion: From a societal perspective utilizing a lifetime horizon, rTMS is a cost-effective first-line treatment option for TRD relative to ECT, as it is less expensive and produces better health outcomes. The reduced side effect profile and greater patient acceptability of rTMS that allow it to be administered more times than ECT in a patient's lifetime may contribute to its cost-effectiveness.

Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed. Energy requirements for transport of salt (NaCl) to leaf vacuoles for osmotic adjustment could be small if there are no substantial leaks back across plasma membrane and tonoplast in root and leaf. The coupling ratio of the H + -ATPase also is a critical component. One proposed leak, that of Na + influx across the plasma membrane through certain aquaporin channels, might be coupled to water flow, thus conserving energy. For the tonoplast, control of two types of cation channels is required for energy efficiency. Transporters controlling the Na + and Cl - concentrations in mitochondria and chloroplasts are largely unknown and could be a major energy cost. The complexity of the system will require a sophisticated modelling approach to identify critical transporters, apoplastic barriers and root structures. This modelling approach will inform experimentation and allow a quantitative assessment of the energy costs of NaCl tolerance to guide breeding and engineering of molecular components., (© 2019 The Authors. New Phytologist © 2019 New Phytologist Trust.)

Main Conclusion: A systematic analysis of NaCl-dependent, plasma-membrane depolarization (∆∆Ψ) in rice roots calls into question the current leading model of rapid membrane cycling of Na + under salt stress. To investigate the character and mechanisms of Na + influx into roots, Na + -dependent changes in plasma-membrane electrical potentials (∆∆Ψ) were measured in root cells of intact rice (Oryza sativa L., cv. Pokkali) seedlings. As external sodium concentrations ([Na + ] ext ) were increased in a step gradient from 0 to 100 mM, membrane potentials depolarized in a saturable manner, fitting a Michaelis-Menten model and contradicting the linear (non-saturating) models developed from radiotracer studies. Clear differences in saturation patterns were found between plants grown under low- and high-nutrient (LN and HN) conditions, with LN plants showing greater depolarization and higher affinity for Na + (i.e., higher V max and lower K m ) than HN plants. In addition, counterion effects on ∆∆Ψ were pronounced in LN plants (with ∆∆Ψ decreasing in the order: Cl -  > SO 4 2-  > HPO 4 2- ), but not seen in HN plants. When effects of osmotic strength, Cl - influx, K + efflux, and H + -ATPase activity on ∆∆Ψ were accounted for, resultant K m and V max values suggested that a single, dominant Na + -transport mechanism was operating under each nutritional condition, with K m values of 1.2 and 16 mM for LN and HN plants, respectively. Comparing saturating patterns of depolarization to linear patterns of 24 Na + radiotracer influx leads to the conclusion that electrophysiological and tracer methods do not report the same phenomena and that the current model of rapid transmembrane sodium cycling may require revision.

Potato plays a key role in global food and nutritional security. Potato is an N fertiliser-responsive crop, producing high tuber yields. However, excessive use of N can result in environmental damage and high production costs, hence improving nitrogen use efficiency (NUE) of potato plants is one of the sustainable options to address these issues and increase yield. Advanced efforts have been undertaken to improve NUE in other plants like Arabidopsis, rice, wheat and maize through molecular and physiological approaches. Conversely, in potato, NUE studies have predominantly focussed on agronomy or soil management, except for a few researchers who have measured gene expression and proteins relevant to N uptake or metabolism. The focus of this review is to adapt knowledge gained from other plants to inform investigation of N metabolism and associated traits in potato with the aim of improving potato NUE using integrated genomics, physiology and breeding methods.

An important trait associated with the salt tolerance of wheat is the exclusion of sodium ions (Na + ) from the shoot. We have previously shown that the sodium transporters TmHKT1;5-A and TaHKT1;5-D, from Triticum monoccocum (Tm) and Triticum aestivum (Ta), are encoded by genes underlying the major shoot Na + -exclusion loci Nax1 and Kna1, respectively. Here, using heterologous expression, we show that the affinity (K m ) for the Na + transport of TmHKT1;5-A, at 2.66 mM, is higher than that of TaHKT1;5-D at 7.50 mM. Through 3D structural modelling, we identify residues D 471 /a gap and D 474 /G 473 that contribute to this property. We identify four additional mutations in amino acid residues that inhibit the transport activity of TmHKT1;5-A, which are predicted to be the result of an occlusion of the pore. We propose that the underlying transport properties of TmHKT1;5-A and TaHKT1;5-D contribute to their unique ability to improve Na + exclusion in wheat that leads to an improved salinity tolerance in the field.

Key Message: We found metabolites, enzyme activities and enzyme transcript abundances vary significantly across the maize lifecycle, but weak correlation exists between the three groups. We identified putative genes regulating nitrate assimilation. Progress in improving nitrogen (N) use efficiency (NUE) of crop plants has been hampered by the complexity of the N uptake and utilisation systems. To understand this complexity we measured the activities of seven enzymes and ten metabolites related to N metabolism in the leaf and root tissues of Gaspe Flint maize plants grown in 0.5 or 2.5 mM NO3 (-) throughout the lifecycle. The amino acids had remarkably similar profiles across the lifecycle except for transient responses, which only appeared in the leaves for aspartate or in the roots for asparagine, serine and glycine. The activities of the enzymes for N assimilation were also coordinated to a certain degree, most noticeably with a peak in root activity late in the lifecycle, but with wide variation in the activity levels over the course of development. We analysed the transcriptional data for gene sets encoding the measured enzymes and found that, unlike the enzyme activities, transcript levels of the corresponding genes did not exhibit the same coordination across the lifecycle and were only weakly correlated with the levels of various amino acids or individual enzyme activities. We identified gene sets which were correlated with the enzyme activity profiles, including seven genes located within previously known quantitative trait loci for enzyme activities and hypothesise that these genes are important for the regulation of enzyme activities. This work provides insights into the complexity of the N assimilation system throughout development and identifies candidate regulatory genes, which warrant further investigation in efforts to improve NUE in crop plants.

Elucidation of the gene networks underlying the response to N supply and demand will facilitate the improvement of the N uptake efficiency of plants. We undertook a transcriptomic analysis of maize to identify genes responding to both a non-growth-limiting decrease in NO3- provision and to development-based N demand changes at seven representative points across the life cycle. Gene co-expression networks were derived by cluster analysis of the transcript profiles. The majority of NO3--responsive transcription occurred at 11 (D11), 18 (D18) and 29 (D29) days after emergence, with differential expression predominating in the root at D11 and D29 and in the leaf at D18. A cluster of 98 probe sets was identified, the expression pattern of which is similar to that of the high-affinity NO3- transporter (NRT2) genes across the life cycle. The cluster is enriched with genes encoding enzymes and proteins of lipid metabolism and transport, respectively. These are candidate genes for the response of maize to N supply and demand. Only a few patterns of differential gene expression were observed over the entire life cycle; however, the composition of the classes of the genes differentially regulated at individual time points was unique, suggesting tightly controlled regulation of NO3--responsive gene expression., (© 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.)

An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply. Genotypic response to N was assessed on the basis of biomass characteristics and the activities of the nitrate ([Formula: see text]) and ammonium ([Formula: see text]) high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Although, the N response in underlying biomass and N transport related characteristics was less than that for biomass, there were clear relationships, most importantly, lines that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both [Formula: see text] and [Formula: see text] increased with reduced N. Transcript levels of putative [Formula: see text] and [Formula: see text] transporter genes in the root tissue of a subset of the genotypes revealed that predominately ZmNRT2 transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotype's ability to maintain biomass with reduced N suggests a role for these transporters in enhancing NUpE. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals.

Over 100million tonnes of nitrogen (N) fertiliser are applied globally each year to maintain high yields in agricultural crops. The rising price of N fertilisers has made them a major cost for farmers. Inefficient use of N fertiliser leads to substantial environmental problems through contamination of air and water resources and can be a significant economic cost. Consequently, there is considerable need to improve the way N fertiliser is used in farming systems. The efficiency with which crops use applied N fertiliser - the nitrogen-use efficiency (NUE) - is currently quite low for cereals. This is the case in both high yielding environments and lower yielding environments characteristic of cereal growing regions of Australia. Multiple studies have attempted to identify the genetic basis of NUE, but the utility of the results is limited because of the complex nature of the trait and the magnitude of genotype by environment interaction. Transgenic approaches have been applied to improve plant NUE but with limited success, due, in part, to a combination of the complexity of the trait but also due to lack of accurate phenotyping methods. This review documents these two approaches and suggests future directions in improving cereal NUE with a focus on the Australian cereal industry.

Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K(+) /Na(+) ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL. Limited recombination has been observed at this locus making it difficult to map genetically and identify the causal gene. Here, we decipher the function of TaHKT1;5-D, a candidate gene underlying the Kna1 locus. Transport studies using the heterologous expression systems Saccharomyces cerevisiae and Xenopus laevis oocytes indicated that TaHKT1;5-D is a Na(+) -selective transporter. Transient expression in Arabidopsis thaliana mesophyll protoplasts and in situ polymerase chain reaction indicated that TaHKT1;5-D is localised on the plasma membrane in the wheat root stele. RNA interference-induced silencing decreased the expression of TaHKT1;5-D in transgenic bread wheat lines which led to an increase in the Na(+) concentration in the leaves. This indicates that TaHKT1;5-D retrieves Na(+) from the xylem vessels in the root and has an important role in restricting the transport of Na(+) from the root to the leaves in bread wheat. Thus, TaHKT1;5-D confers the essential salinity tolerance mechanism in bread wheat associated with the Kna1 locus via shoot Na(+) exclusion and is critical in maintaining a high K(+) /Na(+) ratio in the leaves. These findings show there is potential to increase the salinity tolerance of bread wheat by manipulation of HKT1;5 genes., (© 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.)

An understanding of nitrate (NO3-) uptake throughout the lifecycle of plants, and how this process responds to nitrogen (N) availability, is an important step towards the development of plants with improved nitrogen use efficiency (NUE). NO3- uptake capacity and transcript levels of putative high- and low-affinity NO3- transporters (NRTs) were profiled across the lifecycle of dwarf maize (Zea mays) plants grown at reduced and adequate NO3-. Plants showed major changes in high-affinity NO3- uptake capacity across the lifecycle, which varied with changing relative growth rates of roots and shoots. Transcript abundances of putative high-affinity NRTs (predominantly ZmNRT2.1 and ZmNRT2.2) were correlated with two distinct peaks in high-affinity root NO3- uptake capacity and also N availability. The reduction in NO3- supply during the lifecycle led to a dramatic increase in NO3- uptake capacity, which preceded changes in transcript levels of NRTs, suggesting a model with short-term post-translational regulation and longer term transcriptional regulation of NO3- uptake capacity. These observations offer new insight into the control of NO3- uptake by both plant developmental processes and N availability, and identify key control points that may be targeted by future plant improvement programmes to enhance N uptake relative to availability and/or demand., (© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.)

The ability of wheat to maintain a low sodium concentration ([Na(+)]) in leaves correlates with improved growth under saline conditions. This trait, termed Na(+) exclusion, contributes to the greater salt tolerance of bread wheat relative to durum wheat. To improve the salt tolerance of durum wheat, we explored natural diversity in shoot Na(+) exclusion within ancestral wheat germplasm. Previously, we showed that crossing of Nax2, a gene locus in the wheat relative Triticum monococcum into a commercial durum wheat (Triticum turgidum ssp. durum var. Tamaroi) reduced its leaf [Na(+)] (ref. 5). Here we show that a gene in the Nax2 locus, TmHKT1;5-A, encodes a Na(+)-selective transporter located on the plasma membrane of root cells surrounding xylem vessels, which is therefore ideally localized to withdraw Na(+) from the xylem and reduce transport of Na(+) to leaves. Field trials on saline soils demonstrate that the presence of TmHKT1;5-A significantly reduces leaf [Na(+)] and increases durum wheat grain yield by 25% compared to near-isogenic lines without the Nax2 locus.

The HKT family of Na(+) and Na(+)/K(+) transporters is implicated in plant salinity tolerance. Amongst these transporters, the cereal HKT1;4 and HKT1;5 are responsible for Na(+) exclusion from photosynthetic tissues, a key mechanism for plant salinity tolerance. It has been suggested that Na(+) is retrieved from the xylem transpiration stream either in the root or the leaf sheath, protecting the leaf blades from excessive Na(+) accumulation. However, direct evidence for this scenario is scarce. Comparative modeling and evaluation of rice (Oryza sativa) HKT-transporters based on the recent crystal structure of the bacterial TrkH K(+) transporter allowed to reconcile transcriptomic and physiological data. For OsHKT1;5, both transcript abundance and protein structural features within the selectivity filter could control shoot Na(+) accumulation in a range of rice varieties. For OsHKT1;4, alternative splicing of transcript and the anatomical complexity of the sheath needed to be taken into account. Thus, Na(+) accumulation in a specific leaf blade seems to be regulated by abundance of a correctly spliced OsHKT1;4 transcript in a corresponding sheath. Overall, allelic variation of leaf blade Na(+) accumulation can be explained by a complex interplay of gene transcription, alternative splicing and protein structure.

Elevated salinity imposes osmotic and ion toxicity stresses on living cells and requires a multitude of responses in order to enable plant survival. Building on earlier work profiling transcript levels in rice (Oryza sativa) shoots of FL478, a salt-tolerant indica recombinant inbred line, and IR29, a salt-sensitive cultivar, transcript levels were compared in roots of these two accessions as well as in the roots of two additional salt-tolerant indica genotypes, the landrace Pokkali and the recombinant inbred line IR63731. The aim of this study was to compare transcripts in the sensitive and the tolerant lines in order to identify genes likely to be involved in plant salinity tolerance, rather than in responses to salinity per se. Transcript profiles of several gene families with known links to salinity tolerance are described (e.g. HKTs, NHXs). The putative function of a set of genes identified through their salt responsiveness, transcript levels, and/or chromosomal location (i.e. underneath QTLs for salinity tolerance) is also discussed. Finally, the parental origin of the Saltol region in FL478 is further investigated. Overall, the dataset presented appears to be robust and it seems likely that this system could provide a reliable strategy for the discovery of novel genes involved in salinity tolerance.

A large proportion of the nitrate (NO(3)(-)) acquired by plants from soil is actively transported via members of the NRT families of NO(3)(-) transporters. In Arabidopsis, the NRT1 family has eight functionally characterised members and predominantly comprises low-affinity transporters; the NRT2 family contains seven members which appear to be high-affinity transporters; and there are two NRT3 (NAR2) family members which are known to participate in high-affinity transport. A modified reciprocal best hit (RBH) approach was used to identify putative orthologues of the Arabidopsis NRT genes in the four fully sequenced grass genomes (maize, rice, sorghum, Brachypodium). We also included the poplar genome in our analysis to establish whether differences between Arabidopsis and the grasses may be generally applicable to monocots and dicots. Our analysis reveals fundamental differences between Arabidopsis and the grass species in the gene number and family structure of all three families of NRT transporters. All grass species possessed additional NRT1.1 orthologues and appear to lack NRT1.6/NRT1.7 orthologues. There is significant separation in the NRT2 phylogenetic tree between NRT2 genes from dicots and grass species. This indicates that determination of function of NRT2 genes in grass species will not be possible in cereals based simply on sequence homology to functionally characterised Arabidopsis NRT2 genes and that proper functional analysis will be required. Arabidopsis has a unique NRT3.2 gene which may be a fusion of the NRT3.1 and NRT3.2 genes present in all other species examined here. This work provides a framework for future analysis of NO(3)(-) transporters and NO(3)(-) transport in grass crop species.

Previously, cell type-specific expression of AtHKT1;1, a sodium transporter, improved sodium (Na(+)) exclusion and salinity tolerance in Arabidopsis. In the current work, AtHKT1;1, was expressed specifically in the root cortical and epidermal cells of an Arabidopsis GAL4-GFP enhancer trap line. These transgenic plants were found to have significantly improved Na(+) exclusion under conditions of salinity stress. The feasibility of a similar biotechnological approach in crop plants was explored using a GAL4-GFP enhancer trap rice line to drive expression of AtHKT1;1 specifically in the root cortex. Compared with the background GAL4-GFP line, the rice plants expressing AtHKT1;1 had a higher fresh weight under salinity stress, which was related to a lower concentration of Na(+) in the shoots. The root-to-shoot transport of (22)Na(+) was also decreased and was correlated with an upregulation of OsHKT1;5, the native transporter responsible for Na(+) retrieval from the transpiration stream. Interestingly, in the transgenic Arabidopsis plants overexpressing AtHKT1;1 in the cortex and epidermis, the native AtHKT1;1 gene responsible for Na(+) retrieval from the transpiration stream, was also upregulated. Extra Na(+) retrieved from the xylem was stored in the outer root cells and was correlated with a significant increase in expression of the vacuolar pyrophosphatases (in Arabidopsis and rice) the activity of which would be necessary to move the additional stored Na(+) into the vacuoles of these cells. This work presents an important step in the development of abiotic stress tolerance in crop plants via targeted changes in mineral transport.

Soil salinity decreases the growth rate of plants and can severely limit the productivity of crop plants. The ability to tolerate salinity stress differs widely between species of plants as well as within species. As an important component of salinity tolerance, a better understanding of the mechanisms of Na(+) transport will assist in the development of plants with improved salinity tolerance and, importantly, might lead to increased yields from crop plants growing in challenging environments. This review summarizes the current understanding of the components of Na(+) transport in glycophytic plants, including those at the soil to root interface, transport of Na(+) to the xylem, control of Na(+) loading in the stele and partitioning of the accumulated Na(+) within the shoot and individual cells. Using this knowledge, strategies to modify Na(+) transport and engineer plant salinity tolerance, as well as areas of research which merit particular attention in order to further improve the understanding of salinity tolerance in plants, are discussed.

We present a case of a 44-year-old man with complaints of double-sided nasal obstruction and a foreign body sensation. A polypoid lesion was seen in the nasopharynx and was later completely excised. Histologic examination showed a respiratory epithelial adenomatoid hamartoma. The clinical and pathological features of this rare tumor as a cause of nasal obstruction are discussed.