Search

The gut microbiome of worms from composting facilities potentially harbors organisms that are beneficial to plant growth and development. In this experiment, we sought to examine the potential impacts of rhizosphere microbiomes derived from Eisenia fetida worm castings (i.e. vermicompost) on tomato (Solanum lycopersicum, L.) plant growth and physiology. Our experiment consisted of a greenhouse trial lasting 17 weeks total in which tomato plants were grown with one of three inoculant treatments: a microbial inoculant created from vermicompost (V), a microbial inoculant created from sterilized vermicompost (SV), and a no-compost control inoculant (C). We hypothesized that living microbiomes from the vermicompost inoculant treatment would enhance host plant growth and gene expression profiles compared to plants grown in sterile and control treatments. Our data showed that bacterial community composition was significantly altered in tomato rhizospheres, but fungal community composition was highly variable in each treatment. Plant phenotypes that were significantly enhanced in the vermicompost and sterile vermicompost treatments, compared to the control, included aboveground biomass and foliar δ15N nitrogen. RNA sequencing revealed distinct gene expression changes in the vermicompost treatment, including upregulation of nutrient transporter genes such as Solyc06g074995 (high affinity nitrate transporter), which exhibited a 250.2-fold increase in expression in the vermicompost treatment compared to both the sterile vermicompost and control treatments. The plant transcriptome data suggest that rhizosphere microbiomes derived from vermicompost can influence tomato gene expression and growth-related regulatory pathways, which highlights the value of RNA sequencing in uncovering molecular responses in plant microbiome studies. [ABSTRACT FROM AUTHOR]

On college campuses today, student services staff (administrators and support staff) and faculty members are not only interacting with students but also with their parents. College employee interactions with prospective students and their parents may be common during information sessions and open houses. However, outside of the recruitment season, less is known about the experiences of student affairs staff and faculty who interact with parents. Through semi-structured interviews, this study examined employees’ interactions with parents of students at four colleges of applied arts and technology in Ontario, Canada. Of the interviewees, nine faculty members and 11 student affairs staff (non-academic employees) described interacting with parents. The analysis of the interviews revealed several themes. These included college employees’ interactions with parents regarding students’ program choice and educational decision making, academic challenges, and support services. Professional practices that serve parents (and other supporters) could contribute to institutional goals, including post-secondary student persistence. This study’s research findings may inform student affairs practice and inspire new ways to support students’ college journeys in cooperation with parents and family members. [ABSTRACT FROM AUTHOR]

A large and diverse library of glycan-directed monoclonal antibodies (mAbs) was used to determine if plant cell walls are modified by low-gravity conditions encountered during spaceflight. This method called glycome profiling (glycomics) revealed global differences in non-cellulosic cell wall epitopes in Arabidopsis thaliana root extracts recovered from RNA purification columns between seedlings grown on the International Space Station-based Vegetable Production System and paired ground (1-g) controls. Immunohistochemistry on 11-day-old seedling primary root sections showed that ten of twenty-two mAbs that exhibited spaceflight-induced increases in binding through glycomics, labeled space-grown roots more intensely than those from the ground. The ten mAbs recognized xyloglucan, xylan, and arabinogalactan epitopes. Notably, three xylem-enriched unsubstituted xylan backbone epitopes were more intensely labeled in space-grown roots than in ground-grown roots, suggesting that the spaceflight environment accelerated root secondary cell wall formation. This study highlights the feasibility of glycomics for high-throughput evaluation of cell wall glycans using only root high alkaline extracts from RNA purification columns, and subsequent validation of these results by immunohistochemistry. This approach will benefit plant space biological studies because it extends the analyses possible from the limited amounts of samples returned from spaceflight and help uncover microgravity-induced tissue-specific changes in plant cell walls. [ABSTRACT FROM AUTHOR]

Savin juniper is an excellent species for desertification control in arid and semi‐arid areas, where it typically establishes under the protection of nurse plants. Ultimately, established plants emerge into full light as they grow, and this transition is accompanied by an increase in the preponderance of scale‐like versus needle‐like leaf forms.To test how age and variable light environments affect shade tolerance in savin juniper, we established a pot study under field conditions, with two age cohorts (1‐ and 4‐year‐old rooted scions) and three light regimes (10%, 50% and 100% light transmittance). We measured growth, leaf parameters, photosynthesis, chlorophyll fluorescence and foliar pigments on a monthly basis (seven growing months per year, from 2015 to 2017).Overall, there was little interaction among all variables, and both cohort and light regime had significant effects. Leaf form and spacing varied continuously, tending towards shorter, more closely spaced and more appressed scale leaves with higher dry leaf mass per area in older plants or under higher light. There were no clear age‐related patterns in carotenoids but both cohort and light had significant effects on gas exchange and chlorophyll fluorescence variables.We conclude that savin juniper shows an intermediate tolerance to shade that changes with growth in that younger plants were less tolerant of full sun than older plants, consistent with its reliance on nurse plants for ultimate establishment in the open. [ABSTRACT FROM AUTHOR]

After the nuclear accident in Fukushima Prefecture, Japan, in 2011, 137Caesium (Cs) contaminated nearby agricultural regions. Studies in these rice fields found that low K and high N fertilizer application enhanced Cs uptake in rice shoots. However, the influence of root and soil physics on these findings, as well as precise nutrient levels, remain to be clarified.We sought to analyse these relationships utilizing hydroponically grown rice plants. The rice plants were subjected to various concentrations of K and N nutrient solutions. We measured Cs allocation within the plants and performed transcript analyses using root tissues.Under low‐K conditions, low‐N plants accumulated less Cs in shoots and more in roots when compared to control‐N conditions, even though overall Cs uptake remained unchanged. Expression analyses of root mRNAs showed that low‐N plants accumulated reduced levels of OsAKT1 mRNA, encoding a K transporter. We also found a negative relationship between shoot Cs and K status in control‐N but not in low‐N conditions.Our results suggest that the application of N shifts Cs from roots into the shoots and that OsAKT1 in root vascular tissues influences Cs allocation. In practice, fine tuning N/K application and targeted breeding of K transporters might mitigate Cs contamination in rice plants. [ABSTRACT FROM AUTHOR]

Drought and rising global temperatures are important factors that reduce wheat production. Trehalose protects the reaction centres and improves photosystem II (PSII) activity under diverse stress conditions. However, the underlying mechanism remains unknown. Cyclic electron flow (CEF) plays an important role in protecting PSII under environmental stresses.Our study focused on the effects of exogenous trehalose on the activity of PSII, D1 protein content, plastoquinone (PQ) pool and ATP synthase activity in wheat seedlings under heat and drought stresses to explore the relationship between trehalose and CEF.The results indicated that heat and drought stresses decreased maximum photochemical efficiency of PSII (Fv/Fm) and electron transport rate of PSII (EFR(II)), whereas the trehalose pretreatment improved photochemical efficiency and electron transport rate of PSII. The trehalose pretreatment stimulated CEF under heat and drought stresses. Furthermore, the proton gradient (ΔpH) across the thylakoid membrane and ATPase activity increased. The higher ΔpH and ATPase activity played a key role in protecting PSII under stresses. Trehalose pretreatment could reduce inhibition caused by heat and drought stresses on the PQ pool.Thus, our results indicated that photoinhibition in heat‐ and drought‐stressed plants was alleviated by the trehalose pretreatment, which was mediated by CEF and the PQ pool. [ABSTRACT FROM AUTHOR]

Interspecific differences in sensitivity of the Antarctic moss Sanionia uncinata from King George Island (KGI) and James Ross Island (JRI) to photoinhibitory treatment were studied in laboratory conditions using chlorophyll fluorescence techniques.Slow (Kautsky) and fast (OJIP) kinetics were used for the measurements. Samples were exposed to a short‐term (60 min) photoinhibitory treatment (PIT, 2000 μmol·m−2·s−1 PAR).The photoinhibitory treatment (PIT) led to photoinhibition which was indicated by the decrease in FV/FM and ΦPSII in KGI but not in JRI samples. However, this decrease was small and full recovery was reached 90 min after PIT termination. Non‐photochemical quenching (NPQ) was activated during the PIT, and rapidly relaxed during recovery. Early stages of photoinhibition showed a drop in FV/FM and ΦPSII to minimum values within the first 10 s of the PIT, with their subsequent increase apparent within fast (0–5 min PIT) and slow (5–50 min PIT) phases of adjustment. The PIT caused a decrease in the performance index (Pi_Abs), photosynthetic electron transport per reaction centre (RC) (ET0/RC). The PIT induced an increase in thermal dissipation per RC (DI0/RC), effectivity of thermal dissipation (Phi_D0), absorption per RC (ABS/RC) and trapping rate per RC (TR0/RC).In conclusion, PIT led to only slight photoinhibition followed by fast recovery in S. uncinata from KGI and JRI, since FV/FM and ΦPSII returned to pre‐photoinhibitory conditions. Therefore, S. uncinata might be considered resistant to photoinhibition even in the wet state. The KGI samples showed higher resistance to photoinhibition than the JRI samples. [ABSTRACT FROM AUTHOR]

Acetylcholine (ACh) is believed to improve plant growth. However, regulation at biochemical and molecular levels is largely unknown.The present study investigated the impact of exogenously applied ACh (10 µm) on growth and chlorophyll metabolism in hydroponically grown Nicotiana benthamiana under salt stress (150 mm NaCl).Salinity reduced root hydraulic conductivity while ACh‐treated seedlings exhibited a significant increase, resulting in increased relative water content. Salinity induced a reduction in chlorophyll biosynthetic intermediates, such as protoporphyrin‐IX, Mg‐photoporphyrin‐IX and protochlorophyllide, which were significantly ameliorated in the presence of ACh. This influence of ACh on chlorophyll synthesis was confirmed by up‐regulation of HEMA1, CHLH, CAO and POR genes. Gas exchange parameters, i.e. stomatal conductance, internal CO2 concentration and transpiration rate, increased with ACh, thereby alleviating the salinity effects on photosynthesis. In addition, the salinity‐induced enhancement of lipid peroxidation declined after ACh treatment through modulation of the activity of the assayed antioxidant enzymes (superoxide dismutase and peroxidase). Importantly, ACh significantly reduced the uptake of Na and increased uptake of K, resulting in a decline in the Na/K ratio.Results of the present study indicate that ACh can be effective in ameliorating NaCl‐induced osmotic stress, altering chlorophyll metabolism and thus photosynthesis by maintaining ion homeostasis, hydraulic conductivity and water balance. [ABSTRACT FROM AUTHOR]

Lodging resistance can be improved by enhancing the mechanical strength of culms, and culm carbohydrates could improve this mechanical strength. Culm carbohydrates can regulate development of the culm and affect its toughness.The present study determines the relationship between lodging and carbohydrate content in oat culms. Field experiments were conducted in alpine regions in 2017 and 2018 using three oat varieties with different lodging resistance. Lodging‐related morphological characteristics were directly determined and culm carbohydrate content and enzyme activity related to cellulose synthesis and sucrose metabolism were evaluated with ultraviolet spectrophotometry.Results showed that the lower the gravity height or the lower ratio of gravity height to plant height, the stronger the lodging resistance of the varieties. Higher culm nonstructural (NSC) and structural (SC) carbohydrate content contributed to the ability of culms to resist lodging, especially the content of cellulose and sucrose. PCA showed that sucrose metabolism and SC content were closely related to lodging resistance. Correlation analysis showed that the lodging index (LI) was significantly negatively correlated with NSC. Sucrose content was highly and significantly positively correlated with NSC. Additionally, the activities of sucrose phosphate synthase (SPS) and sucrose synthase (SS) were highly and significantly positively correlated with sucrose and cellulose content.The relationship between field characters and oat lodging, as well as the regulatory mechanism of carbohydrate content on lodging resistance of the culm are discussed. [ABSTRACT FROM AUTHOR]

When positioned horizontally, roots grow down toward the direction of gravity. This phenomenon, called gravitropism, is influenced by most of the major plant hormones including brassinosteroids. Epi-brassinolide (eBL) was previously shown to enhance root gravitropism, a phenomenon similar to the response of roots exposed to the actin inhibitor, latrunculin B (LatB). This led us to hypothesize that eBL might enhance root gravitropism through its effects on filamentous-actin (F-actin). This hypothesis was tested by comparing gravitropic responses of maize (Zea mays) roots treated with eBL or LatB. LatB- and eBL-treated roots displayed similar enhanced downward growth compared with controls when vertical roots were oriented horizontally. Moreover, the effects of the two compounds on root growth directionality were more striking on a slowly-rotating two-dimensional clinostat. Both compounds inhibited autotropism, a process in which the root straightened after the initial gravistimulus was withdrawn by clinorotation. Although eBL reduced F-actin density in chemically-fixed Z. mays roots, the impact was not as strong as that of LatB. Modification of F-actin organization after treatment with both compounds was also observed in living roots of barrel medic (Medicago truncatula) seedlings expressing genetically encoded F-actin reporters. Like in fixed Z. mays roots, eBL effects on F-actin in living M. truncatula roots were modest compared with those of LatB. Furthermore, live cell imaging revealed a decrease in global F-actin dynamics in hypocotyls of etiolated M. truncatula seedlings treated with eBL compared to controls. Collectively, our data indicate that eBL-and LatB-induced enhancement of root gravitropism can be explained by inhibited autotropic root straightening, and that eBL affects this process, in part, by modifying F-actin organization and dynamics. [ABSTRACT FROM AUTHOR]

Tropospheric ozone (O3) is considered a major air pollutant having negative effects on plant growth and productivity. Background concentrations are expected to rise in several regions of the world in the next 50 years, affecting plant responses to diseases, thus requiring new management strategies for food production.The effects of elevated O3 on the severity of a bacterial disease, and the effectiveness of a chemical defence inducer, were examined in two cultivars of tomato, Roma and Moneymaker, which present different tolerance to this pollutant. The two cultivars differ in their ability to produce and accumulate reactive oxygen species (ROS) in leaf tissues. Tomato plants were challenged with a strain of Xanthomonas vesicatoria, Xv9, which is pathogenic on tomato.Ozone consistently increased severity of the disease by over 40% in both cultivars. In the more tolerant cultivar, O3 pollution increased disease intensity, even after applying a commercially available product to enhance resistance (acibenzolar‐S‐methyl, BTH). In the more susceptible cultivar, level of disease attained depended on the oxidative balance that resulted from other stress factors.The antioxidant capacity of the plant at the time of infection was relevant for controlling development of the disease. Our results suggest that development of O3 tolerance in commercial crops might impose a penalty cost in terms of disease management under projected higher O3 concentrations. [ABSTRACT FROM AUTHOR]

Objective: Dietary intake is a complex exposure and a potential risk factor for systemic lupus erythematosus (SLE) due to its impact on lipid and glucose metabolism, oxidative stress, and the intestinal microbiome. We aimed to test whether a prudent dietary pattern is associated with a lower risk of SLE, and whether a Western dietary pattern is associated with a higher risk of SLE. Methods: We prospectively investigated two dietary patterns and SLE risk among women in the Nurses' Health Study (NHS, 1984–2014) and Nurses' Health Study II (NHSII, 1991–2015). Food frequency questionnaires were completed every four years. Congruent with prior work in NHS and NHSII, we derived two separate dietary patterns (prudent and Western) using principal component analysis within each cohort. Incident SLE was confirmed by the American College of Rheumatology's 1997 criteria. We estimated hazard ratios (HR) and 95% confidence intervals (CI) for SLE by dietary pattern quartiles using Cox models adjusted for time-varying covariates. Models were performed separately in each cohort and results were meta-analyzed. Stratified analyses tested the association of dietary patterns with anti-dsDNA positive SLE and anti-dsDNA negative SLE. Results: We confirmed 82 NHS incident SLE cases and 98 NHSII SLE cases during 3,833,054 person-years of follow-up. A higher (healthier) prudent dietary pattern score was not associated with SLE risk (meta-analyzed HRQ4 versus Q1 0.84 [95% CI 0.51, 1.38]). Women with higher (less healthy) Western dietary pattern scores did not have a significantly increased risk for SLE (meta-analyzed HRQ4 versus Q1 1.35 [95% CI 0.77, 2.35]). Results were similar after further adjustment for body mass index. Incident anti-dsDNA positive SLE and anti-dsDNA negative SLE were not associated with either dietary pattern. Conclusion: We did not observe a relationship between prudent or Western dietary pattern score and risk of SLE. [ABSTRACT FROM AUTHOR]

Transfer (T)-DNA insertions in mutants isolated from forward genetic screens are typically identified through thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR), inverse PCR, or plasmid rescue. Despite the popularity and success of these methods, they have limited capabilities, particularly in situations in which the T-DNA is truncated. Here, we present a next generation sequencing (NGS)-based platform to facilitate the identification of complete and truncated T-DNA insertions. Our method enables the detection of the corresponding T-DNA insertion orientation and zygosity as well as insertion annotation. This method, called TDNAscan, was developed to be an open source software. We expect that TDNAscan will be a valuable addition to forward genetics toolkits because it provides a solution to the problem of causal gene identification, particularly genes disrupted by truncated T-DNA insertions. We present a case study in which TDNAscan was used to determine that the recessive Arabidopsis thaliana hypersensitive to latrunculin B (hlb3) mutant isolated in a forward genetic screen of T-DNA mutagenized plants encodes a class II FORMIN. [ABSTRACT FROM AUTHOR]

A design review is presented detailing the development of a vessel concept design to meet the needs of the European Union's (EU's) emerging offshore aquaculture industry. The offshore aquaculture system supported by the vessel was based on research into current inshore practice and proposals of what constitutes a viable offshore aquaculture industry. To increase the commercial viability of the farming operation, the offshore aquaculture support vessel (OASV) design utilises dead haul. This provides the OASV with multi-role capabilities that achieve the primary aim of a single vessel solution. The integration of farm consumables supply, salmon harvest and general maintenance capabilities into the OASV was considered to be essential for the concept design to succeed. Each step of the design process has been critically reviewed to identify the limitations of the concept design, and recommendations for improvement of the concept OASV have been made. [ABSTRACT FROM AUTHOR]

A Personal Remembrance of Dear Friend and Esteemed Colleague Daryl Sharp: January 2 1936-October 8, 2019, Jungian Analyst and General Editor of Inner City Books Later, back in England, Daryl encountered the work of C.G. Jung, followed by his studies at the Jung Institute in Zürich from 1974 through 1978. To Daryl von Franz explained, "Mr. Sharp, either you are a ninnie and have no business being here, or else you have talents as of yet undiscovered.". [Extracted from the article]

Number and Time: Reflections Leading toward the Unification of Depth Psychology and Physics, by Marie-Louise von Franz (1974), explores parallels between the understanding of psychological healing in Jungian psychology and the theory of subatomic particles in quantum physics. Von Franz compares number symbolism in dreams with the mathematical structure of matter to link these two realms of life. The parallel role of numbers in the psyche and in matter is described to explain the interrelationship of our inner images and the outer world, as well to represent fundamental processes of personal development. [ABSTRACT FROM AUTHOR]

An experiment was conducted to test the hypothesis that inclusion of increasing concentrations of an Escherichia coli phytase to a corn-soybean meal (SBM) diet results in improved digestibility of DM, GE, CP, NDF, ADF, macrominerals, microminerals, and AA. Twenty-four growing barrows (initial BW: 37.0 ± 1.4 kg) were equipped with a T-cannula in the distal ileum and placed individually in metabolism crates, and allotted to a 2-period switch-back design with 6 diets and 4 replicate pigs per diet in each period. The positive control diet was a corn-SBM diet that contained limestone and dicalcium phosphate to meet the requirement for standardized total tract digestible (STTD) P and Ca (0.31% STTD P and 0.70% Ca). A negative control diet that was similar to the positive control diet, with the exception that no dicalcium phosphate was used, was also formulated, and this diet contained 0.16% STTD P and 0.43% Ca. Four additional diets were formulated by adding 500, 1,000, 2,000, or 4,000 units of microbial phytase (FTU) to the negative control diet. Each period lasted 14 d. Fecal and urine samples were collected from the feed provided from days 6 to 11 of each period following 5 d of adaptation to the diets. Ileal digesta were collected for 8 h on days 13 and 14. Results indicated that addition of the E. coli phytase to the negative control diet tended to quadratically improve the apparent ileal digestibility of Phe (P = 0.086) and Asp (P = 0.054), and linearly increased (P < 0.05) the apparent total tract digestibility (ATTD) of ADF, K, and Fe. Microbial phytase also quadratically increased (P < 0.05) the ATTD of NDF and Mg, and linearly and quadratically increased (P < 0.05) the ATTD and retention of Ca and P. However, no effects of the phytase on ATTD of GE or the concentration of DE were observed. In conclusion, the increased absorption of several minerals including Ca, P, K, Mg, and Fe that was observed as increasing concentrations of an E. coli phytase was added to a corn-SBM meal diet indicates that the dietary provision of these minerals may be reduced if phytase is fed. [ABSTRACT FROM AUTHOR]

AGD1, a plant ACAP-type ADP-ribosylation factor-GTPase activating protein (ARF-GAP), functions in specifying root hair polarity in Arabidopsis thaliana. To better understand how AGD1 modulates root hair growth, we generated full-length and domain-deleted AGD1-green fluorescent protein (GFP) constructs, and followed their localization during root hair development. AGD1-GFP localized to the cytoplasm and was recruited to specific regions of the root hair plasma membrane (PM). Distinct PMAGD1-GFP signal was first detected along the site of root hair bulge formation. The construct continued tomark the PMat the root hair apical dome, but only during periods of reduced growth. During rapid tip growth, AGD1-GFP labeled the PM of the lateral flanks and dissipated from the apical-most PM. Deletion analysis and a single domain GFP fusion revealed that the pleckstrin homology (PH) domain is the minimal unit required for recruitment of AGD1 to the PM. Our results indicate that differential recruitment of AGD1 to specific PM domains is an essential component of the membrane trafficking machinery that facilitates root hair developmental phase transitions and responses to changes in the root microenvironment. [ABSTRACT FROM AUTHOR]

The pharmacokinetics of intramuscularly administered ceftiofur crystalline-free acid ( CCFA) were determined in pigs that were clinically healthy ( n = 8), vaccinated with a Porcine reproductive and respiratory syndrome modified live virus ( PRRS MLV) ( n = 10), challenged with wild-type porcine reproductive and respiratory syndrome virus ( PRRSv) VR-2385 ( n = 10), or vaccinated with PRRS MLV and later challenged with wild-type PRRSv VR-2385 ( n = 10). Animals were given a single dose of CCFA intramuscularly at 5 mg/kg body weight. Blood was collected at 0 (pretreatment), 0.25, 0.5, 1, 6, 12, 24, 48, 96, 144, 192, and 240 h postinjection. Plasma was analyzed using liquid chromatography-mass spectrometry. Plasma concentration-time curves for each group were evaluated with noncompartmental modeling. When compared to control animals, those receiving the PRRSv wild-type challenge only had a lower AUC0-last, higher Cl/F, and higher Vz/F. The PRRSv wild-type challenge only group had the longest T1/2 λ. The Cmax did not differ among all four treatments. Control animals had no statistically significant differences from animals vaccinated with PRRS MLV alone or animals vaccinated with PRRS MLV and later challenged with wild-type PRRSv. Our results suggest that PRRSv wild-type infection has the potential to alter CCFA pharmacokinetics and PRRS MLV vaccination may attenuate those changes. [ABSTRACT FROM AUTHOR]

Functional gene approaches have been used to better understand the roles of microbes in driving forest soil nitrogen (N) cycling rates and bioavailability. Ammonia oxidation is a rate limiting step in nitrification, and is a key area for understanding environmental constraints on N availability in forests. We studied how increasing temperature affects the role of ammonia oxidizing archaea ( AOA) and bacteria ( AOB) in soil N cycling and availability by using a highly constrained natural mean annual temperature ( MAT) elevation gradient in a tropical montane wet forest. We found that net nitrate ( NO3−) bioavailability is positively related to MAT ( r2 = 0.79, P = 0.0033), and AOA DNA abundance is positively related to both NO3− availability ( r2 = 0.34, P = 0.0071) and MAT ( r2 = 0.34, P < 0.001). In contrast, AOB DNA was only detected in some soils across the gradient. We identified three distinct phylotypes within the AOA which differed from one another in abundance and relative gene expression. In addition, one AOA phylotype increased in abundance with MAT, while others did not. We conclude that MAT is the primary driver of ecosystem N availability across this gradient, and AOA population size and structure appear to mediate the relationship between the nitrification and N bioavailability. These findings hold important implications for nutrient limitation in forests and feedbacks to primary production under changing climate. [ABSTRACT FROM AUTHOR]

The chenopod Beta macrocarpa Guss (wild Swiss chard) is known for its salt tolerance, but the mechanisms involved are still debated. In order to elucidate the processes involved, we grew wild Swiss chard exposed to three salinity levels (0, 100 and 200 m m NaCl) for 45 days, and determined several physiological parameters at the end of this time. All plants survived despite reductions in growth, photosynthesis and stomatal conductance in plants exposed to salinity (100 and 200 m m NaCl). As expected, the negative effects of salinity were more pronounced at 200 m m than at 100 m m NaCl: (i) leaf apoplastic water content was maintained or increased despite a significant reduction in leaf water potential, revealing the halophytic character of B. macrocarpa; (ii) osmotic adjustment occurred, which presumably enhanced the driving force for water extraction from soil, and avoided toxic build up of Na+ and Cl- in the mesophyll apoplast of leaves. Osmotic adjustment mainly occurred through accumulation of inorganic ions and to a lesser extent soluble sugars; proline was not implicated in osmotic adjustment. Overall, two important mechanisms of salt tolerance in B. macrocarpa were identified: osmotic and apoplastic water adjustment. [ABSTRACT FROM AUTHOR]

Based on previous results, which showed that the secondary metabolite citral causes disturbances to plant water status, the present study is focused on demonstrating and detailing these effects on the water-related parameters of Arabidopsis thaliana adult plants, and their impact on plant fitness. Clear evidence of effects on water status and fitness were observed: plants treated with 1200 and 2400 μ m citral showed decreased RWC, reduced Ψs, increased Ψw and reduced stomatal opening, even 7 days after the beginning of the experiment. Plant protection signals, such as leaf rolling or increased anthocyanin content, were also detected in these plants. In contrast, 14 days after beginning the treatment, treated plants showed signs of citral-related damage. Moreover, the reproductive success of treated plants was critically compromised, with prematurely withered flowers and no silique or seed development. This effect of citral on fitness of adult plants suggests a promising application of this natural compound in weed management by reducing the weed seed bank in the soil. [ABSTRACT FROM AUTHOR]

The endomembrane system plays essential roles in plant development, but the proteome responsible for its function and organization remains largely uncharacterized in plants. Here, we identified and characterized the HYPERSENSITIVE TO LATRUNCULIN B1 (HLB1) protein isolated through a forward-genetic screen in Arabidopsis thaliana for mutants with heightened sensitivity to actin-disrupting drugs. HLB1 is a plant-specific tetratricopeptide repeat domain-containing protein of unknown function encoded by a single Arabidopsis gene. HLB1 associated with the trans -Golgi network (TGN)/early endosome (EE) and tracked along filamentous actin, indicating that it could link post-Golgi traffic with the actin cytoskeleton in plants. HLB1 was found to interact with the ADP-ribosylation-factor guanine nucleotide exchange factor, MIN7/BEN1 (HOPM INTERACTOR7/BREFELDIN A-VISUALIZED ENDOCYTIC TRAFFICKING DEFECTIVE1) by coimmunoprecipitation. The min7/ben1 mutant phenocopied the mild root developmental defects and latrunculin B hypersensitivity of hlb1 , and analyses of a hlb1/ min7/ben1 double mutant showed that hlb1 and min7/ben1 operate in common genetic pathways. Based on these data, we propose that HLB1 together with MIN7/BEN1 form a complex with actin to modulate the function of the TGN / EE at the intersection of the exocytic and endocytic pathways in plants. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine if intestinal function and integrity is altered due to porcine reproductive and respiratory syndrome (PRRS) virus and porcine epidemic diarrhea (PED) virus infection in growing pigs. Forty-two gilts (16.8 ± 0.6 kg BW), naïve for PRRS and PED, were selected and randomly assigned to 1 of 4 treatments: 1) a control (CON; n = 6), 2) PRRS virus challenge only (PRRS; n = 12), 3) PED virus challenge only (PED; n = 12), or 4) coinfection of PRRS + PED viruses (PRP; n = 12). Treatments 2 and 4 were inoculated with a live field strain of PRRS virus on d 0 after inoculation. Treatments 3 and 4 were inoculated with PED virus on 14 d after inoculation (dpi) and all pigs were euthanized 7 d later (21 dpi). Infection with PRRS virus was determined by viremia and seroconversion. Fecal quantitative PCR was used to confirm PED virus infection. Control pigs remained PRRS and PED virus negative throughout the study. Compared with the CON, intestinal morphology was unaffected by PRRS. As expected, PED and PRP treatments resulted in duodenum, jejunum, and ileum villus atrophy compared with the CON treatment (P < 0.01). Ex vivo transepithelial electrical resistance (TER) did not differ between CON and PRRS pigs (P < 0.05) but was reduced by 40% in PED alone (P < 0.01). Interestingly, TER was increased (P < 0.01) in the PRP pigs. Active transport of glucose was increased in PRRS pigs over CON pigs (P < 0.01), whereas PED had pigs increased (P < 0.01) active glutamine transport over the CON pigs. Jejunum GLUT2 mRNA abundance and sucrase, maltase, and Na+/K+ adenosine triphosphatase activities tended to be increased in PRRS pigs compared with CON pigs (P < 0.06). The jejunum AA transporter, SLC6A14, and mucin 2 mRNA abundance tended to be increased in PED-only pigs (P < 0.10). These data suggest that PRRS infection supports a higher affinity for glucose uptake, whereas PED favors glutamine uptake. Interestingly, digestive machinery during PED challenge remained intact. Altogether, PED but not PRRS challenges alter intestinal morphology and integrity in growing pigs. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED) are two diseases costly to the U.S. swine industry. The objective of this study was to determine the impact of PRRS virus and PED virus, alone or in combination, on growth performance, feed efficiency, and digestibility in grower pigs. Forty-two gilts (16 ± 0.98 kg BW) naïve for PRRS and PED were selected and allocated to 1 of 4 treatments. Treatments included 1) a control, 2) PRRS virus infected, 3) PED virus infected, and 4) PRRS+PED coinfection (PRP). Pigs in treatments 2 and 4 were inoculated with a live field strain of PRRS virus via intramuscular and intranasal routes at 0 d after inoculation (dpi). Treatments 3 and 4 were orally inoculated with a cloned PED virus at 15 dpi. Infection with PRRS virus was confirmed by quantitative PCR and seroconversion. Infection with PED virus was confirmed with PCR. Control pigs remained PRRS and PED virus negative throughout the study. All pigs were offered, ad libitum, a standard diet with free access to water. During the test period, PRRS reduced ADG and ADFI by 30 and 26%, respectively (P < 0.05), compared with control pigs, whereas PRP decreased ADG, ADFI, and G:F by 45, 30, and 23%, respectively (P < 0.05). Additional reductions in ADG and G:F were detected in PRP pigs compared with singular PED or PRRS treatments (33 and 16%, respectively). The impact of PED, alone or in combination, on performance (15-21 dpi) reduced ADG (0.66 vs. 0.35 vs. 0.20 kg/d; P < 0.01), ADFI (1.22 vs. 0.88 vs. 0.67 kg/d; P = 0.003), and G:F (0.54 vs. 0.39 vs. 0.31; P = 0.001) compared with control pigs. Compared with control pigs, PRRS infection did not reduce apparent total tract digestibility (ATTD) of nutrients and energy. However, PED infection, alone or in combination, decreased ATTD of DM and energy by 8 and 12%, respectively (P < 0.05). Compared with control pigs, PRP reduced N and OM ATTD by 13 and 3%, respectively (P < 0.05). No significant differences in apparent ileal digestibility (AID) were detected between virus challenges. However, Lys AID tended to be reduced in both PED treatments compared with the control (10 and 12%; P = 0.095). Altogether, PRRS reduced growth but did not alter digestibility. Pigs challenged with PED and, to a greater extent, the coinfection of PED and PRRS viruses had reduced ADG, ADFI, G:F, and ATTD of nutrients and energy. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the efficacy and safety of a dietary vitamin D source on growth performance and tissue deposition of 25-hydroxycholecalciferol (25OHD3) in growing swine. Dietary treatments were a control with vitamin D3 at NRC recommended concentrations (C) and 3 diets composed of C + increasing inclusions (25, 50, and 250 µg/kg BioD, Huvepharma) of 25OHD3 (C+25; C+50; and C+250 respectively). Pigs (n = 144) were assigned to 24 pens which were allotted to 1 of 4 dietary treatments and fed for 42 d. On d 0, 39, and 63, serum was collected for 25OHD3 concentration determination and individual BW were measured. At d 42, tissues from 48 pigs (12 pigs per treatment) were analyzed for 25OHD3 concentration, blood chemistry and hematology (BCH) analysis was conducted, and 1 femur from each pig was collected for dual-energy X-ray absorptiometry scanning. Data were analyzed with SAS PROC GLIMMIX and means separated at P = 0.05. No differences among treatments were observed for growth performance (P = 0.2239). Serum and tissue 25OHD3 concentrations increased linearly as dietary 25OHD3 inclusion increased (P < 0.0001). Following a 21-d withdrawal period, 25OHD3 serum concentrations decreased to that of or within 2.76 ± 0.89 ng/mL of C-fed pigs (P > 0.0005). All BCH variables measured were similar among treatments (P = 0.0967). At day 42, femurs from C+50 and C+250-fed pigs had the greatest bone mineral content (BMC) and density (BMD; P < 0.0326). Concentrations of 25OHD3 in serum and tissue increased and BMC and BMD were improved as dietary vitamin D supplementation increased, but pig growth performance was unaltered. Absence of gross abnormalities and changes in BCH as well return of circulating 25OHD3 concentrations to that of C-fed pigs following withdrawal indicate this source can safely improve vitamin D status in growing pigs. [ABSTRACT FROM AUTHOR]

This study determined the impact of porcine reproductive and respiratory syndrome virus ( PRRSV) and Streptococcus suis coinfection on the pharmacokinetic ( PK) profile of ceftiofur hydrochloride in pigs after intramuscular (i.m.) injection. Eighteen clinically normal crossbred gilts were assigned by weight into a challenge group (10 pigs) and control group (eight pigs). Pigs in both groups received a single i.m. injection of ceftiofur hydrochloride ( Excenel RTU Sterile Suspension; Zoetis) at a 5 mg/kg BW dose. Serial blood samples were collected to characterize the plasma concentration curve. After a 10 days drug washout period, the challenge group was inoculated with 2 mL of PRRSV isolate VR-2385 (105.75 50% tissue culture infective doses per mL) intranasally and 8 days later inoculated S. suis. When clinical disease was evident, the second PK assessment began in both challenge and control groups. Coinfected pigs demonstrated lower values of AUC and CMAX, but higher values of Cl/ F and Vz/ F indicating drug kinetics were altered by infection. The data from this study have implications on ceftiofur treatment regimens in diseased pigs. [ABSTRACT FROM AUTHOR]

There is substantial genetic variation for drought adaption in pearl millet in terms of traits controlling plant water use. It is important to understand genomic regions responsible for these traits. Here, F7 recombinant inbred lines were used to identify quantitative trait loci ( QTL) and allelic interactions for traits affecting plant water use, and their relevance is discussed for crop productivity in water-limited environments. Four QTL contributed to increased transpiration rate under high vapour pressure deficit ( VPD) conditions, all with alleles from drought-sensitive parent ICMB 841. Of these four QTL, a major QTL (35.7%) was mapped on linkage group ( LG) 6. The alleles for 863B at this QTL decreased transpiration rate and this QTL co-mapped to a previously detected LG 6 QTL, with alleles from 863B for grain weight and panicle harvest index across severe terminal drought stress environments. This provided additional support for a link between water saving from a lower transpiration rate under high VPD and drought tolerance. 863B alleles in this same genomic region also increased shoot weight, leaf area and total transpiration under well-watered conditions. One unexpected outcome was reduced transpiration under high VPD (15%) from the interaction of two alleles for high VPD transpiration ( LG 6 (B), 40.7) and specific leaf mass and biomass ( LG 7 (A), 35.3), (A, allele from ICMB 841, B, allele from 863B, marker position). The LG 6 QTL appears to combine alleles for growth potential, beneficial for non-stress conditions, and for saving water under high evaporative demand, beneficial under stressful conditions. Mapping QTL for water-use traits, and assessing their interactions offers considerable potential for improving pearl millet adaptation to specific stress conditions through physiology-informed marker-assisted selection. [ABSTRACT FROM AUTHOR]

We explored potential of morphological and anatomical leaf traits for predicting ecophysiological key functions in subtropical trees. We asked whether the ecophysiological parameters stomatal conductance and xylem cavitation vulnerability could be predicted from microscopy leaf traits. We investigated 21 deciduous and 19 evergreen subtropical tree species, using individuals of the same age and from the same environment in the Biodiversity-Ecosystem Functioning experiment at Jiangxi ( BEF-China). Information-theoretic linear model selection was used to identify the best combination of morphological and anatomical predictors for ecophysiological functions. Leaf anatomy and morphology strongly depended on leaf habit. Evergreen species tended to have thicker leaves, thicker spongy and palisade mesophyll, more palisade mesophyll layers and a thicker subepidermis. Over 50% of all evergreen species had leaves with multi-layered palisade parenchyma, while only one deciduous species ( Koelreuteria bipinnata) had this. Interactions with leaf habit were also included in best multi-predictor models for stomatal conductance ( g s) and xylem cavitation vulnerability. In addition, maximum g s was positively related to log ratio of palisade to spongy mesophyll thickness. Vapour pressure deficit (vpd) for maximum g s increased with the log ratio of palisade to spongy mesophyll thickness in species having leaves with papillae. In contrast, maximum specific hydraulic conductivity and xylem pressure at which 50% loss of maximum specific xylem hydraulic conductivity occurred (Ψ50) were best predicted by leaf habit and density of spongy parenchyma. Evergreen species had lower Ψ50 values and lower maximum xylem hydraulic conductivities. As hydraulic leaf and wood characteristics were reflected in structural leaf traits, there is high potential for identifying further linkages between morphological and anatomical leaf traits and ecophysiological responses. [ABSTRACT FROM AUTHOR]

In the present study, we analysed the habitat association of tree species in an old-growth temperate forest across all life stages to test theories on the coexistence of tree species in forest communities. An inventory for trees was implemented at a 6-ha plot in Ogawa Forest Reserve for adults, juveniles, saplings and seedlings. Volumetric soil water content ( SMC) and light levels were measured in 10-m grids. Relationships between the actual number of stems and environmental variables were determined for 35 major tree species, and the spatial correlations within and among species were analysed. The light level had no statistically significant effect on distribution of saplings and seedlings of any species. In contrast, most species had specific optimal values along the SMC gradient. The optimal values were almost identical in earlier life stages, but were more variable in later life stages among species. However, no effective niche partitioning among the species was apparent even at the adult stage. Furthermore, results of spatial analyses suggest that dispersal limitation was not sufficient to mitigate competition between species. This might result from well-scattered seed distribution via wind and bird dispersal, as well as conspecific density-dependent mortality of seeds and seedlings. Thus, both niche partitioning and dispersal limitation appeared less important for facilitating coexistence of species within this forest than expected in tropical forests. The tree species assembly in this temperate forest might be controlled through a neutral process at the spatial scale tested in this study. [ABSTRACT FROM AUTHOR]

An untested theory states that C4 grass seeds could germinate under lower water potentials (Ψ) than C3 grass seeds. We used hydrotime modelling to study seed water relations of C4 and C3 Canadian prairie grasses to address Ψ divergent sensitivities and germination strategies along a risk-spreading continuum of responses to limited water. C4 grasses were Bouteloua gracilis, Calamovilfa longifolia and Schizachyrium scoparium; C3 grasses were Bromus carinatus, Elymus trachycaulus, Festuca hallii and Koeleria macrantha. Hydrotime parameters were obtained after incubation of non-dormant seeds under different Ψ PEG 6000 solutions. A t-test between C3 and C4 grasses did not find statistical differences in population mean base Ψ (Ψb(50)). We found idiosyncratic responses of C4 grasses along the risk-spreading continuum. B. gracilis showed a risk-taker strategy of a species able to quickly germinate in a dry soil due to its low Ψb(50) and hydrotime (θH). The high Ψb(50) of S. scoparium indicates it follows the risk-averse strategy so it can only germinate in wet soils. C. longifolia showed an intermediate strategy: the lowest Ψb(50) yet the highest θH. K. macrantha, a C3 grass which thrives in dry habitats, had the highest Ψb(50), suggesting a risk-averse strategy for a C3 species. Other C3 species showed intermediate germination patterns in response to Ψ relative to C4 species. Our results indicate that grasses display germination sensitivities to Ψ across the risk-spreading continuum of responses. Thus seed water relations may be poor predictors to explain differential recruitment and distribution of C3 and C4 grasses in the Canadian prairies. [ABSTRACT FROM AUTHOR]

* Premise of the study: Plants will be an important component of advanced life support systems during space exploration missions. Therefore, understanding their biology in the spacecraft environment will be essential before they can be used for such systems. * Methods: Seedlings of Arabidopsis thaliana were grown for 2 wk in the Biological Research in Canisters (BRIC) hardware on board the second to the last mission of the space shuttle Discovery (STS-131). Transcript profiles between ground controls and space-grown seedlings were compared using stringent selection criteria. * Key results: Expression of transcripts associated with oxidative stress and cell wall remodeling was repressed in microgravity. These downregulated genes were previously shown to be enriched in root hairs consistent with seedling phenotypes observed in space. Mutations in genes that were downregulated in microgravity, including two uncharacterized root hair-expressed class III peroxidase genes (PRX44 and PRX57), led to defective polar root hair growth on Earth. PRX44 and PRX57 mutants had ruptured root hairs, which is a typical phenotype of tip-growing cells with defective cell walls and those subjected to stress. * Conclusions: Long-term exposure to microgravity negatively impacts tip growth by repressing expression of genes essential for normal root hair development. Whereas changes in peroxidase gene expression leading to reduced root hair growth in space are actin-independent, root hair development modulated by phosphoinositides could be dependent on the actin cytoskeleton. These results have profound implications for plant adaptation to microgravity given the importance of tip growing cells such as root hairs for efficient nutrient capture. [ABSTRACT FROM AUTHOR]

Ozone (O3) is a phytotoxic greenhouse gas that has increased more than threefold at Earth's surface from preindustrial values. In addition to directly increasing radiative forcing as a greenhouse gas, O3 indirectly impacts climate through altering the plant processes of photosynthesis and transpiration. While global estimates of gross primary productivity (GPP) have incorporated the effects of O3, few studies have explicitly determined the independent effects of O3 on transpiration. In this study, the authors include effects of O3 on photosynthesis and stomatal conductance from a recent literature review to determine the impact on GPP and transpiration and highlight uncertainty in modeling plant responses to O3. Using the Community Land Model, the authors estimate that present-day O3 exposure reduces GPP and transpiration globally by 8%-12% and 2%-2.4%, respectively. The largest reductions were in midlatitudes, with GPP decreasing up to 20% in the eastern United States, Europe, and Southeast Asia and transpiration reductions of up to 15% in the same regions. Larger reductions in GPP compared to transpiration decreased water-use efficiency 5%-10% in the eastern United States, Southeast Asia, Europe, and central Africa; increased surface runoff more than 15% in eastern North America; and altered patterns of energy fluxes in the tropics, high latitudes, and eastern North America. Future climate predictions will be improved if plant responses to O3 are incorporated into models such that stomatal conductance is modified independently of photosynthesis and the effects on transpiration are explicitly considered in surface energy budgets. Improvements will help inform regional decisions for managing changes in hydrology and surface temperatures in response to O3 pollution. [ABSTRACT FROM AUTHOR]

Nitrogen (N) transformations in forest soils are fundamentally important to plant and microbial N nutrition and the N balance of forest ecosystems, but changes in the patterns and rates of N transformations during forest succession are poorly understood. In order to better understand how soil N cycling changes during ecosystem succession, we analyzed four years of soil N cycling measurements in a 90-year-old secondary forest undergoing dieback of early-successional, dominant canopy trees. We expected that tree mortality would decrease root biomass, leading to increased soil NH availability, and that these changes would prompt fundamental shifts in the N cycle such as the initiation of significant nitrification and increased cycling of oxidized N compounds in gas phase and soil solution. As expected, indices of soil NH and NO availability increased with successional stage (defined as the proportion of dead trees), and were negatively correlated with the amount of fine root biomass. However, the standing amount of fine root biomass was not affected by tree mortality; increased soil NH and NO availability therefore more likely resulted from successional increases in N-mineralization than decreases in root N uptake. Nitrification (as indicated by NO efflux as a proxy) increased due to elevated substrate (NH) availability, and the soil solution NO concentration increased as a result. Soil NO efflux was not affected by succession, nor was it related to other N cycling parameters. Collectively, these results indicate that recent successional advancement has accelerated soil N cycling and shifted the N economy of this ecosystem towards greater importance of NO. [ABSTRACT FROM AUTHOR]

Water stress is one of the most important factors limiting the growth and productivity of crops. The implication of compatible osmolytes such as proline and polyamines in osmotic adjustment has been widely described in numerous plants species under stress conditions. In the present study, we investigated the response of five cherry tomato cultivars ( Solanum lycopersicum L.) subjected to moderate water stress in order to shed light on the involvement of proline and polyamine metabolism in the mechanisms of tolerance to moderate water stress. Our results indicate that the most water stress-resistant cultivar ( Zarina) had increased degradation of proline associated with increased polyamine synthesis, with a higher concentration of spermidine and spermine under stress conditions. In contrast, Josefina, the cultivar most sensitive to water stress, showed a proline accumulation associated with increased synthesis after being subjected to stress. In turn, in this cultivar, no rise in polyamine synthesis was detected. Therefore, all the data appear to indicate that polyamine metabolism is more involved in the tolerance response to moderate water stress. [ABSTRACT FROM AUTHOR]