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Abstract  Poly-γ-glutamic acid (γ-PGA) is a kind of water-soluble and biodegradable polymer made from d- and l-glutamic acid units, which are linked by amide bonds formed between α-amino and γ-carboxylic acid groups. As a potential targeted biopolymer that can be refined from biomass directly, γ-PGA has been increasingly applied to food, cosmetic, and pharmaceutical industries. In this work, a suitable nitrogen source was screened out for the high and cost-effective production of γ-PGA in Bacillus subtilis ZJU-7. The effects of inoculation time and initial glucose concentration on the γ-PGA production were investigated systematically in both shake flasks and a bench-top 15-l fermentor. Under the optimized culture conditions, a high γ-PGA productivity (46.4 g/l) was obtained after 48 h cultivation at 37 °C. Finally, the large-scale fermentation of γ-PGA production was successfully scaled up to a 100-l fermentor, with the highest γ-PGA productivity for over 54.0 g/l. [ABSTRACT FROM AUTHOR]

The preference of paddy rice for NH4+ rather than NO3- is associated with its tolerance to low pH since a rhizosphere acidification occurs during NH4+ absorption. However, the adaptation of rice root to low pH has not been fully elucidated. This study investigated the acclimation of plasma membrane H+-ATPase of rice root to low pH. Rice seedlings were grown either with NH4+ or NO3-. For both nitrogen forms, the pH value of nutrient solutions was gradually adjusted to pH 6.5 or 3.0. After 4 d cultivation, hydrolytic H+-ATPase activity, Vmax, Km, H+-pumping activity, H+ permeability and pH gradient across the plasma membrane were significantly higher in rice roots grown at pH 3.0 than at 6.5, irrespective of the nitrogen forms supplied. The higher activity of plasma membrane H+-ATPase of adapted rice roots was attributed to the increase in expression of OSA1, OSA3, OSA7, OSA8 and OSA9 genes, which resulted in an increase of H+-ATPase protein concentration. In conclusion, a high regulation of various plasma membrane H+-ATPase genes is responsible for the adaptation of rice roots to low pH. This mechanism may be partly responsible for the preference of rice plants to NH4+ nutrition. [ABSTRACT FROM AUTHOR]

Porous NaO2–MgO–CaO–P2O5 bioglass doped beta-tri-calcium phosphate (β-TCP) bioceramic possessing high mechanical properties and well pore structure with high porosity and high pore connectivity has been prepared through dipping method with the porous polyurethane as the pore forming template. The sintering mechanism and the mechanical properties of the bioglass doped β-TCP scaffold have been investigated by the X-ray diffraction (XRD) analysis, Scanning electron microscope (SEM) and thermal differential analysis (DTA). The scaffold’s in vivo osteoconductivity has been evaluated by implantation of scaffolds into the femurs of New Zealand rabbits. The results show that the porous structure can achieve the densification process at a low temperature about 950°C by a solid solution sintering mechanism and hence dense macropore scaffold with a compressive strength of 4.32 MPa when the porosity is 75% has been obtained. The in vivo test shows that the Na2O–MgO–CaO–P2O5 bioglass doped porous β-TCP bioceramic has a relatively fast bone formation after implantation; after 1 month implantation new deposited bone tissue has been detected on the strut of the porous scaffold and degraded particles also has been found on the surface of the new formed bone. After 6 months implantation the porous scaffold has been thoroughly covered with new formed bone. Results show that the Na2O–MgO–CaO–P2O5 bioglass doped porous β-TCP bioceramic is potential bone tissue engineering scaffold for orthopedic use. [ABSTRACT FROM AUTHOR]

The plasma membrane (PM) proton pump ATPases (H+-ATPases) are involved in almost all aspects of biology. They are plant specific and several members of this family are supposed to play a key role in nutrient acquisition. At present, only some members of this gene family in plants have been characterized. However, no nutrient uptake associated H+-ATPase gene in rice has been functionally analysed. It is reported here that OsA8, a typical PM H+-ATPases gene that was predominantly expressed in roots of rice, is down-regulated by nutrient deficiency. The Osa8 mutant had a relatively smaller size and root to shoot biomass ratio, but higher ATPase activity than its wild-type counterparts under phosphorus (P) starvation conditions. Knockout of OsA8 affected the expression of several OsA genes and the high affinity phosphate transporter, OsPT6, and resulted in a higher P concentration in the roots and a lower amount of P in the shoots. These analyses demonstrate that OsA8 not only influences the uptake of P by roots, but also the translocation of P from the roots to the shoots in rice. [ABSTRACT FROM PUBLISHER]

Abstract   Dendrobium officinale is commonly used as a traditional valuable Chinese tonic hygienic food. In order to authenticate the quality of hygienic food in the market and geoherbalism in the process of GAP (good agriculture practice), sequences of chloroplast genes (matK and rbcL), the nuclear rDNA ITS region and mitochondria gene nad1 intron2 were used to survey eight populations of D. officinale. No difference was found in sequences of matK, rbcL and nad1 intron2 between populations, except for nine single nucleotide polymorphisms (SNPs) sites in rDNA ITS regions. Two pairs of allele-specific PCR primers based on SNPs were designed to authenticate two genuine populations (GSG and FSC populations). The AS-PCR (allele-specific PCR) fragments of GSG and FSC populations are about 600 and 560 bp, and annealing temperatures are 55–57 and 58–60°C, respectively. Dried “Fengdou” food samples from genuine populations could also be authenticated using two pairs of diagnostic primers. It is demonstrated that methods based on SNPs of rDNA ITS region and AS-PCR are simple, practical and effective for genuine germplasm authentication of D. officinale during the process of GAP and hygienic food quality control. [ABSTRACT FROM AUTHOR]

Abstract  In arbuscular mycorrhizal (AM) symbiosis, there is a reciprocal nutrient exchange between symbiotic partners. AM fungi assist the plants with uptake of mineral nutrients from the soil, especially phosphate (Pi). The host plants, in return, provide the fungi with sugar. In contrast to the studies on the symbiotic transport of Pi in arbuscular mycorrhiza, there have been few investigations devoted specifically to sugar transport in AM symbiosis. Using reverse transcriptase PCR (RT-PCR), we analyzed the effects of mycorrhiza and Pi on the expression of seven putative sugar transporter genes in tomato plants. The expression of LeSUT1 and LeHT2, classified, respectively, as putative sucrose and hexose transporter genes, were down-regulated in the roots inoculated with AM fungi Glomus caledonium or Glomus intraradices. Unexpectedly, the expression of LeST3, a putative monosaccharide transporter gene, was decreased by inoculation of Glomus caledonium, but was enhanced by inoculation of Glomus intraradices in both the roots and leaves. High-Pi in the tomato decreased the expression of LeHT2 and LeST3 in the roots, and enhanced that of LeHT2 in the leaves. The contradictory regulation of the expression of LeST3 in the AM symbiosis indicates that different interaction may take place during mycorrhizal colonization, and a quite complicated regulation of expression of the sugar transporter genes exist in mycorrhizal tomato. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To describe the MRI findings and discuss the pathogenesis formation mechanism of syringomyelia in the patients after spine surgical operation. Methods: Totally 13 patients were been enrolled in the study. Before operation, none of our patients presented with spinal cord syringomyelia. The mean follow-up duration was 6 years (range 2–10 months) by MRI. Four of the 13 patients after spinal cord tumor removed operation, 3 patients after spinal trauma operation, 2 cases had scoliosis before, 2 cases were cervical spondylotic myelopathy and 2 cases had tethered cord syndrome before operation. MR features of pre- and post-operation on all patients were been studied in contrast with surgical results and clinical symptoms. The radiology diagnostic was made by 3 different radiologists respectively. The characteristics of length, width, signals, shape of cavity and spinal cord position as well as subarachnoid shape were focused on. Results: All the patients had no syringomyelia on MRI before operation. The spinal cord of 7 patients showed persist compression and 2 patients had tethered cord before operation. MRI features of syringomyelia after operation in our cases showed longitudinal cavity with syrinx fluid had T1 and T2 relation characteristics of cerebrospinal fluid (CSF). The mean length was 5.5 spinal segment, 4 cord of 13 patients presented cord compressed from anterior materials, 4 occurred postoperative adhesion to the back of lumbar spinal canal and spinal cord of 1 cases clung to the front wall of cervical spinal canal. Conclusion: The mechanism of syringomyelia in the patients after spinal surgical intervention may be the persisting compression or intention of the spinal cord in the period of pre- or post-operation. The edema, cyst, malacia of spinal cord are the most important lesions and risk factors resulted in the syringomyelia. [Copyright &y& Elsevier]

• Here, orthologous genes of six phosphate transporter (PiT) genes, which are members of the Pht1 and Pht2 families in tomato and potato, have been cloned from the solanaceous species pepper, eggplant and tobacco. • Overall, expressions of these genes in pepper, eggplant and tobacco showed similar patterns to those in tomato and potato: P-starvation enhancement in both leaves and roots for Pht1;1, P-depletion induction exclusively in roots for Pht1;2, mycorrhizal enhancement for Pht1;3, and mycorrhizal induction for both Pht1;4 and Pht1;5. • In the roots of nonmycorrhizal eggplant, SmPht1;3, SmPht1;4 and SmPht1;5 were also expressed under extreme P starvation. Mycorrhizal symbiosis under high-P supply conditions reduced plant growth, with concurrent enhancement of Pht1;2 expression in the roots of pepper as well as eggplant. In addition, the mycorrhizal symbiosis down-regulated the expression of Pht2;1 genes greatly in the leaves of pepper and tobacco. • The discrepancies between the evolutionary distances of the PiT genes and their expression patterns among the five species suggest greater complexity in function of PiT in plants than previously expected. [ABSTRACT FROM AUTHOR]

• Background Population and environmental pressure have imposed a great challenge on agriculture in China to explore innovative and effective solutions to its pressing plant nutritional problems. Plant nutriomics is a new frontier in plant biology that can provide innovative solutions for improving plant nutrient efficiency, thus increasing crop productivity through genetic and molecular approaches.• Scope This review summarizes current efforts and progress in plant nutriomic research in China with examples from several case studies. It also points out potential obstacles and depicts future perspectives in this emerging frontier of plant nutrition.• Conclusions Although plant nutriomics is still at a conceptual stage, substantial efforts are being made in China aimed at increasing plant nutrient efficiency through a nationwide, co-ordinated project on plant nutriomics. Future studies involving both national and international collaborations are needed to develop nutrient-efficient, stress-tolerant and high-quality crop varieties for both China and elsewhere. [ABSTRACT FROM AUTHOR]

Provides information on a study that examined the influences of climate conditions during the growth of sweet pepper on the accumulation, distribution and leakage of mineral nutrients of hybrid seeds and to reveal their association with seed emergence quality. Methodology of the study; Results and discussion on the study.

Gives an theoretical model of how to determine an equivalent diameter of the circular defect for real defect data. Characterization of the probability that the circular defect causes a fault; Description of the methodology used to decipher the equivalent diameter of a circular defect for real data; Observation made.

Osteoporosis is a common disease among the ageing society. Oxidative stress caused by excessive accumulation of reactive oxygen species (ROS) is the aetiology of osteoporosis. α-Lipoic acid (ALA) is an antioxidant in the body, which can eliminate excess ROS in the body and inhibits levels of oxidative stress in cells. Herein, we designed PEGylated hollow gold nanoparticles (HGNPs) loaded with ALA (mPEG@HGNPs-ALA) to remove ROS in the treatment of osteoporosis. First, mPEG@HGNPs with a particle size of ~63nm has been successfully synthesized. By comparing the drug loading of mPEG@HGNPs, it was concluded that the optimal mass ratio of mPEG@HGNPs (calculated by the amount of gold) to ALA was ~1:2. ABTS antioxidant assay showed that free radical removal ability. In vitro results revealed that the preparation had good biocompatibility. At the gold concentration of 1-150 lg/mL, the cell viability of mPEG@HGNPs was more than 100%, which indicated that it could promote the proliferation of osteoblasts. What's more, mPEG@HGNPs-ALA could effectively remove the ROS caused by H2O2 injury and improve the cell viability. According to these results, it can be considered that mPEG@HGNPs-ALA has the potential to treat osteoporosis. [ABSTRACT FROM AUTHOR]

High-affinity potassium (K+) transporter (HAK)/K+ uptake permease (KUP)/K+ transporter (KT) have been identified in all genome-sequenced terrestrial plants. They play an important role in K+ acquisition and translocation and in enhancing salt tolerance. Here, we report that plasma membrane-located OsHAK18 functions in K+ and sodium (Na+) circulation and sugar translocation in rice (Oryza sativa). OsHAK18 was expressed mainly, though not exclusively, in vascular tissues and particularly in the phloem. Knockout (KO) of OsHAK18 reduced K+ concentration in phloem sap and roots but increased K+ accumulation in the shoot of both 'Nipponbare' and 'Zhonghua11' cultivars, while overexpression (OX) of OsHAK18 driven by its endogenous promoter increased K+ concentration in phloem sap and roots and promoted Na+ retrieval from the shoot to the root under salt stress. Split-root experimental analysis of rubidium (Rb+) uptake and circulation indicated that OsHAK18-OX promoted Rb+ translocation from the shoot to the root. In addition, OsHAK18-KO increased while OsHAK18-OX reduced soluble sugar content in the shoot and oppositely affected the sugar concentration in the phloem and its content in the root. Moreover, OsHAK18-OX dramatically increased grain yield and physiological K+ utilization efficiency. Our results suggest that--unlike other OsHAKs analyzed heretofore--OsHAK18 is critical for K+ and Na+ recirculation from the shoot to the root and enhances the source-to-sink translocation of photo-assimilates. [ABSTRACT FROM AUTHOR]

Plants have evolved delicate systems for stimulating or inhibiting inorganic phosphate (Pi) uptake in response to the fluctuating Pi availability in soil. However, the negative regulators inhibiting Pi uptake at the transcriptional level are largely unexplored. Here, we functionally characterized a transcription factor in rice (Oryza sativa), OsWRKY10. OsWRKY10 encodes a nucleus-localized protein and showed preferential tissue localization. Knockout of OsWRKY10 led to increased Pi uptake and accumulation under Pi-replete conditions. In accordance with this phenotype, OsWRKY10 was transcriptionally induced by Pi, and a subset of PHOSPHATE TRANSPORTER 1 (PHT1) genes were up-regulated upon its mutation, suggesting that OsWRKY10 is a transcriptional repressor of Pi uptake. Moreover, rice plants expressing the OsWRKY10–VP16 fusion protein (a dominant transcriptional activator) accumulated even more Pi than oswrky10. Several lines of biochemical evidence demonstrated that OsWRKY10 directly suppressed OsPHT1;2 expression. Genetic analysis showed that OsPHT1;2 was responsible for the increased Pi accumulation in oswrky10. Furthermore, during Pi starvation, OsWRKY10 protein was degraded through the 26S proteasome. Altogether, the OsWRKY10–OsPHT1;2 module represents a crucial loop in the Pi signaling network in rice, inhibiting Pi uptake when there is ample Pi in the environment. [ABSTRACT FROM AUTHOR]

Astragaloside (AS) has an anti-osteoporotic effect, but its poor water solubility and low bioavailability limit its application. In this study, a novel nano-carrier with bone targeting was prepared by modifying mPEG-PLGA with alendronate (AL) before incorporation into astragaloside nano-micelles (AS-AL-mPEGPLGA) to enhance the oral bioavailability, bone targeting and anti-osteoporosis effect of AS. The release behavior of AS-AL-mPEG-PLGA in vitro was investigated via dialysis. The pharmacokinetics of AS-AL-mPEG-PLGA was studied in Sprague-Dawley (SD) rats. The cytotoxicity of AS-AL-mPEG-PLGA in vitro (via MTT method), coupled with bone targeting ability in vitro and in vivo were evaluated. The therapeutic effects of free AS and AS-AL-mPEG-PLGA (ELISA, micro-CT, H&E staining) were compared in osteoporotic rats. AS-AL-mPEG-PLGA with smaller particle size (45.3 ± 3.8 nm) and high absolute zeta potential (-23.02 ± 0.51 mV) were successfully prepared, wherein it demonstrated higher entrapment efficiency (96.16 ± 0.18%), a significant sustained-release effect for 96 h and acceptable safety within 10-200 lg/mL. AS-AL-mPEG-PLGA could enhance the hydroxyapatite affinity and bone tissue concentration of AS. The relative bioavailability of AS-AL-mPEG-PLGA was 233.90% compared with free AS. In addition, the effect of AS in reducing serum levels of bone metabolism-related indicators, restoring the bone microarchitecture and improving bone injury could be enhanced by AS-AL-mPEG-PLGA. ASAL-mPEG-PLGA with small particle size, good stability, remarkable sustained-release effect, safety and bone targeting was successfully constructed in this experiment to potentially improve the oral bioavailability and anti-osteoporosis effect of AS. Thus, AS-AL-mPEG-PLGA may be a promising strategy to prevent and treat osteoporosis. [ABSTRACT FROM AUTHOR]

Bioactive ceramics coated magnesium alloys with a combination of suitable mechanical strength and adjustable corrosion resistance are desired for biodegradable implants. In this study, a dense bioglass coated magnesium alloy was fabricated by uniaxial pressing and microwave hybrid heating technique. The microstructure, bond strength and corrosion behavior of the samples were evaluated by means of scanning electron microscopy, X-ray diffraction, tensile bond test, electrochemical and immersion test. It was shown that uniaxial pressing conducted at the glass transition temperature significantly densified the sol-gel derived bioglass coating, which was free of pores and micro-cracks. The compact coating structure combined with mild interfacial stress not only improved the cohesion/adhesion strength (25.8 ± 2.6 MPa) but also enhanced corrosion resistance by retarding the penetration of corrosive solution. Furthermore, the formed CaP precipitates on the surface of the coating would provide another protection for the magnesium alloy to some extent. [ABSTRACT FROM AUTHOR]

The article presents a study on the significant role of an unidentified allele of the nitrate transporter gene OsNRT2.3 in maintaining high yield and high nitrogen use efficiency under high temperatures. Topics discussed include the structure of small RNA and OsNRT2.3a/b transcription, and the implications of the study for breeding rice varieties with higher grain yield and lower nitrogen fertilizer input.

Forming mutualistic symbioses with arbuscular mycorrhizae (AMs) improves the acquisition of mineral nutrients for most terrestrial plants. However, the formation of AM symbiosis usually occurs under phosphate (Pi)-deficient conditions. Here, we identify SlSPX1 (SYG1 (suppressor of yeast GPA1)/Pho81(phosphate 81)/XPR1 (xenotropic and polytropic retrovirus receptor 1) as the major repressor of the AM symbiosis in tomato (Solanum lycopersicum) under phosphate-replete conditions. Loss of SlSPX1 function promotes direct Pi uptake and enhances AM colonization under phosphate-replete conditions. We determine that SlSPX1 integrates Pi signaling and AM symbiosis by directly interacting with a set of arbuscule-induced SlPHR proteins (SlPHR1, SlPHR4, SlPHR10, SlPHR11, and SlPHR12). The association with SlSPX1 represses the ability of SlPHR proteins to activate AM marker genes required for the arbuscular mycorrhizal symbiosis. SlPHR proteins exhibit functional redundancy, and no defective AM symbiosis was detected in the single mutant of SlPHR proteins. However, silencing SlPHR4 in the Slphr1 mutant background led to reduced AM colonization. Therefore, our results support the conclusion that SlSPX1-SlPHRs form a Pi-sensing module to coordinate the AM symbiosis under different Pi-availability conditions. [ABSTRACT FROM AUTHOR]

Plants adjust root architecture and nitrogen (N) transporter activity to meet the variable N demand, but their integrated regulatory mechanism remains unclear. We have previously reported that a floral factor in rice (Oryza sativa), N-mediated heading date-1 (Nhd1), regulates flowering time. Here, we show that Nhd1 can directly activate the transcription of the high-affinity ammonium (NH+4) transporter 1;3 (OsAMT1;3) and the dual affinity nitrate (NO-3) transporter 2.4 (OsNRT2.4). Knockout of Nhd1 inhibited root growth in the presence of NO-3 or a low concentration of NH+4. Compared to the wild-type (WT), nhd1 and osamt1;3 mutants showed a similar decrease in root growth and N uptake under low NH+4 supply, while nhd1 and osnrt2.4 mutants showed comparable root inhibition and altered NO-3 translocation in shoots. The defects of nhd1 mutants in NH+4 uptake and root growth response to various N supplies were restored by overexpression of OsAMT1;3 or OsNRT2.4. However, when grown in a paddy field with low N availability, nhd1 mutants accumulated more N and achieved a higher N uptake efficiency (NUpE) due to the delayed flowering time and prolonged growth period. Our findings reveal a molecular mechanism underlying the growth duration-dependent NUpE. [ABSTRACT FROM AUTHOR]

A phytic acid conversion coating was developed on AZ31 magnesium alloy by dipping the magnesium alloy into the phytic acid solution. The effects of heat treatment in the temperature range of 150 °C-400 °C on the chemical composition of the coatings and the crack healing were investigated, and the corrosion resistance of the coatings in simulated body fluid was studied by electrochemical measurements. The results showed that with the increase of the heat treatment temperature, the cracks on the surface of the conversion coating gradually healed up, that subsequently improved the corrosion resistance of these coated magnesium alloy. During the heat treatment process, the conversion coating composed of amorphous magnesium phytate was transformed to crystalline Mg2P2O7. Meanwhile, the macromolecular complex changed into small organic structure, and accompanied the increase of the volume, leading to the surface crack self-healing. The coating heat-treated at 400 °C exhibited superior surface integrity and corrosion resistance due to the great crystallization of Mg2P2O7 and crack healing. [ABSTRACT FROM AUTHOR]

Inorganic phosphate (Pi) is the predominant form of phosphorus (P) readily accessible to plants, and Pi Transporter 1 (PHT1) genes are the major contributors to root Pi uptake. However, the mechanisms underlying the transport and recycling of Pi within plants, which are vital for optimizing P use efficiency, remain elusive. Here, we characterized a functionally unknown rice (Oryza sativa) PHT1 member barely expressed in roots, OsPHT1;7. Yeast complementation and Xenopus laevis oocyte assay demonstrated that OsPHT1;7 could mediate Pi transport. Reverse-transcription quantitative polymerase chain reaction and histochemical analyses showed that OsPHT1;7 was preferentially expressed in source leaves and nodes. A further fine-localization analysis by immunostaining showed that OsPHT1;7 expression was restricted in the vascular bundle (VB) sheath and phloem of source leaves as well as in the phloem of regular/diffuse- and enlarged-VBs of nodes. In accordance with this expression pattern, mutation of OsPHT1;7 led to increased and decreased P distribution in source (old leaves) and sink organs (new leaves/panicles), respectively, indicating that OsPHT1;7 is involved in P redistribution. Furthermore, OsPHT1;7 showed an overwhelmingly higher transcript abundance in anthers than other PHT1 members, and ospht1;7 mutants were impaired in P accumulation in anthers but not in pistils or husks. Moreover, the germination of pollen grains was significantly inhibited upon OsPHT1;7 mutation, leading to a >80% decrease in seed-setting rate and grain yield. Taken together, our results provide evidence that OsPHT1;7 is a crucial Pi transporter for Pi transport and recycling within rice plants, stimulating both vegetative and reproductive growth. [ABSTRACT FROM AUTHOR]

As sessile organisms, plants rely on their roots for anchorage and uptake of water and nutrients. Plant root is an organ showing extensive morphological and metabolic plasticity in response to diverse environmental stimuli including nitrogen (N) and phosphorus (P) nutrition/stresses. N and P are two essential macronutrients serving as not only cell structural components but also local and systemic signals triggering root acclimatory responses. Here, we mainly focused on the current advances on root responses to N and P nutrition/stresses regarding transporters as well as long-distance mobile proteins and peptides, which largely represent local and systemic regulators, respectively. Moreover, we exemplified some of the potential pitfalls in experimental design, which has been routinely adopted for decades. These commonly accepted methods may help researchers gain fundamental mechanistic insights into plant intrinsic responses, yet the output might lack strong relevance to the real situation in the context of natural and agricultural ecosystems. On this basis, we further discuss the established--and yet to be validated--improvements in experimental design, aiming at interpreting the data obtained under laboratory conditions in a more practical view. [ABSTRACT FROM AUTHOR]

The article provides information on a study which suggested a pleiotropic messenger strategy based on near-infrared (NIR) light-triggered on-demand nitric oxide (NO) release at the lesion area for traumatic spinal cord injury (SCI) recovery. Topics discussed include synthesis and characterization of UCZN, cytocompatibility and spatiotemporally controlled NO release of UCZN, and neurite growth-promoting property of UCZN.

Legume biological nitrogen (N) fixation is the most important N source in agroecosystems, but it is also a process requiring a considerable amount of phosphorus (P). Therefore, developing legume varieties with effective N2 fixation under P-limited conditions could have profound significance for improving agricultural sustainability. We show here that inoculation with effective rhizobial strains enhanced soybean (Glycine max) N2 fixation and P nutrition in the field as well as in hydroponics. Furthermore, we identified and characterized a nodule high-affinity phosphate (Pi) transporter gene, GmPT5, whose expression was elevated in response to low P. Yeast heterologous expression verified that GmPT5 was indeed a high-affinity Pi transporter. Localization of GmPT5 expression based on β-glucuronidase staining in soybean composite plants with transgenic roots and nodules showed that GmPT5 expression occurred principally in the junction area between roots and young nodules and in the nodule vascular bundles for juvenile and mature nodules, implying that GmPT5 might function in transporting Pi from the root vascular system into nodules. Overexpression or knockdown of GmPT5 in transgenic composite soybean plants altered nodulation and plant growth performance, which was partially dependent on P supply. Through both in situ and in vitro 33p uptake assays using transgenic soybean roots and nodules, we demonstrated that GmPT5 mainly functions in transporting Pi from roots to nodules, especially under P-limited conditions. We conclude that the high-affinity Pi transporter, GmPT5, controls Pi entry from roots to nodules, is critical for maintaining Pi homeostasis in nodules, and subsequently regulates soybean nodulation and growth performance. [ABSTRACT FROM AUTHOR]

A number of phosphate (Pi) starvation- or mycorrhiza-regulated Pi transporters belonging to the Phtl family have been functionally characterized in several plant species, whereas functions of the Pi transporters that are not regulated by changes in Pi supply are lacking. In this study, we show that rice (Oryza sativa) Phtl;1 (OsPT1), one of the 13 Phtl Pi transporters in rice, was expressed abundantly and constitutively in various cell types of both roots and shoots. OsPT1 was able to complement the proton-coupled Pi transporter activities in a yeast mutant defective in Pi uptake. Transgenic plants of OsPT1 overexpression lines and RNA interference knockdown lines contained significantly higher and lower phosphorus concentrations, respectively, compared with the wild-type control in Pi-sufficient shoots. These responses of the transgenic plants to Pi supply were further confirmed by the changes in depolarization of root cell membrane potential, root hair occurrence, 33p uptake rate and transportation, as well as phosphorus accumulation in young leaves at Pi-sufficient levels. Furthermore, OsPT1 expression was strongly enhanced by the mutation of Phosphate Overaccumulator2 (OsPH02) but not by Phosphate Starvation Response2, indicating that OsPT1 is involved in the OsPHO2-regulated Pi pathway. These results indicate that OsPT1 is a key member of the Phtl family involved in Pi uptake and translocation in rice under Pi-replete conditions. [ABSTRACT FROM AUTHOR]