myo-Inositol-1,2,3,4,5,6-hexakisphosphate

Life at the conservative end of the leaf economics spectrum: intergeneric variation in the allocation of phosphorus to biochemical fractions in species of Banksia (Proteaceae) and Hakea (Proteaceae)

In severely phosphorus (P)-impoverished environments, plants have evolved to use P very efficiently. Yet, it is unclear how P allocation in leaves contributes to their photosynthetic P-use efficiency (PPUE) and position along the leaf economics spectrum (LES). We address this question in 10 species of Banksia and Hakea, two highly P-efficient Proteaceae genera. We characterised traits in leaves of Banksia and Hakea associated with the LES: leaf mass per area, light-saturated photosynthetic rates, P and nitrogen concentrations, and PPUE. We also determined leaf P partitioning to five biochemical fractions (lipid, nucleic acid, metabolite, inorganic and residual P) and their possible association with the LES. For both genera, PPUE was negatively correlated with fractional allocation of P to lipids, but positively correlated with that to metabolites. For Banksia only, PPUE was negatively correlated with residual P, highlighting a strategy contrasting to that of Hakea. Phosphorus-allocation patterns significantly explained PPUE but were not linked to the resource acquisition vs resource conservation gradient defined by the LES. We conclude that distinct P-allocation patterns enable species from different genera to achieve high PPUE and discuss the implications of different P investments. We surmise that different LES axes representing different ecological strategies coexist in extremely P-impoverished environments.

The Efficacy of Encapsulated Phytase Based on Recombinant Yarrowia lipolytica on Quails' Zootechnic Features and Phosphorus Assimilation

In this study, we used the Manchurian golden breed of quails. We assessed the efficacy of the food additives of the phytase from Obesumbacterium proteus encapsulated in the recombinant Yarrowia lipolytica yeast, which was supplied at a concentration of 500 phytase activity units per kg of the feed. One hundred fifty one-day-old quails were distributed into six treatment groups. The results showed that adding the O. proteus encapsulated phytase to the quails' diets improved live weight, body weight gain, and feed conversion compared to those in the control groups and the groups using a commercial phytase from Aspergillus ficuum. The results obtained during the experiments indicate a high degree of assimilation of phytate-containing feeds if the encapsulated phytase was fed by the quails compared to that in the other groups. We can conclude that the class D encapsulated phytase is an expedient additive to the diets possessing better kinetic features compared to the PhyA and PhyC classes phytases when it acts inside the quail's chyme.

An Overview of Targeted Genome Editing Strategies for Reducing the Biosynthesis of Phytic Acid: an Anti-nutrient in Crop Plants

Anti-nutrients are substances either found naturally or are of synthetic origin, which leads to the inactivation of nutrients and limits their utilization in metabolic processes. Phytic acid is classified as an anti-nutrient, as it has a strong binding affinity with most minerals like Fe, Zn, Mg, Ca, Mn, and Cd and impairs their proper metabolism. Removing anti-nutrients from cereal grains may enable the bioavailability of both macro- and micronutrients which is the desired goal of genetic engineering tools for the betterment of agronomic traits. Several strategies have been adopted to minimize phytic acid content in plants. Pursuing the molecular strategies, there are several studies, which result in the decrement of the total phytic acid content in grains of major as well as minor crops. Biosynthesis of phytic acid mainly takes place in the seed comprising lipid-dependent and lipid-independent pathways, involving various enzymes. Furthermore, some studies show that interruption of these enzymes may involve the pleiotropic effect. However, using modern biotechnological approaches, undesirable agronomic traits can be removed. This review presents an overview of different genes encoding the various enzymes involved in the biosynthetic pathway of phytic acid which is being targeted for its reduction. It also, highlights and enumerates the variety of potential applications of genome editing tools such as TALEN, ZFN, and CRISPR/Cas9 to knock out the desired genes, and RNAi for their silencing.

Structural Insight on Supramolecular Polyion Salts: Inositol Hexaphosphate Enclosed in Cationic Macrocyclic Clusters

Supramolecular macrocyclic forces have been used to trap phytate, myo-inositol-1,2,3,4,5,6-hexakisphosphate, a key bioanion with multiple roles in metabolic processes. Due to the complex chemistry of six multivalent phosphates surrounding the small, cyclic inositol framework, crystallographic information of simple phytate salts has been elusive. This report represents a combined crystallographic, theoretical, and solution binding investigation of a supramolecular macrocyclic complex of phytate. Together, the results provide significant insight to phytate's intramolecular and intermolecular interactions at the microenvironment level. The macrocycle-phytate aggregates consist of phytate anionic pairs, each partly sandwiched by two 24-membered, amide/amine-based cationic macrocycles. The phytate ion pairs hold the tetrameric macrocyclic array together by six strong intermolecular hydrogen bonds. Both phytates crystallize in 1a5e phosphate conformations (one axial (P2) and five equatorial phosphates). Solution NMR binding studies in 1 : 1 DMSO-d6  : D2 O indicate 2 : 1 macrocycle:phytate associations, suggesting that the sandwich-like nature of the complex holds together in solution. DFT studies indicate the likely occurrence of dynamic intramolecular interchange of phosphate protons, as well as important roles for the axial (P2) phosphate in both intramolecular and intermolecular hydrogen bonding interactions.

Two-sided effects of the organic phosphorus phytate on a globally important marine coccolithophorid phytoplankton

Dissolved organic phosphorus (DOP) is a potential source of aquatic eutrophication and pollution because it can potentially stimulate growth in some species and inhibit growth in other species of algae, the foundation of the marine ecosystem. Inositol hexaphosphate (also named phytic acid or PA), an abundant organophosphate, is presumably ubiquitous in the marine environment, but how it affects marine primary producers is poorly understood. Here, we investigated the bioavailability of this DOP to the cosmopolitan coccolithophore Emiliania huxleyi. Our results showed that E. huxleyi cells can take up PA and dissolved inorganic phosphorus (DIP) simultaneously. Absorbed PA can efficiently support algal growth, producing cell yield between DIP and phosphorus (P)-depleted conditions. Accordingly, PA supply as the sole P source highly influences cellular metabolism and nutrient stoichiometry. Particularly, PA-grown cultures exhibited enhanced carbon fixation, increased lipid content, activated energy metabolism, and induced nitrogen assimilation. However, our data suggest that PA may also exert some levels of toxic effects on E. huxleyi. This study provides novel insights into the variable effects of a DOP on marine phytoplankton, which will inform new inquiries about how the complex DOP constituencies in the ocean will shape phytoplankton community structure and function. IMPORTANCE The dissolved organic phosphorus (DOP) utilization in phytoplankton plays vital roles in cellular P homeostasis, P-nutrient niche, and the dynamics of community structure in marine ecosystems, but its mechanisms, potentially varying with species, are far from clear. In this study, we investigated the utilization of a widespread DOP species, which is commonly produced by plants (land plants and marine macrophytes) and released into coastal areas, in a globally distributed bloom-forming coccolithophore species in various phosphorus environments. Using a combination of physiological and transcriptomic measurements and analyses, our experimental results revealed the complex mechanism and two-sided effects of DOP (major algal growth-supporting and minor toxic effects) in this species, providing a novel perspective on phytoplankton nutrient regulation.

Evaluation of the effects of different chelation agents on root dentin roughness

Successful root canal treatment requires effective irrigation of the entire root canal system. While chelating agents support irrigation, they can also alter physicochemical properties of the root dentin structure. The aim of this study is to evaluate the effect of different chelation agents on root dentin roughness. Twenty-five extracted maxillary incisors were used in this study. Samples were separated longitudinally and divided into five groups: distilled water, NaOCl, ethylenediaminetetraacetic acid (EDTA), phytic acid and citric acid (CA). Atomic force microscope and energy dispersive X-ray spectroscopy analyses were used for analysing. One-way analysis of variance and Turkey tests were used in the statistical analysis of the study. EDTA, CA and phytic acid solutions increased the roughness and phytic acid and CA solutions decreased the Ca/P ratio in dentin tissue. No statistical difference was observed in the other groups. The decrease of Ca/P ratio should be taken under consideration during irrigation. The increase in surface roughness may provide clinical benefit by supporting the adhesion of the root canal filling materials to the dentin surface.

Wheat derived glucuronokinase as a potential target for regulating ascorbic acid and phytic acid content with increased root length under drought and ABA stresses in Arabidopsis thaliana

Glucuronokinase (GlcAK) converts glucuronic acid into glucuronic acid-1-phosphate, which is then converted into UDP-glucuronic acid (UDP-GlcA) via myo-inositol oxygenase (MIOX) pathway. UDP-GlcA acts as a precursor in the synthesis of nucleotide-sugar moieties forming cell wall biomass. GlcAK being present at the bifurcation point between UDP-GlcA and ascorbic acid (AsA) biosyntheses, makes it necessary to study its role in plants. In this study, the three homoeologs of GlcAK gene from hexaploid wheat were overexpressed in Arabidopsis thaliana. The GlcAK overexpressing transgenic lines showed decreased contents of AsA and phytic acid (PA) as compared to control plants. Root length and seed germination analyses under abiotic stress (drought and abscisic acid) conditions revealed enhanced root length in transgenic lines as compared to control plants. These results indicate that the MIOX pathway might be contributing towards AsA biosynthesis as evident by the decreased AsA content in the GlcAK overexpressing transgenic Arabidopsis thaliana plants. Findings of the present study will enhance the understanding of the involvement of GlcAK gene in MIOX pathway and subsequent physiological effects in plants.

Seed phytic acid concentration affects rice seedling vigor irrespective of soil phosphorus bioavailability

Rice with a black-colored pericarp (hereafter, black rice) is well-known as an antioxidant-rich food, but a high grain phytic acid (PA) concentration affects its nutritional quality. However, phytic acid helps improve seedling vigor, which is crucial for enhancing subsequent plant growth. This study investigated the effect of seed phytic acid concentration in black rice on seedling vigor compared to the effects on white rice. In the first experiment, three phytic acid concentrations in the seeds of black rice, low (LPA, 15.5 mg g^-1 per seed), medium (MPA, 24.7 mg g^-1 per seed), and high (HPA, 35.4 mg g^-1 per seed) were tested for seedling vigor in phosphorus-deficient soils. The HPA seedlings showed substantially increased seedling vigor and shoot P uptake due to early root development and enhanced physiological processes. LPA grown seedlings showed increased ethylene production in response to P stress, which is the main physiological mechanism modulating seedling growth under P stress conditions. In the second experiment, the three phytic acid concentrations in black and white rice seeds were tested under low and high soil P conditions. Again, LPA seedlings showed significantly reduced seedling vigor in both rice varieties in P-deficient soils. Interestingly, seed phytic acid and external P application had an additive effect on seedling vigor, suggesting that the combined effect further improved seedling growth. Our results reveal that black rice seeds with a HPA concentration can be used as a seed source for planting in P-deficient ecosystems for rice plants as they can increase seedling vigor and subsequent growth, thus reducing dependence on finite P resources.

Estimated Phytate Intake Is Associated with Bone Mineral Density in Mediterranean Postmenopausal Women

The main objective of this work was to explore the association of dietary phytate intake with bone mineral density (BMD) in a Mediterranean population of postmenopausal women. For this purpose, a cross-sectional analysis of 561 women aged 55-75 years with overweight/obesity and metabolic syndrome from a Mediterranean area and with data on dual-energy X-ray absorptiometry (DXA) scans in femur and lumbar spine was performed. Estimated phytate intake was calculated using a validated food frequency questionnaire. Our results indicated that phytate intake was associated with BMD [β(95%CI) per each 25 mg/100 kcal] in femoral neck [0.023(0.060-0.040) g/cm²], femoral Ward's triangle [0.033(0.013-0.054) g/cm²], total femur [0.018(0.001-0.035) g/cm²], and all the analyzed lumbar spine sites [L1-L4: 0.033(0.007-0.059) g/cm²] after adjusting for potential confounders. The sensitivity analysis showed that phytate intake was directly associated with lumbar spine BMD in women younger than 66 years, with a body mass index higher than 32.6 kg/cm² and without type 2 diabetes (all p-for interactions < 0.05). The overall results indicated that phytate, a substance present in food as cereals, legumes and nuts, was positively associated with BMD in Mediterranean postmenopausal women. Phytate may have a protective effect on bone resorption by adsorbing on the surfaces of HAP. Nevertheless, large, long-term, and randomized prospective clinical studies must be performed to assess the possible benefits of phytate consumption on BMD in postmenopausal women.

Unraveling the genetics underlying micronutrient signatures of diversity panel present in brown rice through genome-ionome linkages

Rice (Oryza sativa) is an important staple crop to address the Hidden Hunger problem not only in Asia but also in Africa where rice is fast becoming an important source of calories. The brown rice (whole grain with bran) is known to be more nutritious due to elevated mineral composition. The genetics underlying brown rice ionome (sum total of such mineral composition) remains largely unexplored. Hence, we conducted a comprehensive study to dissect the genetic architecture of the brown rice ionome. We used genome-wide association studies, gene set analysis, and targeted association analysis for 12 micronutrients in the brown rice grains. A diverse panel of 300 resequenced indica accessions, with more than 1.02 million single nucleotide polymorphisms, was used. We identified 109 candidate genes with 5-20% phenotypic variation explained for the 12 micronutrients and identified epistatic interactions with multiple micronutrients. Pooling all candidate genes per micronutrient exhibited phenotypic variation explained values ranging from 11% to almost 40%. The key donor lines with larger concentrations for most of the micronutrients possessed superior alleles, which were absent in the breeding lines. Through gene regulatory networks we identified enriched functional pathways for central regulators that were detected as key candidate genes through genome-wide association studies. This study provided important insights on the ionome variations in rice, on the genetic basis of the genome-ionome relationships and on the molecular mechanisms underlying micronutrient signatures.

Phosphorus fractions in leaves

Leaf phosphorus (P) comprises four major fractions: inorganic phosphate (P_i ), nucleic acids, phospholipids, P-containing metabolites and a residual fraction. In this review paper, we investigated whether allocation of P fractions varies among groups of terrestrial vascular plants, and is indicative of a species' strategy to use P efficiently. We found that as leaf total P concentration increases, the P_i fraction increases the most, without a plateau, while other fractions plateau. Variability of the concentrations of leaf P fractions is greatest among families > species(family) > regions > plant life forms. The percentage of total P allocated to nucleic acid-P (20-35%) and lipid-P (14-34%) varies less among families/species. High photosynthetic P-use efficiency is associated with low concentrations of all P fractions, and preferential allocation of P to metabolite-P and mesophyll cells. Sequential resorption of P from senescing leaves starts with P_i , followed by metabolite-P, and then other organic P fractions. Allocation of P to leaf P fractions varies with season. Leaf phytate concentrations vary considerably among species, associated with variation in photosynthesis and defence. Plasticity of P allocation to its fractions is important for acclimation to low soil P availability, and species-specific P allocation is needed for co-occurrence with other species.

Regulation of inositol 1,2,4,5,6-pentakisphosphate and inositol hexakisphosphate levels in Gossypium hirsutum by IPK1

The IPK1 genes, which code for 2-kinases that can synthesize Ins(1,2,4,5,6)P₅ from Ins(1,4,5,6)P₄, are expressed throughout cotton plants, resulting in the highest Ins(1,2,4,5,6)P₅ concentrations in young leaves and flower buds. Cotton leaves contain large amounts of Ins(1,2,4,5,6)P₅ and InsP₆ compared to plants not in the Malvaceae family. The inositol polyphosphate pathway has been linked to stress tolerance in numerous plant species. Accordingly, we sought to determine why cotton and other Malvaceae have such high levels of these inositol phosphates. We have quantified the levels of InsP₅ and InsP₆ in different tissues of cotton plants and determined the expression of IPK1 (inositol 1,3,4,5,6-pentakisphosphate 2-kinase gene) in vegetative and reproductive tissues. Gossypium hirsutum was found to contain four IPK1 genes that were grouped into two pair (AB, CD) where each pair consists of very similar sequences that were measured together. More IPK1AB is expressed in leaves than in roots, whereas more IPK1CD is expressed in roots than in leaves. Leaves and flower buds have more InsP₅ and InsP₆ than stems and roots. Leaves and roots contain more InsP₅ than InsP₆, whereas flower buds and stems contain more InsP₆ than InsP₅. Dark-grown seedlings contain more InsP₅ and InsP₆ than those grown under lights, and the ratio of InsP₅ to InsP₆ is greater in the light-grown seedlings. During 35 days of the life cycle of the third true leaf, InsP₅ and InsP₆ gradually decreased by more than 50%. Silencing IPK1AB and IPK1CD with Cotton Leaf Crumple Virus-induced gene silencing (VIGS) resulted in plants with an intense viral phenotype, reduced IPK1AB expression and lowered amounts of InsP₅. The results are consistent with Ins(1,2,4,5,6)P₅ synthesis from Ins(1,4,5,6)P₄ by IPK1. This study detailed the central role of IPK1 in cotton inositol polyphosphate metabolism, which has potential to be harnessed to improve the resistance of plants to different kinds of stress.

Phytate and Arsenic Enhance Each Other's Uptake in As-hyperaccumulator Pteris vittata: Root Exudation of Phytate and Phytase, and Plant Uptake of Phytate-P

Phytate as a root exudate is rare in plants as it mainly serves as a P storage in the seeds; however, As-hyperaccumulator Pteris vittata effectively secretes phytate and utilizes phytate-P, especially under As exposure. This study investigated the effects of As on its phytate and phytase exudation and the impacts of As and/or phytate on each other's uptake in P. vittata through two hydroponic experiments. Under 10-100 μM arsenate (AsV), the exudation of phytate and phytase by P. vittata was increased by 50-72% to 20.4-23.4 μmol h^-1 g^-1 and by 28-104% to 18.6-29.5 nmol h^-1 plant^-1, but they were undetected in non-hyperaccumulator Pteris ensiformis at 10 μM AsV. Furthermore, compared to 500 μM phytate, the phytate concentration in the growth media was reduced by 69% to 155 μM, whereas the P and As contents in P. vittata fronds and roots were enhanced by 68-134% and 44-81% to 2423-2954 and 82-407 mg kg^-1 under 500 μM phytate plus 50 μM AsV. The increased P/As uptake in P. vittata was probably attributed to 3.0-4.5-fold increase in expressions of P transporters PvPht1;3-1;4. Besides, under As exposure, plant P may be converted to phytate in P. vittata roots, thereby increasing phytate's contents by 84% to 840 mg kg^-1. Overall, our results suggest that As-induced phytate/phytase exudation and phytate-P uptake stimulate its growth and As hyperaccumulation by P. vittata.

Retardation factors in controlling the transport of inorganic, organic, and particulate phosphorus in fluvo-aquic soil

Excessive application of fertilizers has caused a high load of phosphorus (P) in the North China Plain. The fate of P and its effects on aquatic ecosystems depend on its chemical speciation in soils. However, few studies systematically investigated the transport and retardation of different P species in the fluvo-aquic soil. In this study, the transport of inorganic P (orthophosphate, PO₄), organic P (phytic acid, PA) and particulate P (hydroxyapatite nanoparticles, nHAP) in the fluvo-aquic soil were investigated by column experiments, and their retardation from major soil components such as kaolin, CaCO₃, Al₂O₃, and goethite (GT) was also investigated by monitoring breakthrough curves and fitting transport models. The transport of P species in fluvo-aquic soil followed the order of PO₄ > PA > nHAP. A high fraction of increased clay and mineral particle-associated P (P-E) was observed for PO₄ and PA; while significant Ca-associated P (P-Ca) for nHAP. Under the experimental conditions, both CaCO₃ and GT were the most influential factors for PO₄, PA, and nHAP retention. Goethite strongly inhibited PO₄ transport due to its high PO₄ adsorption capacity, while CaCO₃ strongly inhibited PA transport due to its strong association with PA under alkaline conditions. Both CaCO₃ and GT can severely inhibit nHAP transport due to the favorable electrostatic conditions as well as the Ca²⁺ bridging effect. These results indicated that CaCO₃ played a key role in regulating the retention of organic P and particulate P in the calcareous soil, and also suggested the important role of Fe (hydr)oxides in controlling the transport of inorganic P, which could out-compete that of CaCO₃.

Phytates as a natural source for health promotion: A critical evaluation of clinical trials

Phytates are a type of organophosphorus compound produced in terrestrial ecosystems by plants. In plant feeds, phytic acid and its salt form, phytate, account for 60%-80% of total phosphorus. Because phytate is a polyanionic molecule, it can chelate positively charged cations such as calcium, iron, and zinc. Due to its prevalence in vegetal tissues and the fact that people consume plants, phytate was first considered a potential health benefit. This updated review aims to summarize the current data on the results of clinical trials of phytates on human health, highlighting both beneficial and undesirable effects. To obtain these updated data, published papers in electronic databases such as PubMed/MedLine, TRIP database, Wiley, Google Scholar, Baidu, and Scopus were searched. Study results have shown that phytate can have beneficial health effects such as antioxidant, anticancer potential and reduction of pathological calcifications in blood vessels and organs; but also, negative effects by reducing the absorption of minerals important for maintaining the homeostasis of the human body. According to these recent results derived from recent clinical studies, phytates may be a potential natural source for health benefits. To improve clinical efficacy and human health benefits, further dose-response studies are needed to determine effective therapeutic doses and potential interactions with conventional drugs.

Transcriptional regulation of the raffinose family oligosaccharides pathway in Sorghum bicolor reveals potential roles in leaf sucrose transport and stem sucrose accumulation

Bioenergy sorghum hybrids are being developed with enhanced drought tolerance and high levels of stem sugars. Raffinose family oligosaccharides (RFOs) contribute to plant environmental stress tolerance, sugar storage, transport, and signaling. To better understand the role of RFOs in sorghum, genes involved in myo-inositol and RFO metabolism were identified and relative transcript abundance analyzed during development. Genes involved in RFO biosynthesis (SbMIPS1, SbInsPase, SbGolS1, SbRS) were more highly expressed in leaves compared to stems and roots, with peak expression early in the morning in leaves. SbGolS, SbRS, SbAGA1 and SbAGA2 were also expressed at high levels in the leaf collar and leaf sheath. In leaf blades, genes involved in myo-inositol biosynthesis (SbMIPS1, SbInsPase) were expressed in bundle sheath cells, whereas genes involved in galactinol and raffinose synthesis (SbGolS1, SbRS) were expressed in mesophyll cells. Furthermore, SbAGA1 and SbAGA2, genes that encode neutral-alkaline alpha-galactosidases that hydrolyze raffinose, were differentially expressed in minor vein bundle sheath cells and major vein and mid-rib vascular and xylem parenchyma. This suggests that raffinose synthesized from sucrose and galactinol in mesophyll cells diffuses into vascular bundles where hydrolysis releases sucrose for long distance phloem transport. Increased expression (>20-fold) of SbAGA1 and SbAGA2 in stem storage pith parenchyma of sweet sorghum between floral initiation and grain maturity, and higher expression in sweet sorghum compared to grain sorghum, indicates these genes may play a key role in non-structural carbohydrate accumulation in stems.

Genetic Approaches for Iron and Zinc Biofortification and Arsenic Decrease in Oryza sativa L. Grains

Rice is the staple diet to half of the world's population, being a major source of carbohydrates, vitamins, and some essential elements. However, rice naturally contains low amounts of essential minerals such as iron (Fe) and zinc (Zn), which are drastically decreased after milling. Thus, populations that consume mostly rice may have micronutrient deficiency, which is associated with different diseases. On the other hand, rice irrigated by flooding has a high ability to accumulate arsenic (As) in the grain. Therefore, when rice is grown in areas with contaminated soil or irrigation water, it represents a risk factor for consumers, since As is associated with cancer and other diseases. Different strategies have been used to mitigate micronutrient deficiencies such as Fe and Zn and to prevent As from entering the food chain. Each strategy has its positive and its negative sides. The development of genetically biofortified rice plants with Fe and Zn and with low As accumulation is one of the most promising strategies, since it does not represent an additional cost for farmers, and gives benefits to consumers as well. Considering the importance of genetic improvement (traditional or molecular) to decrease the impact of micronutrient deficiencies such as Fe and Zn and contamination with As, this review aimed to summarize the major efforts, advances, and challenges for genetic biofortification of Fe and Zn and decrease in As content in rice grains.

Effects of exogenous selenium application on nutritional quality and metabolomic characteristics of mung bean (Vigna radiata L.)

Selenium (Se) biofortification is an important strategy for reducing hidden hunger by increasing the nutritional quality of crops. However, there is limited metabolomic information on the nutritional quality of Se-enriched mung beans. In this study, physiological assays and LC-MS/MS based widely targeted metabolomics approach was employed to reveal the Se biofortification potential of mung bean by evaluating the effect of Se on mung bean nutraceutical compounds and their qualitative parameters. Physiological data showed that foliar application of 30 g ha^-1 Se at key growth stages significantly increased the content of Se, protein, fat, total phenols, and total flavonoids content in two mung bean varieties. Widely targeted metabolomics identified 1,080 metabolites, among which L-Alanyl-L-leucine, 9,10-Dihydroxy-12,13-epoxyoctadecanoic acid, and 1-caffeoylquinic acid could serve as biomarkers for identifying highly nutritious mung bean varieties. Pathway enrichment analysis revealed that the metabolic pathways of different metabolites were different in the Se-enriched mung bean. Specifically, P1 was mainly enriched in the linoleic acid metabolic pathway, while P2 was mainly enriched in the phosphonate and phosphinate metabolic pathways. Overall, these results revealed the specific Se enrichment mechanism of different mung bean varieties. This study provides new insights into the comprehensive improvement of the nutritional quality of mung beans.

Effect of Myo-inositol on sperm quality and biochemical factors in cryopreserved semen of patients with Asthenospermia

In this study, the influence of myoinositol (MYO) as an antioxidant on the inhibition of the negative impacts of cryopreservation on sperm quality in men with Asthenospermia was investigated. In this prospective study, each semen sample from 25 cases was separated into three groups: Fresh, Control (with freezing medium), Myoinositol (2 mg/ml). According to the World Health Organization criteria (WHO) (2010), total motility, progressive sperm motility, viability, normal morphology, and DNA integrity were assessed. In addition, the hypo-osmotic swelling (HOS) test and mitochondrial membrane potential (MMP) were used. Total antioxidant capacity (TAC), malondialdehyde (MDA), and antioxidant enzyme activity were determined by the ELISA method. In contrast to the fresh samples, lipid peroxidation, DNA integrity damage, DNA fragmentation, HOST, and MMP had significant enhancement in the control samples. Sperm quality was significantly decreased (p < 0.05). Mean percentage viability, normal morphology, total motility, progressive motility, and DNA integrity were significantly enhanced in the MYO group in comparison to the control group (p < 0.05). The MDA and TAC levels and DNA damage in the MYO group were significantly lower compared to the control group (p < 0.05). The findings confirm that sperm quality in patients with Asthenospermia is improved by the administration of 2 mg/ml of myoinositol together with the freezing medium after sperm cryopreservation.

A crucial role for a node-localized transporter, HvSPDT, in loading phosphorus into barley grains

Grains are the major sink of phosphorus (P) in cereal crops, accounting for 60-85% of total plant P, but the mechanisms underlying P loading into the grains are poorly understood. We functionally characterized a transporter gene required for the distribution of P to the grains in barley (Hordeum vulgare), HvSPDT (SULTR-like phosphorus distribution transporter). HvSPDT encoded a plasma membrane-localized Pi/H⁺ cotransporter. It was mainly expressed in the nodes at both the vegetative and reproductive stages. Furthermore, its expression was induced by inorganic phosphate (Pi) deficiency. In the nodes, HvSPDT was expressed in both the xylem and phloem region of enlarged and diffuse vascular bundles. Knockout of HvSPDT decreased the distribution of P to new leaves, but increased the distribution to old leaves at the vegetative growth stage under low P supply. However, knockout of HvSPDT did not alter the redistribution of P from old to young organs. At the reproductive stage, knockout of HvSPDT significantly decreased P allocation to the grains, resulting in a considerable reduction in grain yield, especially under P-limited conditions. Our results indicate that node-based HvSPDT plays a crucial role in loading P into barley grains through preferentially distributing P from the xylem and further to the phloem.

A Natural Low Phytic Acid Finger Millet Accession Significantly Improves Iron Bioavailability in Indian Women

Iron deficiency and anemia are common in low- and middle-income countries. This is due to a poor dietary iron density and low iron absorption resulting from the high inhibitory phytic acid content in cereal and millet-based diets. Here, we report that a naturally occurring low phytic acid finger millet accession (571 mg 100 g⁻¹), stable across three growing seasons with normal iron content (3.6 mg 100 g⁻¹), increases iron absorption by 3-folds in normal Indian women. The accessions differing in grain phytic acid content, GE 2358 (low), and GE1004 (high) were selected from a core collection of 623 accessions. Whole genome re-sequencing of the accessions revealed significant single nucleotide variations segregating them into distinct clades. A non-synonymous mutation in the EcABCC phytic acid transporter gene between high and low accessions could affect gene function and result in phytic acid differences. The highly sensitive dual stable-isotope erythrocyte incorporation method was adopted to assess the fractional iron absorption. The low phytic acid accession resulted in a significantly higher iron absorption compared with the high phytic acid accession (3.7 vs. 1.3%, p < 0.05). The low phytic acid accession could be effective in preventing iron deficiency in regions where finger millet is habitually eaten. With its low water requirement, finger millet leaves low environmental footprints and hence would be an excellent sustainable strategy to mitigate iron deficiency.

Effect of phytase supplementation on plasma and organ myo-inositol content and erythrocyte inositol phosphates as pertaining to breast meat quality issues in chickens

‘Woody breast’ (WB) and ‘white striping’ in broiler meat is a global problem. With unknown etiology, WB negatively impacts bird health, welfare and is a significant economic burden to the poultry industry. New evidence has shown that WB is associated with dysregulation in systemic and breast muscle-oxygen homeostasis, resulting in hypoxia and anaemia. However, it has been observed that phytase (Quantum Blue (QB) a modified, E. coli-derived 6-phytase) super dosing can reverse dysregulation of muscle-oxygen homeostasis and reduces WB severity by ~5%. The objective of this study was to assess whether levels of Ins(1,3,4,5,6)P5, the main allosteric regulator of haemoglobin, are influenced by changes in plasma myo-inositol arising from super dosing with phytase. To enable this, methods suitable for measurement of myo-inositol in tissues and inositol phosphates in blood were developed. Data were collected from independent trials, including male Ross 308 broilers fed low and adequate calcium/available phosphate (Ca/AvP) diets supplemented with QB at 1,500 phytase units (FTU)/kg, which simultaneously decreased gizzard InsP6 (P<0.001) and increased gizzard myo-inositol (P<0.001). Similarly, male Cobb 500 broiler chicks fed a negative control (NC) diet deficient in AvP, Ca and sodium or diet supplemented with the QB phytase at 500, 1000 or 2,000 FTU/kg increased plasma (P<0.001) and liver (P=0.007) myo-inositol of 18d-old birds at 2,000 FTU/kg. Finally, QB supplementation of Cobb 500 breeder flock diet at 1,250 FTU/kg increased blood myo-inositol (P<0.001) and erythrocyte Ins(1,3,4,5,6)P5 (P=0.011) of their 1d-old hatchlings. These data confirmed the ability of phytase to modulate inositol phosphate pathways by provision of metabolic precursors of important signalling molecules. The ameliorations of WB afforded by super doses of phytase may include modulation of hypoxia pathways that also involve inositol signalling molecules. Elevations of erythrocyte Ins(1,3,4,5,6)P5 by phytase supplementation may enhance systemic oxygen carrying capacity, an important factor in the amelioration of WB and WS myopathy.

Zinc in plants: Integrating homeostasis and biofortification

Zinc plays many essential roles in life. As a strong Lewis acid that lacks redox activity under environmental and cellular conditions, the Zn²⁺ cation is central in determining protein structure and catalytic function of nearly 10% of most eukaryotic proteomes. While specific functions of zinc have been elucidated at a molecular level in a number of plant proteins, wider issues abound with respect to the acquisition and distribution of zinc by plants. An important challenge is to understand how plants balance between Zn supply in soil and their own nutritional requirement for zinc, particularly where edaphic factors lead to a lack of bioavailable zinc or, conversely, an excess of zinc that bears a major risk of phytotoxicity. Plants are the ultimate source of zinc in the human diet, and human Zn deficiency accounts for over 400 000 deaths annually. Here, we review the current understanding of zinc homeostasis in plants from the molecular and physiological perspectives. We provide an overview of approaches pursued so far in Zn biofortification of crops. Finally, we outline a "push-pull" model of zinc nutrition in plants as a simplifying concept. In summary, this review discusses avenues that can potentially deliver wider benefits for both plant and human Zn nutrition.

Oligomeric phosphate clusters in macrocyclic channels

Thirty-six-membered ring macrocycles form sandwich-like channels for oligomeric chains of hexaphosphate clusters.

Phytic Acid and Whole Grains for Health Controversy

Phytate (PA) serves as a phosphate storage molecule in cereals and other plant foods. In food and in the human body, PA has a high affinity to chelate Zn²⁺ and Fe²⁺, Mg²⁺, Ca²⁺, K⁺, Mn²⁺ and Cu²⁺. As a consequence, minerals chelated in PA are not bio-available, which is a concern for public health in conditions of poor food availability and low mineral intakes, ultimately leading to an impaired micronutrient status, growth, development and increased mortality. For low-income countries this has resulted in communications on how to reduce the content of PA in food, by appropriate at home food processing. However, claims that a reduction in PA in food by processing per definition leads to a measurable improvement in mineral status and that the consumption of grains rich in PA impairs mineral status requires nuance. Frequently observed decreases of PA and increases in soluble minerals in in vitro food digestion (increased bio-accessibility) are used to promote food benefits. However, these do not necessarily translate into an increased bioavailability and mineral status in vivo. In vitro essays have limitations, such as the absence of blood flow, hormonal responses, neural regulation, gut epithelium associated factors and the presence of microbiota, which mutually influence the in vivo effects and should be considered. In Western countries, increased consumption of whole grain foods is associated with improved health outcomes, which does not justify advice to refrain from grain-based foods because they contain PA. The present commentary aims to clarify these seemingly controversial aspects.

High-Phytate Diets Increase Amyloid β Deposition and Apoptotic Neuronal Cell Death in a Rat Model

Amyloid-β (Aβ) accumulation in the hippocampus is an essential event in the pathogenesis of Alzheimer's disease. Insoluble Aβ is formed through the sequential proteolytic hydrolysis of the Aβ precursor protein, which is cleaved by proteolytic secretases. However, the pathophysiological mechanisms of Aβ accumulation remain elusive. Here, we report that rats fed high-phytate diets showed Aβ accumulation and increased apoptotic neuronal cell death in the hippocampus through the activation of the amyloidogenic pathway in the hippocampus. Immunoblotting and immunohistochemical analyses confirmed that the overexpression of BACE1 β-secretase, a critical enzyme for Aβ generation, exacerbated the hippocampal Aβ accumulation in rats fed high-phytate diets. Moreover, we identified that parathyroid hormone, a physiological hormone responding to the phytate-mediated dysregulation of calcium and phosphate homeostasis, plays an essential role in the transcriptional activation of the Aβ precursor protein and BACE1 through the vitamin D receptor and retinoid X receptor axis. Thus, our findings suggest that phytate-mediated dysregulation of calcium and phosphate is a substantial risk factor for elevated Aβ accumulation and apoptotic neuronal cell death in rats.

Genome-wide association studies of mineral and phytic acid concentrations in pea (Pisum sativum L.) to evaluate biofortification potential

Pea (Pisum sativum L.) is an important cool season food legume for sustainable food production and human nutrition due to its nitrogen fixation capabilities and nutrient-dense seed. However, minimal breeding research has been conducted to improve the nutritional quality of the seed for biofortification, and most genomic-assisted breeding studies utilize small populations with few single nucleotide polymorphisms (SNPs). Genomic resources for pea have lagged behind those of other grain crops, but the recent release of the Pea Single Plant Plus Collection (PSPPC) and the pea reference genome provide new tools to study nutritional traits for biofortification. Calcium, phosphorus, potassium, iron, zinc, and phytic acid concentrations were measured in a study population of 299 different accessions grown under greenhouse conditions. Broad phenotypic variation was detected for all parameters except phytic acid. Calcium exhibited moderate broad-sense heritability (H2) estimates, at 50%, while all other minerals exhibited low heritability. Of the accessions used, 267 were previously genotyped in the PSPPC release by the USDA, and we mapped the genotyping data to the pea reference genome for the first time. This study generated 54,344 high-quality SNPs used to investigate the population structure of the PSPPC and perform a genome-wide association study to identify genomic loci associated with mineral concentrations in mature pea seed. Overall, we were able to identify multiple significant SNPs and candidate genes for iron, phosphorus, and zinc. These results can be used for genetic improvement in pea for nutritional traits and biofortification, and the candidate genes provide insight into mineral metabolism.

Response of Normal and Low-Phytate Genotypes of Pea (Pisum sativum L.) on Phosphorus Foliar Fertilization

Phosphorus (P) is an important nutrient in plant nutrition. Its absorption by plants from the soil is influenced by many factors. Therefore, a foliar application of this nutrient could be utilized for the optimal nutrition state of plants. The premise of the study is that foliar application of phosphorus will increase the yield of normal-phytate (npa) cultivars (CDC Bronco a Cutlass) and low-phytate (lpa) lines (1-2347-144, 1-150-81) grown in soils with low phosphorus supply and affect seed quality depending on the ability of the pea to produce phytate. A graded application of phosphorus (H₃PO₄) in four doses: without P (P0), 27.3 mg P (P1), 54.5 mg P (P2), and 81.8 mg P/pot (P3) realized at the development stages of the 6th true leaf led to a significant increase of chlorophyll contents, and fluorescence parameters of chlorophyll expressing the CO₂ assimilation velocity. The P fertilization increased the yield of seeds significantly, except the highest dose of phosphorus (P3) at which the yield of the npa cultivars was reduced. The line 1-2347-144 was the most sensible to the P application when the dose P3 increased the seed production by 42.1%. Only the lpa line 1-150-81 showed a decreased tendency in the phytate content at the stepped application of the P nutrition. Foliar application of phosphorus significantly increased ash material in seed, but did not tend to affect the protein and mineral content of seeds. Only the zinc content in seeds was significantly reduced by foliar application of P in npa and lpa pea genotypes. It is concluded from the present study that foliar phosphorus application could be an effective way to enhance the pea growth in P-deficient condition with a direct effect on seed yield and quality.

Influence of a novel consensus bacterial 6-phytase variant on mineral digestibility and bone ash in young growing pigs fed diets with different concentrations of phytate-bound phosphorus

A 20-d experiment was conducted to test the hypothesis that phytase increases nutrient digestibility, bone ash, and growth performance of pigs fed diets containing 0.23%, 0.29%, or 0.35% phytate-bound P. Within each level of phytate, five diets were formulated to contain 0, 500, 1,000, 2,000, or 4,000 phytase units (FTU)/kg of a novel phytase (PhyG). Three reference diets were formulated by adding a commercial Buttiauxella phytase (PhyB) at 1,000 FTU/kg to diets containing 0.23%, 0.29%, or 0.35% phytate-bound P. A randomized complete block design with 144 individually housed pigs (12.70 ± 4.01 kg), 18 diets, and 8 replicate pigs per diet was used. Pigs were adapted to diets for 15 d followed by 4 d of fecal collection. Femurs were collected on the last day of the experiment. Results indicated that diets containing 0.35% phytate-bound P had reduced (P < 0.01) digestibility of Ca, P, Mg, and K compared with diets containing less phytate-bound P. Due to increased concentration of total P in diets with high phytate, apparent total tract digestible P and bone ash were increased by PhyG to a greater extent in diets with 0.29% or 0.35% phytate-bound P than in diets with 0.23% phytate-bound P (interaction, P < 0.05). At 1,000 FTU/kg, PhyG increased P digestibility and bone P more (P < 0.05) than PhyB. The PhyG increased (P < 0.01) pig growth performance, and pigs fed diets containing 0.35% or 0.29% phytate-bound P performed better (P < 0.01) than pigs fed the 0.23% phytate-bound P diets. In conclusion, the novel phytase (i.e., PhyG) is effective in increasing bone ash, mineral digestibility, and growth performance of pigs regardless of dietary phytate level.

Effect of feeding acidified or fermented barley using Limosilactobacillus reuteri with or without supplemental phytase on diet nutrient digestibility in growing pigs

Fermentation of cereal grains may degrade myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6) thereby increasing nutrient digestibility. Effects of chemical acidification or fermentation with Limosilactobacillus (L.) reuteri with or without phytase of high β-glucan hull-less barley grain on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and gross energy (GE), standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AAs), and standardized total tract digestibility (STTD) of P were assessed in growing pigs. Pigs were fed four mash barley-based diets balanced for water content: 1) unfermented barley (Control); 2) chemically acidified barley (ACD) with lactic acid and acidic acid (0.019 L/kg barley grain at a ratio of 4:1 [vol/vol]); 3) barley fermented with L. reuteri TMW 1.656 (Fermented without phytase); and 4) barley fermented with L. reuteri TMW 1.656 and phytase (Fermented with phytase; 500 FYT/kg barley grain). The acidification and fermentation treatments occurred for 24 h at 37 °C in a water bath. The four diets were fed to eight ileal-cannulated barrows (initial body weight [BW], 17.4 kg) for four 11-d periods in a double 4 × 4 Latin square. Barley grain InsP6 content of Control, ACD, Fermented without phytase, or Fermented with phytase was 1.12%, 0.59%, 0.52% dry matter (DM), or not detectable, respectively. Diet ATTD of DM, CP, Ca, and GE, digestible energy (DE), predicted net energy (NE) value, and urinary excretion of P were greater (P < 0.05) for ACD than Control. Diet ATTD of DM, CP, Ca, GE, DE and predicted NE value, urinary excretion of P was greater (P < 0.05), and diet AID of Ca and ATTD and STTD of P tended to be greater (P < 0.10) for Fermented without phytase than Control. Diet ATTD of GE was lower (P < 0.05) and diet ATTD and STTD of P, AID and ATTD of Ca was greater (P < 0.05) for Fermented with phytase than Fermented without phytase. Acidification or fermentation with/without phytase did not affect diet SID of CP and AA. In conclusion, ACD or Fermented without phytase partially degraded InsP6 in barley grain and increased diet ATTD of DM, CP, and GE, but not SID of CP and most AA in growing pigs. Fermentation with phytase entirely degraded InsP6 in barley grain and maximized P and Ca digestibility, thereby reducing the need to provide inorganic dietary P to meet P requirements of growing pigs.

Estimated Phytate Intake Is Associated with Improved Cognitive Function in the Elderly, NHANES 2013-2014

Phytate, an antioxidant, may improve cognition by inhibiting iron catalyzed hydroxyl radical formation. Particularly in the elderly, this provides a potential dietary approach for mitigating age-related brain neuronal dysfunction and loss. In this study, we investigated the relationship between phytate intake and cognitive function in the elderly. We used data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) and the corresponding Food Patterns Equivalents Database (FPED). Phytate content of food groups from published data were merged with the appropriate FPED data to estimate the total phytate intake for each subject. Principal component analysis was used to develop a composite score from four cognitive function scores in NHANES data, and regression analysis was used to determine the relationship between this score and phytate intake. Median phytate intake was 0.65 (0.61, 0.71) g/day. It was low among females, non-Hispanic blacks, and people with history of at least one chronic disease (p < 0.05). In regression analysis adjusted for confounders, phytate intake was positively associated with cognitive function (β (95% CI) = 1.90 (0.73-3.07); p = 0.015). These results suggest that phytate may be associated with improved cognition, hence the need to consider including phytate-rich foods in the diet among the elderly.

Zinc in cereal grains: Concentration, distribution, speciation, bioavailability, and barriers to transport from roots to grains in wheat

Zinc (Zn) is an essential micro-nutrient for humans, and Zn deficiency is of global concern. In addition to inherited and pathological Zn deficiencies, insufficient dietary intake is leading cause, especially in those consuming cereal grains as a stable food, in which Zn concentration and bioavailability are relatively low. To improve Zn levels in the human body, it is important to understand the accumulation and bioavailability of Zn in cereal grains. In recent years, knowledge on the molecular mechanisms underlying Zn uptake, transport, homeostasis, and deposition within cereal crops has been accumulating, paving the way for a more targeted approach to improving the nutrient status of crop plants. In this paper, we briefly review existing studies on the distribution and transport pathways of Zn in major small-grained cereals, using wheat as a case study. The findings confirm that Zn transport in plants is a complex physiological process mainly governed by Zn transporters and metal chelators. This work reviews studies on Zn uptake, transport, and deposition in wheat plants, summarizes the possible barriers impairing Zn deposition in wheat grains, and describes strategies for increasing Zn concentration in wheat grains.

CRISPR/Cas9 mediated disruption of Inositol Pentakisphosphate 2-Kinase 1 (TaIPK1) reduces phytic acid and improves iron and zinc accumulation in wheat grains

•

This study, for the first time, used CRISPR/Cas9 to disrupt TaIPK1 gene in wheat.

•

Disruption of TaIPK1 gene reduces phytic acid and enhanced Iron and Zinc in wheat grains.

•

This study will help to develop the biofortified wheat and reducing the malnutrition.

•

This study provided a great resource for the development of biofortified wheat using CRISPR/Cas9.

Introduction

Phytic acid (PA) is an important antinutrient agent present in cereal grains which reduces the bioavailability of iron and zinc in human body, causing malnutrition. Inositol pentakisphosphate 2- kinase 1 (IPK1) gene has been reported to be an important gene for PA biosynthesis.

Objective

A recent genome editing tool CRISPR/Cas9 has been successfully applied to develop biofortified rice by disrupting IPK1 gene, however, it remained a challenge in wheat. The aim of this study was to biofortify wheat using CRISPR/Cas9.

Methods

In this study, we isolated 3 TaIPK1 homeologs in wheat designated as TaIPK1.A, TaIPK1.B and TaIPK1.D and found that the expression abundance of TaIPK1.A was stronger in early stages of grain filling. Using CRISPR/Cas9, we have disrupted TaIPK1.A gene in cv. Borlaug-2016 with two guide RNAs targeting the 1st and 2nd exons.

Results

We got several genome-edited lines in the T₀ generation at frequencies of 12.7% and 10.8%. Sequencing analysis revealed deletion of 1–23 nucleotides and even an addition of 1 nucleotide in various lines. Analysis of the genome-edited lines revealed a significant decrease in the PA content and an increase in iron and zinc accumulation in grains compared with control plants.

Conclusion

Our study demonstrates the potential application of CRISPR/Cas9 technique for the rapid generation of biofortified wheat cultivars.

Phytic acid accumulation in plants: Biosynthesis pathway regulation and role in human diet

Phytate or phytic acid (PA), is a phosphorus (P) containing compound generated by the stepwise phosphorylation of myo-inositol. It forms complexes with some nutrient cations, such as Ca, Fe and Zn, compromising their absorption and thus acting as an anti-nutrient in the digestive tract of humans and monogastric animals. Conversely, PAs are an important form of P storage in seeds, making up to 90% of total seed P. Phytates also play a role in germination and are related to the synthesis of abscisic acid and gibberellins, the hormones involved in seed germination. Decreasing PA content in plants is desirable for human dietary. Therefore, low phytic acid (lpa) mutants might present some negative pleiotropic effects, which could impair germination and seed viability. In the present study, we review current knowledge of the genes encoding enzymes that function in different stages of PA synthesis, from the first phosphorylation of myo-inositol to PA transport into seed reserve tissues, and the application of this knowledge to reduce PA concentrations in edible crops to enhance human diet. Finally, phylogenetic data for PA concentrations in different plant families and distributed across several countries under different environmental conditions are compiled. The results of the present study help explain the importance of PA accumulation in different plant families and the distribution of PA accumulation in different foods.

Biofortification of pea (Pisum sativum L.): a review

Biofortification refers to an approach to increase micronutrient concentrations in the edible parts of plants with increased bioavailability to the human population. Conventional, agronomic and transgenic breeding methods can be used to develop these biofortified crops, offering sustainable and cost-effective strategies. Pea has long been recognized as a valuable, nutritious food for the human diet, but there is a limited amount of information about it, which prevents the full micronutrient enrichment potential of this pulse crop to be reached. Considerations must include not only micronutrient concentrations but also the amount of the nutrient that can be absorbed by the consumer, after processing and cooking. Development of biofortified pea that retains nutrients during cooking and processing is not only essential for fighting micronutrient malnutrition, but also necessary to improve agricultural productivity. © 2021 Society of Chemical Industry.

Delayed hydrolysis of Raffinose Family Oligosaccharides (RFO) affects critical germination of chickpeas

Seed raffinose family oligosaccharides (RFOs) are converted into sucrose and galactose by α-galactosidase during germination. Seed osmopriming with a low concentration of potassium nitrate (KNO₃) induces early and synchronized germination by activating hydrolases. Here, we report the effect of osmopriming on the germination indices of chickpea, its effects on α-galactosidase, and the fate of total RFOs. Chickpea seeds primed with 100 µM KNO₃ show early and synchronized germination but with reduced vigour after 48 h after imbibition (HAI) due to excess sucrose accumulation. The KNO₃ suppressed the activity of α-galactosidase during the imbibition stage that was later derepressed after 24 HAI, hence decreased the RFO levels accumulating high levels of sucrose after 48 HAI. The accumulated sucrose imposed a negative effect on the germination characteristics, particularly on seed vigour. Our results suggested that the sugar release and utilization were highly regulated and crucial during imbibition and germination; the enzyme α-galactosidase regulates sugar release from seed RFO reserve.

Lipase - The fascinating dynamics of enzyme in seed storage and germination - A real challenge to pearl millet

Pearl millet is considered as 'nutri-cereal' because of high nutrient density of the seeds. The grain has limited use because of low keeping quality of the flour due to the activities of rancidity causing enzymes like lipase, lox, pox and PPO. Among all the enzymes, lipase is most notorious because of its robust nature and high activity under different conditions. we have identified 2180 putative transcripts showing homology with different variants of lipase precursor through transcriptome data mining (NCBI BioProject acc. no. PRJNA625418). Lipase plays dual role of facilitating the germination of seeds and deteriorating the quality of the pearl millet flour through hydrolytic rancidity. Different physiochemical methods like heat treatment, micro oven, hydrothermal, etc. have been developed to inhibit lipase activity in pearl millet flour. There is further need to develop improved processing technologies to inhibit the hydrolytic and oxidative rancidity in the floor with enhanced shelf-life.

Phytic acid: Blessing in disguise, a prime compound required for both plant and human nutrition

Phytic acid (PA), [myo-inositol 1,2,3,4,5,6-hexakisphosphate] is the principal storage compound of phosphorus (P) and account for 65%-85% of the seeds total P. The negative charge on PA attracts and chelates metal cations resulting in a mixed insoluble salt, phytate. Phytate contains six negatively charged ions, chelates divalent cations such as Fe2+, Zn2+, Mg2+, and Ca2+ rendering them unavailable for absorption by monogastric animals. This may lead to micronutrient deficiencies in humans since they lack the enzyme phytase that hydrolyzes phytate and releases the bound micronutrients. There are two main concerns about the presence of PA in human diet. The first is its negative impact on the bioavailability of several minerals and the second is the evidence of PA inhibiting various proteases essential for protein degradation and the subsequent digestion in stomach and small intestine. The beneficial role of PA has been underestimated due to its distinct negative consequences. PA is reported to be a potent natural plant antioxidant which plays a protective role against oxidative stress in seeds and preventive role in various human diseases. Recently beneficial roles of PA as an antidiabetic and antibacterial agent has been reported. Thus, the development of grains with low-PA and modified distribution pattern can be achieved through fine-tuning of its content in the seeds.

An ATP-responsive metabolic cassette comprised of inositol tris/tetrakisphosphate kinase 1 (ITPK1) and inositol pentakisphosphate 2-kinase (IPK1) buffers diphosphosphoinositol phosphate levels

Inositol polyphosphates are ubiquitous molecular signals in metazoans, as are their pyrophosphorylated derivatives that bear a so-called ‘high-energy’ phosphoanhydride bond. A structural rationale is provided for the ability of Arabidopsis inositol tris/tetrakisphosphate kinase 1 to discriminate between symmetric and enantiomeric substrates in the production of diverse symmetric and asymmetric myo-inositol phosphate and diphospho-myo-inositol phosphate (inositol pyrophosphate) products. Simple tools are applied to chromatographic resolution and detection of known and novel diphosphoinositol phosphates without resort to radiolabeling approaches. It is shown that inositol tris/tetrakisphosphate kinase 1 and inositol pentakisphosphate 2-kinase comprise a reversible metabolic cassette converting Ins(3,4,5,6)P₄ into 5-InsP₇ and back in a nucleotide-dependent manner. Thus, inositol tris/tetrakisphosphate kinase 1 is a nexus of bioenergetics status and inositol polyphosphate/diphosphoinositol phosphate metabolism. As such, it commands a role in plants that evolution has assigned to a different class of enzyme in mammalian cells. The findings and the methods described will enable a full appraisal of the role of diphosphoinositol phosphates in plants and particularly the relative contribution of reversible inositol phosphate hydroxykinase and inositol phosphate phosphokinase activities to plant physiology.

Excess Zinc Alters Cell Wall Class III Peroxidase Activity and Flavonoid Content in the Maize Scutellum

Maize is one of the most important cereal crop species due to its uses for human and cattle nourishment, as well as its industrial use as a raw material. The yield and grain quality of maize depend on plant establishment, which starts with germination. Germination is dependent on embryo vigor and the stored reserves in the scutellum and endosperm. During germination, the scutellum epidermis changes and secretes enzymes and hormones into the endosperm. As a result, the hydrolysis products of the reserves and the different soluble nutrients are translocated to the scutellum through epithelial cells. Then, the reserves are directed to the embryo axis to sustain its growth. Therefore, the microenvironment surrounding the scutellum modulates its function. Zinc (Zn) is a micronutrient stored in the maize scutellum and endosperm; during imbibition, Zn from the endosperm is solubilized and mobilized towards the scutellum. During this process, Zn first becomes concentrated and interacts with cell wall charges, after which excess Zn is internalized in the vacuole. Currently, the effect of high Zn concentrations on the scutellum function and germinative processes are not known. In this paper, we show that, as a function of the concentration and time of exposure, Zn causes decreases in the radicle and plumule lengths and promotes the accumulation of reactive oxygen species (ROS) and flavonoids as well as changes in the activity of the cell wall Class III peroxidase (POD), which was quantified with guaiacol or catechin in the presence of H2O2. The relationship between the activity index or proportion of POD activity in the scutellum and the changes in the flavonoid concentration is proposed as a marker of stress and the state of vigor of the embryo.

Contrasting Expression of Rhizobial Phytase in Nodules of Two Soybean Cultivars Grown Under Low Phosphorus Availability

Phosphorus deficiency can be a major limitation to legume growth when plant nitrogen nutrition depends on symbiotic nitrogen fixation. One possible approach to overcome this constraint is the selection of plant and rhizobial genotypes capable of metabolizing complex forms of phosphorus in the nodules. The aim of this research was to study the rhizobial phytase transcript abundance in nodules of two soybean cultivars (Glycine max (L.) Merr.) grown under two different phosphorus conditions in hydroaeroponic conditions. An in situ RT-PCR of a rhizobial phytase was performed in microtome sections of soybean nodules of two cultivars growing under phosphorus sufficiency vs. phosphorus deficiency. The results showed that the plant cultivar may influence the level of transcript abundance of the bacterial phytase and in consequence affect the phosphorus use efficiency of nitrogen-dependent Bradyrhizobium spp.-soybean symbioses. Thus, the selection of a good combination of plant and rhizobial genotypes should be a priority when breeding for phosphorus deficiency is performed.

Snapshots of "crystalline" salt-water solutions of inositol hexaphosphate conformers

Supramolecular insight to intra- and inter-ionic interactions in two inositol hexaphosphate conformers as a function of pH was enabled by NMR and crystallographic studies. These findings also shed light on the complex interactive roles of extended salt-water arrays through the crystal "solution" lattice.

Analyses of Inositol Phosphates and Phosphoinositides by Strong Anion Exchange (SAX)-HPLC

The phosphate esters of myo-inositol (Ins) occur ubiquitously in biology. These molecules exist as soluble or membrane-resident derivatives and regulate a plethora of cellular functions including phosphate homeostasis, DNA repair, vesicle trafficking, metabolism, cell polarity, tip-directed growth, and membrane morphogenesis. Phosphorylation of all inositol hydroxyl groups generates phytic acid (InsP₆), the most abundant inositol phosphate present in eukaryotic cells. However, phytic acid is not the most highly phosphorylated naturally occurring inositol phosphate. Specialized small molecule kinases catalyze the formation of the so-called myo-inositol pyrophosphates (PP-InsPs), such as InsP₇ and InsP₈. These molecules are characterized by one or several "high-energy" diphosphate moieties and are ubiquitous in eukaryotic cells. In plants, PP-InsPs play critical roles in immune responses and nutrient sensing. The detection of inositol derivatives in plants is challenging. This is particularly the case for inositol pyrophosphates because diphospho bonds are labile in plant cell extracts due to high amounts of acid phosphatase activity. We present two steady-state inositol labeling-based techniques coupled with strong anion exchange (SAX)-HPLC analyses that allow robust detection and quantification of soluble and membrane-resident inositol polyphosphates in plant extracts. These techniques will be instrumental to uncover the cellular and physiological processes controlled by these intriguing regulatory molecules in plants.

Phytic Acid in Brown Rice Can Be Reduced by Increasing Soaking Temperature

Phytic acid (PA) is a storage form of phosphorus in seeds. Phytase enzyme is activated at germination and hydrolyses PA into myo-inositol and inorganic phosphate. PA inhibits the absorption of minerals in the human intestine by chelation. Its degradation, therefore, is a key factor to improve mineral bioavailability in rice. Germinated brown rice (GBR) is favoured because it improves the availability of nutrients, and thus have a positive effect on health. In this study, we show the effects of soaking temperature on phytase activity and PA content in GBR. Rice phytase showed thermostability and its activity peaked at 50 °C. After 36 h of soaking, phytase activity was significantly increased at 50 °C and PA content was significantly decreased, compared to that at 30 °C. Zinc (Zn) analysis revealed that there was no significant difference in Zn content among different temperature treatments. Calculated total daily absorbed Zn (TAZ) was significantly higher in GBR compared with non-soaked seeds. Moreover, brown rice grains germinated at 50 °C showed a higher TAZ value than that at 30 °C. Seed germination and seed water soaking at high temperatures reduce PA content in brown rice showing a potentially effective way to improve mineral bioavailability in brown rice.

Effect of phytic acid as an endodontic chelator on resin adhesion to sodium hypochlorite-treated dentin

Objectives

Phytic acid (IP6), a naturally occurring agent, has been previously reported as a potential alternative to ethylenediaminetetraacetic acid (EDTA). However, its effect on adhesion to sodium hypochlorite (NaOCl)-treated dentin and its interactions with NaOCl have not been previously reported. Thus, in this study, the effects of IP6 on resin adhesion to NaOCl-treated dentin and the failure mode were investigated and the interactions between the used agents were analyzed.

Materials and Methods

Micro-tensile bond strength (µTBS) testing was performed until failure on dentin treated with either distilled water (control), 5% NaOCl, or 5% NaOCl followed with chelators: 17% EDTA for 1 minute or 1% IP6 for 30 seconds or 1 minute. The failed specimens were assessed under a scanning electron microscope. The reaction of NaOCl with EDTA or IP6 was analyzed in terms of temperature, pH, effervescence, and chlorine odor, and the effects of the resulting mixtures on the color of a stained paper were recorded.

Results

The µTBS values of the control and NaOCl with chelator groups were not significantly different, but were all significantly higher than that of the group treated with NaOCl only. In the failure analysis, a distinctive feature was the presence of resin tags in samples conditioned with IP6 after treatment with NaOCl. The reaction of 1% IP6 with 5% NaOCl was less aggressive than the reaction of the latter with 17% EDTA.

Conclusions

IP6 reversed the adverse effects of NaOCl on resin-dentin adhesion without the chlorine-depleting effect of EDTA.