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In order to visualize the specific state of tobacco pollen undergoing dedifferentiation from immature pollen to embryogenic cells, we established tobacco marker lines transgenic for a vital reporter gene regulated under the transcriptional control of an 840 bp fragment, named A22pro. This fragment was obtained from the 5′-flanking region of a gene corresponding to a cDNA named A22 that was previously isolated through differential screening from a cDNA library prepared from tobacco pollen undergoing dedifferentiation. The reporter gene, named H3sGFP, consisting of synthetic green fluorescent protein gene (sGFP) and tobacco H3 histone gene for nuclear localization, was designed to distinguish the gene expression in the generative cell from that in the vegetative cell in a pollen grain. The marker line produced pollen showing a green fluorescent signal in the generative nuclei (GN) but the expression level of the transgene was low. Pollen after culture for dedifferentiation showed an intense signal transiently in the vegetative nuclei (VN), at a specific developmental stage of pollen, with a rapid increase of expression level of the transgene. Serial observations revealed that all androgenic embryos originated from the pollen grains that had shown the signal in their VN. Thus, A22pro is originally functional in gametogenesis but is activated in VN of pollen undergoing embryogenic dedifferentiation. Additionally, we observed a gene expression pattern identical to that described above, using another 5′-flanking region of a gene for a cDNA, named B27pro, homologous to A22 as a promoter of the reporter gene. [ABSTRACT FROM AUTHOR]

Iron (Fe) is essential for plant growth and development, but the molecular mechanisms underlying its distribution to different organs are poorly understood. We found that OsFRDL1 (FERRIC REDUCTASE DEFECTIVE LIKE 1), a plasma membrane-localized transporter for citrate, was highly expressed in the upper nodes of rice at the reproductive growth stage. OsFRDL1 was expressed in most cells of enlarged vascular bundles, diffuse vascular bundles, and the interjacent parenchyma cell bridges of uppermost node I, as well as vascular tissues of the leaf blade, leaf sheath, peduncle, rachis, husk, and stamen. Knockout of OsFRDL1 decreased pollen viability and grain fertility when grown in a paddy field. Iron was deposited in the parenchyma cell bridges, a few of the cell layers of the parenchyma tissues outside of the bundle sheath of enlarged vascular bundles in node I in both the wild-type rice and osfrdl1 mutant, but the mutant accumulated more Fe than the wild-type rice in this area. A stem-fed experiment with stable isotope 57Fe showed that the distribution of Fe in the anther and panicle decreased in the knockout line, but that in the flag leaf it increased compared with the wild-type rice. Taken together, our results show that OsFRDL1 expressed in the upper nodes is required for the distribution of Fe in the panicles through solubilizing Fe deposited in the apoplastic part of nodes in rice. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa) is characterized by having fibrous root systems; however, the molecular mechanisms underlying the root development are not fully understood. Here, we isolated a rice mutant with short roots and found that the mutant had a decreased cell size of the roots and shoots compared with wild-type rice. Map-based cloning combined with whole-genome sequencing revealed that a single nucleotide mutation occurred in a gene, which encodes a putative cation-chloride cotransporter (OsCCC1). Introduction of OsCCC1 cDNA into the mutant rescued the mutant growth, indicating that growth defects of both the roots and shoots are caused by loss of function of OsCCC1. Physiological analysis showed that the mutant had a lower concentration of Cl- and K+ and lower osmolality in the root cell sap than the wild type at all KCl supply conditions tested; however, the mutant only showed a lower Na+ concentration at high external Na+. Expression of OsCCC1 in yeast increased accumulation of K+, Na+, and Cl-. The expression of OsCCC1 was found in both the roots and shoots, although higher expression was found in the root tips. Furthermore, the expression in the roots did not respond to different Na+, K+, and Cl- supply. OsCCC1 was expressed in all cells of the roots, leaf, and basal node. Immunoblot analysis revealed that OsCCC1 was mainly localized to the plasma membrane. These results suggest that OsCCC1 is involved in the cell elongation by regulating ion (Cl-, K+, and Na+) homeostasis to maintain cellular osmotic potential. [ABSTRACT FROM AUTHOR]

Silicon (Si) is known to alleviate manganese (Mn) toxicity in a number of plant species; however, the mechanisms responsible for this effect are poorly understood. Here, we investigated the interaction between Si and Mn in rice (Oryza sativa) by using a mutant defective in Si uptake. Silicon alleviated Mn toxicity in the wild-type (WT) rice, but not in the mutant exposed to high Mn. The Mn concentration in the shoots was decreased, but that in the roots was increased by Si in the WT. In contrast, the Mn concentration in the roots and shoots was unaffected by Si in the mutant. Furthermore, Si supply resulted in an increased Mn in the root cell sap, decreased Mn in the xylem sap in the WT, but these effects of Si were not observed in the mutant. A short-term labelling experiment with 54Mn showed that the uptake of Mn was similar between plants with and without Si and between WT and the mutant. However, Si decreased root-to-shoot translocation of Mn in the WT, but not in the mutant. The expression of a Mn transporter gene for uptake, OsNramp5, was unaffected by a short exposure (<1 d) to Si, but down-regulated by relatively long-term exposure to Si in WT. In contrast, the expression of OsNramp5 was unaffected by Si in the mutant. These results indicated that Si-decreased Mn accumulation results from both Si-decreased root-to-shoot translocation of Mn, probably by the formation of Mn-Si complex in root cells, and uptake by down-regulating Mn transporter gene. [ABSTRACT FROM AUTHOR]

Arsenic (As) is a chronic poison that causes severe skin lesions and cancer. Rice (Oryza sativa L.) is a major dietary source of As; therefore, reducing As accumulation in the rice grain and thereby diminishing the amount of As that enters the food chain is of critical importance. Here, we report that a member of the Oryza sativa C-type ATP-binding cassette (ABC) transporter (OsABCC) family, OsABCCI, is involved in the detoxification and reduction of As in rice grains. We found that OsABCCI was expressed in many organs, including the roots, leaves, nodes, peduncle, and rachis. Expression was not affected when plants were exposed to low levels of As but was up-regulated in response to high levels of As. In both the basal nodes and upper nodes, which are connected to the panicle, OsABCCI was localized to the phloem region of vascular bundles. Furthermore, OsABCCI was localized to the to-noplast and conferred phytochelatin-dependent As resistance in yeast. Knockout of OsABCO in rice resulted in decreased tolerance to As, but did not affect cadmium toxicity. At the reproductive growth stage, the As content was higher in the nodes and in other tissues of wild-type rice than in those of OsABCCI knockout mutants, but was significantly lower in the grain. Taken together, our results indicate that OsABCCI limits As transport to the grains by sequestering As in the vacuoles of the phloem companion cells of the nodes in rice. [ABSTRACT FROM AUTHOR]

Heavy metal-transporting P-type ATPase (HMA) has been implicated in the transport of heavy metals in plants. Here, we report the function and role of an uncharacterized member of HMA, OsHMA5 in rice (Oryza sativa). Knockout of OsHMA5 resulted in a decreased copper (Cu) concentration in the shoots but an increased Cu concentration in the roots at the vegetative stage. At the reproductive stage, the concentration of Cu in the brown rice was significantly lower in the mutants than in the wild-type rice; however, there was no difference in the concentrations of iron, manganese, and zinc between two independent mutants and the wild type. The Cu concentration of xylem sap was lower in the mutants than in the wild-type rice. OsHMA5 was mainly expressed in the roots at the vegetative stage but also in nodes, peduncle, rachis, and husk at the reproductive stage. The expression was up-regulated by excess Cu but not by the deficiency of Cu and other metals, including zinc, iron, and manganese, at the vegetative stage. Analysis of the transgenic rice carrying the OsHMA5 promoter fused with green fluorescent protein revealed that it was localized at the root pericycle cells and xylem region of diffuse vascular bundles in node I, vascular tissues of peduncle, rachis, and husk. Furthermore, immunostaining with an antibody against OsHMA5 revealed that it was localized to the plasma membrane. Expression of OsHMA5 in a Cu transport-defective mutant yeast (Saccharomyces cerevisiae) strain restored the growth. Taken together, OsHMA5 is involved in loading Cu to the xylem of the roots and other organs. [ABSTRACT FROM AUTHOR]

Heavy metal-transporting P-type ATPase (HMA) has been implicated in the transport of heavy metals in plants. Here, we report the function and role of an uncharacterized member of HMA, OsHMA5 in rice (Oryza sativa). Knockout of OsHMA5 resulted in a decreased copper (Cu) concentration in the shoots but an increased Cu concentration in the roots at the vegetative stage. At the reproductive stage, the concentration of Cu in the brown rice was significantly lower in the mutants than in the wild-type rice; however, there was no difference in the concentrations of iron, manganese, and zinc between two independent mutants and the wild type. The Cu concentration of xylem sap was lower in the mutants than in the wild-type rice. OsHMA5 was mainly expressed in the roots at the vegetative stage but also in nodes, peduncle, rachis, and husk at the reproductive stage. The expression was up-regulated by excess Cu but not by the deficiency of Cu and other metals, including zinc, iron, and manganese, at the vegetative stage. Analysis of the transgenic rice carrying the OsHMA5 promoter fused with green fluorescent protein revealed that it was localized at the root pericycle cells and xylem region of diffuse vascular bundles in node I, vascular tissues of peduncle, rachis, and husk. Furthermore, immunostaining with an antibody against OsHMA5 revealed that it was localized to the plasma membrane. Expression of OsHMA5 in a Cu transport-defective mutant yeast (Saccharomyces cerevisiae) strain restored the growth. Taken together, OsHMA5 is involved in loading Cu to the xylem of the roots and other organs. [ABSTRACT FROM AUTHOR]

Magnesium (Mg)-mediated alleviation of aluminum (A1) toxicity has been observed in a number of plant species, but the mechanisms underlying the alleviation are still poorly understood. When a putative rice (Oryza sativa) Mg transporter gene, Oryza sativa MAGNESIUM TRANSPORTER1 (OsMGT1), was knocked out, the tolerance to A1, but not to cadmium and lanthanum, was decreased. However, this inhibition could be rescued by addition of 10 µM Mg, but not by the same concentration of barium or strontium. OsMGT1 was expressed in both the roots and shoots in the absence of A1, but the expression only in the roots was rapidly up-regulated by A1. Furthermore, the expression did not respond to low pH and other metals including cadmium and lanthanum, and was regulated by an Al-responsive transcription factor, AL RESISTANCE TRANSCRIPTION FACTOR1. An investigation of subcellular localization showed that OsMGT1 was localized to the plasma membrane. A short-term (30 min) uptake experiment with stable isotope 25Mg showed that knockout of OsMGT1 resulted in decreased Mg uptake, but that the uptake in the wild type was enhanced by A1. Mg concentration in the cell sap of the root tips was also increased in the wild-type rice, but not in the knockout lines in the presence of A1. A microarray analysis showed that transcripts of genes related to stress were more up- and down-regulated in the knockout lines. Taken together, our results indicate that OsMGT1 is a transporter for Mg uptake in the roots and that up-regulation of this gene is required for conferring A1 tolerance in rice by increasing Mg concentration in the cell. [ABSTRACT FROM AUTHOR]

ATP-binding cassette (ABC) transporters represent a large family in plants, but the functions of most of these transporters are unknown. Here we report a gene, AtSTAR1, only encoding an ATP-binding domain of a bacterial-type ABC transporter in Arabidopsis (Arabidopsis thaliana). AtSTAR1 is an ortholog of rice (Oryza sativa) OsSTAR1, which has been implicated in aluminum (A1) tolerance. Knockout of AtSTAR1 resulted in increased sensitivity to A1 and earlier flowering. Unlike OsSTAR1, AtSTAR1 was expressed in both the roots and shoots and its expression was not induced by A1 or other stresses. Investigation of tissue-specific localization of AtSTAR1 through β-glucuronidase fusion revealed that AtSTAR1 was predominantly expressed at outer cell layers of root tips and developing leaves, whose localization is also different from those of OsSTAR1. However, introduction of OsSTAR1 into atstar1 mutant rescued the sensitivity of atstar1 to A1, indicating that AtSTAR1 has a similar function as OsSTAR1. Furthermore, we found that AtSTAR1 may interact with ALS3, a transmembrane-binding domain in Arabidopsis to form a complex because introduction of OsSTAR1, a functional substitute of AtSTAR1, into als3 mutant resulted in the loss of OsSTAR1 protein. All these findings indicate that AtSTAR1 is involved in the basic detoxification of A1 in Arabidopsis. [ABSTRACT FROM AUTHOR]

Background and AimsEthylene diamine tetraacetic acid (EDTA)-assisted phytoremediation has been developed to clean up lead (Pb)-contaminated soil; however, the mechanism responsible for the uptake of EDTA–Pb complex is not well understood. In this study, the accumulation process of Pb from EDTA–Pb is characterized in comparison to ionic Pb [Pb(NO3)2] in sorghum (Sorghum bicolor).MethodsSorghum seedlings were exposed to a 0·5 mm CaCl2 (pH 5·0) solution containing 0, 1 mm Pb(NO3)2 or EDTA–Pb complexes at a molar ratio of 1:0·5, 1:1, 1:2 and 1:4 (Pb:EDTA). The root elongation of sorghum at different ratios of Pb:EDTA was measured. Xylem sap was collected after the stem was severed at different times. The concentration of Pb in the shoots and roots were determined by an atomic absorption spectrometer. In addition, the roots were stained with Fluostain I for observation of the root structure.Key ResultsLead accumulation in the shoots of the plants exposed to EDTA–Pb at 1:1 ratio was only one-fifth of that exposed to ionic Pb at the same concentration. Lead accumulation decreased when transpiration was suppressed. The concentration of Pb in the xylem sap from the EDTA–Pb-treated plants was about 1/25 000 of that in the external solution. Root elongation was severely inhibited by ionic Pb, but not by EDTA–Pb at a 1:1 ratio. Root staining showed that a physiological barrier was damaged in the roots exposed to ionic Pb, but not in the roots exposed to EDTA–Pb.ConclusionsAll these results suggest that sorghum roots are inefficient in uptake of EDTA-chelated Pb and that enhanced Pb accumulation from ionic Pb was attributed to the damaged structure of the roots. [ABSTRACT FROM AUTHOR]

Plants take up metals, including essential micronutrients [iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn)] and the toxic heavy metal cadmium (Cd), from soil and accumulate these metals in their edible parts, which are direct and indirect intake sources for humans. Multiple transporters belonging to different families are required to transport a metal from the soil to different organs and tissues, but only a few of them have been fully functionally characterized. The transport systems (the transporters required for uptake, translocation, distribution, redistribution, and their regulation) differ with metals and plant species, depending on the physiological roles, requirements of each metal, and anatomies of different organs and tissues. To maintain metal homeostasis in response to spatiotemporal fluctuations of metals in soil, plants have developed sophisticated and tightly regulated mechanisms through the regulation of transporters at the transcriptional and/or posttranscriptional levels. The manipulation of some transporters has succeeded in generating crops rich in essential metals but low in Cd accumulation. A better understanding of metal transport systems will contribute to better and safer crop production. [ABSTRACT FROM AUTHOR]

Soluble ionic aluminum (Al) inhibits root growth and reduces crop production on acid soils. Al-resistant cultivars of barley (Hordeum vulgare L.) detoxify Al by secreting citrate from the roots, but the responsible gene has not been identified yet. Here, we identified a gene (HvAACT1) responsible for the Al-activated citrate secretion by fine mapping combined with microarray analysis, using an Al-resistant cultivar, Murasakimochi, and an Al-sensitive cultivar, Morex. This gene belongs to the multidrug and toxic compound extrusion (MATE) family and was constitutively expressed mainly in the roots of the Al-resistant barley cultivar. Heterologous expression of HvAACT1 in Xenopus oocytes showed efflux activity for 14C-labeled citrate, but not for malate. Two-electrode voltage clamp analysis also showed transport activity of citrate in the HvAACT1-expressing oocytes in the presence of Al. Overexpression of this gene in tobacco enhanced citrate secretion and Al resistance compared with the wild-type plants. Transiently expressed green fluorescent protein-tagged HvAACT1 was localized at the plasma membrane of the onion epidermal cells, and immunostaining showed that HvAACT1 was localized in the epidermal cells of the barley root tips. A good correlation was found between the expression of HvAACT1 and citrate secretion in 10 barley cultivars differing in Al resistance. Taken together, our results demonstrate that HvAACT1 is an Al-activated citrate transporter responsible for Al resistance in barley. [ABSTRACT FROM AUTHOR]

Please find below the full list of 2022 reviewers: Mark Aarts Javier Abadia Robert Abaidoo Diego Abalos Ghulam Abbas Azza Abbo Geoff Abbott Islam Abdel-Daim Wajiha Abdullahi Mu'az Anna Abrahão Alexis Achim Jose Acosta Motos Alejandra Acuna Ioannis-Dimosthenis Adamakis Bartosz Adamczyk George Adamidis Martino Adamo Catharine A. Adams Shalom Addo-Danso Toluwase Adegoke Ardeshir Adeli Alessandra Adessi Adewole T. Adetunji Kamal Adhikari Michael Adomako Niraj Agarwala Goran Agren Mario Aguilar Cid Aguilar-Carpio Carlos Aguilar-Trigueros Agnese Aguzzoni Golam Jalal Ahammed Ambreen Ahmed Mukhtar Ahmed James Ajal Nudrat Akram Emre Aksoy Lucas Albano Felipe Albornoz Josu Alday Laura Aldrich-Wolfe Anne Alexandre Maria Del Mar Alguacil Baber Ali Ignazio Allegretta Damian Allen Juliana Almario Leidivan Almeida Frazão Teresa Altabella Mario Alejandro Alvarez Salas Ana Álvarez-Fernández Vanessa Alvarez-Lopez Bruno Alves Monica Yorlady Alzate Zuluaga Elena Ambros F. M. Aminuzzaman Shao-Shan An Yuan An Zhengfeng An Stig Andersen Anne Anderson Geoffrey Anderson Anna Andreetta Samantha Andres Mitchell Andrews Jasmine Anenberg Marco Anisetti Tyler Anthony Anita Antoninka Jacek Antonkiewicz Maria Soledad Anzuay Lina Aoyama Pedro Aphalo Roxana Aragón Fabrizio Araniti Adelson Araujo Julie Ardley Rebeca Arias Del Real Cristina Armas Roger Armstrong Ricardo Aroca. [Extracted from the article]

Summary: Rice grain is a poor dietary source of zinc (Zn) but the primary source of cadmium (Cd) for humans; however, the molecular mechanisms for their accumulation in rice grain remain incompletely understood.This study functionally characterized a tonoplast‐localized transporter, OsMTP1. OsMTP1 was preferentially expressed in the roots, aleurone layer, and embryo of seeds. OsMTP1 knockout decreased Zn concentration in the root cell sap, roots, aleurone layer and embryo, and subsequently increased Zn concentration in shoots and polished rice (endosperm) without yield penalty. OsMTP1 haplotype analysis revealed elite alleles associated with increased Zn level in polished rice, mostly because of the decreased OsMTP1 transcripts.OsMTP1 expression in yeast enhanced Zn tolerance but did not affect that of Cd. While OsMTP1 knockout resulted in decreased uptake, translocation and accumulation of Cd in plant and rice grain, which could be attributed to the indirect effects of altered Zn accumulation.Our results suggest that rice OsMTP1 primarily functions as a tonoplast‐localized transporter for sequestrating Zn into vacuole. OsMTP1 knockout elevated Zn concentration but prevented Cd deposition in polished rice without yield penalty. Thus, OsMTP1 is a candidate gene for enhancing Zn level and reducing Cd level in rice grains. [ABSTRACT FROM AUTHOR]

Background: One of the most important roles of plant roots is to take up mineral nutrients from soils for growth and development. The uptake of mineral nutrients is mediated by many different transporters expressed in the roots. The morphology and anatomy of the roots differ within plant species, but their link with nutrient uptake is poorly understood. Scope: In this review, we aim to describe the spatial uptake site of mineral nutrients along the root axes and the different roles of root hairs and lateral roots in mineral element uptake in association with the distinct expression pattern of transporters, mainly by comparing two typical model plants: Arabidopsis and rice. Conclusions: We propose different uptake systems for mineral elements, which are formed by a pair of influx-efflux transporters, based on the root anatomy, allocation and polar localization of transporters. Furthermore, we discuss the role of Casparian strips in the uptake of mineral nutrients. Finally, we propose future prospects for linking root morphology and anatomy to transporters for a better and safe crop production. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) shows a high accumulation of silicon (Si), but transporters involved in the uptake and distribution have not been identified. In the present study, we isolated two genes (ZmLsi1 and ZmLsi6), which are homologous to rice influx Si transporter OsLsi1. Heterologous expression in Xenopus laevis oocytes showed that both ZmLsi1 and ZmLsi6 are permeable to silicic acid. ZmLsi1 was mainly expressed in the roots. By contrast, ZmLsi6 was expressed more in the leaf sheaths and blades. Different from OsLsi1, the expression level of both ZmLsi1 and ZmLsi6 was unaffected by Si supply. Immunostaining showed that ZmLsi1 was localized on the plasma membrane of the distal side of root epidermal and hypodermal cells in the seminal and crown roots, and also in cortex cells in lateral roots. In the shoots, ZmLsi6 was found in the xylem parenchyma cells that are adjacent to the vessels in both leaf sheaths and leaf blades. ZmLsi6 in the leaf sheaths and blades also exhibited polar localization on the side facing towards the vessel. Taken together, it can be concluded that ZmLsi1 is an influx transporter of Si, which is responsible for the transport of Si from the external solution to the root cells and that ZmLsi6 mainly functions as a Si transporter for xylem unloading. [ABSTRACT FROM AUTHOR]

FE UPTAKE‐INDUCING PEPTIDE1 (FEP1), also named IRON MAN3 (IMA3) is a short peptide involved in the iron deficiency response in Arabidopsis thaliana. Recent studies uncovered its molecular function, but its physiological function in the systemic Fe response is not fully understood. To explore the physiological function of FEP1 in iron homoeostasis, we performed a transcriptome analysis using the FEP1 loss‐of‐function mutant fep1‐1 and a transgenic line with oestrogen‐inducible expression of FEP1. We determined that FEP1 specifically regulates several iron deficiency‐responsive genes, indicating that FEP1 participates in iron translocation rather than iron uptake in roots. The iron concentration in xylem sap under iron‐deficient conditions was lower in the fep1‐1 mutant and higher in FEP1‐induced transgenic plants compared with the wild type (WT). Perls staining revealed a greater accumulation of iron in the cortex of fep1‐1 roots than in the WT root cortex, although total iron levels in roots were comparable in the two genotypes. Moreover, the fep1‐1 mutation partially suppressed the iron overaccumulation phenotype in the leaves of the oligopeptide transporter3‐2 (opt3‐2) mutant. These data suggest that FEP1 plays a pivotal role in iron movement and in maintaining the iron quota in vascular tissues in Arabidopsis. [ABSTRACT FROM AUTHOR]

SUMMARY: Glycosyltransferases (GTs) form a large family in plants and are important enzymes for the synthesis of various polysaccharides, but only a few members have been functionally characterized. Here, through mutant screening with gene mapping, we found that an Oryza sativa (rice) mutant with a short‐root phenotype was caused by a frame‐shift mutation of a gene (OsGT14;1) belonging to the glycosyltransferase gene family 14. Further analysis indicated that the mutant also had a brittle culm and produced lower grain yield compared with wild‐type rice, but the roots showed similar root structure and function in terms of the uptake of mineral nutrients. OsGT14;1 was broadly expressed in all organs throughout the entire growth period, with a relatively high expression in the roots, stems, node I and husk. Furthermore, OsGT14;1 was expressed in all tissues of these organs. Subcellular observation revealed that OsGT14;1 encoded a Golgi‐localized protein. Mutation of OsGT14;1 resulted in decreased cellulose content and increased hemicellulose, but did not alter pectin in the cell wall of roots and shoots. The knockout of OsGT14;1 did not affect the tolerance to toxic mineral elements, including Al, As, Cd and salt stress, but did increase the sensitivity to low pH. Taken together, OsGT14;1 located at the Golgi is required for growth of both roots and shoots in rice through affecting cellulose synthesis. [ABSTRACT FROM AUTHOR]

SUMMARY: The essential micronutrient manganese (Mn) in plants regulates multiple biological processes including photosynthesis and oxidative stress. Some Natural Resistance‐Associated Macrophage Proteins (NRAMPs) have been reported to play critical roles in Mn uptake and reutilization in low Mn conditions. NRAMP6 was demonstrated to regulate cadmium tolerance and iron utilization in Arabidopsis. Nevertheless, it is unclear whether NRAMP6 plays a role in Mn nutrition. Here, we report that NRAMP6 cooperates with NRAMP1 in Mn utilization. Mutation of NRAMP6 in nramp1 but not in a wild‐type background reduces root growth and Mn translocation from the roots to shoots under Mn deficient conditions. Grafting experiments revealed that NRAMP6 expression in both the roots and shoots is required for root growth and Mn translocation under Mn deficiency. We also showed that NRAMP1 could replace NRAMP6 to sustain root growth under Mn deficiency, but not vice versa. Mn deficiency does not affect the transcript level of NRAMP6, but is able to increase and decrease the protein accumulation of NRAMP6 in roots and shoots, respectively. Furthermore, NRAMP6 can be localized to both the plasma membrane and endomembranes including the endoplasmic reticulum, and Mn deficiency enhances the localization of NRAMP6 to the plasma membrane in Arabidopsis plants. NRAMP6 could rescue the defective growth of the yeast mutant Δsmf2, which is deficient in endomembrane Mn transport. Our results reveal the important role of NRAMP6 in Mn nutrition and in the long‐distance signaling between the roots and shoots under Mn deficient conditions. Significance Statement: The essential micronutrient manganese (Mn) plays important roles in multiple biological processes. It is unknown whether the Natural Resistance‐Associated Macrophage Protein family member NRAMP6 plays a role in Mn nutrition. We demonstrate that NRAMP6 cooperates with NRAMP1 in the regulation of root growth and Mn translocation from roots to shoots and that NRAMP6 is involved in long‐distance signaling between the roots and shoots under Mn deficiency. [ABSTRACT FROM AUTHOR]

Summary: 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. [ABSTRACT FROM AUTHOR]

Silicon (Si) is an important nutrient required for sustainable and high production of rice and its uptake is mediated by a pair of influx (OsLsi1)–efflux (OsLsi2) transporters showing polar localization. However, the mechanisms underlying their polarity are unknown. Here, we revealed that the polarity of the Si transporters depends on cell types. The polar localization of both OsLsi1 and OsLsi2 was not altered by Si supply, but their protein abundance was reduced. Double immunostaining showed that localization of OsLsi1 and OsLsi2 was separated at the edge of the lateral polar domain by Casparian strips in the endodermis, whereas they were slightly overlapped at the transversal side of the exodermis. When OsLsi1 was ectopically expressed in the shoots, it showed polar localization at the xylem parenchyma cells of the basal node and leaf sheath, but not at the phloem companion cells. Ectopic expression of non-polar Si transporters, barley HvLsi2 and maize ZmLsi2 in rice, resulted in their polar localization at the proximal side. The polar localization of OsLsi1 and OsLsi2 was not altered by inhibition of clathrin-mediated endocytosis (CME) by dominant-negative induction of dynamin-related protein1A and knockout of mu subunit of adaptor protein 2 complex, although the knockout mutants of OsAP2M gene showed dwarf phenotype. These results indicate that CME is not required for the polar localization of Si transporters. Taken together, our results indicate that CME-independent machinery controls the polar localization of Si transporters in exodermis, endodermis of root cells and xylem parenchyma cells. [ABSTRACT FROM AUTHOR]

The roots of many plant species contain large amounts of pectin and it contributes to the formation of the rhizosphere. In the present study, the relationship between the root-tip pectin content and aluminium (Al) tolerance in wild-type (WT) and demethylesterified pectin degradation enzyme gene overexpressor (OsPG2 -FOX) rice lines was compared. OsPG2 -FOX rice showed reduced pectin content in roots, even under control conditions; Al treatment reduced root elongation and the pectin content in the root elongation zone. Wild-type rice showed more pectin accumulation in the root elongation zone after Al treatment. Relative to WT rice, OsPG2 -FOX rice showed more Al accumulation in the root elongation zone. These results indicate that the amount of pectin influences Al tolerance and that the distribution of pectin in the root elongation zone inhibits Al accumulation in rice roots. Pectin accumulation in cell walls in the root elongation zone may play a role in protecting rice plants from the Al-induced inhibition of root elongation by regulating pectin distribution. [ABSTRACT FROM AUTHOR]

Summary: Rice is able to accumulate high concentrations of silicon (Si) in the shoots, and this ability is required for the mitigation of abiotic and biotic stresses. Although transporters for Si uptake have been identified, a transporter for the xylem loading of Si has not been found.We functionally characterized a Si transporter, OsLsi3, in terms of tissue‐specific localization, knockout line phenotype and mathematic simulation.OsLsi3 was shown to be an efflux Si transporter. OsLsi3 was mainly expressed in the mature root region, and its expression was downregulated by Si. Immunostaining with a specific antibody showed that OsLsi3 was localized to the pericycle in the roots, without polarity. However, when it was expressed under the control of the OsLsi2 promoter, OsLsi3 became polarly localized to the proximal side of both the exodermis and endodermis. Knockout of this gene resulted in decreased Si uptake and concentration in the xylem sap under low Si supply, but not under high Si supply. Mathematical modeling showed that localization of OsLsi3 to the pericycle accounts for c. 30% of the total Si loading to the xylem under low Si concentrations.In summary, OsLsi3 was involved in the xylem loading of Si in rice roots, which is required for the efficient root‐to‐shoot translocation of Si. [ABSTRACT FROM AUTHOR]

Zinc (Zn) is an essential micronutrient for both plants and animals, while its deficiency in crops and humans is a global problem that affects both crop productivity and human health. Since plants and humans differ in their Zn requirements, it is crucial to balance plant nutrition and human nutrition for Zn. In this review, we focus on the transport system of Zn from soil to grain in rice (Oryza sativa), which is a major dietary source of Zn for people subsiding on rice-based diets. We describe transporters belonging to the different families that are involved in the uptake, vacuolar sequestration, root-to-shoot translocation, and distribution of Zn, and discuss their mechanisms of regulation. We give examples for enhancing Zn accumulation and bioavailability in rice grains through the manipulation of genes that are highly expressed in the nodes, where Zn is deposited at high concentrations. Finally, we provide our perspectives on breeding rice cultivars with both increased tolerance to Zn-deficiency stress and high Zn density in the grains. [ABSTRACT FROM AUTHOR]

Molybdenum (Mo) is an essential micronutrient for almost all living organisms. The Mo uptake process in plants has been well investigated. However, the mechanisms controlling Mo translocation and remobilization among different plant tissues are largely unknown, especially the allocation of Mo to rice grains that are the major dietary source of Mo for humans. In this study, we characterized the functions of a molybdate transporter, OsMOT1;2, in the interorgan allocation of Mo in rice. Heterologous expression in yeast established the molybdate transport activity of OsMOT1;2. OsMOT1;2 was highly expressed in the blades of the flag leaf and the second leaf during the grain filling stage. Subcellular localization revealed that OsMOT1;2 localizes to the tonoplast. Knockout of OsMOT1;2 led to more Mo accumulation in roots and less Mo translocation to shoots at the seedling stage and to grains at the maturity stage. The remobilization of Mo from older leaves to young leaves under molybdate-depleted condition was also decreased in the osmot1;2 knockout mutant. In contrast, overexpression of OsMOT1;2 enhanced the translocation of Mo from roots to shoots at the seedling stage. The remobilization of Mo from upper leaves to grains was also enhanced in the overexpression lines during grain filling. Our results suggest that OsMOT1;2 may function as a vacuolar molybdate exporter facilitating the efflux of Mo from the vacuole into the cytoplasm, and thus, it plays an important role in the root-to-shoot translocation of Mo and the remobilization of Mo from leaves to grains. [ABSTRACT FROM AUTHOR]

Silicon (Si) is a beneficial element for plants, the accumulation of which in plant cell walls prevents water loss through transpiration, which may represent an adaptive strategy for coping with drought stress. Future climate change scenarios predict that drought will become an increasingly important stress factor affecting crop productivity. This problem will be exacerbated by the tendency to irrigate crops with excessive amounts of water, a practice that is both environmentally and economically unsustainable. In this study, we aimed to evaluate the agronomic, physiological, and metabolic aspects of Si translocation in corn crops subjected to drought conditions and excess irrigation. The study was organized in a completely randomized factorial scheme, with five concentrations of applied Si and five levels of irrigation. The findings of the study indicated that the application of Si increased plant growth, stomatal density, and bulliform cell diameter, which provide a better balance in water use and photosynthesis, thereby favoring greater Si translocation and, consequently, an increase in the grain production of corn plants. Furthermore, we found that the application of water to the soil equivalent to 130% and 160% of the recommended level (excess water stress) does not increase plant metabolism or grain production, but does increase water consumption and production costs. [ABSTRACT FROM AUTHOR]

Observing chromosomes is a time-consuming and labor-intensive process, and chromosomes have been analyzed manually for many years. In the last decade, automated acquisition systems for microscopic images have advanced dramatically due to advances in their controlling computer systems, and nowadays, it is possible to automatically acquire sets of tiling-images consisting of large number, more than 1000, of images from large areas of specimens. However, there has been no simple and inexpensive system to efficiently select images containing mitotic cells among these images. In this paper, a classification system of chromosomal images by deep learning artificial intelligence (AI) that can be easily handled by non-data scientists was applied. With this system, models suitable for our own samples could be easily built on a Macintosh computer with Create ML. As examples, models constructed by learning using chromosome images derived from various plant species were able to classify images containing mitotic cells among samples from plant species not used for learning in addition to samples from the species used. The system also worked for cells in tissue sections and tetrads. Since this system is inexpensive and can be easily trained via deep learning using scientists' own samples, it can be used not only for chromosomal image analysis but also for analysis of other biology-related images. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) can accumulate high manganese (Mn) in the shoots through uptake by the roots, which consist of crown roots, lateral roots and root hairs. We investigated the role of lateral roots and root hairs in Mn and cadmium (Cd) uptake by using two indica rice mutants defective in formation of lateral roots (osiaa11) and root hairs (osrhl1). The uptake of Mn and Cd in osiaa11 was significantly lower than that in wild type 'Kasalath', but there was no difference between wild type and osrhl1. Furthermore, a kinetic study showed that Mn uptake in osiaa11 was much lower than that in wild type and osrhl1 across a wide range of Mn concentrations. The role of lateral roots in Mn and Cd uptake was further confirmed in a japonica rice mutant defective in lateral root formation. We found that expression of Mn transporter gene Natural Resistance-Associated Macrophage Protein 5 (OsNRAMP5), but not of Metal Tolerance Protein 9 (OsMTP9) , was lower in osiaa11 than in wild type; however, there were no differences between osrhl1 and the wild type. Immunostaining showed that OsNRAMP5 and OsMTP9 were localized in the exodermis and endodermis of crown roots and lateral roots, but not in the root hairs. Taken together, our results indicate that lateral roots, but not root hairs, play an important role in high Mn and Cd uptake in rice. [ABSTRACT FROM AUTHOR]

Summary: Iron (Fe) from rice grains is an important source of dietary intake; however, the molecular mechanisms responsible for loading of Fe to the grains are poorly understood.We functionally characterized a vacuolar iron transporter gene, OsVIT2 in terms of expression pattern, cellular localization, and mutant phenotypes.OsVIT2 was expressed in the parenchyma cell bridges of nodes, in the mestome sheath of leaf sheath and aleurone of the caryopsis. Mutation of OsVIT2 resulted in decreased Fe distribution to the leaf sheath, nodes, and aleurone, but increased Fe to the leaf blade and grains. Furthermore, Fe was heavily deposited in the parenchyma cell bridges, mestome sheath and aleurone in the wild‐type rice, but this accumulation was decreased in the knockout lines. Conversely, heavier deposition of Fe was observed in the embryo and endosperm of the grains of knockout lines compared with the wild‐type rice, resulting in increased Fe accumulation in the polished rice without yield penalty.These results indicate that OsVIT2 is involved in the distribution of Fe to the grains through sequestering Fe into vacuoles in mestome sheath, nodes, and aleurone layer and that knockout of this gene provides a potential way for Fe biofortification without yield penalty. [ABSTRACT FROM AUTHOR]

Summary: Boron (B) is essential for growth and development, with the B requirement differing depending on the particular organs and tissues, but the molecular mechanisms underlying the preferential distribution of B to different tissues are poorly understood.We investigated the role of a rice gene (OsBOR1) encoding a B efflux transporter in the distribution of B to different tissues under different B supplies.OsBOR1 was highly expressed in the nodes at all growth stages. The OsBOR1 protein shows polar localization at the distal side of bundle sheath cells in nodes and xylem parenchyma cells of elongating leaf sheath, but in the mature leaf sheath and blade at the proximal side of bundle sheath cells. Furthermore, the expression of OsBOR1 was not affected by external B fluctuations, but the OsBOR1 protein was gradually degraded in response to high B. Knockout of this gene altered B distribution, decreasing the distribution of B to new leaves and panicles but increasing B distribution to old leaves.These results indicate that OsBOR1 expressed in nodes and leaf sheath is involved in the preferential distribution of B to different tissues in rice. Furthermore, the OsBOR1 undergoes degradation in response to high B for fine regulation of B distribution to different tissues. [ABSTRACT FROM AUTHOR]

Manganese (Mn) is an essential element for plant growth and development, but transporters required for Mn uptake have only been identified in a few plant species. Here, we functionally characterized a member of the natural resistance-associated macrophage proteins (Nramps) family, FeNramp5 in buckwheat (Fagopyrum esculentum Moench), which is known as a species well adapted to acidic soils. FeNramp5 was mainly expressed in the roots, and its expression was upregulated by the deficiency of Mn and Fe. Furthermore, spatial and tissue-specific expression analysis showed that FeNramp5 was expressed in all tissues of the basal root regions. FeNramp5-GFP protein was localized to the plasma membrane when transiently expressed in buckwheat leaf protoplast. FeNramp5 showed the transport activity for Mn2+ and Cd2+ but not for Fe2+ when expressed in yeast. Furthermore, the transport activity for Mn2+ was higher in yeast expressing FeNramp5 than in yeast expressing AtNramp1. FeNramp5 was also able to complement the phenotype of Arabidopsis atnramp1 mutant in terms of the growth and accumulation of Mn and Cd. The absolute expression level of AtNramp1 was comparable to that of FeNramp5 in the roots, but buckwheat accumulated higher Mn than Arabidopsis when grown under the same condition. Further analysis showed that at least motif B in FeNramp5 seems important for its high transport activity for Mn. These results indicate that FeNramp5 is a transporter for the uptake of Mn and Cd and its higher transport activity for Mn is probably associated with higher Mn accumulation in buckwheat. [ABSTRACT FROM AUTHOR]

SUMMARY: Tiller number is one of the most important agronomic traits that determine rice (Oryza sativa) yield. Active growth of tiller bud (TB) requires high amount of mineral nutrients; however, the mechanism underlying the distribution of mineral nutrients to TB with low transpiration is unknown. Here, we found that the distribution of Zn to TB is mediated by OsZIP4, one of the ZIP (ZRT, IRT‐like protein) family members. The expression of OsZIP4 was highly detected in TB and nodes, and was induced by Zn deficiency. Immunostaining analysis revealed that OsZIP4 was mainly expressed in phloem of diffuse vascular bundles in the nodes and the axillary meristem. The mutation of OsZIP4 did not affect the total Zn uptake, but altered Zn distribution; less Zn was delivered to TB and new leaf, but more Zn was retained in the basal stems at the vegetative growth stage. Bioimaging analysis showed that the mutant aberrantly accumulated Zn in enlarged and transit vascular bundles of the basal node, whereas in wild‐type high accumulation of Zn was observed in the meristem part. At the reproductive stage, mutation of OsZIP4 resulted in delayed panicle development, which is associated with decreased Zn distribution to the panicles. Collectively, OsZIP4 is involved in transporting Zn to the phloem of diffuse vascular bundles in the nodes for subsequent distribution to TBs and other developing tissues. It also plays a role in transporting Zn to meristem cells in the TBs. Significance Statement: A zinc transporter OsZIP4 localized at the node plays an important role in preferential distribution of zinc to the tiller buds and panicles in rice, which is required for outgrowth of tiller buds and panicle development. [ABSTRACT FROM AUTHOR]

Summary: A rice node is a hub for distribution of mineral elements; however, most genes highly expressed in the node have not been functionally characterized.Transcriptomic analysis of a rice node revealed that two metallothionein genes, OsMT2b and OsMT2c, were highly expressed in the node I. We functionally characterized these genes in terms of gene expression pattern, cellular and subcellular localization, phenotypic analysis of the single and double knockout mutants and metal‐binding ability.Both OsMT2b and OsMT2c were mainly and constitutively expressed in the phloem region of enlarged and diffuse vascular bundles in the nodes and of the anther. Knockout of either OsMT2b or OsMT2c increased zinc (Zn) accumulation in the nodes, but decreased Zn distribution to the panicle, resulting in decreased grain yield. A double mutant, osmt2bmt2c, showed further negative effects on the Zn distribution and grain yield. By contrast, knockout of OsMT2b had a small effect on copper (Cu) accumulation. Both OsMT2b and OsMT2c showed binding ability with Zn, whereas only OsMT2b showed binding ability with Cu in yeast.Our results suggest that both OsMT2b and OsMT2c play an important role mainly in the distribution of Zn to grain through chelation and subsequent transport of Zn in the phloem in rice. [ABSTRACT FROM AUTHOR]

Rice is a major dietary source of the toxic metal, cadmium (Cd). Previous studies reported that the rice transporter, OsNRAMP1, (Natural resistance‐associated macrophage protein 1) could transport iron (Fe), Cd and arsenic (As) in heterologous yeast assays. However, the in planta function of OsNRAMP1 remains unknown. Here, we showed that OsNRAMP1 was able to transport Cd and manganese (Mn) when expressed in yeast, but did not transport Fe or As. OsNRAMP1 was mainly expressed in roots and leaves and encoded a plasma membrane‐localized protein. OsNRAMP1 expression was induced by Cd treatment and Fe deficiency. Immunostaining showed that OsNRAMP1 was localized in all root cells, except the central vasculature, and in leaf mesophyll cells. The knockout of OsNRAMP1 resulted in significant decreases in root uptake of Cd and Mn and their accumulation in rice shoots and grains, and increased sensitivity to Mn deficiency. The knockout of OsNRAMP1 had smaller effects on Cd and Mn uptake than knockout of OsNRAMP5, while knockout of both genes resulted in large decreases in the uptake of the two metals. Taken together, OsNRAMP1 contributes significantly to the uptake of Mn and Cd in rice, and the functions of OsNRAMP1 and OsNRAMP5 are similar but not redundant. Rice is the major dietary source of the toxic metal cadmium. Understand how rice takes up Cd is important. Two previous studies showed that OsNRAMP1 could transport iron (Fe), Cd and arsenic (As) in heterologous yeast assays, but its in planta function remains unknown. Here, we functionally characterize OsNRAMP1 and show that the transporter contributes significantly to the uptake of Cd and Mn in rice, but not the uptake of Fe or As. OsNRAMP1 and OsNRAMP5 play similar but non‐redundant functions. Our study sheds light on the mechanisms of Cd and Mn uptake by rice. [ABSTRACT FROM AUTHOR]

About 60–85% of total phosphorus (P) in cereal crops is finally allocated to seeds, where it is required for seed development, germination and early growth. However, little is known about the molecular mechanisms underlying P allocation to seeds. Here, we found that two members (OsPHO1;1 and OsPHO1;2) of the PHO1 gene family are involved in the distribution of P to seeds in rice. Both OsPHO1;1 and OsPHO1;2 were localized to the plasma membrane and showed influx transport activities for inorganic phosphate. At the reproductive stage, both OsPHO1;1 and OsPHO1;2 showed higher expression in node I, the uppermost node connecting to the panicle. OsPHO1;1 was mainly localized at the phloem region of diffuse vascular bundles (DVBs) of node I, while OsPHO1;2 was expressed in the xylem parenchyma cells of the enlarged vascular bundles (EVBs). In addition, they were also expressed in the ovular vascular trace, the outer layer of the inner integument (OsPHO1;1) and in the nucellar epidermis (OsPHO1;2) of caryopses. Knockout of OsPHO1;2, as well as OsPHO1;1 to a lesser extent, decreased the distribution of P to the seed, resulting in decreased seed size and delayed germination. Taken together, OsPHO1;2 expressed in node I is responsible for the unloading of P from the xylem of EVBs, while OsPHO1;1 is involved in reloading P into the phloem of DVBs for subsequent allocation of P to seeds. Furthermore, OsPHO1;1 and OsPHO1;2 expression in the caryopsis is important for delivering P from the maternal tissues to the filial tissues for seed development. [ABSTRACT FROM AUTHOR]

Summary: Climate change will increase frequency of drought and flooding, which threaten global crop productivity and food security. Rice (Oryza sativa) is unique in that it is able to grow in both flooded and upland conditions, which have large differences in the concentrations and chemical forms of mineral elements available to plants.To comprehensively understand the mechanisms of rice for coping with different water status, we performed ionomics and transcriptomics analysis of the roots, nodes and leaves of rice grown in flooded and upland conditions.Focusing the analysis on genes encoding proteins involved in transport functions for mineral elements, it was found that, although rice plants maintained similar levels of each element in the shoots for optimal growth, different transporters for mineral elements were utilised for nitrogen, iron, copper and zinc to deal with different soil water conditions. For example, under flooded conditions, rice roots take up nitrogen using transporters for both ammonium (OsAMT1/2) and nitrate (OsNPF2.4, OsNRT1.1A and OsNRT2.3), whereas under upland conditions, nitrogen uptake is mediated by different nitrate transporters (OsNRT1.1B and OsNRT1.5A).This study shows that rice possesses plastic transport systems for mineral elements in response to different water conditions (upland and flooding). [ABSTRACT FROM AUTHOR]

One of the most important roles of plant roots is to take up mineral elements for their growth. Although several genes involved in root growth have been identified, the association between root structure and mineral element uptake is less investigated. In this study, we isolated a rice mutant (dice1 , defective in cell elongation 1) with short-root phenotype. This mutant was characterized by partial defect in the formation of root outer cell layers. Mapping of the responsible gene revealed that the short-root phenotype in the mutant was caused by a single-nucleotide substitution of a gene encoding a membrane-anchored endo-1,4-beta-glucanase (OsGlu3). The growth of both the roots and shoots was partially recovered with increasing strength of nutrient solution and glucose in the mutant. The mutant showed a decreased uptake (normalized by root dry weight) for Mg, Mn, Fe, Cu, Zn, Cd, As and Ge but increased uptake for K and Ca. The expression level of some transporter genes including OsLsi1 and OsLsi2 for Si uptake and OsNramp5 for Mn uptake was significantly decreased in the mutant compared with the wild-type (WT) rice. Furthermore, the cellular localization of OsLsi1 was altered; OsLsi1 localized at the root exodermis of the WT rice was changed to be localized to other cell layers of the mutant roots. However, this localization became normal in the presence of exogenous glucose in the mutant. Our results indicate that a normal root structure is required for maintaining the expression and localization of transporters involved in the mineral element uptake. [ABSTRACT FROM AUTHOR]

Summary: Plants have evolved two strategies to acquire ferrous (Strategy I) or ferric (Strategy II) iron from soil. The iron‐related bHLH transcription factor 2 (IRO2) has been identified as a key regulator of iron acquisition (Strategy II) in rice. However, its mode of action, subcellular localisation and binding partners are not clearly defined.Using RNA‐seq analyses, we identified a novel bHLH‐type transcription factor, OsbHLH156. The function of OsbHLH156 in Fe homeostasis was analysed by characterisation of the phenotypes, elemental content, transcriptome, interaction and subcellular localisation of OsbHLH156 and IRO2.OsbHLH156 is primarily expressed in the roots and transcript abundance is greatly increased by Fe deficiency. Loss of function of OsbHLH156 resulted in Fe‐deficiency‐induced chlorosis and reduced Fe concentration in the shoots under upland or Fe(III) supplied conditions. Transcriptome analyses revealed that the expression of most Fe‐deficiency‐responsive genes involved in Strategy II were not induced in the osbhlh156‐1 mutant. Furthermore, OsbHLH156 was required for nuclear localisation of IRO2.We conclude that OsbHLH156 is required for a Strategy II uptake mechanism in rice, partnering with a previously identified 'master' regulator IRO2. Mechanistically it is required for the nuclear localisation of IRO2. [ABSTRACT FROM AUTHOR]

The 7th International Conference on Silicon in Agriculture (www.silicon2017.com) was organized at University of Agricultural Sciences (UAS), Bangalore, India during 24th to 28th October, 2017. This was a unique event, being hosted for the first time in India, despite being the 7th in a triennial International series. More than 150 participants, national as well as international, have attended this conference. In this article, we made an attempt to briefly mention about the minutes of this conference. [ABSTRACT FROM AUTHOR]

Increased soil exchangeable calcium increased the soil pH (H SB 2 sb O) and reduced the soil carbon content, while increased soil pH (H SB 2 sb O) increased the grass canopy coverage and soil eukaryotic microbiota diversity. Grassland soil has a high soil carbon content and functions as a carbon dioxide absorption source. In this study, simple sigmoidal soil pH buffer curves were drawn from the data obtained from adding converter furnace slag or lime hydrate to approximately 230 paddy soil samples from eastern Japan and Hokkaido. [Extracted from the article]