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Rescooped by Fenglin Deng from Plant roots and rhizosphere
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An aquaporin PvTIP4;1 from Pteris vittata may mediate arsenite uptake - New Phytologist -

An aquaporin PvTIP4;1 from Pteris vittata may mediate arsenite uptake - New Phytologist - | Plant nutrition & stress | Scoop.it
The fern Pteris vittata is an arsenic hyperaccumulator. The genes involved in arsenite (As(III)) transport are not yet clear. Here, we describe the isolation and characterization of a new P. vittata aquaporin gene, PvTIP4;1, which may mediate As(III) uptake.
PvTIP4;1 was identified from yeast functional complement cDNA library of P. vittata. Arsenic toxicity and accumulating activities of PvTIP4;1 were analyzed in Saccharomyces cerevisiae and Arabidopsis. Subcellular localization of PvTIP4;1–GFP fusion protein in P. vittata protoplast and callus was conducted. The tissue expression of PvTIP4;1 was investigated by quantitative real-time PCR. Site-directed mutagenesis of the PvTIP4;1 aromatic/arginine (Ar/R) domain was studied.
Heterologous expression in yeast demonstrates that PvTIP4;1 was able to facilitate As(III) diffusion. Transgenic Arabidopsis showed that PvTIP4;1 increases arsenic accumulation and induces arsenic sensitivity. Images and FM4-64 staining suggest that PvTIP4;1 localizes to the plasma membrane in P. vittata cells. A tissue location study shows that PvTIP4;1 transcripts are mainly expressed in roots. Site-directed mutation in yeast further proved that the cysteine at the LE1 position of PvTIP4;1 Ar/R domain is a functional site.
PvTIP4;1 is a new represented tonoplast intrinsic protein (TIP) aquaporin from P. vittata and the function and location results imply that PvTIP4;1 may be involved in As(III) uptake.

Via Christophe Jacquet
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Orchestration of three transporters and distinct vascular structures in node for intervascular transfer of silicon in rice

Fenglin Deng's insight:

Requirement of mineral elements differs with different organs and tissues; therefore, plants have developed systems for preferentially delivering mineral elements to tissues with high requirement. However, the molecular mechanisms for these systems are poorly understood. We took silicon (Si) as an example and revealed an efficient distribution system occurring in the node of rice, which is a hub for distribution. We found that hyperaccumulation of Si in the husk (more than 10%) is achieved by cooperation of three different Si transporters localized at the different cell layers in the node. Furthermore, mathematical modeling showed that an apoplastic barrier and development of enlarged vascular bundles are also required. Our work revealed a set of players for efficient distribution control in node.

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Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water

Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water | Plant nutrition & stress | Scoop.it
A novel way of cooking rice to maximize the removal of the carcinogen inorganic arsenic (As i ) is presented here. In conventional rice cooking water and grain are in continuous contact, and it is known that the larger the water:rice cooking ratio, the more As i removed by cooking, suggesting that the As i in the grain is mobile in water. Experiments were designed where rice is cooked in a continual stream of percolating near boiling water, either low in As i , or As i free. This h
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Scientific Reports: The mitochondrial malate dehydrogenase 1 gene GhmMDH1 is involved in plant and root growth under phosphorus deficiency conditions in cotton

Cotton, an important commercial crop, is cultivated for its natural fibers, and requires an adequate supply of soil nutrients, including phosphorus, for its growth. Soil phosporus exists primarily in insoluble forms. We isolated a mitochondrial malate dehydrogenase (MDH) gene, designated as GhmMDH1, from Gossypium hirsutum L. to assess its effect in enhancing P availability and absorption. An enzyme kinetic assay showed that the recombinant GhmMDH1 possesses the capacity to catalyze the interconversion of oxaloacetate and malate. The malate contents in the roots, leaves and root exudates was significantly higher in GhmMDH1-overexpressing plants and lower in knockdown plants compared with the wild-type control. Knockdown of GhmMDH1 gene resulted in increased respiration rate and reduced biomass whilst overexpression of GhmMDH1 gave rise to decreased respiration rate and higher biomass in the transgenic plants. When cultured in medium containing only insoluble phosphorus, Al-phosphorus, Fe-phosphorus, or Ca-phosphorus, GhmMDH1-overexpressing plants produced significantly longer roots and had a higher biomass and P content than WT plants, however, knockdown plants showed the opposite results for these traits. Collectively, our results show that GhmMDH1 is involved in plant and root growth under phosphorus deficiency conditions in cotton, owing to its functions in leaf respiration and P acquisition.
Wang Z-A, Li Q,    Ge X-Y,    Yang C-L, Luo X-L, Zhang A-H, Xiao J-L,    Tian Y-C, Xia G-X, Chen X-Y,    Li F-G & Wu J-H.
DOI:10.1038/srep10343


Via Coline Balzergue
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Rescooped by Fenglin Deng from Plant Gene Seeker -PGS
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Uncovering miRNAs involved in crosstalk between nutrient deficiencies in Arabidopsis

Uncovering miRNAs involved in crosstalk between nutrient deficiencies in Arabidopsis | Plant nutrition & stress | Scoop.it

Via Andres Zurita
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Andres Zurita's curator insight, July 7, 2015 2:41 PM

Integrating carbon (C), nitrogen (N), and sulfur (S) metabolism is essential for the growth and development of living organisms. MicroRNAs (miRNAs) play key roles in regulating nutrient metabolism in plants. However, how plant miRNAs mediate crosstalk between different nutrient metabolic pathways is unclear. In this study, deep sequencing of Arabidopsis thaliana small RNAs was used to reveal miRNAs that were differentially expressed in response to C, N, or S deficiency. Comparative analysis revealed that the targets of the differentially expressed miRNAs are involved in different cellular responses and metabolic processes, including transcriptional regulation, auxin signal transduction, nutrient homeostasis, and regulation of development. C, N, and S deficiency specifically induced miR169b/c, miR826 and miR395, respectively. In contrast, miR167, miR172, miR397, miR398, miR399, miR408, miR775, miR827, miR841, miR857, and miR2111 are commonly suppressed by C, N, and S deficiency. In particular, the miRNAs that are induced specifically by a certain nutrient deficiency are often suppressed by other nutrient deficiencies. Further investigation indicated that the modulation of nutrient-responsive miRNA abundance affects the adaptation of plants to nutrient starvation conditions. This study revealed that miRNAs function as important regulatory nodes of different nutrient metabolic pathways.

Rescooped by Fenglin Deng from Plant roots and rhizosphere
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qRT9, a quantitative trait locus controlling root thickness and root length in upland rice

qRT9, a quantitative trait locus controlling root thickness and root length in upland rice | Plant nutrition & stress | Scoop.it
Breeding for strong root systems is an important strategy for improving drought avoidance in rice. To clone genes responsible for strong root traits, an upland rice introgression line IL392 with thicker and longer roots than the background parent lowland rice Yuefu was selected. A quantitative trait locus (QTL), qRT9, controlling root thickness and root length was detected under hydroponic culture using 203 F2:3 populations derived from a cross between Yuefu and IL392. The qRT9 locus explained 32.5% and 28.1% of the variance for root thickness and root length, respectively. Using 3185 F2 plants, qRT9 was ultimately narrowed down to an 11.5kb region by substitution mapping. One putative basic helix–loop–helix (bHLH) transcription factor gene, LOC_Os09g28210 (named OsbHLH120), is annotated in this region. Sequences of OsbHLH120 in 11 upland rice and 13 lowland rice indicated that a single nucleotide polymorphism (SNP) at position 82 and an insertion/deletion (Indel) at position 628–642 cause amino acid changes and are conserved between upland rice and lowland rice. Phenotypic analysis indicated that the two polymorphisms were significantly associated with root thickness and root length under hydroponic culture. Quantitative real-time PCR showed that OsbHLH120 was strongly induced by polyethylene glycol (PEG), salt, and abscisic acid, but higher expression was present in IL392 roots than in Yuefu under PEG and salt stress. The successfully isolated locus, qRT9, enriches our knowledge of the genetic basis for drought avoidance and provides an opportunity for breeding drought avoidance varieties by utilizing valuable genes in the upland rice germplasm.

Via Christophe Jacquet
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Nature Biotechnology: Engineering insect-free cereals (2015)

Nature Biotechnology: Engineering insect-free cereals (2015) | Plant nutrition & stress | Scoop.it

A cluster of three rice lectin receptor kinases confers resistance to planthopper insects.

 

Insect pests reduce yields of crops worldwide through direct damage and because they spread devastating viral diseases. In Asia, the brown planthopper (BPH) decimates rice (Oryza sativa) crops, causing the loss of billions of dollars annually1. In this issue, Liu et al.2 report the cloning of a rice genetic locus that confers broad-spectrum resistance to BPH and at least one other planthopper species (white back planthopper). Introducing this locus into plant genomes is likely to provide an effective means of combating insect pests of rice and of other cereals such as maize.

 

In modern rice agriculture, BPH damage is controlled through breeding and the application of vast amounts of chemical pesticides1. Pesticides are not a sustainable approach, however, owing to high costs, harmful environmental effects and rapid development of resistant insects. Breeding programs have identified more than 20 genetic loci in cultivated or wild rice species that confer BPH resistance1. However, these Bph loci are usually only effective against specific BPH biotypes, and newly evolved BPH populations have rapidly overcome several Bph resistance loci deployed in the field..

 

Of the >20 identified Bph loci, only Bph14 and Bph26 have been cloned. Both of these loci encode coiled-coil, nucleotide-binding and leucine-rich repeat proteins3, 4, the main class of plant intracellular immune receptors5. Bph3 is a resistance locus that was first pinpointed genetically in the Sri Lankan rice indica cultivar Rathu Heenati. Notably, unlike most other Bph loci, including Bph14 and Bph26, Bph3 confers broad-spectrum resistance to many BPH biotypes as well as to the white back planthopper1, 2. The success of Bph3 as a resistance locus might be linked to the fact that it acts against BPH at an early stage of the feeding cycle, before the insect can deploy its arsenal of virulence proteins that circumvent plant defenses.

 

Despite the huge potential of Bph3 for rice agriculture, its molecular identity has been unknown. Liu et al.2 now identify Bph3 through map-based cloning in a cross between the resistant indica cultivar Rathu Heenati and the susceptible japonica cultivar 02428. Bph3 maps to a 79-kb genomic region that contains a cluster of three lectin receptor kinases, OsLecRK1–3 (ref. 2) (Fig. 1). The authors find that single-nucleotide polymorphisms in these genes are associated with BPH resistance in different cultivated rice accessions. They also show that ectopic expression of the OsLecRK1–3 gene cluster in the susceptible japonica Kitaake cultivar confers BPH resistance.

 

See Liu et al. Nature Biotechnology http://www.nature.com/nbt/journal/v33/n3/full/nbt.3069.html


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Rescooped by Fenglin Deng from Plant phosphate nutrition
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Tha Plant Cell: The Rice CK2 Kinase Regulates Trafficking of Phosphate Transporters in Response to Phosphate Levels

Tha Plant Cell: The Rice CK2 Kinase Regulates Trafficking of Phosphate Transporters in Response to Phosphate Levels | Plant nutrition & stress | Scoop.it

Phosphate transporters (PTs) mediate phosphorus uptake and are regulated at the transcriptional and posttranslational levels. In one key mechanism of posttranslational regulation, phosphorylation of PTs affects their trafficking from the endoplasmic reticulum (ER) to the plasma membrane. However, the kinase(s) mediating PT phosphorylation and the mechanism leading to ER retention of phosphorylated PTs remain unclear. In this study, we identified a rice (Oryza sativa) kinase subunit, CK2β3, which interacts with PT2 and PT8 in a yeast two-hybrid screen. Also, the CK2α3/β3 holoenzyme phosphorylates PT8 under phosphate-sufficient conditions. This phosphorylation inhibited the interaction of PT8 with PHOSPHATE TRANSPORTER TRAFFIC FACILITATOR1, a key cofactor regulating the exit of PTs from the ER to the plasma membrane. Additionally, phosphorus starvation promoted CK2β3 degradation, relieving the negative regulation of PT phosphorus-insufficient conditions. In accordance, transgenic expression of a nonphosphorylatable version of OsPT8 resulted in elevated levels of that protein at the plasma membrane and enhanced phosphorus accumulation and plant growth under various phosphorus regimes. Taken together, these results indicate that CK2α3/β3 negatively regulates PTs and phosphorus status regulates CK2α3/β3.
Chen J, Wang Y, Wang F, Yang J, Gao M, Li C, Liu Y, Liu Y, Yamaji N, Ma JF, Paz-Ares J, Nussaume L, Zhang S, Yi K, Wu Z, Wu P
The Plant Cell February 2015 tpc.114.135335


Via Coline Balzergue
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Frontiers | Linking salinity stress tolerance with tissue-specific Na+ sequestration in wheat roots | Plant Physiology

Frontiers | Linking salinity stress tolerance with tissue-specific Na+ sequestration in wheat roots | Plant Physiology | Plant nutrition & stress | Scoop.it
Salinity stress tolerance is a physiologically complex trait that is conferred by the large array of interacting mechanisms. Among these, vacuolar Na+ sequestration has always been considered as one of the key components differentiating between sensitive and tolerant species and genotypes. However, vacuolar Na+ sequestration has been rarely considered in the context of the tissue-specific expression and regulation of appropriate transporters contributing to Na+ removal from the cytosol. In this work, six bread wheat varieties contrasting in their salinity tolerance (three tolerant and three sensitive) were used to understand the essentiality of vacuolar Na+ sequestration between functionally different root tissues, and link it with the overall salinity stress tolerance in this species. Roots of 4-day old wheat seedlings were treated with 100 mM NaCl for 3 days, and then Na+ distribution between cytosol and vacuole was quantified by CoroNa Green fluorescent dye imaging. Our major observations were as follows: (1) salinity stress tolerance correlated positively with vacuolar Na+ sequestration ability in the mature root zone but not in the root apex; (2) contrary to expectations, cytosolic Na+ levels in root meristem were significantly higher in salt tolerant than sensitive group, while vacuolar Na+ levels showed an opposite trend. These results are interpreted as meristem cells playing a role of the “salt sensor;” (3) no significant difference in the vacuolar Na+ sequestration ability was found between sensitive and tolerant groups in either transition or elongation zones; (4) the overall Na+ accumulation was highest in the elongation zone, suggesting its role in osmotic adjustment and turgor maintenance required to drive root expansion growth. Overall, the reported results suggest high tissue-specificity of Na+ uptake, signaling, and sequestration in wheat roots. The implications of these findings for plant breeding for salinity stress tolerance are discussed.

Via Christophe Jacquet
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Digging deeper: high-resolution genome-scale data yields new insights into root biology

Digging deeper: high-resolution genome-scale data yields new insights into root biology | Plant nutrition & stress | Scoop.it

Highlights•

Cell-type specific hormone signaling is important for the high-resolution salt stress response in the root.

Computational modeling of cell-type specific data illustrates the complexity of these networks.

Mutants that lack morphological phenotypes often have molecular phenotypes that are revealed with cell-type specific data.

High-resolution analysis of auxin responses identifies a bipartite auxin response along the longitudinal axis of the root.

New advances allowing simultaneous root growth and cellular imaging identify novel regulators of root growth and development.

Development in multicellular organisms is the result of designated cellular programs occurring at specific points in time and space. The root is an excellent model to address how spatio-temporal complexity impacts organ development. High-resolution ‘omic’ approaches have delineated the transcriptional, proteomic, metabolomic, and small RNA profiles of multiple cell types in the Arabidopsis root. Similar approaches have shed light on root cell-type specific transcriptional programs in rice and soybean. These data are being used to identify specific spatio-temporal mechanisms of root development, dissect regulatory networks that control cell identity, and understand hormone responses in the root. Computational modeling of these data combined with new advances in imaging technologies is generating new biological insights into root growth and development.


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TOND1 confers tolerance to nitrogen deficiency in rice - Zhang - 2015 - The Plant Journal - Wiley Online Library

TOND1 confers tolerance to nitrogen deficiency in rice - Zhang - 2015 - The Plant Journal - Wiley Online Library | Plant nutrition & stress | Scoop.it
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http://onlinelibrary.wiley.com/doi/10.1111/tpj.12736/full

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PNAS: Structure, variation, and assembly of the root-associated microbiomes of rice

PNAS: Structure, variation, and assembly of the root-associated microbiomes of rice | Plant nutrition & stress | Scoop.it

Plants depend upon beneficial interactions between roots and microbes for nutrient availability, growth promotion, and disease suppression. High-throughput sequencing approaches have provided recent insights into root microbiomes, but our current understanding is still limited relative to animal microbiomes. Here we present a detailed characterization of the root-associated microbiomes of the crop plant rice by deep sequencing, using plants grown under controlled conditions as well as field cultivation at multiple sites. The spatial resolution of the study distinguished three root-associated compartments, the endosphere (root interior), rhizoplane (root surface), and rhizosphere (soil close to the root surface), each of which was found to harbor a distinct microbiome. Under controlled greenhouse conditions, microbiome composition varied with soil source and genotype. In field conditions, geographical location and cultivation practice, namely organic vs. conventional, were factors contributing to microbiome variation. Rice cultivation is a major source of global methane emissions, and methanogenic archaea could be detected in all spatial compartments of field-grown rice. The depth and scale of this study were used to build coabundance networks that revealed potential microbial consortia, some of which were involved in methane cycling. Dynamic changes observed during microbiome acquisition, as well as steady-state compositions of spatial compartments, support a multistep model for root microbiome assembly from soil wherein the rhizoplane plays a selective gating role. Similarities in the distribution of phyla in the root microbiomes of rice and other plants suggest that conclusions derived from this study might be generally applicable to land plants.


Via Stéphane Hacquard
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Identification of the transporter responsible for sucrose accumulation in sugar beet taproots

Identification of the transporter responsible for sucrose accumulation in sugar beet taproots | Plant nutrition & stress | Scoop.it
Nature Plants, Published online: 8 January 2015; | doi:10.1038/nplants.2014.1

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Andres Zurita's curator insight, January 8, 2015 7:36 AM

Sugar beet provides around one third of the sugar consumed worldwide and serves as a significant source of bioenergy in the form of ethanol. Sucrose accounts for up to 18% of plant fresh weight in sugar beet. Most of the sucrose is concentrated in the taproot, where it accumulates in the vacuoles. Despite 30 years of intensive research, the transporter that facilitates taproot sucrose accumulation has escaped identification. Here, we combine proteomic analyses of the taproot vacuolar membrane, the tonoplast, with electrophysiological analyses to show that the transporter BvTST2.1 is responsible for vacuolar sucrose uptake in sugar beet taproots. We show that BvTST2.1 is a sucrose-specific transporter, and present evidence to suggest that it operates as a proton antiporter, coupling the import of sucrose into the vacuole to the export of protons. BvTST2.1 exhibits a high amino acid sequence similarity to members of the tonoplast monosaccharide transporter family in Arabidopsis, prompting us to rename this group of proteins ‘tonoplast sugar transporters’. The identification of BvTST2.1 could help to increase sugar yields from sugar beet and other sugar-storing plants in future breeding programs.

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Functional analysis of the three HMA4 copies of the metal hyperaccumulator Arabidopsis halleri

Functional analysis of the three HMA4 copies of the metal hyperaccumulator Arabidopsis halleri | Plant nutrition & stress | Scoop.it
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Mechanism of potassium ion uptake by the Na+/K+-ATPase : (Nature Communications)

Mechanism of potassium ion uptake by the Na+/K+-ATPase : (Nature Communications) | Plant nutrition & stress | Scoop.it
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Model depicting high-starch low-methane-emission SUSIBA2 rice. : Expression of barley SUSIBA2 transcription factor yields high-starch low-methane rice : Nature : Nature Publishing Group

Model depicting high-starch low-methane-emission SUSIBA2 rice. : Expression of barley SUSIBA2 transcription factor yields high-starch low-methane rice : Nature : Nature Publishing Group | Plant nutrition & stress | Scoop.it
Atmospheric methane is the second most important greenhouse gas after carbon dioxide, and is responsible for about 20% of the global warming effect since pre-industrial times. Rice paddies are the largest anthropogenic methane source and produce 7-17% of atmospheric methane. Warm waterlogged soil and exuded nutrients from rice roots provide ideal conditions for methanogenesis in paddies with annual methane emissions of 25-100-million tonnes. This scenario will be exacerbated by an expansion in rice cultivation needed to meet the escalating demand for food in the coming decades. There is an urgent need to establish sustainable technologies for increasing rice production while reducing methane fluxes from rice paddies. However, ongoing efforts for methane mitigation in rice paddies are mainly based on farming practices and measures that are difficult to implement. Despite proposed strategies to increase rice productivity and reduce methane emissions, no high-starch low-methane-emission rice has been developed. Here we show that the addition of a single transcription factor gene, barley SUSIBA2 (refs 7, 8), conferred a shift of carbon flux to SUSIBA2 rice, favouring the allocation of photosynthates to aboveground biomass over allocation to roots. The altered allocation resulted in an increased biomass and starch content in the seeds and stems, and suppressed methanogenesis, possibly through a reduction in root exudates. Three-year field trials in China demonstrated that the cultivation of SUSIBA2 rice was associated with a significant reduction in methane emissions and a decrease in rhizospheric methanogen levels. SUSIBA2 rice offers a sustainable means of providing increased starch content for food production while reducing greenhouse gas emissions from rice cultivation. Approaches to increase rice productivity and reduce methane emissions as seen in SUSIBA2 rice may be particularly beneficial in a future climate with rising temperatures resulting in increased methane emissions from paddies.
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Variation in NRT1.1B contributes to nitrate-use divergence between rice subspecies : Nature Genetics : Nature Publishing Group

Variation in NRT1.1B contributes to nitrate-use divergence between rice subspecies : Nature Genetics : Nature Publishing Group | Plant nutrition & stress | Scoop.it
Chengcai Chu and colleagues show that genetic variation in NRT1.1B/OsNPF6.5 contributes to nitrate-use divergence between two main subspecies of Asian cultivated rice. Their findings may help to improve nitrogen-use efficiency in plant production.
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Rescooped by Fenglin Deng from Plant Biology Teaching Resources (Higher Education)
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Plant Nutrition-Opoly?

Plant Nutrition-Opoly? | Plant nutrition & stress | Scoop.it

I worked too late last night and then dreamed I was playing Plant Nutrition-Opoly.....

 

Designing and playing games is a terrific way for students to learn. What would the Railroads be - ion transporters? What events would be described on the Chance cards - Mycorrhizal symbiosis, win $10?

For an introductory class, students could redesign the board using plant taxa... orchids for the high-rent squares?

 

What other games can be modified for teaching? I've seen Top Trumps (http://en.wikipedia.org/wiki/Top_Trumps) adapted which is great game for students to design themselves. Here's a link to a Cambridge University  "Meet the algae" Top Trumps card set http://www.plantsci.cam.ac.uk/meetthealgae/pdfs/top-trumps.pdf/view

and here's a link to a Top Trumps game called "Journey to the Centre of the Earth - The First 23 cm"  from Rothamsted http://www.rothamsted.ac.uk/Content/JourneyCentreEarth/TopTrumps.pdf.

 

Have you designed a game to teach plant science, or asked your students to demonstrate their understanding by designing a game?


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Rescooped by Fenglin Deng from Plant phosphate nutrition
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Plant Physiol: Reducing the genetic redundancy of Arabidopsis PHT1 transporters to study phosphate uptake and signaling

Arabidopsis thaliana absorb inorganic phosphate (Pi) from the soil through an active transport process mediated by the 9 members of the PHT1 family. These proteins share a high level of similarity (greater than 61%), with overlapping expression patterns. The resulting genetic and functional redundancy prevents the analysis of their specific roles. To overcome this difficulty, our approach combined several mutations with gene silencing to inactivate multiple members of the PHT1 family, including a cluster of genes localized on chromosome 5 (PHT1;1, PHT1;2 and PHT1;3). Physiological analyses of these lines established that these three genes, along with PHT1;4, are the main contributors to Pi uptake. Furthermore, PHT1;1 plays an important role in translocation from roots to leaves in high phosphate conditions. These genetic tools also revealed that some PHT1 transporters likely exhibit a dual affinity for phosphate, suggesting that their activity is post-translationally controlled. These lines display significant phosphate deficiency-related phenotypes (e.g. biomass and yield) due to a massive (80 to 96%) reduction in phosphate uptake activities. These defects limited the amount of internal Pi pool, inducing compensatory mechanisms triggered by the systemic Pi starvation response. Such reactions have been uncoupled from PHT1 activity suggesting that systemic Pi sensing is most probably acting downstream of PHT1.
Ayadi A, David P, Arrighi JF, Chiarenza S, Thibaud MC, Nussaume L, Marin E.
Plant Physiology February 2015
DOI: 10.1104/pp.114.252338


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Plant salt tolerance: adaptations in halophytes

Plant salt tolerance: adaptations in halophytes | Plant nutrition & stress | Scoop.it

Via Andres Zurita
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Andres Zurita's curator insight, February 24, 2015 10:50 AM

Background 

Most of the water on Earth is seawater, each kilogram of which contains about 35 g of salts, and yet most plants cannot grow in this solution; less than 0·2 % of species can develop and reproduce with repeated exposure to seawater. These ‘extremophiles’ are called halophytes.

Scope 

Improved knowledge of halophytes is of importance to understanding our natural world and to enable the use of some of these fascinating plants in land re-vegetation, as forages for livestock, and to develop salt-tolerant crops. In this Preface to a Special Issue on halophytes and saline adaptations, the evolution of salt tolerance in halophytes, their life-history traits and progress in understanding the molecular, biochemical and physiological mechanisms contributing to salt tolerance are summarized. In particular, cellular processes that underpin the ability of halophytes to tolerate high tissue concentrations of Na+ and Cl−, including regulation of membrane transport, their ability to synthesize compatible solutes and to deal with reactive oxygen species, are highlighted. Interacting stress factors in addition to salinity, such as heavy metals and flooding, are also topics gaining increased attention in the search to understand the biology of halophytes.

Conclusions 

Halophytes will play increasingly important roles as models for understanding plant salt tolerance, as genetic resources contributing towards the goal of improvement of salt tolerance in some crops, for re-vegetation of saline lands, and as ‘niche crops’ in their own right for landscapes with saline soils.

Rescooped by Fenglin Deng from Plant roots and rhizosphere
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Molecular mechanisms governing Arabidopsis iron uptake

Highlights



Arabidopsis employs reduction-based Fe-deficiency-induced Fe uptake.


Multiple novel transcriptional regulators of Fe uptake have recently been identified.


IRT1 gene expression responds to developmental and environmental cues.


IRT1 localization and stability emerge as important factors in Fe-uptake regulation.

Plants are the principal source of dietary iron (Fe) for most of Earth's population and Fe deficiency can lead to major health problems. Developing strategies to improve plant Fe content is a challenge because Fe is essential and toxic and therefore regulating Fe uptake is crucial for plant survival. Acquiring soil Fe relies on complex regulatory events that occur in root epidermal cells. We review recent advances in elucidating many aspects of the regulation of Fe acquisition. These include the expanding protein network involved in FER-LIKE IRON DEFICIENCY INDUCED TRANSCRIPTION FACTOR (FIT)-dependent gene regulation and novel findings on the intracellular trafficking of the Fe transporter IRON-REGULATED TRANSPORTER 1 (IRT1). We outline future challenges and propose strategies, such as exploiting natural variation, to further expand our knowledge.

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Rescooped by Fenglin Deng from Emerging Research in Plant Cell Biology
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Internalization and vacuolar targeting of the brassinosteroid hormone receptor ​BRI1 are regulated by ubiquitination

Brassinosteroids are plant steroid hormones that control many aspects of plant growth and development, and are perceived at the cell surface by the plasma membrane-localized receptor kinase BRI1. Here we show that BRI1 is post-translationally modified by K63 polyubiquitin chainsin vivo. Using both artificial ubiquitination of BRI1 and generation of an ubiquitination-defective BRI1 mutant form, we demonstrate that ubiquitination promotes BRI1 internalization from the cell surface and is essential for its recognition at the trans-Golgi network/early endosomes (TGN/EE) for vacuolar targeting. Finally, we demonstrate that the control of BRI1 protein dynamics by ubiquitination is an important control mechanism for brassinosteroid responses in plants. Altogether, our results identify ubiquitination and K63-linked polyubiquitin chain formation as a dual targeting signal for BRI1 internalization and sorting along the endocytic pathway, and highlight its role in hormonally controlled plant development.


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The Plant Cell Reviews Dynamic Aspects of Plant Hormone Signaling and Crosstalk

The Plant Cell Reviews Dynamic Aspects of Plant Hormone Signaling and Crosstalk | Plant nutrition & stress | Scoop.it

The Roles of ROS and ABA in Systemic Acquired Acclimation

Ron Mittler and Eduardo Blumwald

Plant Cell 2015 tpc.114.133090; First Published on January 20, 2015; doi:10.1105/tpc.114.133090 OPEN

http://www.plantcell.org/content/early/2015/01/20/tpc.114.133090.abstract

 

SCFTIR1/AFB-Based Auxin Perception: Mechanism and Role in Plant Growth and Development

Mohammad Salehin, Rammyani Bagchi, and Mark Estelle

Plant Cell 2015 tpc.114.133744; First Published on January 20, 2015; doi:10.1105/tpc.114.133744

http://www.plantcell.org/content/early/2015/01/20/tpc.114.133744.abstract

 

The PB1 Domain in Auxin Response Factor and Aux/IAA Proteins: A Versatile Protein Interaction Module in the Auxin Response

Tom J. Guilfoyle

Plant Cell 2015 tpc.114.132753; First Published on January 20, 2015; doi:10.1105/tpc.114.132753 OPEN

http://www.plantcell.org/content/early/2015/01/20/tpc.114.132753.abstract

 

PIN-Dependent Auxin Transport: Action, Regulation, and Evolution

Maciek Adamowski and Jiří Friml

Plant Cell 2015 tpc.114.134874; First Published on January 20, 2015; doi:10.1105/tpc.114.134874

http://www.plantcell.org/content/early/2015/01/20/tpc.114.134874.abstract

 

The Yin-Yang of Hormones: Cytokinin and Auxin Interactions in Plant Development

G. Eric Schaller, Anthony Bishopp, and Joseph J. Kieber

Plant Cell 2015 tpc.114.133595; First Published on January 20, 2015; doi:10.1105/tpc.114.133595

http://www.plantcell.org/content/early/2015/01/20/tpc.114.133595.abstract


Via Mary Williams
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Rescooped by Fenglin Deng from Plant roots and rhizosphere
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PHIV-RootCell: a supervised image analysis tool for rice root anatomical parameter quantification

PHIV-RootCell: a supervised image analysis tool for rice root anatomical parameter quantification | Plant nutrition & stress | Scoop.it
We developed the PHIV-RootCell software to quantify anatomical traits of rice roots transverse section images. Combined with an efficient root sample processing method for image acquisition, this program permits supervised measurements of areas (those of whole root section, stele, cortex, and central metaxylem vessels), number of cell layers and number of cells per cell layer. The PHIV-RootCell toolset runs under ImageJ, an independent operating system that has a license-free status. To demonstrate the usefulness of PHIV-RootCell, we conducted a genetic diversity study and an analysis of salt stress responses of root anatomical parameters in rice (Oryza sativa L.). Using 16 cultivars, we showed that we could discriminate between some of the varieties even at the 6 day-olds stage, and that tropical japonica varieties had larger root sections due to an increase in cell number. We observed, as described previously, that root sections become enlarged under salt stress. However, our results show an increase in cell number in ground tissues (endodermis and cortex) but a decrease in external (peripheral) tissues (sclerenchyma, exodermis, and epidermis). Thus, the PHIV-RootCell program is a user-friendly tool that will be helpful for future genetic and physiological studies that investigate root anatomical trait variations.

Via Christophe Jacquet
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