scholarly journals Chloride as a Beneficial Macronutrient in Higher Plants: New Roles and Regulation

2019 ◽  
Vol 20 (19) ◽  
pp. 4686 ◽  
Author(s):  
José M. Colmenero-Flores ◽  
Juan D. Franco-Navarro ◽  
Paloma Cubero-Font ◽  
Procopio Peinado-Torrubia ◽  
Miguel A. Rosales
Keyword(s):  
Higher Plants ◽  
Optimal Growth ◽  
Long Distance ◽  
Root Cells ◽  
Long Distance Transport ◽  
New Genes ◽  
Genes Encoding ◽  
Cell Turgor ◽  
Use Efficiency ◽  
High Concentrations

Chloride (Cl−) has traditionally been considered a micronutrient largely excluded by plants due to its ubiquity and abundance in nature, its antagonism with nitrate (NO3−), and its toxicity when accumulated at high concentrations. In recent years, there has been a paradigm shift in this regard since Cl− has gone from being considered a harmful ion, accidentally absorbed through NO3− transporters, to being considered a beneficial macronutrient whose transport is finely regulated by plants. As a beneficial macronutrient, Cl− determines increased fresh and dry biomass, greater leaf expansion, increased elongation of leaf and root cells, improved water relations, higher mesophyll diffusion to CO2, and better water- and nitrogen-use efficiency. While optimal growth of plants requires the synchronic supply of both Cl− and NO3− molecules, the NO3−/Cl− plant selectivity varies between species and varieties, and in the same plant it can be modified by environmental cues such as water deficit or salinity. Recently, new genes encoding transporters mediating Cl− influx (ZmNPF6.4 and ZmNPF6.6), Cl− efflux (AtSLAH3 and AtSLAH1), and Cl− compartmentalization (AtDTX33, AtDTX35, AtALMT4, and GsCLC2) have been identified and characterized. These transporters have proven to be highly relevant for nutrition, long-distance transport and compartmentalization of Cl−, as well as for cell turgor regulation and stress tolerance in plants.

Phloem long-distance transport of CmNACP mRNA: implications for supracellular regulation in plants

Development ◽  
1999 ◽  
Vol 126 (20) ◽  
pp. 4405-4419 ◽  
Author(s):  
R. Ruiz-Medrano ◽  
B. Xoconostle-Cazares ◽  
W.J. Lucas
Keyword(s):  
Higher Plants ◽  
Phloem Transport ◽  
The Body ◽  
Pcr Analysis ◽  
Rt Pcr ◽  
Long Distance ◽  
Rna Molecules ◽  
Long Distance Transport ◽  
Meristem Development

Direct support for the concept that RNA molecules circulate throughout the plant, via the phloem, is provided through the characterisation of mRNA from phloem sap of mature pumpkin (Cucurbita maxima) leaves and stems. One of these mRNAs, CmNACP, is a member of the NAC domain gene family, some of whose members have been shown to be involved in apical meristem development. In situ RT-PCR analysis revealed the presence of CmNACP RNA in the companion cell-sieve element complex of leaf, stem and root phloem. Longitudinal and transverse sections showed continuity of transcript distribution between meristems and sieve elements of the protophloem, suggesting CmNACP mRNA transport over long distances and accumulation in vegetative, root and floral meristems. In situ hybridization studies conducted on CmNACP confirmed the results obtained using in situ RT-PCR. Phloem transport of CmNACP mRNA was proved directly by heterograft studies between pumpkin and cucumber plants, in which CmNACP transcripts were shown to accumulate in cucumber scion phloem and apical tissues. Similar experiments were conducted with 7 additional phloem-related transcripts. Collectively, these studies established the existence of a system for the delivery of specific mRNA transcripts from the body of the plant to the shoot apex. These findings provide insight into the presence of a novel mechanism likely used by higher plants to integrate developmental and physiological processes on a whole-plant basis.

scholarly journals Regulation of Sulfur Homeostasis in Mycorrhizal Maize Plants Grown in a Fe-Limited Environment

2020 ◽  
Vol 21 (9) ◽  
pp. 3249
Author(s):  
Styliani N. Chorianopoulou ◽  
Petros P. Sigalas ◽  
Niki Tsoutsoura ◽  
Anastasia Apodiakou ◽  
Georgios Saridis ◽  
...  
Keyword(s):  
Higher Plants ◽  
Expression Patterns ◽  
Soluble Form ◽  
Mycorrhizal Symbiosis ◽  
Sulfur Deprivation ◽  
Long Distance ◽  
Sulfate Anion ◽  
Long Distance Transport ◽  
Maize Plants ◽  
Distance Transport

Sulfur is an essential macronutrient for growth of higher plants. The entry of the sulfate anion into the plant, its importation into the plastids for assimilation, its long-distance transport through the vasculature, and its storage in the vacuoles require specific sulfate transporter proteins. In this study, mycorrhizal and non-mycorrhizal maize plants were grown for 60 days in an S-deprived substrate, whilst iron was provided to the plants in the sparingly soluble form of FePO4. On day 60, sulfate was provided to the plants. The gene expression patterns of a number of sulfate transporters as well as sulfate assimilation enzymes were studied in leaves and roots of maize plants, both before as well as after sulfate supply. Prolonged sulfur deprivation resulted in a more or less uniform response of the genes’ expressions in the roots of non-mycorrhizal and mycorrhizal plants. This was not the case neither in the roots and leaves after the supply of sulfur, nor in the leaves of the plants during the S-deprived period of time. It is concluded that mycorrhizal symbiosis modified plant demands for reduced sulfur, regulating accordingly the uptake, distribution, and assimilation of the sulfate anion.

scholarly journals Some Evidence of Long-Distance Transport, Local Sources and Fractionation Between Air and Snow for Metallic Aerosols Deposited in Antarctic Snows Since the 1880s (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 348-348 ◽  
Author(s):  
P Buat-Menard ◽  
C Boutron
Keyword(s):  
Absorption Spectrometry ◽  
Long Distance ◽  
Long Distance Transport ◽  
Physico Chemical ◽  
Rate Of Increase ◽  
Range Transport ◽  
Flameless Atomic Absorption Spectrometry ◽  
Antarctic Snow ◽  
Chemical Segregation ◽  
High Concentrations

Using instrumental neutron activation analysis, we have determined the concentrations of Na, CI, Al, Sc, V, Cr, Mn, Co, Fe, Zn, As, Se, Br, Sb, and J in ultra-clean dated snow samples collected in central East Antarctica. These samples had been previously analysed by flameless atomic absorption spectrometry (Boutron 1980). For the elements determined by both techniques (Na, Al, Mn, Fe, and Zn) the results are in remarkable agreement. These new data confirm and extend the conclusion that background concentrations of trace elements observed at present in Antarctic snow are close to those observed about 100 a BP and thus that Antarctic aerosol is still little affected by global atmospheric pollution. These data also confirm that, for several metals, episodes of anomalously high concentrations are in phase with increased sulphate and acidity, which could result from volcanic fallout. However, during such episodes, a straightforward relationship between the rate of increase in trace metals and the rate of increase in sulphate and acidity is not observed. This also affects volatile elements such as Cl, Br, Se, and I. This is probably due to a combined effect of local versus long-range transport of volcanic aerosols together with a physico-chemical segregation between the various components of this aerosol.

scholarly journals TIP Aquaporins in Plants: Role in Abiotic Stress Tolerance

2020 ◽  
Author(s):  
Marzena Małgorzata Kurowska
Keyword(s):  
Abiotic Stress ◽  
Stress Tolerance ◽  
Higher Plants ◽  
Abiotic Stress Tolerance ◽  
Transmembrane Helices ◽  
Regulatory Motifs ◽  
Genes Expression ◽  
Genes Encoding ◽  
Cell Turgor ◽  
Encoding Genes

Tonoplast Intrinsic Proteins (TIP) are one of five subfamilies of aquaporins in higher plants. Plants typically contain a large number of TIP genes, ranging from 6 to 35 compared to humans. The molecular weight of the TIP subfamily members ranges from 25 to 28 kDa. Despite their sequence diversity, all TIP monomers have the same structure, which consists of six transmembrane helices and five inter-helical loops that form an hourglass shape with a central pore. Four monomers form tetramers, which are functional units in the membrane. TIPs form channels in the tonoplast that basically function as regulators of the intracellular water flow, which implies that they have a role in regulating cell turgor. TIPs are responsible for precisely regulating the movement of not only water, but also some small neutral molecules such as glycerol, urea, ammonia, hydrogen peroxide and formamide. The expression of TIPs may be affected by different environmental stresses, including drought, salinity and cold. TIPs expression is also altered by phytohormones and the appropriate cis-regulatory motifs are identified in the promotor region of the genes encoding TIPs in different plant species. It was shown that manipulating TIP-encoding genes expression in plants could have the potential to improve abiotic stress tolerance.

scholarly journals The role of roots and rhizosphere in providing tolerance to toxic metals and metalloids

2021 ◽  
Author(s):  
Dorina Podar ◽  
Frans J.M. Maathuis
Keyword(s):  
Negative Impact ◽  
Transport Processes ◽  
Long Distance ◽  
Root Cells ◽  
Metals And Metalloids ◽  
Natural Processes ◽  
Long Distance Transport ◽  
Bacteria And Fungi ◽  
Distance Transport

Human activity and natural processes have led to widespread dissemination of metals and metalloids, many of which are toxic and have a negative impact on agronomic production. Roots, as the first point of contact, are essential in endowing plants with tolerance to excess metal(loid) in the soil. The most important root responses include: adaptation of transport processes that affect uptake, efflux and long distance transport of metal(loid)s; metal(loid) detoxification within root cells via conjugation to thiol rich compounds and subsequent sequestration in the vacuole; plasticity in root architecture; the presence of bacteria and fungi in the rhizosphere that impact on metal(loid) bioavailability; the role of root exudates. In this review we will provide details on these processes and assess their relevance for the detoxification of arsenic, cadmium, mercury and zinc. Furthermore, we will assess if any of these methodologies has been tested in field conditions and whether they are effective in terms of improving crop metal(loid) tolerance.

scholarly journals Characterization of a vacuolar sucrose transporter, HbSUT5, from Hevea brasiliensis: involvement in latex production through regulation of intracellular sucrose transport in the bark and laticifers

2019 ◽  
Author(s):  
xiangyu long ◽  
Heping Li ◽  
Jianghua Yang ◽  
Lusheng Xin ◽  
Bin He ◽  
...  
Keyword(s):  
Hevea Brasiliensis ◽  
Higher Plants ◽  
Transcript Level ◽  
Active Role ◽  
Sucrose Transporter ◽  
Sucrose Transport ◽  
Long Distance ◽  
Rubber Biosynthesis ◽  
Long Distance Transport ◽  
Latex Production

Abstract Background: Sucrose (Suc), as the precursor molecule for rubber biosynthesis in Hevea brasiliensis, is transported via phloem-mediated long-distance transport from leaves to laticifers in trunk bark, where latex (cytoplasm of laticifers) is tapped for rubber. Suc transporters (SUTs) play important roles during various steps of Suc transport in higher plants. Results: In our previous report, six SUT genes have been cloned in Hevea tree, among which HbSUT3 has been verified to play an active role in Suc loading to the laticifers. In this study, another latex-abundant SUT isoform, HbSUT5, with expressions only inferior to HbSUT3 was characterized especially for its roles in latex production. Both phylogenetic analysis and subcellular localization identify HbSUT5 as a SUT4-clade (=type III) vacuolar membrane SUT, suggesting its potential participation in Suc exchange between lutoids (polydispersed microvacuoles) and cytosol in latex. Suc uptake assay in yeast identifies HbSUT5 as a typical Suc-H+ symporter, but the high affinity of HbSUT5 for Suc (Km = 2.03 mM at pH 5.5) and its similar efficiency in transporting maltose making it a peculiar SUT under the SUT4-clade. At the transcript level, HbSUT5 is abundantly and preferentially expressed in Hevea barks. It is contrary to HbSUT3 that the transcripts of HbSUT5 are obviously decreased both in Hevea latex and bark during the treatments of tapping and ethephon, indicating it counteracts the yield-stimulating effects of two treatments. Conclusions: A vacuolar sucrose transporter, HbSUT5, may play an important role in Suc exchange between lutoids (polydispersed vacuoles) and latex in laticifers. It is better to understand that the whole HbSUT family regulate and control Suc accumulation in laticifers, influencing rubber yield formation in Hevea.

The regulation of assimilate allocation and transport

2000 ◽  
Vol 27 (6) ◽  
pp. 583 ◽  
Author(s):  
Hanjo Hellmann ◽  
Laurence Barker ◽  
Dietmar Funck ◽  
Wolf B. Frommer
Keyword(s):  
Higher Plants ◽  
Sugar Transport ◽  
Long Distance ◽  
Regulatory Pathways ◽  
Sugar Transporters ◽  
E Coli ◽  
Long Distance Transport ◽  
N Metabolism ◽  
C And N ◽  
And Storage

In higher plants, sugars possess multiplefunctions: transport and storage of carbon and energy as well as signalmolecules. A variety of sugar transporters have been cloned that showdifferential expression between source and sink tissues. Expression of thesetransporters is highly regulated, according to the local metabolic status andthe demands of long distance transport. Very little knowledge is available onmechanisms underlying the regulation of sugar transporter expression inplants. Studies in E. coli, yeast and mammals haveunravelled complex regulatory pathways with crosstalk between sugar transportand metabolism. Recent studies in plants provide increasing evidence for theexistence of similar regulatory mechanisms. In many cases, connections havebeen found between C-and N-metabolism, implicating a tight network of signaltransduction and metabolism. Some aspects of this network are presented inthis review, emphasising sugar transport and sugar signaltransduction.

scholarly journals KCH kinesin drives nuclear transport and cytoskeletal coalescence for tip cell growth

2018 ◽  
Author(s):  
Moé Yamada ◽  
Gohta Goshima
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens ◽  
Focal Point ◽  
Nuclear Transport ◽  
Apical Cell ◽  
Cytoplasmic Dynein ◽  
Long Distance ◽  
Long Distance Transport ◽  
Genes Encoding ◽  
Distance Transport

Long-distance transport along microtubules (MTs) is critical for intracellular organisation. In animals, antagonistic motor proteins kinesin (plus end-directed) and dynein (minus end-directed) drive cargo transport. In land plants, however, the identity of motors responsible for transport is poorly understood, as genes encoding cytoplasmic dynein are missing. How other functions of dynein are brought about in plants also remains unknown. Here, we show that a subclass of the kinesin-14 family, KCH—which can also bind actin—drives MT minus end-directed nuclear transport in the moss Physcomitrella patens. When all four KCH genes were deleted, the nucleus was not maintained in the cell centre but was translocated to the apical end of protonemal cells. In the knockout (KO) line, apical cell tip growth was also severely suppressed. KCH was localised on MTs, including at the MT focal point near the tip where MT plus ends coalesced with actin filaments. MT focus was not persistent in KCH KO lines, whereas actin destabilisation also disrupted the focus despite KCH remaining on unfocused MTs. Functions of nuclear transport and tip growth were distinct, as a truncated KCH construct restored nuclear transport activity but not tip growth retardation of the KO line. Thus, our study identified KCH as a long-distance retrograde transporter as well as a cytoskeletal crosslinker, reminiscent of the versatile animal dynein.

scholarly journals Transport of organic anions in root cells and its role in cell signaling in higher plants

2021 ◽  
Vol 65 (3) ◽  
pp. 320-329
Author(s):  
V. V. Demidchik ◽  
P. V. Hryvusevich ◽  
M. A. Vaitsiakhovich ◽  
J. V. Talkachova ◽  
A. V. Kulinkovich ◽  
...  
Keyword(s):  
Higher Plants ◽  
Organic Anion ◽  
Plant Stress ◽  
Anion Channel ◽  
Organic Anions ◽  
Anion Channels ◽  
Patch Clamp Technique ◽  
Long Distance ◽  
Root Cells ◽  
Rapid Activation

The organic anion balance is critical for metabolic, bioenergetic, and electrochemical processes in plant cells, controlling the quality and quantity of yield and plant stress resistance. Nevertheless, the redistribution and membrane transport of these substances in plant tissues have not been investigated in detail. The mechanism of passive anion efflux from a plant cell through the ion channels has not been established so far. Here, using the patch-clamp technique, we have characterized the ion channel-mediated conductances of ascorbate, malate, gluconate, citrate, fumarate, and pronionate in the root cells of Arabidopsis thaliana, Triticum aestivum, and Helianthus annuus. These conductances showed high permeability to ascorbate, malate, and citrate, as well as low permeability to fumarate, propionate, and gluconate. Anion channel conductances of root cells showed rapid activation kinetics and low potential dependence. They were also inhibited by 9-anthracenecarboxylic acid, suggesting that they belong to the ALMT family of anion channels found only in higher plants. Aequorin chemilu minometry was used to test the effect of organic anions on the Ca2+ signaling in root cells. Among four organic anions tested, only ascorbate induced a significant increase in the cytosolic Ca2+ activity at physiological levels (1 and 10 mM). This effect may underlie the previously unknown functions of exogenous ascorbate related to short- and long-distance signaling in higher plants.

A study of phloem sieve element structure using electron, fluorescent, and confocal microscopy

1991 ◽  
Vol 49 ◽  
pp. 202-203
Author(s):  
Richard D. Sjolund ◽  
Chi Wang
Keyword(s):  
Cell Walls ◽  
Higher Plants ◽  
Post Injury ◽  
Long Distance ◽  
Callose Deposition ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Sieve Tubes ◽  
Distance Transport

Phloem sieve elements are the cells responsible for the long distance transport of nutrients, primarily sugars and amino acids, in higher plants. The translocation of nutrients in these cells, joined together to form long sieve tubes, is dependent on the development of high hydrostatic pressures (20 bars or higher). The dissection of plant tissues containing these phloem cells which is necessary for microscopic study usually results in the cutting of the sieve elements and a resultant loss of phloem contents due to the explosive release of the hydrostatic pressure. Wound-sealing mechanisms involving P-protein filaments and callose deposition in the cell walls rapidly seal off wound sites and prevent the loss of translocates, especially in Angiosperms. As a result, most electron microscope images of sieve elements obtained from plant organs reveal post-injury structure following wounding.

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