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Zhou Y, Nguyen BT, Zhou C, Straka L, Lai YS, Xia S, Rittmann BE. The distribution of phosphorus and its transformations during batch growth of Synechocystis. WATER RESEARCH 2017; 122:355-362. [PMID: 28618360 DOI: 10.1016/j.watres.2017.06.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 05/19/2017] [Accepted: 06/06/2017] [Indexed: 06/07/2023]
Abstract
Phosphorus (P) is an essential nutrient that affects the growth and metabolism of microalgal biomass. Despite the obvious importance of P, the dynamics of how it is taken up and distributed in microalgae are largely undefined. In this study, we tracked the fate of P during batch growth of the cyanobacterium Synechocystis sp. PCC 6803. We determined the distribution of P in intracellular polymeric substances (IPS), extracellular polymeric substances (EPS), and soluble microbial products (SMP) for three initial ortho-phosphate concentrations. Results show that the initial P concentration had no impact on the production of biomass, SMP, and EPS. While the initial P concentration affected the rate and the timing of how P was transformed among internal and external forms of inorganic P (IP) and organic P (OP), the trends were the same no matter the starting P concentration. Initially, IP in the bulk solution was rapidly and simultaneously adsorbed by EPS (IPEPS) and taken up as internal IP (IPint). As the bulk-solution's IP was depleted, desorption of IPEPS became the predominant source for IP that was taken up by the growing cells and converted into OPint. At the end of the 9-d batch experiments, almost all P was OP, and most of the OP was intracellular. Based on all of the results, we propose a set of transformation pathways for P during the growth of Synechocystis. Key is that EPS and intracellular P pool play important and distinct roles in the uptake and storage of P.
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Affiliation(s)
- Yun Zhou
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States; State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Binh T Nguyen
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States
| | - Chen Zhou
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States
| | - Levi Straka
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States
| | - YenJung Sean Lai
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States
| | - Siqing Xia
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Bruce E Rittmann
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States.
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Bozzo GG, Singh VK, Plaxton WC. Phosphate or phosphite addition promotes the proteolytic turnover of phosphate-starvation inducible tomato purple acid phosphatase isozymes. FEBS Lett 2004; 573:51-4. [PMID: 15327974 DOI: 10.1016/j.febslet.2004.07.051] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2004] [Accepted: 07/08/2004] [Indexed: 10/26/2022]
Abstract
Within 48 h of the addition of 2.5 mM phosphate (HPO42-, Pi) or phosphite (H2PO3-, Phi) to 8-day-old Pi-starved (-Pi) tomato suspension cells: (i) secreted and intracellular purple acid phosphatase (PAP) activities decreased by about 12- and 6-fold, respectively and (ii) immunoreactive PAP polypeptides either disappeared (secreted PAPs) or were substantially reduced (intracellular PAP). The degradation of both secreted PAP isozymes was correlated with the de novo synthesis of two extracellular serine proteases having M(r)s of 137 and 121 kDa. In vitro proteolysis of purified secreted tomato PAP isozymes occurred following their 24 h incubation with culture filtrate from Pi-resupplied cells. The results indicate that Pi or Phi addition to -Pi tomato cells induces serine proteases that degrade Pi-starvation inducible extracellular proteins.
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Affiliation(s)
- Gale G Bozzo
- Department of Biology, Queens University, Kingston, Canada K7L 3N6
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3
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Façanha AR, Okorokova-Façanha AL. Inhibition of phosphate uptake in corn roots by aluminum-fluoride complexes. PLANT PHYSIOLOGY 2002; 129:1763-1772. [PMID: 12177489 PMCID: PMC166764 DOI: 10.1104/pp.001651] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2001] [Revised: 02/06/2002] [Accepted: 04/04/2002] [Indexed: 05/25/2023]
Abstract
F forms stable complexes with Al at conditions found in the soil. Fluoroaluminate complexes (AlF(x)) have been widely described as effective analogs of inorganic phosphate (Pi) in Pi-binding sites of several proteins. In this work, we explored the possibility that the phytotoxicity of AlF(x) reflects their activity as Pi analogs. For this purpose, (32)P-labeled phosphate uptake by excised roots and plasma membrane H(+)-ATPase activity were investigated in an Al-tolerant variety of maize (Zea mays L. var. dwarf hybrid), either treated or not with AlF(x). In vitro, AlF(x) competitively inhibited the rate of root phosphate uptake as well as the H(+)-ATPase activity. Conversely, pretreatment of seedlings with AlF(x) in vivo promoted no effect on the H(+)-ATPase activity, whereas a biphasic effect on Pi uptake by roots was observed. Although the initial rate of phosphate uptake by roots was inhibited by AlF(x) pretreatment, this situation changed over the following minutes as the rate of uptake increased and a pronounced stimulation in subsequent (32)Pi uptake was observed. This kinetic behavior suggests a reversible and competitive inhibition of the phosphate transporter by fluoroaluminates. The stimulation of root (32)Pi uptake induced by AlF(x) pretreatment was tentatively interpreted as a phosphate starvation response. This report places AlF(3) and AlF(4)(-) among Al-phytotoxic species and suggests a mechanism of action where the accumulation of Pi-mimicking fluoroaluminates in the soil may affect the phosphate absorption by plants. The biochemical, physiological, and environmental significance of these findings is discussed.
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Affiliation(s)
- Arnoldo Rocha Façanha
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes-RJ, CEP 28015-620, Brazil
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Façanha AR, Okorokova-Façanha AL. Inhibition of phosphate uptake in corn roots by aluminum-fluoride complexes. PLANT PHYSIOLOGY 2002; 129:1763-1772. [PMID: 12177489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
F forms stable complexes with Al at conditions found in the soil. Fluoroaluminate complexes (AlF(x)) have been widely described as effective analogs of inorganic phosphate (Pi) in Pi-binding sites of several proteins. In this work, we explored the possibility that the phytotoxicity of AlF(x) reflects their activity as Pi analogs. For this purpose, (32)P-labeled phosphate uptake by excised roots and plasma membrane H(+)-ATPase activity were investigated in an Al-tolerant variety of maize (Zea mays L. var. dwarf hybrid), either treated or not with AlF(x). In vitro, AlF(x) competitively inhibited the rate of root phosphate uptake as well as the H(+)-ATPase activity. Conversely, pretreatment of seedlings with AlF(x) in vivo promoted no effect on the H(+)-ATPase activity, whereas a biphasic effect on Pi uptake by roots was observed. Although the initial rate of phosphate uptake by roots was inhibited by AlF(x) pretreatment, this situation changed over the following minutes as the rate of uptake increased and a pronounced stimulation in subsequent (32)Pi uptake was observed. This kinetic behavior suggests a reversible and competitive inhibition of the phosphate transporter by fluoroaluminates. The stimulation of root (32)Pi uptake induced by AlF(x) pretreatment was tentatively interpreted as a phosphate starvation response. This report places AlF(3) and AlF(4)(-) among Al-phytotoxic species and suggests a mechanism of action where the accumulation of Pi-mimicking fluoroaluminates in the soil may affect the phosphate absorption by plants. The biochemical, physiological, and environmental significance of these findings is discussed.
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Affiliation(s)
- Arnoldo Rocha Façanha
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes-RJ, CEP 28015-620, Brazil
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5
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Tasaki Y, Azwan A, Hara T, Joh T. Effect of phosphate deficiency on growth and protein profile in three strains of Pholiota nameko. MYCOSCIENCE 2001. [DOI: 10.1007/bf02460947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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6
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Abstract
Phosphorus is one of the major plant nutrients that is least available in the soil. Consequently, plants have developed numerous morphological, physiological, biochemical, and molecular adaptations to acquire phosphate (Pi). Enhanced ability to acquire Pi and altered gene expression are the hallmarks of plant adaptation to Pi deficiency. The intricate mechanisms involved in maintaining Pi homeostasis reflect the complexity of Pi acquisition and translocation in plants. Recent discoveries of multiple Pi transporters have opened up opportunities to study the molecular basis of Pi acquisition by plants. An increasing number of genes are now known to be activated under Pi starvation. Some of these genes may be involved in Pi acquisition, transfer, and signal transduction during Pi stress. This review provides an overview of plant adaptations leading to enhanced Pi acquisition, with special emphasis on recent developments in the molecular biology of Pi acquisition.
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Affiliation(s)
- K. G. Raghothama
- Department of Horticulture, Purdue University, West Lafayette, Indiana 47907; e-mail:
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Muchhal US, Raghothama KG. Transcriptional regulation of plant phosphate transporters. Proc Natl Acad Sci U S A 1999; 96:5868-72. [PMID: 10318976 PMCID: PMC21952 DOI: 10.1073/pnas.96.10.5868] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphorus is acquired by plant roots primarily via the high-affinity inorganic phosphate (Pi) transporters. The transcripts for Pi transporters are highly inducible upon Pi starvation, which also results in enhanced Pi uptake when Pi is resupplied. Using antibodies specific to one of the tomato Pi transporters (encoded by LePT1), we show that an increase in the LePT1 transcript under Pi starvation leads to a concurrent increase in the transporter protein, suggesting a transcriptional regulation for Pi acquisition. LePT1 protein accumulates rapidly in tomato roots in response to Pi starvation. The level of transporter protein accumulation depends on the Pi concentration in the medium, and it is reversible upon resupply of Pi. LePT1 protein accumulates all along the roots under Pi starvation and is localized primarily in the plasma membranes. These results clearly demonstrate that plants increase their capacity for Pi uptake during Pi starvation by synthesis of additional transporter molecules.
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Affiliation(s)
- U S Muchhal
- Department of Horticulture and Landscape Architecture, Center for Plant Environmental Stress Physiology, Purdue University, West Lafayette, IN 47907, USA
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8
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Abstract
Previously we identified Mt4, a phosphate starvation inducible cDNA from Medicago truncatula which is down-regulated in roots in response to phosphate fertilization as well as colonization by arbuscular mycorrhizal (AM) fungi (AM). Here we present further studies of Mt4. Expression was highly sensitive to exogenous applications of phosphate fertilizer; transcripts were abundant in roots fertilized with nutrient solution lacking phosphate, reduced when fertilized with 0.02 or 0.1 mM phosphate and undetectable when fertilized with 1 or 5 mM phosphate. A time course experiment, to study the expression of Mt4 following colonization by AM fungi, revealed that Mt4 transcripts increased in uncolonized roots during the first three weeks of growth and then plateaued, while transcript levels in roots colonized with the AM fungus, Glomas versiforme, increased transiently and then decreased. Although the Mt4 gene is expressed exclusively in roots, transcripts were also detected in M. truncatula cell suspension cultures following phosphate starvation. A genomic clone containing the Mt4 gene and 1133 bp of the 5' flanking sequence was identified from a M. truncatula genomic library. The promoter region contains a conserved cis-element found in the promoters of phosphate starvation inducible genes of yeast and tomato. As Mt4 is the first cDNA reported to show independent regulation by both phosphate and mycorrhizal fungi, the genomic clone may provide a starting point from which to analyze the signal transduction pathways involved in these two processes.
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Affiliation(s)
- S M Burleigh
- The Samuel Roberts Noble Foundation, Plant Biology Division, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA
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Liu C, Muchhal US, Raghothama KG. Differential expression of TPS11, a phosphate starvation-induced gene in tomato. PLANT MOLECULAR BIOLOGY 1997; 33:867-74. [PMID: 9106510 DOI: 10.1023/a:1005729309569] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Plants respond to phosphate (Pi) deficiency through adaptive mechanisms involving several morphological, biochemical and molecular changes. In this study, we have characterized the structure and expression of a tomato (Lycopersicon esculentum L.) phosphate starvation-induced gene (TPSI1). A 3.5 kb genomic fragment containing the 474 bp TPSI1 transcript was isolated. The TPSI1 transcript contains an open reading frame of 174 nucleotides encoding a 58 amino acid polypeptide. TPSI1 is an intron-less gene and only one copy could be detected in the tomato genome. The promoter region of TPSI1 contains several conserved sequences found in phosphate starvation induced genes of yeast. The TPSI1 transcripts are rapidly induced in roots and leaves during Pi starvation. A significant increase in the TPSI1 mRNA was observed in cell cultures and roots after 3 and 12 h of Pi starvation, respectively. Induction of the TPSI1 gene appears to be a response specific to Pi starvation since it is not affected by starvation of other nutrients (nitrogen, potassium and iron). The amount of TPSI1 transcript decreased rapidly when Pi-starved tomato plants were resupplied with Pi. These results suggest that TPSI1 gene expression may be a part of the early Pi starvation response mechanism in plants.
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Affiliation(s)
- C Liu
- Department of Horticulture, Purdue University, West Lafayette, IN 47907-1165, USA
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Malboobi MA, Lefebvre DD. Isolation of cDNA clones of genes with altered expression levels in phosphate-starved Brassica nigra suspension cells. PLANT MOLECULAR BIOLOGY 1995; 28:859-870. [PMID: 7640358 DOI: 10.1007/bf00042071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Differential gene expression at the transcriptional level was examined as an initial step in the investigation of the P(i) starvation response of Brassica nigra suspension cells. Total RNA was extracted from 7-day old cells grown in media containing either no P(i), 1.25 mM or 10 mM Pi. In vitro translation was carried out using their respective poly(A)+ RNA isolates and the resultant polypeptides were separated on a high-resolution SDS-PAGE gel. Scanning densitometry identified four polypeptides (ca. 31.7, 32.3, 52.5 and 64.8 kDa) present only in the P(i)-starved samples. Screening by differential hybridization was performed on a cDNA library constructed from mRNA isolated from P(i)-starved cells. Probes prepared from mRNA from P(i)-deficient and P(i)-sufficient cells identified a number of clones representing mRNA species that were preferentially transcribed under P(i) deficiency. These phosphate starvation-responsive (psr) clones were placed into eleven groups as determined by cross-hybridization. Northern blots showed that the corresponding genes are inducible in both mild and severe P(i) starvation conditions. Preliminary sequencing identified one of the clones as being homologous to beta-glucosidases from several plant species. The possible role of beta-glucosidase during Pi starvation and the identities of the other psr genes are discussed.
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Affiliation(s)
- M A Malboobi
- Department of Biology, Queen's University, Kingston, ON, Canada
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11
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McArthur DAJ, Knowles NR. Influence of Vesicular-Arbuscular Mycorrhizal Fungi on the Response of Potato to Phosphorus Deficiency. PLANT PHYSIOLOGY 1993; 101:147-160. [PMID: 12231674 PMCID: PMC158659 DOI: 10.1104/pp.101.1.147] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Morphological and biochemical interactions between a vesicular-arbuscular mycorrhizal (VAM) fungus (Glomus fasciculatum [Thaxt. sensu Gerdemann] Gerdemann and Trappe) and potato (Solanum tuberosum L.) plants during the development of P deficiency were characterized. Nonmycorrhizal (NM) plants grown for 63 d with low abiotic P supply (0.5 mM) produced 34, 52, and 73% less root, shoot, and tuber dry matter, respectively, than plants grown with high P (2.5 mM). The total leaf area and the leaf area:plant dry weight ratio of low-P plants were substantially lower than those of high-P plants. Moreover, a lower shoot:root dry weight ratio and tuber:plant dry weight ratio in low-P plants than in high-P plants characterized a major effect of P deficiency stress on dry matter partitioning. In addition to a slower rate of growth, low-P plants accumulated nonreducing sugars and nitrate. Furthermore, root respiration and leaf nitrate reductase activity were lower in low-P plants than in high-P plants. Low abiotic P supply also induced physiological changes that contributed to the greater efficiency of P acquisition by low-P plants than by high-P plants. For example, allocation of dry matter and P to root growth was less restricted by P deficiency stress than to shoot and tuber growth. Also, the specific activities of root acid phosphatases and vanadate-sensitive microsomal ATPases were enhanced in P-deficient plants. The establishment of a VAM symbiosis by low-P plants was essential for efficient P acquisition, and a greater root infection level for P-stressed plants indicated increased compatibility to the VAM fungus. By 63 d after planting, low-P VAM plants had recovered 42% more of the available soil P than low-P NM plants. However, the VAM fungus only partially alleviated P deficiency stress and did not completely compensate for inadequate abiotic P supply. Although the specific activities of acid phosphatases and microsomal ATPases were only marginally influenced by VAM infection, VAM roots characteristically had a higher protein concentration and, consequently, enhanced microsomal ATPase and acid phosphatase activities on a fresh weight basis compared with NM roots. Morphological and ultrastructural details of VAM plants are discussed in relation to the influence of the VAM symbiosis on P nutrition of potato.
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Affiliation(s)
- DAJ. McArthur
- Department of Plant Science, 4-10 Agriculture/Forestry Center, University of Alberta, Edmonton, Alberta, Canada T6G 2P5
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Duff SM, Plaxton WC, Lefebvre DD. Phosphate-starvation response in plant cells: de novo synthesis and degradation of acid phosphatases. Proc Natl Acad Sci U S A 1991; 88:9538-42. [PMID: 11607228 PMCID: PMC52753 DOI: 10.1073/pnas.88.21.9538] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Induction of phosphatase activity is an important component of the plant cell response to phosphate deficiency. Suspension cell cultures of Brassica nigra contain two major inducible acid phosphatase (APase) isozymes; vacuolar phosphoenolpyruvate (PEP) APase and cell wall nonspecific APase. Polyclonal antibodies raised against purified PEP-APase crossreacted specifically with both isozymes. Furthermore, anti-(PEP-APase) IgG detected proteins from a wide range of higher plants, suggesting that the major plant APase isozymes have diverged from a common ancestral form. Quantification on immunoblots indicated that in B. nigra suspension cells experiencing transition from Pi sufficiency to deficiency or vice versa, the amount of total antigenic APase protein correlated closely with total enzyme activity. This was also shown in intact plant roots. Therefore, the activity was governed by the synthesis and degradation of APases. Increases in the amounts of both major APase isozymes occurred simultaneously following Pi deprivation of B. nigra suspension cells, suggesting the involvement of a common regulatory mechanism.
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Affiliation(s)
- S M Duff
- Department of Biology, Queen's University, Kingston, ON, Canada
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Hawkesford MJ, Belcher AR. Differential protein synthesis in response to sulphate and phosphate deprivation: Identification of possible components of plasma-membrane transport systems in cultured tomato roots. PLANTA 1991; 185:323-329. [PMID: 24186413 DOI: 10.1007/bf00201051] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/04/1991] [Indexed: 06/02/2023]
Abstract
Isolated roots of Lycopersicon esculentum Mill., cultured in axenic conditions were starved of sulphate or phosphate, and uptake capacities for the respective oxyanion-transport systems were observed for several days after sulphate or phosphate withdrawal. Sulphate-uptake capacity of the intact roots, measured in a 20-min period, increased from a control level of 100 nmol · g(-1) · h(-1) to 1100 nmol · g(-1) · h(-1) in 10 d, and phosphate-uptake capacity increased from 500 to 1400 nmol · g(-1) · h(-1) over 4 d. Newly synthesised polypeptides of these root cultures were pulse-labelled in vivo for 2 h, by adding [(3)H]leucine to the culture medium. The tissue was immediately homogenised and soluble and membrane fractions were prepared. A highly purified plasma-membrane fraction was separated from the crude microsomal membrane fraction using an aqueous two-phase partitioning technique. All fractions were analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and autoradiography. A 28-kilodalton (kDa) soluble polypeptide, and 36-, 43-, and 47-kDa plasma-membrane polypeptides were observed to have increased labelling after 4 d of sulphate deprivation. Longer periods resulted in additional polypeptides with increased [(3)H]leucine incorporation. The synthesis of a 25-kDa membrane polypeptide and a 65-kDa soluble polypeptide was increased after 4 d of phosphate deprivation. Two-dimensional electrophoresis afforded greater resolution of the plasmamembrane polypeptides, confirming increased synthesis of the 36-kDa polypeptide and the presence of the 28-kDa polypeptide in the plasma-membrane preparation from sulphate-starved roots. These polypeptides were also observed in protein-stained two-dimensional gels as low-abundant protein components of the plasmamembrane fraction. It is suggested that the 36-kDa polypeptide may be a component of the plasma-membrane sulphate-transport system and that the 25-kDa polypeptide may be a component of a phosphate-transport system.
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Affiliation(s)
- M J Hawkesford
- Department of Agricultural Sciences, University of Bristol, AFRC Institute of Arable Crops Research, Long Ashton Research Station, BS18 9AF, Long Ashton, Bristol, UK
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Goldstein AH. Plant cells selected for resistance to phosphate starvation show enhanced P use efficiency. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1991; 82:191-194. [PMID: 24213065 DOI: 10.1007/bf00226212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/1990] [Accepted: 01/08/1991] [Indexed: 06/02/2023]
Abstract
In many organisms, phosphate starvation induces multigene systems that act to increase the availability and uptake of exogenous phosphates. Tissue-cultured tomato cells were plated onto solid media containing starvation levels of phosphate. While most cells died, we identified isolated clumps of callus capable of near-normal rates of growth. Starvation-resistant cells were used to start suspension cultures that were kept under phosphate starvation conditions. A selected cell line showed constitutively enhanced secretion of acid phosphatase and greatly increased rates of phosphate uptake. These pleiotropic effects suggest modification of a regulatory apparatus that controls coordinated changes in the expression of a multigene system. The somaclonal variant cell line grew normally under phosphate-sufficient conditions, but did significantly better than unselected cells under phosphate-limited conditions. In vitro selection may be a useful system for developing phosphate ultraefficient crop plants.
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Affiliation(s)
- A H Goldstein
- Department of Biology, California State University at Los Angeles, 90032, Los Angeles, CA, USA
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15
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Martin FM, Hilbert JL. Morphological, biochemical and molecular changes during ectomycorrhiza development. ACTA ACUST UNITED AC 1991. [DOI: 10.1007/bf01972073] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Theodorou ME, Elrifi IR, Turpin DH, Plaxton WC. Effects of Phosphorus Limitation on Respiratory Metabolism in the Green Alga Selenastrum minutum. PLANT PHYSIOLOGY 1991; 95:1089-95. [PMID: 16668095 PMCID: PMC1077656 DOI: 10.1104/pp.95.4.1089] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The effects of phosphorus nutrition on several physiological and biochemical parameters of the green alga, Selenastrum minutum, have been examined. Algal cells were cultured in chemostats under conditions of either Pi limitation or nutrient sufficiency. Pi limitation resulted in: (a) a 5-fold lower rate of respiration, (b) a 3-fold decline in rates of photosynthetic carbon dioxide fixation and oxygen evolution, (c) a 3-fold higher rate of dark carbon dioxide fixation, (d) significant increases in activities of phosphoenolpyruvate (PEP) carboxylase and PEP phosphatase (128% and 158% of nutrient sufficient activities, respectively), (e) significant reductions in activities of nonphosphorylating NADP-glyceraldehyde-3-phosphate dehydrogenase and NAD malic enzyme, and (f) no change in levels of ATP:fructose-6-phosphate 1-phosphotransferase, phosphorylating NAD-glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase, and pyruvate kinase. The intracellular concentrations of Pi, ATP, AMP, soluble protein, and chlorophyll were also significantly reduced in response to Pi limitation. As well, the level of ADP was about 11-fold lower in the Pi-limited cells as compared to the nutrient sufficient controls. It was predicted that because of this low level of ADP, pyruvate kinase catalyzed conversion of PEP to pyruvate may be restricted in Pi-limited cells. During Pi limitation, PEP carboxylase and PEP phosphatase may function to "bypass" the ADP dependent pyruvate kinase, as well as to recycle Pi for its reassimilation into cellular metabolism.
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Affiliation(s)
- M E Theodorou
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6
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Intracellular Pi-Compartmentation during Phosphate Starvation-Triggered Induction of an Extracellular Ribonuclease in Tomato Cell Culture. ACTA ACUST UNITED AC 1990. [DOI: 10.1007/978-94-009-2103-0_51] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
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