Molecular Cloning and Regulation of a Mineral Phosphate Solubilizing Gene from Erwinia Herbicola

Goldstein, Alan H.; Liu, S. T.

doi:10.1038/nbt0187-72

Cited by 121 publications

(95 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is probable that further study of psi metabolism will add to our understanding of the regulation of plant gene expression. In addition, organic and mineral phosphate solubilizing genes (7,8) could play a role in the development of biological P fertilizers.…”

Section: Discussionmentioning

confidence: 99%

Phosphate Starvation Inducible Metabolism in Lycopersicon esculentum

Goldstein¹,

Danon²,

Baertlein³

et al. 1988

Plant Physiol.

View full text Add to dashboard Cite

Three-day-old suspension cultured cells of Lycopersicon esculentum transferred to a Pi-depleted medium had 2.7 times the excreted acid phosphatase (Apase) activity of cells transferred to a Pi-sufficient medium. Cell growth during this time period was identical for the two treatments. Excreted Apase activity was resolved into two fractions on a Sephadex G-150 column. Most of the phosphate starvation inducible (psi) enhancement in activity was in the lower molecular weight fraction. These two fractions exhibited different substrate versus pH activity profiles. With a native polyacrylamide gel electrophoresis assay, the lower molecular weight fraction resolved into two bands of activity. Both column fractions resolved into the same single band of activity with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The apparent molecular weight of this enzyme was 57 kilodalton. These data indicate that L. esculentum has at least two isozymes of the psi-excreted Apase and that these isozymes may associate to form high molecular weight aggregates. Labeling studies using [3SJmethionine show that the psi response in tomato cells is complex and involves changes in the steady state levels of several excreted proteins.Data from a number ofdifferent experimental systems indicate that plants have evolved starvation rescue systems composed of psi2 gene systems which effectively act to increase the concentration of exogenous Pi (9,21,24 Enzyme activity was mainly extracellular with the heaviest concentration in corner spaces between the epidermal and hypodermal layers. Based on the apparent intraspatial organization of regions of high activity, this worker proposed a specific secretory apparatus and further suggested the possibility of a subcutaneous pore through which the enzyme could be released to the root surface. Bieleski and Johnson (1) studied the psi induction and location ofApase in duckweed (S. oligorrhiza). They showed that Apase in control plants was located primarily in and around the vascular strands. In Pi-deficient plants, psi Apase activity was 10 to 20 times control with enzyme activity primarily located in the epidermis of the root and undersurface of the frond, the tissue locations most likely to be in contact with the external environment. They placed plants in solutions containing phosphatase substrates. Control plants hydrolyzed the substrates at 4 to 8% of the rates of tissue homogenates whereas Pi-deficient plants hydrolyzed substrate at 30 to 40% ofthe homogenate rate. When 32P-labeled glucose-l-phosphate was supplied to intact plants, more 32Pi appeared in the medium than in the tissue. The pattern of appearance was consistent with hydrolysis of substrate in the external apoplast followed by uptake into the cell.A number of other workers have found plant Apase activity either in the cell wall space or secreted by roots into the external medium. Oparka and Johnson (17) found Apase in the intercellular spaces of Nymphoides pelata. Hirata et al. (12) observed psi stimulation of excretion ...

show abstract

Section: Discussionmentioning

confidence: 99%

Phosphate Starvation Inducible Metabolism in Lycopersicon esculentum

Goldstein¹,

Danon²,

Baertlein³

et al. 1988

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…This type of stability would be expected for an enzyme that functions in the rhizosphere. Studies of this system will enhance our understanding of gene regulation in plants and may play a role in the development of biorational approaches to P fertilization in agriculture (4,5).…”

Section: Discussionmentioning

confidence: 99%

Phosphate Starvation Inducible Metabolism in Lycopersicon esculentum

Goldstein¹,

Baertlein²,

McDaniel³

1988

Plant Physiol.

160

View full text Add to dashboard Cite

Both tomato (Lycopersicon esculentum cv VF 36) plants and suspension cultured cells show phosphate starvation inducible (psi) excretion of acid phosphatase (Apase). Apase excretion in vitro was proportional to the level of exogenous orthophosphate (Pi). Intracellular Apase activity remained the same in both Pi-starved and sufficient cells, while Apase excreted by the starved cells increased by as much as six times over unstressed control cells on a dry weight basis. At peak induction, 50% of total Apase was excreted. Ten day old tomato seedlings grown without Pi showed slight growth reduction versus unstressed control plants. The Pi-depleted roots showed psi enhancement of Apase activity. Severely starved seedlings (17 days) reached only one-third of the biomass of unstressed control plants but, because of a combination of psi Apase excretion by roots and a shift in biomass to this organ, they excreted 5.5 times the Apase activity of the unstressed control. Observed psi Apase excretion may be part of a phosphate starvation rescue system in plants. The utility of the visible indicator dye 5-bromo4-chloro-3-indolyl-phosphate-p-toluidine as a phenotypic marker for plant Apase excretion is demonstrated.Phosphorus is an essential nutrient for all cells. For organisms that absorb their mineral nutrients directly from the external medium, the orthophosphate anion (Pi, H2PO4-or HP04-2) is the preferentially absorbed form of P. A macronutrient based on its contribution to biomass, Pi2 is one of the least available mineral nutrients in many environments. The level of Pi in the solution phase of soils (1.0 ,lM or less) is often below those of many micronutrients (3, 10). In contrast to low levels of soluble Pi, ecosystems often contain large amounts of both organic and insoluble mineral Pi (6). This ecological paradox has resulted in the evolution of a number of gene systems that function to enhance the availability of P. These coordinately expressed psi operons, collectively called a psi regulon, have been studied extensively in both bacteria and yeast (12,16,17 operons called the pho regulon. The pho regulon includes a minimum of 20 to 24 genes that share a common positive regulatory element encoded by the gene phoB. The PhoB protein (mol wt 29 kD), which is itself psi, binds specifically to DNA sequences containing the promoter regions of several genes in the pho regulon. It activates in vitro transcription of these genes (12). Many of the psi genes function to enhance Pi availability in, and uptake from, the external medium. For example, phosphate starvation induces phoA, the gene that codes for alkaline phosphatase. This hydrolytic enzyme is excreted into the periplasmic space where it acts to cleave extracellular organic P to Pi. A second psi gene system, the phosphate specific transport (Pst) operon uses energy to transport Pi across the E. coli membrane. The Pi transport efficiency of this system is much greater than that of the constitutive Pi shuttle (12). Under Pi starvation, the strategy is to solubiliz...

show abstract

“…However, it was also shown that the P-solubilizing activity of microorganisms is affected by the presence of soluble phosphates in medium. Goldstein and Liu (1987) have shown that mineral phosphate solubilizing activity is genetically coded in a gene cluster on plasmids of microorganisms possessing this activity. They also transferred this gene cluster to Escherichia coli strain that had not shown P-solubilizing activity before and could demonstrate the transferred gene expression in the transgenic E. coli strain.…”

mentioning

confidence: 99%

Evaluation of the P-solubilizing activity of soil microorganisms and its sensitivity to soluble phosphate

Mikanová¹,

Nováková²

2002

PLANT SOIL ENVIRON

View full text Add to dashboard Cite

Microbial solubilization of hardly soluble mineral phosphates in soil is an important process in natural ecosystems and in agricultural soils. Regulation of the P-solubilizing activity by the presence of soluble phosphates in medium was determined. For this reason we decided to test a number of soil bacteria showing a high P-solubilizing activity for its sensitivity to the presence of soluble dihydrogen potassium phosphate in medium. At these studies, the direct determination of the solubilized phosphate in medium was masked by the presence of relatively high concentrations of soluble phosphate added. Therefore, we have modified the method, determining the residual tricalcium phosphate. The effect of soluble phosphate in medium on the P-solubilizing activity of rhizosphere isolates and strains of Rhizobium were tested in liquid cultures with the addition of various concentrations of soluble KH 2 PO 4. The medium was filtered after incubation and the remaining tricalcium phosphate was separated by filtration. Filter papers with the remaining tricalcium phosphate were hydrolysed with 2N H 2 SO 4 . Phosphorus was determined spectrophotometrically. The P-solubilizing activity was expressed as a difference between the tricalcium phosphate added and its remainder after the incubation. These results fully confirmed that there exist the strains, whose P-solubilizing activity is inhibited and other strains, whose P-solubilizing activity is not inhibited or is inhibited very little in the presence of soluble phosphate. The use of our adapted method was much more suitable for this type of experiments.

show abstract

Molecular Cloning and Regulation of a Mineral Phosphate Solubilizing Gene from Erwinia Herbicola

Cited by 121 publications

References 15 publications

Phosphate Starvation Inducible Metabolism in Lycopersicon esculentum

Phosphate Starvation Inducible Metabolism in Lycopersicon esculentum

Phosphate Starvation Inducible Metabolism in Lycopersicon esculentum

Evaluation of the P-solubilizing activity of soil microorganisms and its sensitivity to soluble phosphate

Contact Info

Product

Resources

About