Phospholipid Composition of a Plasma Membrane-Enriched Fraction from Developing Soybean Roots

Whitman, Carol E.; Travis, R. L.

doi:10.1104/pp.79.2.494

Cited by 47 publications

(22 citation statements)

References 27 publications

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“…In both the coleoptile and the root, PC and PE appeared in almost equal molar amounts and, aside from PA, were the most abundant phospholipids, while the other phospholipids (LPC, PI, PS, PG) were present in significantly reduced amounts. These results are typical of plant PM analyses (19,21,22,(33)(34)(35). Of interest here was the elevated amount of lysolecithin (LPC) in the oat root (1.7 mol %) when compared to the coleoptile (approximately 0.6 mol %).…”

Section: Resultsmentioning

confidence: 77%

Comparison of the Lipid Composition of Oat Root and Coleoptile Plasma Membranes

Sandstrom¹,

Cleland²

1989

Plant Physiol.

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The total lipid composition of plasma membranes (PM), isolated by the phase partitioning method from two different oat (Avena sativa L.) tissues, the root and coleoptfle, was compared. In general, the PM lipid composition was not conserved between these two organs of the oat seedling. Oat roots contained 50 mole percent phospholipid, 25 mole percent glycolipid, and 25 mole percent free sterol, whereas comparable amounts in the coleoptile were 42, 39, and 19 mole percent, respectively. Individual lipid components within each lipid class also showed large variations between the two tissues. Maximum specific ATPase activity in the root PM was more than double the activity in the coleoptile. Treatment of coleoptile with auxin for 1 hour resulted in no detectable changes in PM lipids or extractable ATPase activity. Differences in the PM lipid composition between the two tissues that may define the limits of ATPase activity are discussed.The plant PM2 is a critical component ofthe cell, separating the cytoplasm from the apoplasm. It contains proteins involved in the selective transfer of ions and molecules across this membrane. One important protein is the H+-ATPase, whose transport of protons to the apoplast is important both for the subsequent uptake of sugars and amino acids by proton-organic cotransport and as a component of growth regulation (28). The activity of this enzyme, as well as other PM proteins, is influenced by the composition of the lipid phase in which they are embedded. This influence is indicated both by experiments where proteins are reconstituted into synthetic bilayers of differing lipid composition (8,17,29) and by experiments where lipid components are partially removed by surfactants (24).

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Section: Resultsmentioning

confidence: 77%

Comparison of the Lipid Composition of Oat Root and Coleoptile Plasma Membranes

Sandstrom¹,

Cleland²

1989

Plant Physiol.

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“…There have been detailed reports concerning the composition of phospholipids and sterols in plant plasma membranes (8,10,28,29,31,33,36). However, no quantitative analysis has been made on other lipid components including ceramide lipids.…”

Section: Discussionmentioning

confidence: 99%

“…Based on these results, it may be considered that the plasma membrane of mung bean hypocotyls may normally contain such a high percentage of PA. According to Whitman and Travis (36), plasma membranes of meristematic and mature soybean roots contain respectively 2.0 and 8.9% of PA. On the other hand, the plasma membrane-enriched fraction prepared from maize roots has been reported to contain 1.6% of PA (8). Accordingly, the content of PA in plasma membranes may vary with plant species, type of tissue, and physiological state including development, aging, senescence, and probably responses to environmental stresses and diseases.…”

Section: Discussionmentioning

confidence: 99%

Lipid Composition of Plasma Membranes and Tonoplasts Isolated from Etiolated Seedlings of Mung Bean (Vigna radiata L.)

Yoshida¹,

Uemura²

1986

Plant Physiol.

193

102

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The lipid composition of plasma membranes and tonoplasts from etiolated mung bean hypocotyls was examined in detail. Phospholipids, sterols, and ceramide monohexoside(s) were the major lipid classes in both membranes. The content of phospholipids on a protein basis was higher in the tonoplast, but the content of total sterols was similar in both membranes. Accordingly, the sterol to phospholipid molar ratio in the plasma membrane was higher than that of the tonoplast. Phosphatidylethanolamine and phosphatidylcholine comprised the major phospholipids in both membranes. Phosphatidylinositol, phosphatidylserine, and phosphatidylglycerol were identified as minor phospholipid components. The content of phosphatidylinositol and phosphatidylglycerol was relatively high in the tonoplast, comprising 11 and 5% of the total phospholipids, respectively. Although special care was taken against the degradative action of phospholipase D and phosphatidic acid phosphatase during the isolation of these membranes, by adding EDTA, EGTA, KF, choline, and ethanolamine to the homogenizing medium, significant amounts of phosphatidic acid, about 15% of the total phospholipids, were detected in the plasma membrane. On the other hand, the content of phosphatidic acid in tonoplasts and other membrane fractions was very low. This fact may indicate that high levels of phosphatidic acid occur naturally in plasma membranes. Phosphatidylglycerol in both membranes and phosphatidylinositol in the tonoplast contained high levels of palmitic acid, which comprised more than 50% of the total fatty acids. Significant differences were observed in the sterol compositions of plasma membranes and tonoplasts. More than 90% of the sterols in the plasma membrane were unesterified, while the tonoplast was enriched in glycosylated sterols, especially acylated sterylglycosides. Ceramide monohexoside was found to be specifically located in these membranes, in particular, in the tonoplast, in which it comprised nearly 17% of the total lipids. is quite limited regarding the lipid composition of plasma membranes and tonoplasts, which also possess very important physiological functions including in the former, transport (22), cell wall biosynthesis (14), hormone action (24), phytochrome responses (18), and disease resistance (27), and in the latter, cellular compartmentation of lytic enzymes, acids, ions, and secondary products (I 1, 13). In addition, these membranes have been shown to play an important role in cold acclimation (29,31,33), freezing injury (26), and chilling stress (32).Recently we have established isolation methods for plasma membranes and tonoplasts from etiolated mung bean hypocotyls (34,35). In the present study, we have analyzed the lipid composition of both membranes and compared them. Plasma membranes are characterized by their high content of phosphatidic acid and tonoplasts by their high content of ceramide monohexoside. MATERIALS AND METHODSPlant Materials. Seeds of mung bean (Vigna radiata [L] Wilczek) were imbibed and germinate...

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“…The physical state and composition of the lipid bilayer, in which enzymic proteins are embedded, influence both structural and functional properties of membranes. Enzyme activity and transport capacity are affected by the composition and phase properties of the membrane lipids [120,135,136]. Wilson et al, (1987) [137] observed that water deficit caused a significant decline in the relative degree of acylunsaturation (i.e.…”

Section: Plant Lipids -Water Stress Interactionsmentioning

confidence: 99%