Transformation of the cryobehavior of rye protoplasts by modification of the plasma membrane lipid composition

Steponkus, Peter L.; Uemura, Matsuo; Balsamo, Ronald A.; Arvinte, Tudor; Lynch, Daniel V.

doi:10.1073/pnas.85.23.9026

Cited by 103 publications

(67 citation statements)

References 25 publications

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“…The production of LTPs with structural characteristics which accommodate di-unsaturated lipid molecules during frost acclimation in barley, is consistent with a role in membrane lipid modification during acclimation. This is reinforced by the known effect of low temperature on the levels of membrane lipid unsaturation (Harwood et al, 1994) and on membrane cryo-behaviour (Steponkus et al, 1988). Further, the molecular dynamics simulation aided modelling of membrane phospholipids into BLT4.9 suggests a conformation (external acyl group) which would facilitate protein membrane interactions and hence lipid exchange between different membranes.…”

Section: Functional Significancementioning

confidence: 97%

Homology modelling and molecular dynamics aided analysis of ligand complexes demonstrates functional properties of lipid‐transfer proteins encoded by the barley low‐temperature‐inducible gene family, blt4

Keresztessy

Hughes

1998

The Plant Journal

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SummaryThe homology modelling technique was used to predict the tertiary structures of three members of the lowtemperature-inducible barley vegetative shoot epidermal lipid-transfer protein (LTP) family, BLT4, on the basis of the X-ray crystallographically determined three-dimensional structure of a maize seedling LTP. Differences between the maize LTP and the BLT4 family include amino acid substitutions around the entrance and inside the predicted hydrophobic binding tunnels of these proteins. Because of the deletion of the loop region corresponding to Val60-Gly62 of the maize LTP from all three BLT4 LTPs, their internal hydrophobic tunnels are longer. Molecular dynamics modelling shows that BLT4.9 can accommodate hexadecanoic acid in its binding tunnel in similar conformation to the maize LTP. However, modelled cis,cis-9,12-octadecandienoic acid had a more favourable interaction with the BLT4.9 LTP than with the maize protein. Di-cis,cis-9,12-octadecandienoyl phosphatidylglycerol and di-cis,cis-9,12-octadecandienoyl phosphatidylcholine were modelled in the BLT4.9 structure with the fatty acyl group at position 1 embedded in the binding tunnel and the group at position 2 located on the solvent accessible surface of the protein. The results of the modelling suggest that the phospholipid headgroup can form hydrogen and salt bridges with polar and charged residues outside the binding tunnel and the exposed hydrocarbon chain interacts with hydrophobic amino acids on the surface. These results are consistent with the proposal that BLT4 LTPs have a lipid-transfer function associated with frost acclimation in barley.

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Section: Functional Significancementioning

confidence: 97%

Homology modelling and molecular dynamics aided analysis of ligand complexes demonstrates functional properties of lipid‐transfer proteins encoded by the barley low‐temperature‐inducible gene family, blt4

Keresztessy

Hughes

1998

The Plant Journal

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“…Increased membrane lipid unsaturation during low temperature exposure has been interpreted as a beneficial acclimation response. Recently, Steponkus et al (26) have moved beyond correlative findings and have definitively shown that increased lipid unsaturation can impart enhanced cryrobehavior to rye plasma membranes. Increased unsaturation of membrane lipids with low temperatures, or conversely decreased fatty acid unsaturation with high temperatures appears to be a mechanism by which biological membranes regulate membrane viscosity (24).…”

Section: Discussionmentioning

confidence: 99%

“…Many plant tissues including potato tubers have been shown to increase the degree of unsaturation of their membrane fatty acids in response to low temperatures (14,15,26,27,30). Increased membrane lipid unsaturation during low temperature exposure has been interpreted as a beneficial acclimation response.…”

Section: Discussionmentioning

confidence: 99%

Fatty Acids, Membrane Permeability, and Sugars of Stored Potato Tubers

Spychalla¹,

Desborough²

1990

Plant Physiol.

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The relationships of potato (Solanum tuberosum L.) tuber membrane permeability and membrane lipid composition to sugar accumulation were examined. Tubers from four potato cultivars were stored for 40 weeks at 30C and 90C. Rates of tuber membrane electrolyte leakage, total fatty acid composition, free fatty acid composition, and sugar content were measured throughout the storage period. Storage of tubers at 30C caused dramatic increases in total fatty acid unsaturation, membrane permeability, and sugar content compared to tubers stored at 90C. Cultivars with higher levels of fatty acid unsaturation had lower rates of membrane electrolyte leakage and lower sugar contents. We propose that high initial levels or high induced levels of membrane lipid unsaturation mitigate increases in tuber membrane permeability during storage, thus positively influencing the processing quality of stored potato tubers.Sucrose, glucose, and fructose are the major sugars which accumulate in potato (Solanum tuberosum L.) tubers. High levels of reducing sugars (glucose and fructose) lower the suitability of tubers for processing. Reducing sugars react with free amino groups during frying leading to the formation of a brown pigment, which can make chips and french fries (crisps and chips in the United Kingdom) unacceptable for consumers. Excess sugars in stored tubers commonly arise from two situations. Storage of tubers longer than 7 months can lead to 'senescent sweetening,' and storage below approximately 7°C can lead to 'cold-induced sweetening' (1). However, low temperature storage of potato tubers can also have the beneficial results of lowered respiration rates, slowed physiological aging, inhibition of sprouting, reduced evaporative water loss, and minimized microbial pathogenesis (1).Sugars accumulate in tubers when there is an imbalance between starch degradation, starch synthesis, and respiration of carbohydrate. One potential source of metabolic imbalance ' From a disseration submitted to the graduate school of the

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“…Subsequent 'membrane engineering' studies to establish the specific lipid alterations responsible for the differential cryobehavior of the plasma membrane have involved a protoplast x liposome fusion technique (1) to selectively modify the lipid composition of the plasma membrane. Enrichment of the plasma membrane with either mono-or diunsaturated species of phosphatidylcholine transforms the cryobehavior of the plasma membrane such that exocytotic extrusions (rather than endocytotic vesicles) are formed during osmotic contraction, and EIL does not occur during osmotic excursions (13).…”

mentioning

confidence: 99%

“…The objectives of this study were to quantify the progressive increase in freezing tolerance of rye protoplasts and the incidence of the two forms of injury (EIL and LOR) during the cold acclimation process so as to determine when the incidence of EIL first reached a minimum. Further, we wished to determine if artificial enrichment of the plasma membrane with DL2PC, which precludes EIL in NA protoplasts (13) (Fisher Co.) and washed in the appropriate isotonic sorbitol solution. The leaves were cut into small pieces (0.5 to 1 mm in length) and incubated in an isolation medium consisting of 1.3% (w/v) cellulysin (Calbiochem), 0.4% (w/v) macerase (Calbiochem), 0.6% (w/v) potassium dextran sulfate and 10 mm Mes/KOH (pH 5.6) in an isotonic sorbitol solution.…”

mentioning

confidence: 99%

Effect of Cold Acclimation on the Incidence of Two Forms of Freezing Injury in Protoplasts Isolated from Rye Leaves

Uemura

Steponkus²

1989

Plant Physiol.

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The freezing tolerance and incidence of two forms of freezing injury (expansion-induced lysis and loss of osmotic responsiveness) were determined for protoplasts isolated from rye leaves (Secale cereale L. cv Puma) at various times during cold acclimation. During the first 4 weeks of the cold acclimation period, the LT50 (i.e. the minimum temperature at which 50% of the protoplasts survived) decreased from -50C to -250C. In protoplasts isolated from nonacclimated leaves (NA protoplasts), expansion-induced lysis (EIL) was the predominant form of injury at the LT50. However, after only I week of cold acclimation, the incidence of EIL was reduced to less than 10% at any subzero temperature; and loss of osmotic responsiveness was the predominant form of injury, regardless of the freezing temperature. Fusion of either NA protoplasts or protoplasts isolated from leaves of seedlings cold acclimated for 1 week (1-week ACC protoplasts) with liposomes of dilinoleoylphosphatidylcholine also decreased the incidence of EIL to less than 10%. Fusion of protoplasts with dilinoleoylphosphatidylcholine diminished the incidence of loss of osmotic responsiveness, but only in NA protoplasts or 1-week ACC protoplasts that were frozen to temperatures over the range of -5 to -100C. These results suggest that the cold acclimation process, which results in a quantitative increase in freezing resistance, involves several different qualitative changes in the cryobehavior of the plasma membrane.Cold acclimation of rye seedlings is induced by exposure to temperatures of 2 to 5°C, with the maximum freezing tolerance achieved in 4 to 6 weeks. For example, the freezing tolerance ofthe crowns of Secale cereale L. cv Puma increases from approximately -5°C to -25°C after 4 weeks of cold acclimation (14). This difference in freezing tolerance is also observed in protoplasts isolated from both epicotyls (4) and leaves (5) of nonacclimated and fully acclimated seedlings. In the case of isolated mesophyll protoplasts, destabilization of the plasma membrane is a primary cause of freezing injury and is a consequence of freeze-induced osmotic stresses and dehydration (10, 11). However, the mechanism of injury in protoplasts isolated from leaves of nonacclimated seedlings ' This study is, in part, supported by grants from the U.S. Department of Energy (DE-FG03-84ER13214) In NA protoplasts, freeze-induced dehydration results in two different forms ofinjury-the incidence ofwhich depends on the extent of dehydration (which is determined by the minimum temperature to which the protoplast suspension is frozen) (11). When frozen to temperatures over the range of 0 to -5°C, injury is a consequence of osmotic excursions incurred during the freeze/thaw cycle. Freeze-induced osmotic contraction results in endocytotic vesiculation of the plasma membrane and the surface area of the plasma membrane is reduced (5, 7). Sufficiently large area reductions are irreversible and the protoplasts lyse during osmotic expansion following thawing of the suspending medi...

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Transformation of the cryobehavior of rye protoplasts by modification of the plasma membrane lipid composition

Cited by 103 publications

References 25 publications

Homology modelling and molecular dynamics aided analysis of ligand complexes demonstrates functional properties of lipid‐transfer proteins encoded by the barley low‐temperature‐inducible gene family, blt4

Homology modelling and molecular dynamics aided analysis of ligand complexes demonstrates functional properties of lipid‐transfer proteins encoded by the barley low‐temperature‐inducible gene family, blt4

Fatty Acids, Membrane Permeability, and Sugars of Stored Potato Tubers

Effect of Cold Acclimation on the Incidence of Two Forms of Freezing Injury in Protoplasts Isolated from Rye Leaves

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