Galactolipids biosynthesis

DORMANN, P., BALBO, I., BENNING, C., Arabidopsis galactolipid biosynthesis and lipid trafficking mediated by DGD1, Science, 1999, 284,2181-2184. 

Yu, H., Thompson, J. E., Yelle, S. and Willemot, C. (1996) Impairment of galactolipid biosynthesis in tomato pericarp at chilling temperature. J. Plant Physiol, in press. 

DAG species for galactolipid biosynthesis. Then, the question is what causes the loss of GPL content under phosphorus deficiency conditions. Further studies by lipidomics [65, 66] revealed that the loss of PLDi, but not PLDi l, led to a significantly decreased accumulation of PA content in roots under phosphorus deficiency conditions and compromised the ability of plants to hydrolyze GPLs and to increase galactolipid levels. Moreover, plants null of PLD l and PLD( 2 exhibited shorter primary roots than wild-type plants under the phosphoras deficiency conditions. These results indicate that PLD l and PLDt play an important role in regulating root development in response to nutrient limitation. 

GALACTOLIPID BIOSYNTHESIS IN CHLOROPLASTS OF UNHARDENED AND FROSTHARDENED SEEDLINGS OF SCOTS PINE... 

To investigate whether the MGDG to DGDG ratio is actively regulated, the galactolipid biosynthesis was investigated in unhardened and frosthardened Scots pine. 

Measurements of temperature dependent galactolipid biosynthesis showed that frosthardened chloroplasts were about 3 times more active than unhardened chloroplasts (Table 1). The higher activity was found at all temperatures and was thus not due to a change in temperature optimum of the enzymes. 

The higher activity in frosthardened chloroplasts could be due to an augmentation of envelope membranes or to increased specific activity of enzymes. The galactolipid biosynthesis of frosthardened chloroplasts at 7C was only slightly lower than that of unhardened chloroplasts at 20C. 

The frosthardened Scots pine seedlings thus have a capability for galactolipid biosynthesis at low temperature, important for maintenance of the chloroplast during winter. 

Contents W. K. SEIFERT, Carboxylic Acids in Petroleum and Sediments- P. G. SAMMES, Naturally Occurring 2,5-Dioxopiperazines and Related Compounds - R. J. HIGHET and E. A. SOKOLOSKl, Structural Investigations of Natural Products by Newer Methods of NMR Spectroscopy - P. M. SCOPES, Applications of the Chiroptical Techniques to the Study of Natural Products - H. C. VAN HUMMEL, Chemistry and Biosynthesis of Plant Galactolipids - H. KOSSEL and H. SELIGER, Recent Advances in Polynucleotide Synthesis - Author Index - Subject Index. 

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