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Published online: 7 November 2007 | doi:10.1038/nchina.2007.235

Lipid degradation: Freezing and thawing

Wei Zeng

Introduction

© (2007) istockphoto.com/Gordana Sermek

Plants cope with freezing and thawing by altering the lipid composition of their cell membranes. Such cellular responses go through three phases — cold acclimation, freezing and post-freezing recovery. Lipid changes during the first two phases have been well studied, but those of the third phase are poorly understood. Weiqi Li, at the Chinese Academy of Sciences in Kunming, and co-workers found that lipids are differentially degraded and that two types of enzymatic phospholipase D (PLD) have important but opposite roles¹.

By profiling wild-type Arabidopsis thaliana and its mutated strains, the researchers showed that large changes in lipid profiles occur during freezing and post-freezing recovery. However, the alterations in the lipid species are different. During freezing, most lipid hydrolysis occurs in phospholipids outside the major cell organelles, known as plastids — in extraplastidic phospholipids. However, during post-freezing recovery, lipid hydrolysis occurs mainly in plastidic lipids; the degradation of extraplastidic lipids ceases but the degradation of plastidic lipids increases.

These results indicate that the activation of lipid-degrading enzymes occurs at specific sites in the cell during the different phases of freezing and thawing. The researchers further investigated the role of two PLDs — PLD1 and PLD. They found that PLD1 can help to hydrolyse plastidic lipids during freezing and post-freezing recovery, and that phospholipid hydrolysis during post-freezing recovery is also increased in PLD-deficient plants. These findings suggest a negative role for PLD1 and a positive role for PLD in freezing tolerance.

The authors of this work are from:
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China; Department of Biology, University of Missouri and Donald Danforth Plant Science Center, St Louis, Missouri, USA; Department of Biology, Honghe University, Yunnan, China; Kansas Lipidomics Research Center, Division of Biology, Kansas State University, Manhattan, Kansas, USA.

Reference

1. Li, W. et al. Differential degradation of extraplastidic and plastidic lipids during freezing and post-freezing recovery in Arabidopsis thaliana. J. Biol. Chem. doi: 10.1074/jbc.M706692200 (2007). | Article |