Anionic lipids are required for chloroplast structure and function in Arabidopsis

Bin Yu, Christoph Banning

Research output: Contribution to journalArticle

91 Scopus citations

Abstract

Photosynthetic membranes of plants primarily contain non-phosphorous glycolipids. The exception is phosphatidylglycerol (PG), which is an acidic/anionic phospholipid. A second major anionic lipid in chloroplasts is the sulfolipid sulfoquinovosyldiacylglycerol (SQDG). It is hypothesized that under severe phosphate limitation, SQDG substitutes for PG, ensuring a constant proportion of anionic lipids even under adverse conditions. A newly constructed SQDG and PG-deficient double mutant supports this hypothesis. This mutant, sqd2 pgp1-1, carries a T-DNA insertion in the structural gene for SQDG synthase (SQD2) and a point mutation in the structural gene for phosphatidylglycerolphosphate synthase (PGP1). In the sqd2 pgp1-1 double mutant, the fraction of total anionic lipids is reduced by approximately one-third, resulting in pale yellow cotyledons and leaves with reduced chlorophyll content. Photoautotrophic growth of the double mutant is severely compromised, and its photosynthetic capacity is impaired. In particular, photosynthetic electron transfer at the level of photosystem II (PSII) is affected. Besides these physiological changes, the mutant shows altered leaf structure, a reduced number of mesophyll cells, and ultrastructural changes of the chloroplasts. All observations on the sqd2 pgp1-1 mutant lead to the conclusion that the total content of anionic thylakoid lipids is limiting for chloroplast structure and function, and is critical for overall photoautotrophic growth and plant development.

Original languageEnglish (US)
Pages (from-to)762-770
Number of pages9
JournalPlant Journal
Volume36
Issue number6
DOIs
StatePublished - Dec 2003

Keywords

  • Lipid metabolism
  • Phosphate stress
  • Phosphatidylglycerol
  • Photosynthesis
  • Sulfoquinovosyldiacylglycerol
  • Thylakoid membranes

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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