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Planta

, Volume 208, Issue 4, pp 588–598 | Cite as

Composition and role of tapetal lipid bodies in the biogenesis of the pollen coat of Brassica napus

  • Inmaculada Hernández-Pinzón
  • Joanne H. E. Ross
  • Karen A. Barnes
  • Andrew P. Damant
  • Denis J. Murphy
Article

Abstract.

The composition of the two major lipidic organelles of the tapetum of Brassica napus L. has been determined. Elaioplasts contained numerous small (0.2–0.6 μm) lipid bodies that were largely made up of sterol esters and triacylglycerols, with monogalactosyldiacylglycerol as the major polar lipid. This is the first report in any species of the presence of non-cytosolic, sterol ester-rich, lipid bodies. The elaioplast lipid bodies also contained 34- and 36-kDa proteins which were shown by N-terminal sequencing to be homologous to fibrillin and other plastid lipid-associated proteins. Tapetosomes contained mainly polyunsaturated triacylglycerols and associated phospholipids plus a diverse class of oleosin-like proteins. The pollen coat, which is derived from tapetosomes and elaioplasts, was largely made up of sterol esters and the C-terminal domains of the oleosin-like proteins, but contained virtually no galactolipids, triacylglycerols or plastid lipid-associated proteins. The sterol compositions of the elaioplast and pollen coat were almost identical, consisting of stigmasterol > campestdienol > campesterol > sitosterol ≫ cholesterol, which is consistent with the majority of the pollen coat lipids being derived from elaioplasts. These data demonstrate that there is substantial remodelling of both the lipid and protein components of elaioplasts and tapetosomes following their release into the anther locule from lysed tapetal cells, and that components of both organelles contribute to the formation of the lipidic coating of mature pollen grains.

Key words: Brassicaceae Elaioplast Lipid body Protein (oleosin-like) Tapetosome Tapetum 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Inmaculada Hernández-Pinzón
    • 1
  • Joanne H. E. Ross
    • 1
  • Karen A. Barnes
    • 2
  • Andrew P. Damant
    • 2
  • Denis J. Murphy
    • 1
  1. 1.Brassica and Oilseeds Research Department, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UKGB
  2. 2.Ministry of Agriculture, Fisheries and Food, CSL Food Science Laboratory, Norwich Research Park, NR4 7UQ, UKGB

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