The occurrence of 'bulbs', a complex configuration of the vacuolar membrane, is affected by mutations of vacuolar SNARE and phospholipase in Arabidopsis

Chieko Saito, Tomohiro Uemura, Chie Awai, Motoki Tominaga, Kazuo Ebine, Jun Ito, Takashi Ueda, Hiroshi Abe, Miyo Terao Morita, Masao Tasaka, Akihiko Nakano

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24 Citations (Scopus)


The plant vacuole fulfills a variety of functions, and is essential for plant growth and development. We previously identified complex and mobile structures on the continuous vacuolar membrane, which we refer to as 'bulbs'. To ascertain their biological significance and function, we searched for markers associated with bulbs, and mutants that show abnormalities with respect to bulbs. We observed bulb-like structures after expression of non-membranous proteins as well as the functional soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) molecules VAM3 and VTI11. Bulbs are formed in more tissues than previously reported, including flowering organs, suspension culture cells, endodermal cells in the flowering stem, and at very early stages of seed germination. Using existing and newly developed marker lines, we found that the frequency of bulb occurrence is significantly decreased in multiple shoot gravitropism (sgr) mutants, which are known to have a defect in vacuolar membrane properties in endodermal cells. Based on results with new marker lines, which enabled us to observe the process of bulb biogenesis, and analysis of the phenotypes of these mutants, we propose multiple mechanisms for bulb formation, one of which may be that used for formation of transvacuolar strands.

Original languageEnglish
Pages (from-to)64-73
Number of pages10
JournalPlant Journal
Issue number1
Publication statusPublished - 2011 Oct 1



  • Arabidopsis
  • bulbs
  • phospholipase
  • sgr mutants
  • vacuolar membrane

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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