close
Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Oct;50(10):1826-39.
doi: 10.1093/pcp/pcp124. Epub 2009 Sep 16.

New dynamics in an old friend: dynamic tubular vacuoles radiate through the cortical cytoplasm of red onion epidermal cells

Affiliations

New dynamics in an old friend: dynamic tubular vacuoles radiate through the cortical cytoplasm of red onion epidermal cells

Elizabeth J Wiltshire et al. Plant Cell Physiol. 2009 Oct.

Abstract

The textbook image of the plant vacuole sitting passively in the centre of the cell is not always correct. We observed vacuole dynamics in the epidermal cells of red onion (Allium cepa) bulbs, using confocal microscopy to detect autofluorescence from the pigment anthocyanin. The central vacuole was penetrated by highly mobile transvacuolar strands of cytoplasm, which were also visible in concurrent transmitted light images. Tubular vacuoles also extended from the large central vacuole and radiated through the cortical cytoplasm. These tubules were thin, having a diameter of about 1.5 microm, and were connected to the central vacuole as shown by fluorescence recovery after photobleaching (FRAP) experiments. The tubules were bounded by the tonoplast, as revealed by transient expression of green fluorescent protein (GFP) targeted to the vacuolar membrane and through labeling with the dye MDY-64. Expression of endoplasmic reticulum-targeted GFP demonstrated that the vacuolar tubules were distinct from the cortical endoplasmic reticulum. Movement of the tubular vacuoles depended on actin microfilaments, as microfilament disruption blocked tubule movement and caused their collapse into minivacuoles. The close association of the tubules with GFP-tagged actin microfilaments suggests that the tubules are associated with myosin, and that tubules likely move along microfilaments. Tubular vacuoles do not require anthocyanin for their formation, as tubules were also present in white onion cells that lack anthocyanin. The function of these tubular vacuoles remains unknown, but as they greatly increase the surface area of the tonoplast, they might increase transport rates between the cytoplasm and vacuole.

PubMed Disclaimer

Publication types

LinkOut - more resources