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Auxin regulates SNARE-dependent vacuolar morphology restricting cell size.

Löfke C, Dünser K, Scheuring D, Kleine-Vehn J - Elife (2015)

Bottom Line: Here, we reveal that the phytohormone auxin impacts on the shape of the biggest plant organelle, the vacuole.Genetic and pharmacological interference with the auxin effect on vacuolar SNAREs interrelates with auxin-resistant vacuolar morphogenesis and cell size regulation.Vacuolar SNARE VTI11 is strictly required for auxin-reliant vacuolar morphogenesis and loss of function renders cells largely insensitive to auxin-dependent growth inhibition.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.

ABSTRACT
The control of cellular growth is central to multicellular patterning. In plants, the encapsulating cell wall literally binds neighbouring cells to each other and limits cellular sliding/migration. In contrast to its developmental importance, growth regulation is poorly understood in plants. Here, we reveal that the phytohormone auxin impacts on the shape of the biggest plant organelle, the vacuole. TIR1/AFBs-dependent auxin signalling posttranslationally controls the protein abundance of vacuolar SNARE components. Genetic and pharmacological interference with the auxin effect on vacuolar SNAREs interrelates with auxin-resistant vacuolar morphogenesis and cell size regulation. Vacuolar SNARE VTI11 is strictly required for auxin-reliant vacuolar morphogenesis and loss of function renders cells largely insensitive to auxin-dependent growth inhibition. Our data suggests that the adaptation of SNARE-dependent vacuolar morphogenesis allows auxin to limit cellular expansion, contributing to root organ growth rates.

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Tricho-/atrichoblast cell length in wortmannin treated samples.(A and B) Root epidermal tricho-/atrichoblast cells of VAMP711-YFP expressing seedlings after DMSO (A) or WM (B) (10 µM; 20 hr) treatment. (C) Mean epidermal cell length in the root meristem of DMSO or WM (2 µM; 20 hr) treated seedlings. n = 40 quantified cells in eight seedlings. Error bars represent s.e.m. Student's t-test p-value: ***p < 0.001. Scale bar: 15 µm.DOI:http://dx.doi.org/10.7554/eLife.05868.020
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fig7s2: Tricho-/atrichoblast cell length in wortmannin treated samples.(A and B) Root epidermal tricho-/atrichoblast cells of VAMP711-YFP expressing seedlings after DMSO (A) or WM (B) (10 µM; 20 hr) treatment. (C) Mean epidermal cell length in the root meristem of DMSO or WM (2 µM; 20 hr) treated seedlings. n = 40 quantified cells in eight seedlings. Error bars represent s.e.m. Student's t-test p-value: ***p < 0.001. Scale bar: 15 µm.DOI:http://dx.doi.org/10.7554/eLife.05868.020

Mentions: Our data extends the current view of auxin biology, suggesting that auxin coordinates extracellular and intracellular components, such as cell wall acidification (Sauer and Kleine-Vehn, 2011; Spartz et al., 2014) and vacuolar morphogenesis, for driving and restricting cellular growth. In this light, the luminal increase of plant vacuoles alone may not be sufficient to induce larger cell sizes (Figure 6—figure supplement 2; Figure 7—figure supplement 2) due to cell wall limitations. In contrast, limiting cellular vacuolarisation appears sufficient to restrict cellular growth. Such a dual growth mechanism would allow plants to dynamically de- and accelerate cellular expansion, integrating multiple distinct, possibly conflictive internal and external triggers.


Auxin regulates SNARE-dependent vacuolar morphology restricting cell size.

Löfke C, Dünser K, Scheuring D, Kleine-Vehn J - Elife (2015)

Tricho-/atrichoblast cell length in wortmannin treated samples.(A and B) Root epidermal tricho-/atrichoblast cells of VAMP711-YFP expressing seedlings after DMSO (A) or WM (B) (10 µM; 20 hr) treatment. (C) Mean epidermal cell length in the root meristem of DMSO or WM (2 µM; 20 hr) treated seedlings. n = 40 quantified cells in eight seedlings. Error bars represent s.e.m. Student's t-test p-value: ***p < 0.001. Scale bar: 15 µm.DOI:http://dx.doi.org/10.7554/eLife.05868.020
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384535&req=5

fig7s2: Tricho-/atrichoblast cell length in wortmannin treated samples.(A and B) Root epidermal tricho-/atrichoblast cells of VAMP711-YFP expressing seedlings after DMSO (A) or WM (B) (10 µM; 20 hr) treatment. (C) Mean epidermal cell length in the root meristem of DMSO or WM (2 µM; 20 hr) treated seedlings. n = 40 quantified cells in eight seedlings. Error bars represent s.e.m. Student's t-test p-value: ***p < 0.001. Scale bar: 15 µm.DOI:http://dx.doi.org/10.7554/eLife.05868.020
Mentions: Our data extends the current view of auxin biology, suggesting that auxin coordinates extracellular and intracellular components, such as cell wall acidification (Sauer and Kleine-Vehn, 2011; Spartz et al., 2014) and vacuolar morphogenesis, for driving and restricting cellular growth. In this light, the luminal increase of plant vacuoles alone may not be sufficient to induce larger cell sizes (Figure 6—figure supplement 2; Figure 7—figure supplement 2) due to cell wall limitations. In contrast, limiting cellular vacuolarisation appears sufficient to restrict cellular growth. Such a dual growth mechanism would allow plants to dynamically de- and accelerate cellular expansion, integrating multiple distinct, possibly conflictive internal and external triggers.

Bottom Line: Here, we reveal that the phytohormone auxin impacts on the shape of the biggest plant organelle, the vacuole.Genetic and pharmacological interference with the auxin effect on vacuolar SNAREs interrelates with auxin-resistant vacuolar morphogenesis and cell size regulation.Vacuolar SNARE VTI11 is strictly required for auxin-reliant vacuolar morphogenesis and loss of function renders cells largely insensitive to auxin-dependent growth inhibition.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.

ABSTRACT
The control of cellular growth is central to multicellular patterning. In plants, the encapsulating cell wall literally binds neighbouring cells to each other and limits cellular sliding/migration. In contrast to its developmental importance, growth regulation is poorly understood in plants. Here, we reveal that the phytohormone auxin impacts on the shape of the biggest plant organelle, the vacuole. TIR1/AFBs-dependent auxin signalling posttranslationally controls the protein abundance of vacuolar SNARE components. Genetic and pharmacological interference with the auxin effect on vacuolar SNAREs interrelates with auxin-resistant vacuolar morphogenesis and cell size regulation. Vacuolar SNARE VTI11 is strictly required for auxin-reliant vacuolar morphogenesis and loss of function renders cells largely insensitive to auxin-dependent growth inhibition. Our data suggests that the adaptation of SNARE-dependent vacuolar morphogenesis allows auxin to limit cellular expansion, contributing to root organ growth rates.

Show MeSH