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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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The vacuolar morphology in the vti11 mutant remained differentially controlled in tricho-/atrichoblast root epidermal cells.(A and B) Root epidermal tricho- and atrichoblast cells of Col-0 (A) or vti11 mutant (B) were decorated with MDY-64. (C) Vacuolar morphology (vac. morph. [µm2]) index of Col-0 and vti11 tricho- and atrichoblast cells. (D) Mean cell length of Col-0 and vti11 tricho- and atrichoblast cells. For statistical analysis vti11 tricho- and atrichoblast cells were compared to wild-type tricho- and atrichoblast cells. T refers to trichoblast and A to atrichoblast cell files. n = 40 quantified cells in eight seedlings for vacuolar morphology index measurements and n = 40 quantified cells in 10 seedlings for cell length quantification. 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.05868.016
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fig6s2: The vacuolar morphology in the vti11 mutant remained differentially controlled in tricho-/atrichoblast root epidermal cells.(A and B) Root epidermal tricho- and atrichoblast cells of Col-0 (A) or vti11 mutant (B) were decorated with MDY-64. (C) Vacuolar morphology (vac. morph. [µm2]) index of Col-0 and vti11 tricho- and atrichoblast cells. (D) Mean cell length of Col-0 and vti11 tricho- and atrichoblast cells. For statistical analysis vti11 tricho- and atrichoblast cells were compared to wild-type tricho- and atrichoblast cells. T refers to trichoblast and A to atrichoblast cell files. n = 40 quantified cells in eight seedlings for vacuolar morphology index measurements and n = 40 quantified cells in 10 seedlings for cell length quantification. 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.05868.016

Mentions: It has been suggested that several vacuolar SNARE components act redundantly (Yano et al., 2003; Uemura et al., 2010) and also in our conditions most analysed SNARE single mutants displayed vacuolar morphology reminiscent to wild type (Figure 6—figure supplement 1). In contrast, vti11 mutant alleles display roundish vacuoles in untreated conditions (Yano et al., 2003; Zheng et al., 2014) (Figure 6A,C). Despite these apparent defects, vacuoles remained differentially controlled in vti11 mutant tricho- and atrichoblast cells (Figure 6—figure supplement 2), indicating that the cell type-dependent regulation of vacuolar morphology is at least partially operational in vti11 mutants.10.7554/eLife.05868.014Figure 6.SNARE-dependent vacuolar morphogenesis is required for auxin regulated cell size determination.


Auxin regulates SNARE-dependent vacuolar morphology restricting cell size.

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

The vacuolar morphology in the vti11 mutant remained differentially controlled in tricho-/atrichoblast root epidermal cells.(A and B) Root epidermal tricho- and atrichoblast cells of Col-0 (A) or vti11 mutant (B) were decorated with MDY-64. (C) Vacuolar morphology (vac. morph. [µm2]) index of Col-0 and vti11 tricho- and atrichoblast cells. (D) Mean cell length of Col-0 and vti11 tricho- and atrichoblast cells. For statistical analysis vti11 tricho- and atrichoblast cells were compared to wild-type tricho- and atrichoblast cells. T refers to trichoblast and A to atrichoblast cell files. n = 40 quantified cells in eight seedlings for vacuolar morphology index measurements and n = 40 quantified cells in 10 seedlings for cell length quantification. 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.05868.016
© Copyright Policy
Related In: Results  -  Collection

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

fig6s2: The vacuolar morphology in the vti11 mutant remained differentially controlled in tricho-/atrichoblast root epidermal cells.(A and B) Root epidermal tricho- and atrichoblast cells of Col-0 (A) or vti11 mutant (B) were decorated with MDY-64. (C) Vacuolar morphology (vac. morph. [µm2]) index of Col-0 and vti11 tricho- and atrichoblast cells. (D) Mean cell length of Col-0 and vti11 tricho- and atrichoblast cells. For statistical analysis vti11 tricho- and atrichoblast cells were compared to wild-type tricho- and atrichoblast cells. T refers to trichoblast and A to atrichoblast cell files. n = 40 quantified cells in eight seedlings for vacuolar morphology index measurements and n = 40 quantified cells in 10 seedlings for cell length quantification. 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.05868.016
Mentions: It has been suggested that several vacuolar SNARE components act redundantly (Yano et al., 2003; Uemura et al., 2010) and also in our conditions most analysed SNARE single mutants displayed vacuolar morphology reminiscent to wild type (Figure 6—figure supplement 1). In contrast, vti11 mutant alleles display roundish vacuoles in untreated conditions (Yano et al., 2003; Zheng et al., 2014) (Figure 6A,C). Despite these apparent defects, vacuoles remained differentially controlled in vti11 mutant tricho- and atrichoblast cells (Figure 6—figure supplement 2), indicating that the cell type-dependent regulation of vacuolar morphology is at least partially operational in vti11 mutants.10.7554/eLife.05868.014Figure 6.SNARE-dependent vacuolar morphogenesis is required for auxin regulated cell size determination.

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