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Role of callose synthases in transfer cell wall development in tocopherol deficient Arabidopsis mutants.

Maeda H, Song W, Sage T, Dellapenna D - Front Plant Sci (2014)

Bottom Line: However, introduction of gsl4 or gsl11 mutations individually into the vte2 background did not suppress callose deposition or the overall LT-induced phenotypes of vte2.Intriguingly, introduction of a mutation disrupting GSL5, the major GSL responsible for pathogen-induced callose deposition, into vte2 substantially reduced vascular callose deposition at LT, but again had no effect on the photoassimilate export phenotype of LT-treated vte2.These results suggest that GSL5 plays a major role in TCW callose deposition in LT-treated vte2 but that this GSL5-dependent callose deposition is not the primary cause of the impaired photoassimilate export phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Michigan State University East Lansing, MI, USA ; Cell and Molecular Biology Program, Michigan State University East Lansing, MI, USA ; Department of Botany, University of Wisconsin-Madison Madison, WI, USA.

ABSTRACT
Tocopherols (vitamin E) are lipid-soluble antioxidants produced by all plants and algae, and many cyanobacteria, yet their functions in these photosynthetic organisms are still not fully understood. We have previously reported that the vitamin E deficient 2 (vte2) mutant of Arabidopsis thaliana is sensitive to low temperature (LT) due to impaired transfer cell wall (TCW) development and photoassimilate export associated with massive callose deposition in transfer cells of the phloem. To further understand the roles of tocopherols in LT induced TCW development we compared the global transcript profiles of vte2 and wild-type leaves during LT treatment. Tocopherol deficiency had no significant impact on global gene expression in permissive conditions, but significantly affected expression of 77 genes after 48 h of LT treatment. In vte2 relative to wild type, genes associated with solute transport were repressed, while those involved in various pathogen responses and cell wall modifications, including two members of callose synthase gene family, GLUCAN SYNTHASE LIKE 4 (GSL4) and GSL11, were induced. However, introduction of gsl4 or gsl11 mutations individually into the vte2 background did not suppress callose deposition or the overall LT-induced phenotypes of vte2. Intriguingly, introduction of a mutation disrupting GSL5, the major GSL responsible for pathogen-induced callose deposition, into vte2 substantially reduced vascular callose deposition at LT, but again had no effect on the photoassimilate export phenotype of LT-treated vte2. These results suggest that GSL5 plays a major role in TCW callose deposition in LT-treated vte2 but that this GSL5-dependent callose deposition is not the primary cause of the impaired photoassimilate export phenotype.

No MeSH data available.


Related in: MedlinePlus

Whole plant and vascular callose phenotypes of Col, vte2, gsl4, gsl4 vte2, gsl11, and gsl11 vte2. All genotypes were grown under permissive conditions for 4 weeks and then transferred to LT conditions for the specified periods previously shown to maximize each phenotype (Maeda et al., 2006). (A) Whole plant phenotype of the indicated genotypes before (top) and after (bottom) 28 days of LT treatment. Bar = 2 cm. (B) Aniline-blue positive fluorescence in the lower portions of leaves after 3 days of LT treatment. Samples for callose staining were fixed in the middle of the light cycle. Representative images are shown (n = 3). Bar = 1 mm.
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Figure 4: Whole plant and vascular callose phenotypes of Col, vte2, gsl4, gsl4 vte2, gsl11, and gsl11 vte2. All genotypes were grown under permissive conditions for 4 weeks and then transferred to LT conditions for the specified periods previously shown to maximize each phenotype (Maeda et al., 2006). (A) Whole plant phenotype of the indicated genotypes before (top) and after (bottom) 28 days of LT treatment. Bar = 2 cm. (B) Aniline-blue positive fluorescence in the lower portions of leaves after 3 days of LT treatment. Samples for callose staining were fixed in the middle of the light cycle. Representative images are shown (n = 3). Bar = 1 mm.

Mentions: Leaves were prepared for aniline blue fluorescence microscopy and staining and visualization were performed as described (Maeda et al., 2006) except that the gain adjustment of the camera was set to 2.0 for images in Figures 4B, 5A. Leaves were prepared for transmission electron microscopy and immunolocalization of β-1,3-glucan as described (Maeda et al., 2006).


Role of callose synthases in transfer cell wall development in tocopherol deficient Arabidopsis mutants.

Maeda H, Song W, Sage T, Dellapenna D - Front Plant Sci (2014)

Whole plant and vascular callose phenotypes of Col, vte2, gsl4, gsl4 vte2, gsl11, and gsl11 vte2. All genotypes were grown under permissive conditions for 4 weeks and then transferred to LT conditions for the specified periods previously shown to maximize each phenotype (Maeda et al., 2006). (A) Whole plant phenotype of the indicated genotypes before (top) and after (bottom) 28 days of LT treatment. Bar = 2 cm. (B) Aniline-blue positive fluorescence in the lower portions of leaves after 3 days of LT treatment. Samples for callose staining were fixed in the middle of the light cycle. Representative images are shown (n = 3). Bar = 1 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928550&req=5

Figure 4: Whole plant and vascular callose phenotypes of Col, vte2, gsl4, gsl4 vte2, gsl11, and gsl11 vte2. All genotypes were grown under permissive conditions for 4 weeks and then transferred to LT conditions for the specified periods previously shown to maximize each phenotype (Maeda et al., 2006). (A) Whole plant phenotype of the indicated genotypes before (top) and after (bottom) 28 days of LT treatment. Bar = 2 cm. (B) Aniline-blue positive fluorescence in the lower portions of leaves after 3 days of LT treatment. Samples for callose staining were fixed in the middle of the light cycle. Representative images are shown (n = 3). Bar = 1 mm.
Mentions: Leaves were prepared for aniline blue fluorescence microscopy and staining and visualization were performed as described (Maeda et al., 2006) except that the gain adjustment of the camera was set to 2.0 for images in Figures 4B, 5A. Leaves were prepared for transmission electron microscopy and immunolocalization of β-1,3-glucan as described (Maeda et al., 2006).

Bottom Line: However, introduction of gsl4 or gsl11 mutations individually into the vte2 background did not suppress callose deposition or the overall LT-induced phenotypes of vte2.Intriguingly, introduction of a mutation disrupting GSL5, the major GSL responsible for pathogen-induced callose deposition, into vte2 substantially reduced vascular callose deposition at LT, but again had no effect on the photoassimilate export phenotype of LT-treated vte2.These results suggest that GSL5 plays a major role in TCW callose deposition in LT-treated vte2 but that this GSL5-dependent callose deposition is not the primary cause of the impaired photoassimilate export phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Michigan State University East Lansing, MI, USA ; Cell and Molecular Biology Program, Michigan State University East Lansing, MI, USA ; Department of Botany, University of Wisconsin-Madison Madison, WI, USA.

ABSTRACT
Tocopherols (vitamin E) are lipid-soluble antioxidants produced by all plants and algae, and many cyanobacteria, yet their functions in these photosynthetic organisms are still not fully understood. We have previously reported that the vitamin E deficient 2 (vte2) mutant of Arabidopsis thaliana is sensitive to low temperature (LT) due to impaired transfer cell wall (TCW) development and photoassimilate export associated with massive callose deposition in transfer cells of the phloem. To further understand the roles of tocopherols in LT induced TCW development we compared the global transcript profiles of vte2 and wild-type leaves during LT treatment. Tocopherol deficiency had no significant impact on global gene expression in permissive conditions, but significantly affected expression of 77 genes after 48 h of LT treatment. In vte2 relative to wild type, genes associated with solute transport were repressed, while those involved in various pathogen responses and cell wall modifications, including two members of callose synthase gene family, GLUCAN SYNTHASE LIKE 4 (GSL4) and GSL11, were induced. However, introduction of gsl4 or gsl11 mutations individually into the vte2 background did not suppress callose deposition or the overall LT-induced phenotypes of vte2. Intriguingly, introduction of a mutation disrupting GSL5, the major GSL responsible for pathogen-induced callose deposition, into vte2 substantially reduced vascular callose deposition at LT, but again had no effect on the photoassimilate export phenotype of LT-treated vte2. These results suggest that GSL5 plays a major role in TCW callose deposition in LT-treated vte2 but that this GSL5-dependent callose deposition is not the primary cause of the impaired photoassimilate export phenotype.

No MeSH data available.


Related in: MedlinePlus