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Regulatory specialization of xyloglucan (XG) and glucuronoarabinoxylan (GAX) in pericarp cell walls during fruit ripening in tomato (Solanum lycopersicum).

Takizawa A, Hyodo H, Wada K, Ishii T, Satoh S, Iwai H - PLoS ONE (2014)

Bottom Line: GAX was detected only in the skin and inner epidermis of the pericarp using LM11 antibodies, whereas a large increase in XG was detected in all fruit tissues using LM15 antibodies.The activity of hemicellulose degradation enzymes, such as β-xylosidase and α-arabinofuranosidase, decreased gradually during fruit ripening, although the tomato fruits continued to soften.In contrast, GAX and XG biosynthesis-related genes were expressed in all tomato fruit tissues even during ripening, indicating that XG was synthesized throughout the fruit and that GAX may be synthesized only in the vascular bundles and the inner epidermis.

View Article: PubMed Central - PubMed

Affiliation: University of Tsukuba, Faculty of Life and Environmental Sciences, Tsukuba, Ibaraki, Japan.

ABSTRACT
Disassembly of cell wall polysaccharides by various cell wall hydrolases during fruit softening causes structural changes in hemicellulose and pectin that affect the physical properties and softening of tomato fruit. In a previous study, we showed that the changes in pectin during tomato fruit ripening were unique in each fruit tissue. In this study, to clarify the changes in hemicellulose in tissues during tomato fruit ripening, we focused on glucuronoarabinoxylan (GAX) and xyloglucan (XG). GAX was detected only in the skin and inner epidermis of the pericarp using LM11 antibodies, whereas a large increase in XG was detected in all fruit tissues using LM15 antibodies. The activity of hemicellulose degradation enzymes, such as β-xylosidase and α-arabinofuranosidase, decreased gradually during fruit ripening, although the tomato fruits continued to soften. In contrast, GAX and XG biosynthesis-related genes were expressed in all tomato fruit tissues even during ripening, indicating that XG was synthesized throughout the fruit and that GAX may be synthesized only in the vascular bundles and the inner epidermis. Our results suggest that changes in the cell wall architecture and tissue-specific distribution of XG and GAX might be required for the regulation of fruit softening and the maintenance of fruit shape.

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Related in: MedlinePlus

Preparation for tissue-specific analysis.A, The fruit ripening stages of cv. Micro Tom. The six stages included immature green (I), mature green (M), breaker (B), turning (T), red ripe (R), and overripe (O). B, The fruit tissues of cv. Micro Tom. The eight tissues included skin, mesocarp, endocarp, septum, locular tissue, seed, placenta. and core. These were separated by hand-sectioning.
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pone-0089871-g001: Preparation for tissue-specific analysis.A, The fruit ripening stages of cv. Micro Tom. The six stages included immature green (I), mature green (M), breaker (B), turning (T), red ripe (R), and overripe (O). B, The fruit tissues of cv. Micro Tom. The eight tissues included skin, mesocarp, endocarp, septum, locular tissue, seed, placenta. and core. These were separated by hand-sectioning.

Mentions: Tomatoes (Solanum lycopersicum cv. ‘Micro Tom’) were grown inside a cultivation chamber (TOMY CL-301) under 16-h light and 8-h dark at 26°C and 22°C, respectively, and a light intensity of approximately 100 µmol m−2 s−1. Tomato fruits at the corresponding developmental stages were also collected: I [<1 cm length; 15 days after pollination (dap)], M (30 dap), B (35 dap), T (37 dap), R (45 dap), and OR (55 dap); Fig. 1).


Regulatory specialization of xyloglucan (XG) and glucuronoarabinoxylan (GAX) in pericarp cell walls during fruit ripening in tomato (Solanum lycopersicum).

Takizawa A, Hyodo H, Wada K, Ishii T, Satoh S, Iwai H - PLoS ONE (2014)

Preparation for tissue-specific analysis.A, The fruit ripening stages of cv. Micro Tom. The six stages included immature green (I), mature green (M), breaker (B), turning (T), red ripe (R), and overripe (O). B, The fruit tissues of cv. Micro Tom. The eight tissues included skin, mesocarp, endocarp, septum, locular tissue, seed, placenta. and core. These were separated by hand-sectioning.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3935947&req=5

pone-0089871-g001: Preparation for tissue-specific analysis.A, The fruit ripening stages of cv. Micro Tom. The six stages included immature green (I), mature green (M), breaker (B), turning (T), red ripe (R), and overripe (O). B, The fruit tissues of cv. Micro Tom. The eight tissues included skin, mesocarp, endocarp, septum, locular tissue, seed, placenta. and core. These were separated by hand-sectioning.
Mentions: Tomatoes (Solanum lycopersicum cv. ‘Micro Tom’) were grown inside a cultivation chamber (TOMY CL-301) under 16-h light and 8-h dark at 26°C and 22°C, respectively, and a light intensity of approximately 100 µmol m−2 s−1. Tomato fruits at the corresponding developmental stages were also collected: I [<1 cm length; 15 days after pollination (dap)], M (30 dap), B (35 dap), T (37 dap), R (45 dap), and OR (55 dap); Fig. 1).

Bottom Line: GAX was detected only in the skin and inner epidermis of the pericarp using LM11 antibodies, whereas a large increase in XG was detected in all fruit tissues using LM15 antibodies.The activity of hemicellulose degradation enzymes, such as β-xylosidase and α-arabinofuranosidase, decreased gradually during fruit ripening, although the tomato fruits continued to soften.In contrast, GAX and XG biosynthesis-related genes were expressed in all tomato fruit tissues even during ripening, indicating that XG was synthesized throughout the fruit and that GAX may be synthesized only in the vascular bundles and the inner epidermis.

View Article: PubMed Central - PubMed

Affiliation: University of Tsukuba, Faculty of Life and Environmental Sciences, Tsukuba, Ibaraki, Japan.

ABSTRACT
Disassembly of cell wall polysaccharides by various cell wall hydrolases during fruit softening causes structural changes in hemicellulose and pectin that affect the physical properties and softening of tomato fruit. In a previous study, we showed that the changes in pectin during tomato fruit ripening were unique in each fruit tissue. In this study, to clarify the changes in hemicellulose in tissues during tomato fruit ripening, we focused on glucuronoarabinoxylan (GAX) and xyloglucan (XG). GAX was detected only in the skin and inner epidermis of the pericarp using LM11 antibodies, whereas a large increase in XG was detected in all fruit tissues using LM15 antibodies. The activity of hemicellulose degradation enzymes, such as β-xylosidase and α-arabinofuranosidase, decreased gradually during fruit ripening, although the tomato fruits continued to soften. In contrast, GAX and XG biosynthesis-related genes were expressed in all tomato fruit tissues even during ripening, indicating that XG was synthesized throughout the fruit and that GAX may be synthesized only in the vascular bundles and the inner epidermis. Our results suggest that changes in the cell wall architecture and tissue-specific distribution of XG and GAX might be required for the regulation of fruit softening and the maintenance of fruit shape.

Show MeSH
Related in: MedlinePlus