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Characterization, localization, and seasonal changes of the sucrose transporter FeSUT1 in the phloem of Fraxinus excelsior.

Öner-Sieben S, Rappl C, Sauer N, Stadler R, Lohaus G - J. Exp. Bot. (2015)

Bottom Line: The localization and expression pattern point towards functions of FeSUT1 in phloem loading of sucrose as well as in sucrose retrieval.The elevated expression level of FeSUT1 indicated an increased apoplastic carbon export activity from the leaves during spring and late autumn.It is hypothesized that the importance of apoplastic loading is high under low-sucrose conditions and that the availability of two different phloem-loading mechanisms confers advantages for temperate woody species like F. excelsior.

View Article: PubMed Central - PubMed

Affiliation: Molekulare Pflanzenforschung/Pflanzenbiochemie (Botanik), Bergische Universität Wuppertal, Gaußstraße 20, D-42119 Wuppertal, Germany.

No MeSH data available.


Related in: MedlinePlus

Sugar and sugar alcohol content as well as FeSUT1 expression in leaves of F. excelsior in light and during a prolonged dark period. Experiments were performed with three 3-year-old saplings. Leaves were taken in the second half of the normal light period and after 5, 17, and 43h of continuous darkness. (A) Total sugar and sugar alcohol content in leaves. (B) Relative amounts of sugar and sugar alcohol at the total content. (C) Relative sucrose content (■, closed squares, continuous line) and relative expression of FeSUT1 (Δ, open triangles, broken line). Expression levels of FeSUT1 were normalized to actin and values are given as relative expression levels to the first sample of the measurement (calibrator [cal]). Student’s t-test was performed with P ≤ 0.05 to test for significance of changes compared to calibrator [cal]. Hex, hexoses; Mal, maltose; RFO, raffinose-oligosaccharide family sugars; SuAlc, sugar alcohols; Suc, sucrose.
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Figure 6: Sugar and sugar alcohol content as well as FeSUT1 expression in leaves of F. excelsior in light and during a prolonged dark period. Experiments were performed with three 3-year-old saplings. Leaves were taken in the second half of the normal light period and after 5, 17, and 43h of continuous darkness. (A) Total sugar and sugar alcohol content in leaves. (B) Relative amounts of sugar and sugar alcohol at the total content. (C) Relative sucrose content (■, closed squares, continuous line) and relative expression of FeSUT1 (Δ, open triangles, broken line). Expression levels of FeSUT1 were normalized to actin and values are given as relative expression levels to the first sample of the measurement (calibrator [cal]). Student’s t-test was performed with P ≤ 0.05 to test for significance of changes compared to calibrator [cal]. Hex, hexoses; Mal, maltose; RFO, raffinose-oligosaccharide family sugars; SuAlc, sugar alcohols; Suc, sucrose.

Mentions: After transferring plants into continuous darkness, sugar and sugar alcohol content in leaves started to decline (Fig. 6A). Nevertheless, the sugar content in leaves after about 2 days of darkness was still two-thirds of the values found in illuminated leaves. The sugar and sugar alcohol composition also changed slightly during the long dark period. The proportion of sugar alcohol (mainly mannitol) increased whereas the proportion of RFOs and sucrose decreased (Fig. 6B). The expression of FeSUT1 compared with sucrose content in F. excelsior is shown in Fig. 6C. Like the whole sugar content, sucrose content decreased after illumination stopped. In contrast, expression of FeSUT1 increased strongly during the long dark period (Fig. 6C).


Characterization, localization, and seasonal changes of the sucrose transporter FeSUT1 in the phloem of Fraxinus excelsior.

Öner-Sieben S, Rappl C, Sauer N, Stadler R, Lohaus G - J. Exp. Bot. (2015)

Sugar and sugar alcohol content as well as FeSUT1 expression in leaves of F. excelsior in light and during a prolonged dark period. Experiments were performed with three 3-year-old saplings. Leaves were taken in the second half of the normal light period and after 5, 17, and 43h of continuous darkness. (A) Total sugar and sugar alcohol content in leaves. (B) Relative amounts of sugar and sugar alcohol at the total content. (C) Relative sucrose content (■, closed squares, continuous line) and relative expression of FeSUT1 (Δ, open triangles, broken line). Expression levels of FeSUT1 were normalized to actin and values are given as relative expression levels to the first sample of the measurement (calibrator [cal]). Student’s t-test was performed with P ≤ 0.05 to test for significance of changes compared to calibrator [cal]. Hex, hexoses; Mal, maltose; RFO, raffinose-oligosaccharide family sugars; SuAlc, sugar alcohols; Suc, sucrose.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC4507781&req=5

Figure 6: Sugar and sugar alcohol content as well as FeSUT1 expression in leaves of F. excelsior in light and during a prolonged dark period. Experiments were performed with three 3-year-old saplings. Leaves were taken in the second half of the normal light period and after 5, 17, and 43h of continuous darkness. (A) Total sugar and sugar alcohol content in leaves. (B) Relative amounts of sugar and sugar alcohol at the total content. (C) Relative sucrose content (■, closed squares, continuous line) and relative expression of FeSUT1 (Δ, open triangles, broken line). Expression levels of FeSUT1 were normalized to actin and values are given as relative expression levels to the first sample of the measurement (calibrator [cal]). Student’s t-test was performed with P ≤ 0.05 to test for significance of changes compared to calibrator [cal]. Hex, hexoses; Mal, maltose; RFO, raffinose-oligosaccharide family sugars; SuAlc, sugar alcohols; Suc, sucrose.
Mentions: After transferring plants into continuous darkness, sugar and sugar alcohol content in leaves started to decline (Fig. 6A). Nevertheless, the sugar content in leaves after about 2 days of darkness was still two-thirds of the values found in illuminated leaves. The sugar and sugar alcohol composition also changed slightly during the long dark period. The proportion of sugar alcohol (mainly mannitol) increased whereas the proportion of RFOs and sucrose decreased (Fig. 6B). The expression of FeSUT1 compared with sucrose content in F. excelsior is shown in Fig. 6C. Like the whole sugar content, sucrose content decreased after illumination stopped. In contrast, expression of FeSUT1 increased strongly during the long dark period (Fig. 6C).

Bottom Line: The localization and expression pattern point towards functions of FeSUT1 in phloem loading of sucrose as well as in sucrose retrieval.The elevated expression level of FeSUT1 indicated an increased apoplastic carbon export activity from the leaves during spring and late autumn.It is hypothesized that the importance of apoplastic loading is high under low-sucrose conditions and that the availability of two different phloem-loading mechanisms confers advantages for temperate woody species like F. excelsior.

View Article: PubMed Central - PubMed

Affiliation: Molekulare Pflanzenforschung/Pflanzenbiochemie (Botanik), Bergische Universität Wuppertal, Gaußstraße 20, D-42119 Wuppertal, Germany.

No MeSH data available.


Related in: MedlinePlus