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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 during growing season. Samples were taken over a period of 3 years (2010–2012) from three individual trees from a 25- to 30-year-old forest. (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].
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Figure 5: Sugar and sugar alcohol content as well as FeSUT1 expression in leaves of F. excelsior during growing season. Samples were taken over a period of 3 years (2010–2012) from three individual trees from a 25- to 30-year-old forest. (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].

Mentions: Leaves of ~30-year-old trees contained similar amounts of sugars and sugar alcohols between May and October (40 to 50 µmol g FW−1; Fig. 5A). Only in late autumn (November) did sugar content decrease. The high values of standard deviation (SD) are due to the fact that samples were taken from three different plants in their natural environment over a course of 3 years (always at the same time of the day (2 p.m.) and the same date of the month without regard to outside temperature, humidity, or hours of sunshine). The distribution of sugars and sugar alcohols varied during the growing season. Sugar alcohols (mainly mannitol) were the dominant component in leaves of F. excelsior for most of the year, followed by hexoses (hex) and sucrose (Fig. 5B). RFOs started with 1.5% in May and showed higher proportions in summer and autumn (Fig. 5B).


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 during growing season. Samples were taken over a period of 3 years (2010–2012) from three individual trees from a 25- to 30-year-old forest. (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].
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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

Figure 5: Sugar and sugar alcohol content as well as FeSUT1 expression in leaves of F. excelsior during growing season. Samples were taken over a period of 3 years (2010–2012) from three individual trees from a 25- to 30-year-old forest. (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].
Mentions: Leaves of ~30-year-old trees contained similar amounts of sugars and sugar alcohols between May and October (40 to 50 µmol g FW−1; Fig. 5A). Only in late autumn (November) did sugar content decrease. The high values of standard deviation (SD) are due to the fact that samples were taken from three different plants in their natural environment over a course of 3 years (always at the same time of the day (2 p.m.) and the same date of the month without regard to outside temperature, humidity, or hours of sunshine). The distribution of sugars and sugar alcohols varied during the growing season. Sugar alcohols (mainly mannitol) were the dominant component in leaves of F. excelsior for most of the year, followed by hexoses (hex) and sucrose (Fig. 5B). RFOs started with 1.5% in May and showed higher proportions in summer and autumn (Fig. 5B).

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