Hexose uptake by developing cotyledons of Vicia faba: physiological evidence for transporters of differing affinities and specificities

Functional Plant Biology : FPB
Gregory N HarringtonJohn W Patrick

Abstract

Cotyledons of broad bean (Vicia faba L.) develop in an apoplasmic environment that shifts in composition from one dominated by hexoses to one dominated by sucrose. During the latter phase of development, sucrose / H+ symporter activity and expression is restricted to cotyledon epidermal transfer cell complexes that support sucrose fluxes that are 8.5-fold higher than those exhibited by the storage parenchyma. In contrast, the flux difference between these cotyledon tissues is only 1.7-fold for hexoses. Glucose and fructose uptake was shown to be sensitive to PCMBS and phloridzin, both of which slow H+-sugar transport. A low Km (or high affinity transporter, HAT) mechanism transports glucose and glucose-analogues exclusively. No HAT system for fructose could be found. A high Km (low affinity transporter, LAT) mechanism transports a broader range of hexoses, including glucose and fructose. Consistent with glucose and fructose transport being H+-coupled, their uptake was inhibited by dissipating the proton motive force (pmf) by treating cotyledons with carbonyl cyanide m-chlorophenol hydrazone, propionic acid or tetraphenylphosphonium ion. Erythrosin B inhibited hexose uptake, indicating a role for the P-type H+-ATPase in establis...Continue Reading

References

Dec 1, 1993·Archives of Biochemistry and Biophysics·D R Bush
Apr 5, 2000·Biochimica Et Biophysica Acta·M Büttner, N Sauer
Jan 3, 2001·The Plant Journal : for Cell and Molecular Biology·S M ShersonS M Smith
Jan 1, 2003·Journal of Experimental Botany·Ljudmilla BorisjukHans Weber
Mar 1, 2003·Plant & Cell Physiology·Raymond J RitchieJohn W Patrick
Sep 21, 2004·Annual Review of Plant Biology·Sylvie LalondeWolf B Frommer
Dec 1, 1988·Plant Physiology·J H Xia, P H Saglio

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Citations

Oct 22, 2008·Journal of Experimental Botany·Yuchan ZhouJohn W Patrick
May 1, 2007·Functional Plant Biology : FPB·Wen-Hao ZhangJohn W Patrick

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