Arabidopsis sucrose transporter AtSUC9. High-affinity transport activity, intragenic control of expression, and early flowering mutant phenotype

Sivitz, Alicia B., Reinders, Anke, Johnson, Meghan E., Krentz, Anthony D., Grof, Christopher P.L., Perroux, Jai M. and Ward, John M. (2007) Arabidopsis sucrose transporter AtSUC9. High-affinity transport activity, intragenic control of expression, and early flowering mutant phenotype. Plant Physiology, 143 1: 188-198.


Author Sivitz, Alicia B.
Reinders, Anke
Johnson, Meghan E.
Krentz, Anthony D.
Grof, Christopher P.L.
Perroux, Jai M.
Ward, John M.
Title Arabidopsis sucrose transporter AtSUC9. High-affinity transport activity, intragenic control of expression, and early flowering mutant phenotype
Journal name Plant Physiology   Check publisher's open access policy
ISSN 0032-0889
Publication date 2007-01
Year available 2006
Sub-type Article (original research)
DOI 10.1104/pp.106.089003
Volume 143
Issue 1
Start page 188
End page 198
Total pages 11
Place of publication Rockville, M.D., U.S.A.
Publisher American Society of Plant Biologists
Collection year 2008
Language eng
Subject C1
060705 Plant Physiology
Abstract AtSUC9 (At5g06170), a sucrose (Suc) transporter from Arabidopsis (Arabidopsis thaliana) L. Heynh., was expressed in Xenopus (Xenopus laevis) oocytes, and transport activity was analyzed. Compared to all other Suc transporters, AtSUC9 had an ultrahigh affinity for Suc (K-0.5 = 0.066 +/- 0.025 mM). AtSUC9 showed low substrate specificity, similar to AtSUC2 (At1g22710), and transported a wide range of glucosides, including helicin, salicin, arbutin, maltose, fraxin, esculin, turanose, and alpha-methyl-D-glucose. The ability of AtSUC9 to transport 10 glucosides was compared directly with that of AtSUC2, HvSUT1 (from barley [Hordeum vulgare]), and ShSUT1 (from sugarcane [Saccharum hybrid]), and results indicate that type I and type II Suc transporters have different substrate specificities. AtSUC9 protein was localized to the plasma membrane by transient expression in onion (Allium cepa) epidermis. Using a whole-gene translational fusion to beta-glucuronidase, AtSUC9 expression was found in sink tissues throughout the shoots and in flowers. AtSUC9 expression in Arabidopsis was dependent on intragenic sequence, and this was found to also be true for AtSUC1 (At1g71880) but not AtSUC2. Plants containing mutations in Suc transporter gene AtSUC9 were found to have an early flowering phenotype under short-day conditions. The transport properties of AtSUC9 indicate that it is uniquely suited to provide cellular uptake of Suc at very low extracellular Suc concentrations. The mutant phenotype of atsuc9 alleles indicates that AtSUC9 activity leads to a delay in floral transition.
Keyword Plant Sciences
Gene-expression
Higher-plants
Thaliana
Induction
Identification
Proteins
Promoter
Elements
Enhancer
Carrier
Q-Index Code C1
Q-Index Status Confirmed Code
Additional Notes First published online November 10, 2006;

 
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