Plant Physiol. email content delivery
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on May 12, 2006; 10.1104/pp.106.079186

This Article
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrow All Versions of this Article:
141/3/840    most recent
pp.106.079186v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (19)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Sparla, F.
Right arrow Articles by Trost, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Sparla, F.
Right arrow Articles by Trost, P.
Agricola
Right arrow Articles by Sparla, F.
Right arrow Articles by Trost, P.

Received February 14, 2006
Returned for revision February 28, 2006
Accepted May 2, 2006

REDOX REGULATION OF A NOVEL PLASTID-TARGETED {beta}-AMYLASE OF Arabidopsis thaliana

Francesca Sparla , Alex Costa , Fiorella Lo Schiavo , Paolo Pupillo , and Paolo Trost *

Laboratory of Molecular Plant Physiology, Department of Experimental Evolutionary Biology, University of Bologna, Via Irnerio 42, I-40126 Bologna, Italy
Dipartimento di Biologia, Università degli Studi di Padova, Via U. Bassi 58/B, I-35131 Padova, Italy

* Corresponding author; email: trost{at}alma.unibo.it.

Nine genes of Arabidopsis thaliana encode for {beta}-amylase isozymes. Six members of the family are predicted to be extrachloroplastic isozymes and three contain predicted plastid transit peptides. Among the latter, chloroplast-targeted {beta}-amylase (CT-BMY = At4g17090; Lao et al., 1999) and thioredoxin-regulated {beta}-amylase (TR-BAMY = At3g23920; this work) are experimentally demonstrated to be targeted to plastids. Recombinant TR-BAMY was catalytically active only when expressed as a mature protein, i.e. with no transit peptide. Mature TR-BAMY was a monomer of 60 kDa, hydrolyzing soluble starch with optimal activity between pH 6.0 and 8.0. The activity of recombinant TR-BAMY was strictly dependent on redox potential with an Em,7.0 of -302 ± 14 mV. Thioredoxins f1, m1 and y1 of Arabidopsis were all able to mediate the reductive activation of oxidized TR-BAMY. Site-specific mutants showed that TR-BAMY oxidative inhibition depended on the formation of a disulfide bridge between Cys-32 and Cys-470. Consistent with TR-BAMY redox dependency, total {beta}-amylase activity in Arabidopsis chloroplasts was partially redox-regulated and required reducing conditions for full activation.

In Arabidopsis, TR-BAMY transcripts were detected in leaves, roots, flowers, pollen and seeds. TR-BAMY may be the only {beta}-amylase of nonphotosynthetic plastids suggesting a redox regulation of starch metabolism in these organelles. In leaves, where CT-BMY is involved in physiological degradation of starch in the dark, TR-BAMY is proposed to participate to a redox-regulated pathway of starch degradation under specific stress conditions.




This article has been cited by other articles:


Home page
 Plant Physiol.Home page
H.-L. Tsai, W.-L. Lue, K.-J. Lu, M.-H. Hsieh, S.-M. Wang, and J. Chen
Starch Synthesis in Arabidopsis Is Achieved by Spatial Cotranscription of Core Starch Metabolism Genes
Plant Physiology, November 1, 2009; 151(3): 1582 - 1595.
[Abstract] [Full Text] [PDF]

Home page
 GeneticsHome page
P. Deschamps, H. Moreau, A. Z. Worden, D. Dauvillee, and S. G. Ball
Early Gene Duplication Within Chloroplastida and Its Correspondence With Relocation of Starch Metabolism to Chloroplasts
Genetics, April 1, 2008; 178(4): 2373 - 2387.
[Abstract] [Full Text] [PDF]

Home page
 Plant CellHome page
D. C. Fulton, M. Stettler, T. Mettler, C. K. Vaughan, J. Li, P. Francisco, M. Gil, H. Reinhold, S. Eicke, G. Messerli, et al.
{beta}-AMYLASE4, a Noncatalytic Protein Required for Starch Breakdown, Acts Upstream of Three Active {beta}-Amylases in Arabidopsis Chloroplasts
PLANT CELL, April 1, 2008; 20(4): 1040 - 1058.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
J. de Dios Barajas-Lopez, A. J. Serrato, A. Olmedilla, A. Chueca, and M. Sahrawy
Localization in Roots and Flowers of Pea Chloroplastic Thioredoxin f and Thioredoxin m Proteins Reveals New Roles in Nonphotosynthetic Organs
Plant Physiology, November 1, 2007; 145(3): 946 - 960.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
C. Edner, J. Li, T. Albrecht, S. Mahlow, M. Hejazi, H. Hussain, F. Kaplan, C. Guy, S. M. Smith, M. Steup, et al.
Glucan, Water Dikinase Activity Stimulates Breakdown of Starch Granules by Plastidial beta-Amylases
Plant Physiology, September 1, 2007; 145(1): 17 - 28.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
J.-P. Ral, C. Colleoni, F. Wattebled, D. Dauvillee, C. Nempont, P. Deschamps, Z. Li, M. K. Morell, R. Chibbar, S. Purton, et al.
Circadian Clock Regulation of Starch Metabolism Establishes GBSSI as a Major Contributor to Amylopectin Synthesis in Chlamydomonas reinhardtii
Plant Physiology, September 1, 2006; 142(1): 305 - 317.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 2006 by the American Society of Plant Biologists