|
Plant Physiol, December 2001, Vol. 127, pp. 1836-1844
Overexpression of Malate Dehydrogenase in Transgenic Alfalfa
Enhances Organic Acid Synthesis and Confers Tolerance to
Aluminum1
Mesfin
Tesfaye,
Stephen J.
Temple,2
Deborah L.
Allan,
Carroll P.
Vance, and
Deborah A.
Samac*
Departments of Plant Pathology (M.T., D.A.S.), Agronomy and Plant
Genetics (S.J.T., C.P.V.), and Soil, Water, and Climate (D.L.A.), and
U.S. Department of Agriculture-Agricultural Research Service-Plant
Science Research Unit (C.P.V., D.A.S.), University of Minnesota, St.
Paul, Minnesota 55108
Al toxicity is a severe impediment to production of many
crops in acid soil. Toxicity can be reduced through lime application to
raise soil pH, however this amendment does not remedy subsoil acidity,
and liming may not always be practical or cost-effective. Addition of
organic acids to plant nutrient solutions alleviates phytotoxic Al
effects, presumably by chelating Al and rendering it less toxic. In an
effort to increase organic acid secretion and thereby enhance Al
tolerance in alfalfa (Medicago sativa), we produced
transgenic plants using nodule-enhanced forms of malate dehydrogenase
and phosphoenolpyruvate carboxylase cDNAs under the
control of the constitutive cauliflower mosaic virus 35S promoter. We
report that a 1.6-fold increase in malate dehydrogenase enzyme specific
activity in root tips of selected transgenic alfalfa led to a 4.2-fold
increase in root concentration as well as a 7.1-fold increase in root
exudation of citrate, oxalate, malate, succinate, and acetate compared
with untransformed control alfalfa plants. Overexpression of
phosphoenolpyruvate carboxylase enzyme specific activity
in transgenic alfalfa did not result in increased root exudation of
organic acids. The degree of Al tolerance by transformed plants in
hydroponic solutions and in naturally acid soil corresponded with their
patterns of organic acid exudation and supports the concept that
enhancing organic acid synthesis in plants may be an effective strategy
to cope with soil acidity and Al toxicity.
1
This work was funded by the North Central
Biotechnological Initiative (Purdue grant no. 593-0244-05/U.S.
Department of Agriculture [USDA] grant no. 97-34340-3987). This
paper is a joint contribution from the Plant Science Research Unit,
USDA, Agricultural Research Service, and the Minnesota Agricultural
Experiment Station. Mention of a trademark, proprietary product, or
vendor does not constitute a guarantee or warranty of the product by
the USDA and does not imply its approval to the exclusion of other
products and vendors that might also be suitable.
2
Present address: Forage Genetics International, N5292
Gills Coulee Road, West Salem, WI 54669.
*
Corresponding author; e-mail debbys{at}puccini.cdl.umn.edu; fax
651-649-5058.
© 2001 American Society of Plant Physiologists
This article has been cited by other articles:
|
|
|
|
 
Y. Kobayashi, O. A. Hoekenga, H. Itoh, M. Nakashima, S. Saito, J. E. Shaff, L. G. Maron, M. A. Pineros, L. V. Kochian, and H. Koyama
Characterization of AtALMT1 Expression in Aluminum-Inducible Malate Release and Its Role for Rhizotoxic Stress Tolerance in Arabidopsis
Plant Physiology,
November 1, 2007;
145(3):
843 - 852.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. Narasimhamoorthy, E. B. Blancaflor, J. H. Bouton, M. E. Payton, and M. K. Sledge
A Comparison of Hydroponics, Soil, and Root Staining Methods for Evaluation of Aluminum Tolerance in Medicago truncatula (Barrel Medic) Germplasm
Crop Sci.,
February 6, 2007;
47(1):
321 - 328.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Ligaba, M. Katsuhara, P. R. Ryan, M. Shibasaka, and H. Matsumoto
The BnALMT1 and BnALMT2 Genes from Rape Encode Aluminum-Activated Malate Transporters That Enhance the Aluminum Resistance of Plant Cells
Plant Physiology,
November 1, 2006;
142(3):
1294 - 1303.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. L. YANG, L. ZHANG, Y. Y. LI, J. F. YOU, P. WU, and S. J. ZHENG
Citrate Transporters Play a Critical Role in Aluminium-stimulated Citrate Efflux in Rice Bean (Vigna umbellata) Roots
Ann. Bot.,
April 1, 2006;
97(4):
579 - 584.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
E. Delhaize, P. R. Ryan, D. M. Hebb, Y. Yamamoto, T. Sasaki, and H. Matsumoto
Engineering high-level aluminum tolerance in barley with the ALMT1 gene
PNAS,
October 19, 2004;
101(42):
15249 - 15254.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Kihara, T. Wada, Y. Suzuki, T. Hara, and H. Koyama
Alteration of Citrate Metabolism in Cluster Roots of White Lupin
Plant Cell Physiol.,
September 15, 2003;
44(9):
901 - 908.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
V. M. Anoop, U. Basu, M. T. McCammon, L. McAlister-Henn, and G. J. Taylor
Modulation of Citrate Metabolism Alters Aluminum Tolerance in Yeast and Transgenic Canola Overexpressing a Mitochondrial Citrate Synthase
Plant Physiology,
August 1, 2003;
132(4):
2205 - 2217.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. E. Hayes and J. F. Ma
Al-induced efflux of organic acid anions is poorly associated with internal organic acid metabolism in triticale roots
J. Exp. Bot.,
July 1, 2003;
54(388):
1753 - 1759.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. H. Graham and C. P. Vance
Legumes: Importance and Constraints to Greater Use
Plant Physiology,
March 1, 2003;
131(3):
872 - 877.
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Ohno, H. Koyama, and T. Hara
Characterization of Citrate Transport through the Plasma Membrane in a Carrot Mutant Cell Line with Enhanced Citrate Excretion
Plant Cell Physiol.,
February 15, 2003;
44(2):
156 - 162.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Y. Kobayashi and H. Koyama
QTL Analysis of Al Tolerance in Recombinant Inbred Lines of Arabidopsis thaliana
Plant Cell Physiol.,
December 15, 2002;
43(12):
1526 - 1533.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
