Al-Induced, 51-Kilodalton, Membrane-Bound Proteins Are Associated with Resistance to Al in a Segregating Population of WheatReportar como inadecuado

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Stress, Barley roots, Translocating inorganic pyrophosphatase, Nutrient solutions, H+-Pumps, Cultivars, Aluminum tolerance, Triticum-Aestivum L, Toxicity, Genes

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Subject-Keyword: Stress Barley roots Translocating inorganic pyrophosphatase Nutrient solutions H+-Pumps Cultivars Aluminum tolerance Triticum-Aestivum L Toxicity Genes

Type of item: Journal Article Published

Language: English



Description: Incorporation of S-35 into protein is reduced by exposure to Al in wheat Triticum aestivum, but the effects are genotype-specific. Exposure to 10 to 75 mu M Al had little effect on S-35 incorporation into total protein, nuclear and mitochondrial protein, microsomal protein, and cytosolic protein in the Al-resistant cultivar PT741. In contrast, 10 mu M Al reduced incorporation by 21 to 38% in the Al-sensitive cultivar Katepwa, with effects becoming more pronounced 31-62% as concentrations of Al increased. We previously reported that a pair of 51-kD membrane-hound proteins accumulated in root tips of PT741 under conditions of Al stress. We now report that the 51-kD band is labeled with S-35 after 24 h of exposure to 75 mu M Al. The specific induction of the 51-kD band in PT741 suggested a potential role of one or both of these proteins in mediating resistance to Al. Therefore, we analyzed their expression in single plants from an F-2, population arising from a cross between the PT741 and Katepwa cultivars. Accumulation of 1,3-beta-glucans callose in root tips after 24 h of exposure to 100 mu M Al indicated that this population segregated for Al resistance in about a 3:1 ratio. A close correlation between resistance to Al low callose content of root tips and accumulation of the 51-kD band was observed, indicating that at least one of these proteins cosegregates with the Al-resistance phenotype. As a first step in identifying a possible function, we have demonstrated that the 51-kD band is most clearly associated with the tonoplast. Whereas Al has been reported to stimulate the activity of the tonoplast HC-ATPase and H+-PPase, antibodies raised against these proteins did not cross-react with the 51-kD band. Efforts are now under way to purify this protein from tonoplast-enriched fractions.

Date created: 1997

DOI: doi:10.7939-R3HH6C682

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Rights: © 1997 American Society of Plant Biologists. This version of this article is open access and can be downloaded and shared. The original authors and source must be cited.

Autor: Taylor, G. J. Basu, A. Slaski, J. J. Zhang, G. Good, A.



Plant Physiol.
(1997) 114: 363-372 AI-lnduced, 51 -Kilodalton, Membrane-Bound Proteins Are Associated with Resistance to AI in a Segregating Population of Wheat Gregory J.
Taylor*, Atanu Basu, Urmila Basu, Jan J.Slaski, Cuichang Zhang, and Allen Good Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 stad, 1968; Camargo, 1981; Delhaize et al., 1993a, 1993b), whereas other studies indicated polygenic control of this character (Campbell and Lafever, 1981; Aniol, 1984, 1990; Aniol and Gustafson, 1984; Berzonsky, 1992; Bona et al., 1994; Slaski, 1995).
To some extent, differences in the patterns of inheritance reported in the literature could reflect the unique characteristics of germ plasm used in individual experiments.
Even if resistance is mediated by a suite of adaptive traits, careful selection of genetic material may provide a system in which a single component of AI resistance behaves as a single dominant gene. The possibility that AI resistance is mediated by an integrated suite of adaptive traits provides a powerful incentive for the use of near-isogenic or isogenic plant material (Taylor, 1995).
with a truly isogenic system, in which differences between genotypes are directly related to the presente or absence of a single gene, the task of identifying resistance mechanisms is greatly simplified.
Although separating cause and effect remains a concern, the experimental effort required to achieve this objective is considerably less demanding (Taylor, 1995).
Whereas a truly isogenic Al-resistant system will be difficult to develop, genetic material that segregates as a single gene can provide an equally important experimental tool.
If a specific physiological trait fails to segregate with the resistance phenotype, that trait cannot play a role in mediating resistance. For example, Delhaize et al.
(1991) identified severa1 Alinduced polypeptides that were specific to an AI-resistant genotype of wheat (Carazinho) under con...

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