%0 Journal Article
%T Proteomic Analysis of Soybean Roots under Aluminum Stress
%A Dechassa Duressa
%A Khairy Soliman
%A Robert Taylor
%A Zachary Senwo
%J International Journal of Plant Genomics
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/282531
%X Toxic levels of aluminum (Al) in acid soils inhibit root growth and cause substantial reduction in yields of Al-sensitive crops. Aluminum-tolerant cultivars detoxify Al through multiple mechanisms that are currently not well understood at genetic and molecular levels. To enhance our understanding of the molecular mechanisms involved in soybean Al tolerance and toxicity, we conducted proteomic analysis of soybean roots under Al stress using a tandem combination of 2-D-DIGE, mass spectrometry, and bioinformatics tools and Al-tolerant (PI 416937) and Al-sensitive (Young) soybean genotypes at 6, 51 or 72 h of Al treatment. Comparison of the protein profile changes revealed that aluminum induced Al tolerance related proteins and enzymes in Al-tolerant PI 416937 but evoked proteins related to general stress response in Al-sensitive Young. Specifically, Al upregulated: malate dehydrogenase, enolase, malate oxidoreductase, and pyruvate dehydrogenase, in PI 416937 but not in Young. These enzymes contribute to increased synthesis of citrate, a key organic acid involved in Al detoxification. We postulate that simultaneous transgenic overexpression of several of these enzymes would be a robust genetic engineering strategy for developing Al-tolerant crops. 1. Introduction Toxic levels of aluminum (Al) in acid soils inhibit root growth and cause substantial reduction in yields of Al-sensitive crops [1, 2]. Its toxicity mechanisms include interference with nutrient and water uptake and translocation [3], disruption of calcium homeostatis [4], disruption of cytoskeleton [5, 6], callose deposition in apoplast that affects movement of substances from cell to cell [7], lipid peroxidation and reactive oxygen species production [8], and interference with cell division and elongation [9, 10]. In concert, these disorders thwart root growth and development that is typically manifested in stunted and swollen root system at the morphological level [11, 12]. Al disrupts cellular components and processes by high binding affinity to phosphate, sulfate, and carbonyl functional groups of cellular components in apoplast and symplast [11]. Perhaps as a direct and parallel evolutionary response to the nature of Al-ligand interaction, plants secret substances that possess these functional groups namely, organic acids [13], phenolics [14¨C16], and phosphate and polypeptides [17, 18] to bind and detoxify Al in the rhizosphere. Sequestration of Al in the rhizosphere with root secreted organic acids mainly citrate, malate, and oxalate is a common and well-documented physiological mechanism of
%U http://www.hindawi.com/journals/ijpg/2011/282531/