Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract only
Publication Acceptance Date: 2/2/2002
Publication Date: 3/25/2002
Citation: HOEKENGA, O.A., HOWELL, S.H., KOCHIAN, L.V. UNDERSTANDING ALUMINUM TOLERANCE MECHANISMS IN ARABIDOPSIS THALIANA. AMERICAN SOCIETY OF PLANT BIOLOGISTS ANNUAL MEETING. 2002. Interpretive Summary:
Technical Abstract: Aluminum (Al) is the third most abundant element in the earth's crust and toxic to plants if solubilized in acid soils. Al-toxicity diminishes crop yield on approximately one third of the world's arable land, primarily by inhibiting root growth & nutrient/water acquisition. Breeding crops with increased tolerance to Al stress has been a productive and active avenue of fresearch. The underlying physiological and genetic bases for Al-tolerance are not well understood. Al-tolerance in a wide variety of plants is well correlated with an Al-inducible release of ligands (e.g. citrate) that may reduce Al uptake by roots. However, no genes important for Al-tolerance have been cloned and characterized in plants. We report on progress made to identify Al-tolerance genes in the model plant, Arabidopsis thaliana, utilizing two strategies. First, two aluminum tolerance loci were identified using quantitative trait locus (QTL) mapping, using a recombinant inbred population constructed from the tolerant Col and sensitive Ler ecotypes. Together these two loci explain 40% of the difference in Al tolerance observed between the parental lines. Progress towards cloning the tolerance loci and characterizing their functions will be discussed. Second, gene expression during Al-stress was profiled using microarray hybridization. Initial experiments were conducted in collaboration with the Arabidopsis Functional Genomics Consortium; 300 candidate Al-inducible genes were identified. We constructed small-scale microarrays to characterize the kinetics of gene expression and evaluate differences between Col and Ler. We will use a cluster-based analysis to identify suites of genes that are essential to Al-tolerance. This research is supported by USDA-NRI #97-35100-5050.