PAG-XIII  Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA


W003 : Abiotic Stress

Functional And Comparative Genomic Analysis Of Aluminum Tolerance In Zea mays

Owen A. Hoekenga1 , Edward S. Buckler2,3 , Matias Kirst3 , Lyza Maron4 , Paul Mason4 , Miguel Pineros4 , Jon Shaff4 , Jocelyn Rose4 , Leon Kochian1,2,4

1  Boyce Thompson Institute for Plant Research, Cornell University, Ithaca NY 14853 USA
2  USDA-ARS, Cornell University, Ithaca NY 14853 USA
3  Institute for Genomic Diversity, Cornell University, Ithaca NY 14853 USA
4  Dept. of Plant Biology, Cornell University, Ithaca NY 14853 USA

Aluminum (Al) toxicity is a profound limitation to crop production worldwide, reducing yields on up to 50% of potentially arable lands. Breeding for Al tolerance and agronomic practices aimed at ameliorating soil acidity have historically been productive avenues for improved crop production. However, it is widely recognized that additional improvements in crop Al tolerance will depend upon biotechnology. In this project we will identify and characterize Al tolerance genes and their associated mechanisms in maize. Our study populations are derived from diverse sources; thus we should capture a wide range of tolerance levels and useful alleles. First, we used QTL mapping to characterize the genetic basis for Al tolerance in the Intermated B73 x Mo17 (IBM) population. A 5-factor model explains approximately 60% of the variance observed, where Mo17 donates 3 of the 5 loci. These three factors apparently act epistatically. Physiological experiments and fine-scale mapping are underway. Second, we used comparative (in silico) mapping analyses to place our results from the IBM population in context with mapping results from a South American population developed by collaborators at Embrapa Maize and Sorghum, and also with rice. Third, we have initiated experiments to test the range of Al tolerance responses observed in diverse maize materials, in support of future association analyses. Fourth, we have initiated microarray experiments with greatly contrasting genotypes to clarify how Al stress affects patterns of gene expression and to assist in candidate gene identification. This work is supported by NSF Plant Genome Award DBI #0419435 (PI: Kochian).