DETERMINATION AND CHARACTERIZATION OF UNINTENDED EFFECTS IN GENETICALLY MODIFIED FOOD CROPS
Location: Plant, Soil and Nutrition Research
Title: Joint linkage association analysis of aluminum tolerance in maize
Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: August 25, 2009
Publication Date: October 7, 2009
Citation: Hoekenga, O., Buckler Iv, E.S., Kirst, M., Krill, A., Lyi, S., Magalhaes, J., Maron, L., Kochian, L.V. 2009. Joint linkage association analysis of aluminum tolerance in maize. Symposium Proceedings. Proceedings of the 7th International Symposium on Plant-Soil Interaction at Low pH, October 5-10, 2009, Guangzhou, China. p. 136-137.
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 on biotechnology. We used genetic and genomic approaches, building upon our previous work on the physiological bases for Al tolerance in maize. We used comparative genomics to identify gene families related to known aluminum tolerance genes. Microarray analysis was also used to characterize the root tip transcriptome; results were analyzed with respect to the physical and genetic maps of maize and in a comparative sense with the rice genome. Based on these data, we selected candidate Al tolerance genes to evaluate using association analysis. We identified several single nucleotide polymorphisms in multiple genes that are associated with Al tolerance. Results from association analyses were confirmed using linkage analysis. In parallel, we identified 6 Al tolerance loci in the Intermated B73 x Mo17 recombinant inbred population, which together explain nearly 65% of the variance observed. Al exclusion from the root tip correlates highly with Al tolerance, as estimated by net seminal root growth. These loci have been isolated in near isogenic lines, which provide an excellent resource for genomic, proteomic and physiological analyses of Al tolerance.