|Gustin, Jeff -|
|Settles, Mark -|
|Rocheford, Torbert -|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 31, 2010
Publication Date: N/A
Technical Abstract: Heterogeneity in the elemental composition of soils is among the major causes of plant stress worldwide. In order to adapt to these conditions, plants frequently alter their elemental content. We employed mineral nutrient and trace element profiling in diverse maize germplasm, to examine the connections between a plant's genome and its elemental profile or “ionome”. Maize has been adapted to a wider range of soil environments and biomes than any other staple crop. The Nested Association Mapping (NAM) Panel was constructed to take advantage of genetic diversity present in maize, to identify QTL with high precision. The NAM Panel has 25 recombinant inbred (RI) populations sharing B73 as common parent (5,000 RILs). In preparation for analysis of the NAM Panel, we profiled the ionomes of the NAM parents, five of the RIL populations, and the related Intermated B73 x Mo17 RI set. Samples were analyzed from up to three different sites. We found over 150 QTLs for 16 elements, including 18 QTLs that were sensitive to environmental factors (p <0.01). We saw a major Mo QTL on chromosome 1, segregating in 5 of 6 RI sets, accounting for 30–70% of the variance observed in grain Mo. These QTL co-localize with an ortholog of Mot1, the mitochondrial molybdenum transporter from Arabidopsis. Examining this locus further, we sequenced part of the ZmMot1 coding region in the Buckler/Goodman Diversity Panel and 16 teosinte accessions. Allelic diversity among wild and cultivated accessions suggests that ZmMot1 was under selection around domestication. Our studies of the NAM will rapidly lead to the discovery of genes important for control of the ionome. This information should assist the development varieties adapted to stressful soil environments and promote global food security.