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Title: Identification and comparison of quantitiative trait loci associated with seed zinc concentration in Lotus japonicus and Medicago truncatula

item Grusak, Michael

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/12/2007
Publication Date: 5/24/2007
Citation: Klein, M., Sankaran, R., Grusak, M.A. 2007. Identification and comparison of quantitiative trait loci associated with seed zinc concentration in Lotus japonicus and Medicago truncatula [abstract]. In: Zinc Crops 2007, May 24-26, 2007,Istanbul, Turkey. Poster GMB-9.

Interpretive Summary:

Technical Abstract: Reports indicate that zinc deficiency is a widespread problem for crop plants and humans. Increasing the amount of bioavailable micronutrients such as iron and zinc in plant foods for human consumption is a challenge, especially in developing countries where plant foods comprise a significant portion of the diet. Legume seeds are a rich source of proteins and have the potential to provide the essential nutrients required by humans who subsist on a plant-based diet. However, the concentration and bioavailability of minerals in these seeds is limited when compared to animal food products. As such, our research program is interested in improving the nutrient concentration and availability of plant-based protein sources in order to improve human nutrition. In order to improve seed mineral concentrations, we have to understand the genetic basis and identify molecular components involved in mineral distribution. Genetic tools such as recombinant inbred lines can be used to identify quantitative trait loci (QTLs) associated with seed mineral traits. To that end we are conducting research to identify quantitative trait loci (QTLs) linked to a number of nutritive qualities including improved seed Zn concentration in the model legume species Lotus japonicus and Medicago truncatula. In Medicago, frequency distribution of seed Zn showed transgressive segregation in the RIL population. There was no correlation between Zn and other mineral concentrations. Significant Zn QTLs were found on chromosomes 4, 7, and 8 with 24.2, 17.9, and 8.9% of explained variance, respectively. These QTLs overlapped with other mineral QTLs. For example, the Zn QTL on chromosome 7 overlapped with a significant Fe QTL which also had a high level of explained variance (21.2%). Additional Medicago lines have been grown and are currently being analyzed for seed minerals. Mineral analysis is currently being conducted with the Lotus RILs. Transgressive segregation for seed mineral concentrations demonstrates that new allelic combinations can be used to increase seed Zn levels. For loci where different mineral QTLs co-localize, it is possible that a common whole-plant phenotypic trait, such as transpiration efficiency, root size, etc., might be contributing to the seed mineral levels.