|Chandran, D - UNIVERSITY OF MINNESOTA|
|Ivashuta, S - UNIVERSITY OF MINNESOTA|
|Gantt, S - UNIVERSITY OF MINNESOTA|
Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 16, 2005
Publication Date: July 16, 2005
Citation: Chandran, D., Ivashuta, S., Gantt, S., Samac, D.A. 2005. Molecular characterization of Al-induced genes in Medicago truncatula and examination of their role in Al tolerance [abstract]. American Society of Plant Biologists Annual Meeting. Abstract No. 511. Technical Abstract: Aluminum (Al) toxicity is one of the important causes of crop losses in acid soils (pH<5). Under acidic conditions, several phytotoxic species of Al are released into the soil solution at levels that inhibit plant root growth, ultimately resulting in plants impaired in water and mineral uptake. In this study, a molecular approach was used to identify genes that may play a role in Al tolerance in the model legume, Medicago truncatula. Ten aluminum-induced genes, previously identified in long oligonucleotide array experiments, were selected as candidates based on their expression level and predicted function. RNA expression levels of these candidate genes were determined in root tips of an Al-tolerant (T32) and sensitive accession (S70) using real-time PCR and significant differences were observed in expression of eight of these genes. Double-stranded RNA was used to induce gene silencing in transgenic hairy roots of M. truncatula to study the function of some of these genes and results from these experiments will be presented. One of the genes, designated MtAnn1, encodes a protein homologous to the annexin family of calcium- and phospholipid-binding proteins and has been shown to be induced during symbiotic associations with Sinorhizobium meliloti, both at early stages in bacterial-inoculated roots and in nodule structures. However, this is the first report, as far as we know, demonstrating induction of this gene in response to Al stress. PromoterMtAnn1-GUS and pMtAnn1-MtAnn1-GFP constructs will be used to study tissue-specific expression profiles and intracellular distribution of this gene in response to Al stress.