(300-37) Phenotypic characterization and Analysis of Tnt1 insertion mutations in mutants defective in symbiotic nitrogen fixation in the model legume plant Medicago truncatula
Associate Professor Department of Biology, Eastern Connecticut State University Willimantic, Connecticut
Body of Abstract: Legume plants form a symbiosis with the soil bacteria rhizobia and convert atmospheric nitrogen into biologically available ammonia by symbiotic nitrogen fixation (SNF). This is important because agriculture depends on synthetic fertilizers as a major source of nitrogen. Synthetic fertilizer production depends on fossil fuels which is expensive and not sustainable. To discover novel genes that control SNF, I am characterizing four Medicago truncatulaTnt1 retrotransposon insertion mutants defective in SNF including NFxxx44, NFxxx18, NFxxx06 and NFxxx39. Wild-type and mutant plants were grown on aeroponic system in the absence of nitrogen and phenotypes were characterized. WT shoots are green with roots containing large ovoid pink nodules indicating efficient nitrogen fixation. All the SNF mutant plants display reddish-purple shoots with roots showing small spherical white/light pink nodules indicating deficient nitrogen fixation. Tnt1insertions in each mutant will be identified using the Medicago Mutant Database. Genomic DNA sequences flanking Tnt1insertions will be aligned to the Medicago genome to identify the exact locations of Tnt1 insertion mutations. Discovery of genes involved in SNF will help agriculture because farmers would use less artificial nitrogen fertilizers to grow important non-legume crops such as wheat and corn.