Hi! I am Mingkee, an MIBTP-PhD (Midlands Integrative Bioscience Training Partnership) student working in Gifford’s lab and co-supervised by Dr. Sascha Ott (Associate Professor, Department of Computer Science). I am following up a work from a previous study in Gifford's lab that investigated plant's control of nitrogen-fixing nodulation in a model legume plant, Medicago truncatula. Using suites of genomic and phenotypic analyses, to reveal the differentially expressed genes under rhizobia and different nitrogen conditions could find six novel motifs. As promoters were found to be mainly genes involved in the nodulation response, we suggest that they may be one of the regulators for the complex nodulating pathway and root architecture depending on the nitrogen availability. Of particular prevalence among the putative promoters were a multi-gene family called Nodule-Specific Cysteine-Rich (NCR) peptide genes which we are currently investigating.
So, we propose that NCRs could be key molecules in controlling the nodulation and root architecture. We want to test if these novel motifs are functional in their control of NCR genes, discover the upstream regulatory molecules and ask if the regulatory effect has a significant effect on the ability of legumes to nodulate. Remarkably, root nodule symbiosis evolved in plants at least 5 times and is not restricted to legumes (reviewed in Lagunas et al 2015, J. Exp. Bot). We also want to identify if these motifs are conserved across Medicago to other legumes Chamaecrista fasciculata & Parasponia andersonii, a non-legume (which each evolved nodulation independently). Analysing nodulation/lateral root responses across Medicago with phenotypic and molecular methods will provide a valuable comparative resource.
Interested in seeing this idea as a graphical overview of the project?