Genetic network of nicotianamine function in the regulation of metal homeostasis in Arabidopsis thaliana

• Applicant: Professorin Dr. Petra Bauer
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2007 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 50049631

Nicotianamine chelates iron, nickel and other metals and plays an important role in intracellular and intercellular transport of metals, especially iron, and metal detoxification. This plant-specific amino acid is produced by nicotianamine synthase encoded by a multigene family in Arabidopsis. The four NAS genes are likely the result of genome duplication. We generated a quadruple nicotianamine synthase mutant with strongly reduced nicotianamine levels. This mutant shows leaf chlorosis and increased susceptibilitiy to iron deficiency and nickel stress suggesting that nicotianamine was required for adequate metal homeostasis. Here, we will utilise the nas 4x line to explore an exemplary network, namely metal homeostasis regulation. We will study transcriptional and post-transcriptional regulation to identify genes and proteins whose expression level is influenced by nicotianamine upon changes of metal supply. We will determine their functions with respect to iron nutrition and metal homeostasis in roots and in the inflorescence. We are interested in the connection to known members of the putative nicotianamine transporter YSL gene family and the iron-regulated BHLH transcription factor gene family. This way, we will integrate nicotianamine function into an interaction network involved in metal uptake regulation. In addition, the project outcome will likely provide new tools to the community for analysis of complex expression data at multiple levels. It will also provide data on the extent of transcriptional versus post-transcriptional regulation in an exemplary system.

• DFG Programme: Research Grants