Grant: Discovery Grants Program - Individual

Ubiquitin is a highly conserved eukaryotic protein with immensely important and diverse regulatory functions. A well-defined role is within the Ubiquitin Proteasome System (UPS), where the attachment of ubiquitin molecules to select proteins serve as a `flag' for recognition and degradation by the proteasome. A key component of the UPS are the ubiquitin ligases (or E3s), which govern substrate protein selection and mediate the attachment of ubiquitin molecules. Plants utilize a large number of E3s and the UPS to bring about changes in cellular protein content required for growth and surviving sub-optimal growth environments. The purpose of the proposal is to decipher how the UPS assist the root in acquiring nutrients from the soil and coping with low availability in three essential nutrients, iron, phosphorus, and nitrogen. Iron, for example, is a critical component of many cellular processes including photosynthesis. Consequently, plants grown in soil with inadequate levels of iron experience poor health, reduced resilience, and decrease productivity. The impact of climate change on crops include reduction in nutrient availability and decrease nutrient content in the edible parts of crops. Plants are the primary dietary source of nutrients for many people and reducing nutrient content has serious consequences for human nutrition. While the use of amendments can mitigate the negative effects of low nutrient soil, a sustainable approach is to develop strategies for maintaining crop yield and quality with fewer agricultural inputs to reduce green house gas emissions. However, gaps in our understanding of the mechanisms underlying nutrient uptake and tolerance to nutrient deficiencies hinder development of crop improvement strategies. The proposal seeks to address these knowledge gaps by utilizing genetic, molecular, and proteomic approaches for an in-depth analysis of nutrient acquisition facilitated by the UPS. Aims include characterizing the function of candidate E3s in modulating nutrient uptake in response to changes in availability and examining the nutrient-specific root ubiquitinome. Outcomes of the research proposal will translate to maintaining, as well as improving, the ability of crops to acquire nutrients with direct impact on increasing food security and improving human nutrition as we contend with climate change, loss of arable land and a growing population.