Dissection of the mechanisms integrating phosphate nutrition and plant growth involving the kinase ARSK1

Michigan State University, East Lansing MI

Investigators

Abstract

Phosphorus (P) is a non-renewable macronutrient that is vital for all organisms. Plants absorb P through roots but the scarcity of P in soil often requires the use of fertilizers for optimal crop yields, contributing to unsustainable practices grounded in the depletion of global P reserves. Therefore, understanding how plants adapt their root system to soil P levels is of paramount importance, especially as P deficiency induces significant changes in root system architecture very early in development. The primary objective of this project is to deepen the fundamental knowledge of the molecular mechanisms governing early root growth in response to P deficiency in a model plant species. The scientists conducting this project have discovered a crucial gene in a new P signaling pathway regulating early root growth. Based on this important discovery, they aim to determine a complete pathway controlling root growth in a P-dependent manner. In addition to advancing knowledge, this project aims to disseminate research for education and training, engage under-represented students in research, and connect with high-school students. The proposed work offers significant opportunities for student training, education, and outreach by integrating research results into undergraduate courses, utilizing program tools for summer internships for high school students and teachers, and communicating the research's importance at various events such as K-12 school fairs and Girls’ Math and Science Days. This project addresses the fundamental question of how plants adapt their growth in nutrient-deficient conditions, focusing on the root responses to P, an essential non-renewable mineral. The researchers have identified a novel signaling pathway involving Arabidopsis Root-Specific Kinase 1 (ARSK1), a kinase playing a crucial role in controlling early root growth in Arabidopsis in response to low P. The research focuses on defining the yet-unknown mechanisms for translational and post-translational regulation of ARSK1 dependent on P availability as well as the identity of the genes operating in the ARSK1-signaling pathway. This project will employ a unique combination of state-of-the-art computational, biochemical, and molecular physiology approaches in the model plant species Arabidopsis thaliana. Specifically, this project will investigate: i) the regulation of ARSK1 expression by specific transcription factors at a molecular level; ii) the regulation of ARSK1 protein levels by a P-induced ubiquitin E3 ligase. Finally, the research will validate the roles of the newly identified genes and of ARSK1 in regulating early root growth in a P-dependent manner. The results of this project will increase understanding of the signaling cascade connecting nutrient levels with the control of organ growth. Diverse postdoctoral, undergraduate, and high-school students will receive training through this grant, and the impact of the research will be broadened through outreach to under-represented groups and interactions with local community colleges. This award is funded by the Cellular Dynamics and Function Cluster of the Division of Molecular and Cellular Biosciences in the Directorate for Biological Sciences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.