Grant: Discovery Grants Program - Individual

This proposal is about understanding the physical barriers plants use to protect themselves from harsh environments and disease agents. The focus is on the plant cell wall polymer named suberin. Suberin is present in root tissues and the skin of underground tubers. Cells with suberin also form the basis of bark tissue. The main function of suberin is to maintain water and ion balance and protect against pathogen attack. Suberin also forms in response to wounding to seal off exposed tissues. Because of its role in protecting plants suberin is a good target for improving plant resistance to disease, protection against drought and high salt as well as long term storage. To exploit suberin as a natural defense system in the improvement of crops, we need to understand its structure and formation. My objective for this proposal is to establish the structural arrangement of the two component parts of suberin. This is important for understanding how and when suberin is made. Understanding suberin structure is a basic part of my long-term vision to use suberin to improve disease resistance and storage length of important crops such as soybean and potato. To help establish the structure of suberin, I will use techniques to disrupt suberin polymer composition and assembly. I will then determine the impact of the disruption on suberin structure and function. These experiments will help resolve the structure of suberin and establish the importance of the main components to its function as a water barrier. This research will focus on the storability of potato tubers since they are one of the main non-grain staple crops in the world. A major role for suberin in root tissues is the prevention of infection by disease microorganisms. To demonstrate that suberin is essential to root pathogen resistance I will use genetic techniques to obtain soybean lines with lower and higher than normal suberin levels. I will inoculate soybean plants having altered suberin levels with a pathogen and see whether plants with more suberin are more resistant. Since the modified soybean plants will all have a common genetic background, changes in resistance can be connected directly to root suberin levels. Improving crop resistance to pathogens through enhanced root suberin formation provides an alternative approach to crop improvement.