Upon recognition of pathogen attack, plants turn on immune responses to defend themselves from pathogens. The immune signaling network controls the immune response. This research is aimed at answering two questions. (1) How did the sophisticated immune signaling network in contemporary land plants arise during their evolution? (2) How much diversity in the signaling network exists among different flowering plants? Question (2) will be answered by comparing in detail how the signaling network operates in three diverse flowering plant species, tomato, rice, and the model plant Arabidopsis. The results of the research will provide an example of how sophisticated biological systems can evolve. They will also provide ideas about how the plant immune signaling network can be engineered to improve disease resistance in crops. As outreach, a mobile conservatory will be developed and used to teach 3rd grade students about how plants adapt to their environments.
The immune signaling network in the model plant Arabidopsis is highly resilient against pathogen attack on its components. This research will investigate when during the evolution of land plants such a highly resilient signaling network was acquired. This will be achieved by interrogating when specific immune-related subfamilies neofunctionalized within larger protein families using phylogenetic analysis of protein families of diverse land plant species. The subfamily analysis method will be automated and applied at the genome scale to investigate the times at which the networks controlling various other biological processes evolved. Key network components are generally conserved among angiosperms. However, it has never been investigated whether the state of a network (the set of network parameters) is also conserved. The immune signaling network state will be compared among three diverse angiosperm species, Arabidopsis, tomato, and rice. It will be achieved by combinatorially perturbing key network hubs using mutations, measuring the effects of the perturbations on the immune response using transcriptome analysis and other methods, and comparing the relationships among the key network hubs among the three species. This research will provide insights into how a highly resilient biological network has evolved and reveal the extent to which the structure and state of the immune signaling network have diverged among angiosperms. This project is co-funded by the Plant Biotic Interactions Program, the Plant Genome Research Program and the Systems and Synthetic Biology Cluster.
