Assistant Professor Cornell University Ithaca, New York
Body of Abstract: The plant vascular system is an information super highway through which long-distance signaling molecules move across distant organ systems, allowing belowground roots to optimize their growth, development, and physiology with above-ground shoot systems in response to environmental change. Until relatively recently, mRNAs were assumed to function within the cells where they are produced. However, the application of interspecies heterografting in combination with high-throughput RNA sequencing has led to the discovery of thousands of transcripts that move between distant organ systems. We refer to this collection of mobile transcripts as the mRNA “mobileome.” The sheer quantity of mRNAs that have been shown to travel through the long-distance transport system, as well as the consistent discovery of mRNA mobility across diverse interspecies grafting studies, raises the important question: Do these mobile mRNAs serve a function in long-distance communication? Currently, the correlation between abundance driven mobility versus selective transport of mRNAs into the vascular transport stream is poorly understood. To decipher these two modes of transport, we have developed a tomato-eggplant heterografting system that enables mobile mRNAs to be resolved with high-accuracy with exclusive genome mapping between the two parent genomes. Using dense diurnal sampling with “tomplant” and “eggmato,” we are able to test the extent to which dynamic fluctuations in transcript abundance in source tissue have the potential to influence mRNA transit into recipient organ systems. By integrating these mobile mRNAs into gene regulatory networks and emergent phenotypes in the tomato/eggplant heterografts, we can start to decipher putative signaling molecules from the sea of mobile mRNAs.