Poster: Integrated Plant Biology

Abs # 76: Phloem RNA-based Long-distance Signaling Network

Presenter:	Yoo, Byung-Chun , byoo@ucdavis.edu
Authors	Yoo, Byung-Chun  (A)   Miura, Eriko M. (A)   Archer-Evans, Sarah  (A)   Hwang, Nien-Chen  (A)   Lucas, William J. (A)
Affiliations:	(A): University of California

A role for RNA as a non-cell-autonomous signaling macromolecule is emerging as a new paradigm in plant biology. Studies on higher plants have established the operation of cell-to-cell and long-distance communication networks that mediate the transport of both endogenous RNA and viral RNA/DNA. Recent studies have demonstrated that the angiosperm phloem sap contains a unique population of RNA molecules. In addition, heterografting experiments revealed that delivery of specific RNA molecules into the scion could be correlated with a change in developmental phenotype. Plasmodesmata and the phloem also have been implicated in the spread of sequence-specific signals that underlie post-transcriptional gene silencing (PTGS) in plants. Currently, little is known with respect to how RNA molecules enter and exit the phloem translocation pathway. Our research goal is to develop a comprehensive understanding of the processes that underlie the operation of the phloem, both as a nutrient delivery system and as an information superhighway. To achieve this goal, we are currently investigating how non-cell-autonomous proteins and ribonucleoprotein complexes enter and exit the translocation stream via their passage through the unique plasmodesmata that interconnect companion cells and sieve elements. Our findings will be presented and discussed in terms of the role played by plasmodesmal-mediated trafficking of long-distance information macromolecules in the integration of physiological and developmental processes that take place in distantly located organs of the plant.