Some of the mysteries of why lovers can exchange roses andgardeners can root cuttings were solved by recent studies at UC Davis. In a rapidly advancing field of research, scientists are findingthat plant cells engage in a sophisticated conversation using proteins as well as hormones. "It's a totally new concept," says Bill Lucas, a UC Davis professor of plant biology and lead author of a recent Science research report. In their paper, Lucas and his colleagues showed how the genetic blueprint for a protein can be transported from cell to cell. For this to occur, a traveling companion, known as a movement protein, appears to have the ticket to travel through a tiny but extensive network called the plasmodesmata, once thought too narrow to accommodate the transport of proteins and nucleic acids (RNA). While plant cells may be fixed in place, like rooms in a building, the cells can be "remodeled" through internal cell-to-cell communication, to produce stems, roots, flowers or fruit, Lucas says. Previously, plant cell fate was thought to depend upon location and plant hormones that tell a cell to grow or stop growing or to become part of a flower or a fruit. "We plant scientists had no idea that plants had the capacity to traffic their own proteins and RNA from cell to cell," Lucas says. "This sets in place a whole new way of understanding how plants control the development and fate of cells."