Last June, Lucas was formally inducted into the academy at a ceremony in Paris. Lucas admires the broad outlook and intense style of French intellectual debate. Lucas has overlapping interests with some French researchers, and often strong disagreements, too, which have stimulated further debate and helped to drive research. Australian by birth, Lucas obtained his Ph.D. from the University of Adelaide and worked at the University of Toronto in Canada before arriving at UC Davis in 1977. It was at UC Davis that he began to study phloem, the network of highly specialized cellular tubes running through plants.
Phloem forms the communication system that joins leaves, stems and roots into a single plant.
He was trying to investigate the biophysical properties of phloem, but the experiments were compromised by the presence of plasmodesmata, small pores that connect the phloem to the cells in surrounding tissues. At the time, it was thought that plasmodesmata formed simple pores between plant cells to allow the movement of essential nutrients. Initially annoyed by the troublesome plasmodesmata, Lucas soon realized that this opened up a whole new area of research. The movement protein acts as a passport that lets the viral RNA cross the plasmodesmal checkpoint. Lucas realized that these plant viruses were the key to understanding the plant' s own communication system, since they must have either acquired or copied these movement proteins from their hosts.