Faculty conversations: Rob Last
Rob Last studies biochemistry — specifically, the chemical processes in plants.
The recently-named Barnett Rosenberg Professor of Biochemistry in the Department of Biochemistry and Molecular Biology and the Department of Plant Biology is studying tomato plants and how they produce chemicals that protect them from pests.
Trichomes, or small hair cells located on the leaves and stems of the plant, are like chemical factories, Last said. When these cells are ruptured by insects, the pungent smelling or toxic chemicals of a tomato plant are released from these hairs, which may deter insects from eating the plant. He and several other professors are studying the evolution of these protective chemicals.
Last also studies other metabolic processes in plants — how materials are created and destroyed and how energy is captured and utilized for growth — using a small flowering weed known as Arabidopsis thaliana. Metabolism in plants is complex in ways that scientists do not yet understand, so when certain enzymes or environmental factors are manipulated, the outcome is often hard to predict.
“When taught about metabolic biochemistry in college and in graduate school, we’re typically taught about a linear set of reactions or even cycles,” Last said. “But it’s starting to look more and more as though metabolism is really a much more complicated process. It’s not really a pathway or a series of pathways. It’s almost certainly a network.”
Last hopes that by understanding this network, scientists will be able to use that knowledge to metabolically engineer plants. For example, an individual could change a soybean plant to produce more oil from its seeds or create a different kind of cell wall in switchgrass so it may be more easily converted into ethanol.
Last uses Arabidopsis thaliana for his studies because it is a great model — it is fairly common, grows quickly and has a very small genome (hereditary information, which is encoded in DNA) and the exact sequence of chemicals that make up its DNA are already known.
“It’s a really wonderful training tool, whether it’s for undergraduate students in the lab, graduate students or post-docs,” Last said. “When we think about the relevance of a project or scientific relevance, I think it’s also really important to think in terms of training the next generation of students, the next generation of scientists, of citizens and so on.”