Sept. 6, 2013
Michael Thomashow is a University Distinguished Professor of molecular genetics and director of MSU’s Plant Research Laboratory.
After growing up and spending a good part of my young adult life in southern California, it was a shock to my system when I moved to Pullman, Wash., for my first faculty position in the early 1980s. It also was, however, a turning point in my research career.
Winter was very cold in Pullman. I remember looking out my laboratory window at plants surviving in minus 20-degree weather and asking myself, “How are these plants dealing with this incredible cold? How do they overwinter in such a harsh environment?” This got me interested in understanding the genetic mechanisms that plants have evolved to withstand freezing and other environmental stresses.
I looked to the literature and found that specific genes hadn’t been identified for freezing tolerance—most of the work that had been done was biochemical and physiological in nature—but it was clear that freezing tolerance, like heat and drought tolerance, was very complex, involving the interaction of many genes. I decided that I wanted to work on the problem and test the hypothesis that low temperature causes changes in gene expression that impart freezing tolerance.
When I came to MSU in 1986, there was a lot of skepticism in the scientific community about whether the study of cold-regulated gene expression could offer enough information and knowledge to provide significant new insight into the genetic basis of freezing tolerance. Thirty years later, I’m pleased to be able to say that our basic hypothesis was correct and led to the discovery of the CBF cold-response pathway, a genetic pathway found in many plants that controls freezing tolerance. And the pathway contributes to drought tolerance as well.
Recently, we found that the CBF pathway is partially activated by short days. Plants are incredible! They can sense shortening days and “know” that they need to start to increase in freezing tolerance because winter must be coming. Then when they sense low temperature, they pull out the stops and increase to their maximum freezing tolerance. The questions now are, “How do they sense day length and temperature and activate genes that impart freezing tolerance? And of course, why can’t tomatoes and many other plants do this?”
Going step-by-step, our hope is that we can use the basic knowledge that we have gained to improve the freezing of plants, lengthen the growing season and expand the growing regions for as many crops as possible.