Ph.D., Indiana University, 1979-82
Postdoctoral Research: University of Washington
Address: 215B Biochemistry Addn
Research InterestsWe study how the environmental cues that result from seasonal change are perceived and then transduced into developmental changes such as the transition to flowering.
The major developmental change
in the plant life cycle is the initiation of flowering. Many plant
species have evolved the ability to regulate flowering in response to
environmental variables such as changes in day-length or temperature. An
example of a temperature response is that certain plants require
relatively long periods of cold exposure during winter to initiate
flowering the following spring. This acquisition of competence to flower
after prolonged exposure to cold is known as vernalization. Before
competence is achieved, plants must measure exposure to a sufficient
number of days of cold to represent a complete winter; this ensures
flowering only occurs when spring has arrived, rather than during a
temporary warming in the middle of winter.
We are using a combination of genetics and biochemistry to better understand, at a molecular level, the process of vernalization. For example, we identified a gene (FLC) in the crucifer Arabidopsis thaliana that prevents flowering unless they have experienced the cold of winter. Exposure to cold promotes flowering via a stable epigenetic switch of FLC to a repressed state. This epigenetic state of FLC is reset to an active state in the next generation. We are also studying vernalization in the grass Brachypodium distachyon. Grasses have a vernalization system that evolved independently of that in Arabidopsis thaliana. In fact, the vernalization systems in different groups of plants all result from convergent evolution. This is not surprising because when flowering plants were diverging, the earth was much warmer and the landmasses were in different locations than at present. Only after many ecosystems became colder, would a vernalization response (and other cold responses such as cold-mediated release of bud dormancy) be adaptive.
We are also studying biomass traits in Brachypodium distachyon in an effort supported by the Great Lakes Bioenergy Research Center (www.glbrc.org), and have several projects in the area of science education.
Amasino R. 2010. Seasonal and developmental timing of flowering. Plant J. 61:1001-13.
Schwartz, C. J., Doyle, M. R., Manzaneda, A. J., Rey, P. J., Mitchell-Olds, T. & Amasino, R. M. 2010. Natural Variation of Flowering Time and Vernalization Responsiveness in Brachypodium distachyon. Bioenerg. Res. 3:38–46
Tamada, Y., J-Y. Yun, S. Woo and R. M. Amasino. 2009. ARABIDOPSIS TRITHORAX-RELATED 7 is required for methylation of lysine 4 of histone H3 and for transcriptional activation of FLOWERING LOCUS C. Plant Cell: 21: 3257-3269.
Doyle, M. R., and R. M. Amasino. 2009. A single amino acid change in the Enhancer of Zeste ortholog CURLY LEAF results in vernalization-independent, rapid-flowering in Arabidopsis. Plant Physiology: 151: 1688-1697.