AS a senior graduate student contemplating my postdoctoral options, I was struck by the paper “Arabidopsis thaliana mutant that develops as a light-grown plant in the absence of light” (Chory et al. 1989). The temerity of looking for mutant plants that developed as if in the light when in the dark, along with the fact that this idea was only then being brought to fruition, was striking. The possibilities of this new model plant must be vast! The elegance of the screen, the dramatic results, and the clear exposition drew me in, and I moved from yeast to Arabidopsis for my postdoctoral studies. Thus it is a particular honor for me to announce Joanne Chory, Professor and Director of the Plant Molecular and Cellular Biology Laboratory at the Salk Institute and a Howard Hughes Medical Institute Investigator, as the 2012 recipient of the Genetics Society of America Medal in recognition of her many outstanding contributions to the field of genetics.
Joanne did not begin her career as a plant geneticist. After receiving her bachelor's degree in biology from Oberlin College in Ohio, she moved to the University of Illinois at Urbana-Champaign for graduate studies in microbiology. A student with Samuel Kaplan, she studied the morphogenesis of photosynthetic membranes in the purple nonsulfur photosynthetic bacterium, Rhodobacter sphaeroides. In Kaplan's laboratory, Joanne learned bacterial genetics and protein biochemistry while developing an appreciation for working in a system where phenotype can be manipulated by the investigator. As Joanne was finishing her Ph.D. work, Barbara McClintock won a Nobel Prize for her work on maize transposons, and geneticists were beginning to stream from diverse and often nonplant organisms to Arabidopsis thaliana, eager to apply the new tools of molecular biology and transformation to a tractable plant system. One of these converts was Fred Ausubel, a bacterial geneticist at Harvard Medical School, and Joanne joined the Ausubel laboratory for her postdoctoral studies. She wanted to work on signal transduction in plants, and in 1984, light signaling was the one system in which both ends of the pathway were known; a photoreceptor, “phytochrome,” had been purified, and it was already clear that the transcripts of hundreds if not thousands of nuclear and chloroplast genes were regulated by light. The system was ripe for genetic analysis. In the Ausubel laboratory, Joanne applied her expertise in bacterial photosynthesis to develop genetic screens for Arabidopsis light-signaling mutants, including the de-etiolated (det) screen for mutants that constitutively display developmental programs that are light-dependent in wild type (Chory et al. 1989).
Joanne established her group at the Salk Institute in 1988, where she and her colleagues have continued to decipher the mechanisms that plants use to respond to changes in their light environment. In a series of landmark studies, she helped elucidate the roles of individual phytochromes, the red/far-red light receptors that modulate germination, development, neighbor detection, and circadian responses (Chory 2010). She used the genomes uncoupled (gun) screen to implicate chloroplast-derived products of the tetrapyrrole pathway in modulating expression of nuclear genes (Susek et al. 1993; Woodson et al. 2011), providing mechanistic insights into interorganellar communication. While taking full advantage of the experimental control provided by studying the reference plant in a laboratory environment, she recognized early the power of natural variation as a tool to decipher the importance of various genes in the plant's natural (outdoor) habitat (Maloof et al. 2001; Borevitz et al. 2002). Joanne's basic research findings on how plants develop and grow in response to changes in the environment are providing the scientific underpinnings for the increases in crop yields that will be necessary to sustain the earth's population.
As a geneticist, Joanne lets the mutants lead, and she did not shy away when they led into uncharted waters. Her discovery that the Arabidopsis de-etiolated2 mutant was defective in biosynthesis of a brassinosteroid both uncovered a new class of plant hormones and demonstrated a role for these hormones in light signaling (Li et al. 1996). A screen for brassinosteroid-insensitive dwarfs uncovered an astounding 18 alleles with defects in the brassinosteroid receptor (Li and Chory 1997), and over the ensuing 15 years, a series of sophisticated suppressor and enhancer screens by Joanne and her colleagues has illuminated the intricate details of the brassinosteroid signal as it is transduced from perception at the membrane through protein interaction, phosphorylation, and degradation events to transcriptional changes in the nucleus (Belkhadir and Chory 2006; Hothorn et al. 2011).
Joanne also has made important contributions to our understanding of the essential plant hormone auxin. The auxin biosynthetic pathway is plagued by genetic redundancy that hampers traditional loss-of-function genetics. As one of the developers of activation tagging, a method allowing isolation of genes on the basis of their gain-of-function phenotype (Weigel et al. 2000), her group was poised to use this new tool to uncover the rate-limiting enzymes in a previously unanticipated pathway of auxin biosynthesis (Zhao et al. 2001). Several years later, Joanne's group uncovered a second step in this pathway via a novel shade-avoidance screen (Tao et al. 2008), and we are now tantalizingly close to having the first complete biosynthetic pathway for auxin (Won et al. 2011), a plant hormone that has been studied for well over a century.
Joanne remembers fondly the mentoring and advice she received as a part of the tiny Boston Arabidopsis group in the 1980s from Fred Ausubel and Gerry Fink, who have continued to support her throughout her career. In turn, she serves as a mentor and role model to the next generation of scientists. She has trained >70 students and postdocs, many of whom are now faculty members around the world, refining and expanding projects that they started in her laboratory.
Beyond her own research (165 primary papers and 53 refereed reviews), Joanne is a tireless advocate for science in general and plant biology in particular. She was a founding, elected member of the North American Arabidopsis Steering Committee, which was formed in 1992 to organize the national Arabidopsis meeting and advise the National Science Foundation and other agencies on community needs. Her research has been supported by multiple federal funding agencies, but of particular note is her appointment as an investigator of the Howard Hughes Medical Institute (HHMI) in 1997, when she was the first HHMI investigator to use a plant as the primary organism of study. Her remarkable research successes, along with her effective championing of the relevance and importance of plant biology, were undoubtedly key elements in the recent opening of HHMI support to a larger group of plant scientists with the selection of the first HHMI-Gordon and Betty Moore Foundation investigators in 2011.
Joanne's scientific accomplishments are widely recognized: she is a fellow of the American Academy of Arts and Sciences (1998), a member of the U. S. National Academy of Sciences (1999), a fellow of the American Association for the Advancement of Science (2005), an associate member of the European Molecular Biology Organization (2006), a member of the German National Academy of Sciences (2008), a foreign associate of the French Académie des Sciences (2009), and a foreign member of the Royal Society (2011). Her awards include the National Academy of Sciences Award for Initiatives in Research (1994), the Charles Albert Schull Award from the American Society of Plant Biologists (1995), the L'Oreal-UNESCO Award for Women in Science (North America 2000), and the Kumho Award in Plant Molecular Biology (2004). The Genetics Society of America is pleased to add one more richly deserved tribute to this long list, the 2012 GSA Medal.
- Copyright © 2012 by the Genetics Society of America
