Using Arabidopsis as a model plant, Dr. Chua’s lab employs a combination of genetic, molecular and biochemical techniques — including mutant screens and analysis of transgenic plants — to look for different components of signal transduction pathways involved in their response to light and their ability to suppress viral infection and replication.

Light is one of a plant’s most important environmental stimuli, and light signal transduction pathways are central to the regulation of its development. Plants perceive discrete wavelengths of light through photoreceptors, such as phytochromes and cryptochromes, and the signaling pathways enable information about the direction, intensity and duration of specific wavelengths to be amplified and coordinated, resulting in complex physiological and developmental responses throughout the plant’s life cycle. Members of the Chua lab are focusing on the identification of signaling intermediates that promote phytochrome A signal transduction.

Additional areas of focus in the Chua laboratory include investigation into the role of microRNA (miRNA) in plant development, the identification of genes involved in miRNA and small interfering RNA (siRNA) biogenesis, and an effort to understand how these small RNA pathways are regulated. Plants produce miRNAs to regulate the levels of gene transcript that encode important regulatory proteins, and Dr. Chua has identified several miRNAs that control plant hormonal responses.

Plants defend against invading viruses by degrading viral RNAs. Viruses, on the other hand, counter this attack by synthesizing suppressor proteins to block degradation. Members of the Chua lab are investigating this defense and counterdefense strategy as it relates to the synthesis of siRNAs and their mechanism of action of viral suppressors. In a related set of experiments, Dr. Chua has designed artificial miRNAs that can guide cleavage of specific viral RNAs, thereby conferring viral resistance in expressing transgenic plants. He is also using this technique to target specific cellular transcripts with the aim of modifying a plant’s responses to its environment.

Prior work in Dr. Chua’s lab established several of the basic tools necessary to conduct molecular research in plants. One of those tools was a highly controllable and chemically inducible plant gene expression system that allows researchers to turn transgenes on and off as desired. Using this system, Dr. Chua found key proteins involved in the plant’s response to the light/dark transition. Dr. Chua’s research has also identified proteins that play a role in a plant’s reaction to drought. They have constructed different transgenic mutants that are more tolerant of drought conditions and can resume growth when water is no longer a limiting factor.

Learning how plants’ protein intermediates act, and understanding the role of their modifications in signaling, will lead to strategies by which scientists may manipulate plants’ genetics in order to fortify crops against viral infection, drought, flood, pests and other unsatisfactory conditions. The knowledge generated by Dr. Chua through the use of Arabidopsis can be applied toward crop improvement to reduce hunger around the world, as well as to create sustainable economics in portions of the world that are today poorly suited to agriculture.

CAREER

Dr. Chua was born in Singapore and earned his B.S. in botany and biochemistry from the University of Singapore in 1965 and his A.M. and Ph.D. from Harvard University in 1967 and 1969, respectively. He was a lecturer in biochemistry at the University of Singapore Medical School from 1969 to 1971. Dr. Chua joined Rockefeller in 1971 as a research associate in cell biology, was named assistant professor in 1973, associate professor in 1977 and professor in 1981.

Dr. Chua was awarded the International Prize in Biology in 2005, the Singapore Public Administration Gold Medal in 2002 and the Singapore National Science and Technology Gold Medal in 1998. Dr. Chua is an elected member of the Academia Sinica (Taiwan), a fellow of the Royal Society (UK) and a foreign member of the Chinese Academy of Sciences. He is an honorary member of the Japan Biochemical Society and the Japan Society of Plant Physiology.