Nam-Hai Chua, Ph.D.
Andrew W. Mellon Professor
Because they can’t pick up and move, plants must react rapidly to changes in their environment. To do this requires a complex network of signaling pathways that can involve epigenetic factors, such as noncoding RNA molecules. Dr. Chua studies how some of these pathways work. His laboratory is currently investigating how plants respond to stress, including changes in water and nutrient availability.
Using Arabidopsis as a model, Dr. Chua’s lab employs a combination of genetic, molecular, and biochemical techniques — including transcriptome analysis, mutant screens, and transgenic plants — to investigate how plants respond to abiotic and biotic signals and stresses at the molecular level.
Water, nitrogen, and phosphate are some of the most important environmental stimuli for plants. Molecular responses to these factors are integral to the regulation of a plant’s development. Plant homeostasis is maintained by phytohormones and signaling molecules. Changes in water and nutrient availability can modulate hormone and signaling pathways, resulting in complex physiological and developmental responses. Members of the Chua lab are focusing on identifying the molecular mechanisms of these responses, including identifying signaling pathway intermediates and changes in expression due to epigenetic factors, such as chromatin modifications and noncoding RNAs.
In addition to this, members of the Chua lab are investigating the role of long noncoding RNAs in plant stress response. Recently, Dr. Chua’s lab has found that the Arabidopsis genome encodes around 8,000 long intergenic noncoding RNAs (lincRNAs) and 36,000 natural antisense transcripts (NATs) whose functions await identification. Current effort is directed toward the characterization of genes involved in the biogenesis and regulation of lincRNAs and NATs and the elucidation of the functions of these noncoding RNAs.
Prior work in Dr. Chua’s lab established several of the basic tools necessary to conduct molecular research in plants. One of those tools is 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. The lab has 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 roles of their modifications in signaling will lead to strategies by which scientists may manipulate plant genetics in order to fortify crops against viral infection, drought, flood, pests, and other suboptimal 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 agriculture in regions of the world that are today poorly suited to it.