Associate Professor of Biochemistry and Molecular Biology, University of Massachusetts
Ph.D.: Duke University
Our goal is to understand the interaction between multicellular hosts and their microbial partners, with a focus on symbiotic associations. The living world is shaped by complex networks of interactions between organisms, some antagonistic and others beneficial. Symbioses allow diverse species to achieve feats unattainable by individual members. These collaborations frequently reflect elegant co- evolution; some are so successful as to have global-scale effects.We aim to illuminate the molecular basis of highly evolved and intimate forms of symbiosis. Our system is the association between legume plants and nitrogen-fixing bacteria. The two species undergo a complex series of developmental changes, resulting in a specialized symbiotic organ, the root nodule. Within the nodule, bacteria are transformed into intracellular organelles – called symbiosomes – dedicated to converting (fixing) molecular nitrogen into ammonia for the host plant. Because fixed nitrogen is frequently the scarcest soil nutrient for plants, this symbiosis has significant economic and ecological impacts: legume crops provide a large portion of the protein in the human diet without nitrogen fertilizers. Globally, biologically fixed nitrogen constitutes a major component of the nitrogen cycle.
What gives legume species the remarkable ability to provide their own nutrient through an alliance with nitrogen-fixing bacteria? Specifically, what molecular mechanisms allow the host to recognize the appropriate bacteria, internalize the microbes, convert them into specialized organelles, and create the proper cellular environment for nutrient exchange?We use the model legume Medicago truncatula (a relative of alfalfa) to address three research themes:
Wang D and Dong X. A highway for war and peace: the secretory pathway in plant-microbe interactions. Molecular Plant, 4(4):581 (2011).
Wang D, Griffitts J, Starker C, Fedorova E, Limpens E, Ivanov S, Bisseling T, and Long SR. A nodule specific protein secretory pathway required for nitrogen-fixing symbiosis. Science, 327(5969):1126 (2010). (Highlighted in Cell 141(1):5)
Wang D*, Pajerowska-Mukhtar K*, Culler AH, and Dong X. Salicylic acid inhibits pathogen growth in plants through repression of the auxin signaling pathway. Current Biology, 17(20):1784 (2007). *: equal contribution
Sato M, Mitra R, Coller J, Wang D, Spivey N, Dewdney J, Denoux C, Glazebrook J, and Katagiri F. A high performance, small-scale microarray for expression profiling of many samples in Arabidopsis-pathogen studies. Plant Journal, 49(3):565 (2007).
Wang D, Amornsiripanitch N, and Dong X. A genomic approach to identify regulatory nodes in the transcriptional network of systemic acquired resistance in plants. PLoS Pathogens 2(11):e123 (2006). (Cover. Commentary in PLoS Pathogens 2(11): e126.)
Mosher RA, Durrant WE, Wang D, Song J, and Dong X. A comprehensive structure-function analysis of Arabidopsis SNI1 defines essential regions and transcriptional repressor activity. Plant Cell 18(7):1750 (2006).
Wang D, Weaver ND, Kesarwani M, and Dong X. Induction of protein secretory pathway is required for systemic acquired resistance. Science 308(5724):1036 (2005).