Friday, September 21, 2018 at 12:20pm
Department of Molecular Biology, MGH
Department of Genetics, Harvard Medical School
We are probing plant life by developing simple and powerful tools and strategies to unravel plant signal transduction pathways extending from sensors/receptors to signaling cascades and target genes and proteins that are central to energy and metabolic homeostasis, innate immunity, stress adaptation, cell fate specification, plant shape and architecture determination. Our investigations are guided by our curiosity and the desire to promote the use of green plants as a versatile and fascinating model system for discovering fundamental principles in the regulatory networks of living organisms.
Abstract: Nutrient signaling integrates and coordinates gene expression, metabolism and growth. In multicellular organisms, growth factors and hormones are ineffective in growth promotion without the support of nutrient signaling networks. However, surprisingly little is known about the molecular basis of primary nutrient signaling mechanisms in plants and animals. Plants play a central role in bridging the conversion of inorganic carbon and nitrogen to sugars and organic nitrogen in the global carbon-nitrogen cycle via photosynthesis and nitrate assimilation to generate sugars, amino acids, nucleic acids, and organic nitrogen-carbon molecules, which are essential to build and sustain all lives from plants to humans. Despite the fundamental and multifaceted regulatory roles of nitrate in gene expression, metabolism, growth and development, the molecular and cellular mechanisms of nitrate signaling remain mostly elusive in multicellular plants. Hampered by gene redundancy and mutant lethality, classical genetic screens had limited success in identifying key nitrate signaling components in plants over the past decades. By integrated molecular, cellular, biochemical, functional genomic, chemical genetic and systems analyses, we have discovered a surprising molecular link between specific Ca2+-sensor protein kinases (CPKs) and the NODULE INCEPTION-LIKE PROTEIN (NLP) transcription factors as the primary regulators of the nitrate-signaling network in plants. Our research has demonstrated the unique role of nitrate as a central signaling molecule in transcriptome reprograming and shoot-root coordination to shape organ biomass and architecture. I will discuss our efforts on continuing to build on new findings with innovative experimental platforms to elucidate the molecular and cellular basis of the nutrient-growth network that orchestrates system-wide transcription and modulates plant developmental processes.