Arabidopsis 2010: Abiotic stress combination: bridging the gap between Arabidopsis stress research and agriculture.
Ron Mittler Ph.D. Department of Biochemistry and Molecular Biology University of Nevada, Reno NV 89557
Shulaev, Vladimir, Ph.D. Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24061
The project intends to identify the genetic and metabolic networks that respond to abiotic stress combinations, specifically drought and heat, drought and salinity, salinity and heat, as well as drought heat and salinity. Our approach is to first define genes, proteins, pathways and networks specific for abiotic stress combinations, and then pursue mechanistic understanding using an integrated approach of genetics, biochemistry and bioinformatics (Fig. 1). This project is designed to bring Arabidopsis into the front line of applied research on abiotic stress tolerance, and bridge between laboratory studies of stress responses in Arabidopsis and the reality of multiple stress conditions that impact crops in the field. The project also intends to contribute to the long-term goal of elucidating the function of every gene in Arabidopsis.
Abiotic stress research: how good are molecular studies at mimicking the field conditions?
Molecular biologists have traditionally studied abiotic stress in plants by applying a single stress condition such as drought, salinity or heat, and analyzing the different molecular aspects of plant acclimation. However, this type of analysis might not reflect the conditions that occur in the field,
in which crops are routinely subjected to a combination of different abiotic stresses. A considerable gap might exist between the knowledge gained by these studies and the knowledge required to develop plants and crops with enhanced tolerance to field conditions . A focus on molecular, physiological and metabolic aspects of stress combinations in Arabidopsis is vital to bridge this gap and bring Arabidopsis into the front line of applied abiotic stress research.
Unique aspects of stress combination:
Recent studies demonstrated that the molecular, biochemical and metabolic responses of plants to a combination of drought and heat stress are unique and cannot be predicted directly from the response of plants to each of these different stresses applied individually.
Fig. 4. Physiological and molecular characterization of tobacco and Arabidopsis plants subjected to a combination
of drought and heat stress. A. Physiological characterization of tobacco and Arabidopsis plants presented as % of
control to summarize data from tobacco and Arabidopsis (1,2). B. and C. Venn diagrams summarizing transcriptome
(B) and metabolome (C) profiling of Arabidopsis plants subjected to drought, heat or a combination of drought and
heat (after 2). Heat and drought+heat were profiled based on similar leaf temperature (2). Mittler, Trends in Plant Science 11:15-19 (2006).
The approach is to use a time-course of metabolomic, proteomic and transcriptomic measurements under specific stress combinations, followed by a bioinformatic approach to determine which genes, pathways and networks are altered specifically under each stress combination. The hypothesis to be tested is that dedicated genes, networks and pathways are activated in plants simultaneously exposed to two different stress conditions.