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GLOBAL TRANSCRIPTION PROFILING REVEALS DIFFERENTIAL RESPONSES TO CHRONIC NITROGEN STRESS AND PUTATIVE NITROGEN REGULATORY COMPONENTS IN ARABIDOPSIS
Citation:
BI, Y., R. WANG, T. ZHU, AND S. ROTHSTEIN. GLOBAL TRANSCRIPTION PROFILING REVEALS DIFFERENTIAL RESPONSES TO CHRONIC NITROGEN STRESS AND PUTATIVE NITROGEN REGULATORY COMPONENTS IN ARABIDOPSIS. BMC Genomics. BioMed Central Ltd, London, Uk, 8(281):1471-2164, (2007).
Impact/Purpose:
The objective of this task is to develop molecular indicators to evaluate the integrity and sustainability of aquatic fish, invertebrate, and plant communities (GPRA goal 4.5.2). Specifically, this subtask aims to evaluate methods for the measurement of:
fish and invertebrate community composition, especially for morphologically indistinct (cryptic) species
population genetic structure of aquatic indicator species and its relationship to landscape determinants of population structure (to aid in defining natural assessment units and to allow correlation of population substructure with regional stressor coverages)
genetic diversity within populations of aquatic indicator species, as an indicator of vulnerability to further exposure and as an indicator of cumulative exposure
patterns of temporal change in genetic diversity of aquatic indicator species, as a monitoring tool for establishing long-term population trends.
Description:
Background: A large quantity of nitrogen (N) fertilizer is used for crop production to achieve high yields at a significant economic and environmental cost. Efforts have been directed to understanding the molecular basis of plant responses to N and to identifying N-responsive genes in order to manipulate their expression and enable plants to use N more efficiently. No studies have yet delineated the responses at the transcriptional levels when plants are grown under chronic N stress and the knowledge of the regulatory elements involved in N response is very limited. Results: To further our understanding of the response of plants to varying N levels, a growth system was developed where N was the growth-limiting factor. An Arabidopsis whole-genome array was used to give a global evaluation of gene expression under different N conditions. Significantly differentially expressed genes under mild or severe chronic N stress were identified. Mild N stress only triggered a small set of genes significantly different at the transcriptional level and they were largely involved in various stress responses. Plant responses were much more pronounced under severe N stress, with a large number of significant genes identified which are involved in many different processes. Significantly differentially expressed genes were also identified after short- and long-term N availability increase. Putative N regulatory elements were identified along with several previously known motifs involved in the response to N and carbon availability as well as stress responses. We used an Arabidopsis whole genome array for a global evaluation of gene expression under different N conditions. Conclusion: Differentially expressed genes identified provide additional insights into the coordination of the complex N responses of plants and the components of the N response mechanism. Putative N regulatory elements were identified to reveal possible new components of the regulatory network for plant N responses. A better understanding of the complex regulatory network for plant N responses will help lead to strategies to improve N use efficiency.