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United States Department of Agriculture

Agricultural Research Service


Location: Sunflower and Plant Biology Research

2012 Annual Report

1a. Objectives (from AD-416):
1. Implement 454 sequencing technology to compare gene expression impacted by ecological factor affecting invasiveness. 2. To use this technology to also identify regulatory regions and potential targets for future manipulation of invasive perennial weeds.

1b. Approach (from AD-416):
Ecological factors have an impact on invasiveness of perennial weeds of the Northern plains; for example, Canada thistle and leafy spurge. These ecological factors cause changes in gene expression that are regulated by cis-acting elements. Advances in 454 sequencing technology now make it uniquely suited for the rapid and efficient quantification of both 1) gene expression, and 2) the identification of the cis-acting elements that control gene expression. Quantification of gene expression will be accomplished by 454 sequencing of biological samples collected from various ecological settings. This information will be analyzed and compared to obtain a dataset of genes linked to invasive traits. Further, 454 sequencing will be used to characterize genomic DNA to identify the specific cis-acting elements regulating the genes from our dataset.

3. Progress Report:
This SCA resulted in the identification of 15,232 unique Canada thistle transcripts from root tissue covering a time scale involving the transition from para-dormancy to growth-induction. Bioinformatic analysis of differentially-expressed transcripts, based on this time scale, identified processes involved in plant hormone signaling networks, which led us to examine hormone profiles in root sections of Canada thistle. Results from the transcriptome and hormone profiling data helped us to propose a model where sectioning-induced changes in polar auxin transport alters ABA metabolism and signaling, which further impacts gibberellic acid signaling involving interactions between ABA and FUSCA3. Reduced auxin- and ABA-signaling, in conjunction with increased cytokinin biosynthesis or perception, also supports our model, which indicates that cross-talk among hormones drive molecular networks impacting cell cycle processes leading to cell division, differentiation, and vegetative outgrowth. Results of this project were presented at the 2012 Plant and Animal Genome Meeting in San Diego, CA, the 2012 American Society of Plant Biologists Annual Meeting in Auxin, TX, and have been documented in three peer-reviewed publications in 2012 including the American Journal of Botany, Journal of Biogeography, and Functional and Integrative Genomics.

4. Accomplishments

Last Modified: 06/26/2017
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