For vascular plants the phloem network is responsible for the transport of nutrients and signaling components, including small molecules, macromolecules and nucleic acids. The movement of these components is essential to plant metabolism, development and pathogen defense. Plant viruses hijack the phloem network to promote their own systemic movement and because of this represent a unique system in which to investigate the molecular mechanisms that control the trafficking of mobile components within the phloem. The goals of this project focus on understanding how viruses reprogram phloem specific tissues to mediate their own movement. Using a Tobacco mosaic virus (TMV) - Arabidopsis model system, efforts in this study will exploit TMV?s ability to reprogram cellular transcription through an interaction with phloem specific IAA transcription factors. IAA factors are components of the plant's auxin response system and play an essential role in many aspects of plant development, metabolism and defense. Specific efforts in this project will focus on examining the localization of virus interacting IAA proteins; investigating how IAA proteins affect the virus's ability to move within specific phloem cell types; and identifying the transcriptional targets of virus interacting IAA proteins and their potential role in virus mediated phloem transport. Combined results from this study will significantly advance our understanding of virus movement via the phloem and shed new light on the mechanisms that plants use to transport molecules to distal tissues. The broader goals of this project involve the educational integration of virology and plant biology disciplines for the training of post-doctoral, graduate, undergraduate and high school students with an emphasis placed on encouraging undergraduate and high school level students to consider advanced training in these important areas.

National Science Foundation (NSF)
Division of Integrative Organismal Systems (IOS)
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Mary Beth Saffo
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University of Maryland College Park
College Park
United States
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