Research Abstract:
I am interested in the mechanisms underlying how cells become polar and how tissue-specific factors and hormones regulate gene expression in plants. Protonemal cells of moss (Physcomitrella patens) are being used to study cellular polarity, while both moss and Arabidopsis thaliana are the models for analyzing tissue-specific gene expression via the phytohormone abscisic acid (ABA) and its relationship to drought tolerance.
When tip growing moss filaments are given an orienting gradient (e.g. light, gravity), what are the downstream targets for the signaling path to direct polar growth? Our hypothesis is that since the actin cytoskeleton has been an essential and central link in our understanding of polar processes in plants, the protein complexes that regulate the actin network are the targets for signals that govern polar growth. These targets can also help to identify interacting proteins that may localize and stabilize these complexes to the polar site. Hence, our directed approach is to focus on members of the Arp2/3 and the Wave/SCAR protein complexes that regulate actin filament formation in other organisms. Genomic sequences of the several proteins in these complexes are being used for targeted gene disruption and gene replacement studies, using the efficient homologous recombination system in moss (Quatrano, et al., 2007), in order to assess any potential role/position in the downstream signaling pathway. We are also developing an insertional library using T-DNA from Agrobacterium and use of a recently developed genetic map to identify genes associated with phenotypes of interest. All of these approaches are being aided by the release of the complete sequence of the moss genome (http://genome.jgi-psf.org/Physcomitrella).
Projects on gene regulation are focused on the regulatory protein ABI3 from moss and Arabidopsis and its essential role in the regulation via ABA. A comparative genomic approach is underway with homologous genes that are part of an ABA response pathway in moss that appears to be conserved. Moss and Arabidopsis microarrays designed from the genome sequence are showing unique genes that are expressed during drought and appear to play a role in drought tolerance as evidenced by gene deletions and over expression experiments.
Selected Publications:
Rensing, S. A., et al. {corresponding author - Quatrano, R. S.} The Physcomitrella genome reveals insights into the conquest of land by plants. Science 2008 319: 64-69.
Perroud, P-F. and Quatrano, R.S. BRICK1 is required for apical cell growth in filaments of the moss Physcomitrella patens but not for gametophore morphology. The Plant Cell 2008 20: 411-422.
Quatrano RS, McDaniel SF, Khandelwal A, Perroud P-F, and Cove DJ. Physcomitrella patens: mosses enter the genomic age. Current Opinion in Plant Biology 2007 10:182-189.
Khandelwal A, Chandu D, Roe CM, Kopan R, and Quatrano RS. Moonlighting activity of presenilin in plants is independent of γ-secretase and evolutionarily conserved. Proc Natl Acad Sci USA 2007 104:13337-13342.
Harries* P, Pan A, and Quatrano RS. Actin-related protein2/3 complex component ARPC1 is required for proper cell morphogenesis and polarized cell growth in Physcomitrella patens. The Plant Cell 2005 17:2327-2339.
*DBBS Ph.D. student
Last Updated: 07/02/2008 |