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:
Khandelwal A, Chandu D, Roe CM, Kopan R and Quatrano RS. Moonlighting activity of presenilin in plants is independent of ã-secretase and evolutionarily conserved. Proceedings of the National Academy of Science USA 2007 104:13337-13342.
del Viso F, Casaretto JA and Quatrano RS. 14-3-3 proteins are components of the transcription complex of the ATEM1 promoter in Arabidopsis. Planta. 2007 227: 167-175.
Perroud P-F and Quatrano RS. 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.
Khandelwal A, Elvitigala T, Ghosh B and Quatrano RS. Arabidopsis transcriptome reveals control circuits regulating redox homeostasis and the role of an AP2 transcription factor. Plant Physiology 2008 148: 2050-2058.
Charron A and Quatrano RS. Between a rock and a dry place: the water-stressed moss. Molecular Plant 2009 2: 478-486.
Last Updated: 11/09/2009 |