Patricia C. Zambryski

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The phytohormone auxin has wide-ranging effects on growth and development. Genetic and physiological approaches implicate auxin flux in determination of floral organ number and patterning. This study uses a novel technique of transiently applying a polar auxin transport inhibitor, N-1-naphthylphthalamic acid (NPA), to developing Arabidopsis flowers to(More)
Analysis of viral and bacterial pathogenesis has revealed common themes in the ways in which plants and animals respond to pathogenic agents. Pathogenic bacteria use macromolecule delivery systems (types III and IV) to deliver microbial avirulence proteins and transfer DNA-protein complexes directly into plant cells. The molecular events that constitute(More)
The P30 protein of tobacco mosaic virus (TMV) is required for cell to cell movement of viral RNA, which presumably occurs through plant intercellular connections, the plasmodesmata. The mechanism by which P30 mediates transfer of TMV RNA molecules through plasmodesmata channels is unknown. We have identified P30 as an RNA and single-stranded (ss) DNA(More)
Unlike mammalian and yeast cells, little is known about how plants regulate G1 progression and entry into the S phase of the cell cycle. In mammalian cells, a key regulator of this process is the retinoblastoma tumor suppressor protein (RB). In contrast, G1 control in Saccharomyces cerevisiae does not utilize an RB-like protein. We report here the cloning(More)
ettin (ett) mutations have pleiotropic effects on Arabidopsis flower development, causing increases in perianth organ number, decreases in stamen number and anther formation, and apical-basal patterning defects in the gynoecium. The ETTIN gene was cloned and encodes a protein with homology to DNA binding proteins which bind to auxin response elements. ETT(More)
The virulence genes of Agrobacterium are required for this organism to genetically transform plant cells. We show that vir gene expression is specifically induced by a small (<1000 Da) diffusible plant cell metabolite present in limiting quantities in the exudates of a variety of plant cell cultures. Active plant cell metabolism is required for the(More)
A Ti plasmid mutant was constructed in which all the on-cogenic functions of the T-DNA have been deleted and replaced by pBR322. This Ti plasmid, pGV3850, still mediates efficient transfer and stabilization of its truncated T-DNA into infected plant cells. Moreover, integration and expression of this minimal T-DNA in plant cells does not interfere with(More)
The Agrobacterium single-stranded DNA (ssDNA) intermediate T-strand is likely transferred to the plant cell nucleus as a complex with a single VirD2 molecule at its 5' end and multiple VirE2 molecules along its length. VirD2 contains a nuclear localization signal (NLS); however, because the T-strand is principally coated with VirE2 molecules, VirE2 also(More)
The expression of the floral regulators LEAFY, APETALA1 and AGAMOUS-LIKE8 was examined during light treatments that induced flowering in Arabidopsis, and was compared to time points at which floral determination occurred. Extension of an 8-hour day by either continuous red- or far-red-enriched light induced LEAFY and AGAMOUS-LIKE8 expression within 4 hours.(More)
Plasmodesmata provide routes for communication and nutrient transfer between plant cells by interconnecting the cytoplasm of adjacent cells. A simple fluorescent tracer loading assay was developed to monitor patterns of cell-to-cell transport via plasmodesmata specifically during embryogenesis. A developmental transition in plasmodesmatal size exclusion(More)