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Plant Cell Morphogenesis
The control of plant cell expansion is fundamental to the generation of plant form. The long-term objective of the research in our lab is to understand, on a molecular level, how plant cell shape is controlled. We use trichome (plant hair) branch formation in the small flowering plant, Arabidopsis thaliana (mouse ear cress), as a model for the polar, localized cell expansion events that underlie much of plant cell morphogenesis. Arabidopsis trichomes, also called plant hairs, are single cells that consist of several branches perched on top of a stalk. Because these cells have such a distinctive shape, we can easily observe changes in the normal shape produced by mutations that we induce. We use a variety of molecular, genetic, and cell biological tools to determine the function of the genes identified by the mutations. Because the cytoskeleton plays a predominant role in regulating cell expansion and hence cell shape, we are focusing on genes that control cytoskeleton organization.
The image on the left is of a developing trichome on a plant carrying a mutation in a gene for a key regulator of actin polymerization. The trichome was treated with fluorescently labeled antibodies (green for microtubules and red for actin) and the nucleus was stained with the fluorescent DNA-binding dye, DAPI. Optical sections were taken of the trichome using a Zeiss confocal microscope and the sections were reassembled to produce the composite image shown. Place the cursor over the word "actin" in the image to see the actin cytoskeleton and over the word "microtubules" to see the cortical microtubule cytoskeleton. The nucleus appears blue in these images.