Browsing by Author "Woodward, Andrew W."

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    A viable Arabidopsis pex13 missense allele confers severe peroxisomal defects and decreases PEX5 association with peroxisomes
    (Springer, 2014) Woodward, Andrew W.; Fleming, Wendell A.; Burkhart, Sarah E.; Ratzel, Sarah E.; Bjornson, Marta; Bartel, Bonnie
    Peroxisomes are organelles that catabolize fatty acids and compartmentalize other oxidative metabolic processes in eukaryotes. Using a forward-genetic screen designed to recover severe peroxisome-defective mutants, we isolated a viable allele of the peroxisome biogenesis gene PEX13 with striking peroxisomal defects. The pex13-4 mutant requires an exogenous source of fixed carbon for pre-photosynthetic development and is resistant to the protoauxin indole-3-butyric acid. Delivery of peroxisome-targeted matrix proteins depends on the PEX5 receptor docking with PEX13 at the peroxisomal membrane, and we found severely reduced import of matrix proteins and less organelle-associated PEX5 in pex13-4 seedlings. Moreover, pex13-4 physiological and molecular defects were partially ameliorated when PEX5 was overexpressed, suggesting that PEX5 docking is partially compromised in this mutant and can be improved by increasing PEX5 levels. Because previously described Arabidopsis pex13 alleles either are lethal or confer only subtle defects, the pex13-4 mutant provides valuable insight into plant peroxisome receptor docking and matrix protein import.
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    Biology in Bloom: A Primer on the Arabidopsis thaliana Model System
    (The Genetics Society of America, 4/1/2018) Woodward, Andrew W.; Bartel, Bonnie; BioSciences
    Arabidopsis thaliana could have easily escaped human scrutiny. Instead, Arabidopsis has become the most widely studied plant in modern biology despite its absence from the dinner table. Pairing diminutive stature and genome with prodigious resources and tools, Arabidopsis offers a window into the molecular, cellular, and developmental mechanisms underlying life as a multicellular photoautotroph. Many basic discoveries made using this plant have spawned new research areas, even beyond the verdant fields of plant biology. With a suite of resources and tools unmatched among plants and rivaling other model systems, Arabidopsis research continues to offer novel insights and deepen our understanding of fundamental biological processes.
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    Genes, organelles, and molecules that influence plant development through auxin regulation
    (2005) Woodward, Andrew W.; Bartel, Bonnie
    Humankind depends on plants to harvest solar energy and convert it into accessible chemical energy. With booming human population growth and diminishing availability of arable land, understanding plant development is necessary for more efficient agricultural production. Auxin is a plant hormone utilized in many aspects of plant growth and environmental responses. This work examines genes that regulate or are regulated by auxin, biogenesis and function of an organelle that is an auxin source, and molecules that behave as auxins to influence plant development. Within the plant cell, peroxisomes are organelles that house many processes including fatty acid metabolism to produce energy and also proto-auxin metabolism to produce the active hormone. Peroxisomal proteins are translated in the cytoplasm and imported into peroxisomes by a host of machinery. Peroxisomal targeting signal sequences are recognized by one of two receptors; these receptors interact with each other physically and functionally in some organisms. Here, I identify the receptor machinery present in diverse organisms to predict and compare methods of peroxisomal matrix protein import. I also characterize mutants of the model plant Arabidopsis thaliana defective in import of one class of peroxisomal matrix proteins. In addition, I examine various molecules that influence plant development in an auxin-like fashion. I identify genes with mRNA accumulation regulated by a proto-auxin in a background that inefficiently converts this compound into auxin. I describe the characterization of responses to a second auxin-related molecule that impacts plant development through auxin signaling. I also describe the isolation, characterization, and cloning of a mutant with reduced sensitivity to a specific subset of auxin-like molecules. Data obtained in this work reveal a host of factors that affect auxin regulation and thereby influence plant life. The results of these experiments in plant biology highlight the diversity, complexity, and essentiality of auxin responses.