- Bachelor of Science, Miami (OH) University, 2001
- Doctor of Philosophy, Indiana University, 2008
Teaching areas: For the 2012-2013 academic year I will teach BIOL213/214 Cell and Molecular Biology and BIOL310 Genetics. Previously I have taught BIOL334 Physiology and Development of Vascular Plants. Please contact me if you are interested in these courses and want more information!
Research interests: The proper differentiation of specialized cell, tissue, and organ types during plant growth and development depends on many internal and environmental factors. One important component of proper cellular function is the development and maintenance of an organelle class termed ‘plastids.’ Plastids are semi-independent endosymbiotic organelles that perform a variety of essential functions in plant cells. Among these functions, plastids are the sites for photosynthesis and for the storage of high-energy compounds such as starches, lipids, and proteins. Additionally, biochemical reactions within plastids lead to the synthesis and accumulation of several amino acids, nucleic acids, and other plant growth regulators. The number and complexity of plastid functions make focused research on them critical for our understanding and advancement of key issues in plant science such as agriculture and bioenergetics.
One important property of plastids is their ability to interconvert from one form to another. This property allows for specialization among the different plastid types, with interconversion correlating with cellular status and function. All plastids are originally derived from a basal-state proplastid found in zygotic cells during embryogenesis or meristematic cells during vegetative growth. Proplastids can convert into more specialized plastids, which include, but are not limited to, the starch-storing amyloplast, the pigment-containing chromoplast, and the photosynthetically active chloroplast. Amazingly, cellular conditions can also dictate interconversion among these specialized plastids. In many cases, when tracing the physical development of a particular plastid, certain functional distinctions are visually evident at different stages of the life cycle. For example, the cotyledon cells of a plant germinated in the dark appear yellow prior to the perception of light; once light is perceived, the etioplasts present in these cells interconvert to chloroplasts, resulting in cotyledons that appear green. Research in my lab uses similar visual cues as a system to study plastid development and interconversion in the model plant species Arabidopsis thaliana, a plant ideal for this topic because of the wide availability of molecular and genetic resources.
The objective of my research is to determine and characterize molecular regulators critical to the plastid interconversion process. My research focuses on the timeframe of seed germination and seedling growth. It is at this juncture in the life cycle that a plant must transition from a heterotrophic organism energetically dependent upon storage reserves to an autotrophic mode of metabolism via photosynthesis. Although the timeframe is quite short, the metabolic transitions involved require several essential plastid interconversions, ultimately resulting in the development of chloroplasts within seedling tissues. My studies on the seedling plastid development 1 (spd1) mutant in A. thaliana previously demonstrated an important molecular regulators during these transitions. The spd1 mutant is unable to properly undergo the conversion processes that result in chloroplasts within normal seedling cotyledon cells. My long-term research goals will incorporate molecular biology, genetic, and biochemical techniques to identify and characterize the cellular functions of plastid developmental regulators, including further characterization of SPD1 and its homologs as well as identification of additional regulators essential to plastid interconversion.
Summer 2012 (L to R) Nick Ruppel, Thomas McShane, Sarah Reach, and Steve Bii
Hsu S-C, Endow JK, Ruppel NJ, Roston RL, Baldwin AJ, Inoue K (2011) Functional diversification of thylakoid processing peptidases in Arabidopsis thaliana. PLoS One 6(11): e27258
Ruppel NJ*, Logsdon CA*, Whippo CW, Inoue K, Hangarter RP (2011) A mutation in Arabidopsis thaliana SEEDLING PLASTID DEVELOPMENT 1 affects plastid differentiation in embryo-derived tissues during seedling growth. Plant Physiol 155: 342-353 *equal contributions
Endow JK*, Ruppel NJ*, and Inoue K (2010) Keep the balloon deflated: The significance of protein maturation for thylakoid flattening. Plant Sig Beh 5: 721-723 *equal contributions
Shipman-Roston RL, Ruppel NJ, Damoc C, Phinney BS, Inoue K (2010) The significance of protein maturation by plastidic type I signal peptidase 1 for thylakoid development in Arabidopsis thaliana chloroplasts. Plant Physiol 152: 1297-1308
Ruppel NJ, Hangarter RP (2007) Mutations in a plastid-localized elongation factor G alter early stages of plastid development in Arabidopsis thaliana. BMC Plant Biol 7: 37
Ybe JA, Ruppel NJ, Mishra S, VanHaaften E (2003) Contribution of cysteines to clathrin trimerization domain stability and mapping of light chain binding. Traffic 4: 850-856
Ruppel NJ, Hangarter RP, Kiss JZ (2001) Red-light-induced positive phototropism in Arabidopsis roots. Planta 212: 424-430
Kiss JZ, Ruppel NJ, Hangarter RP (2001) Phototropism in Arabidopsis roots is mediated by two sensory systems. Adv Space Res 27: 877-885