This research is a functional analysis of the xyloglucan endotransglucosylase/hydrolase (XTH) genes of the model plant Arabidopsis. XTHs are capable of modifying xyloglucan, a major component of the plant cell wall, and yet the physiological functions of these enzymes are not understood. The wall is a fundamental structure of plant cells that controls cellular shape, size and integrity, and plays a role in signal transduction. Enzymes that modify wall polysaccharides likely play critical roles in plant morphogenesis and physiology.
A broad-based integrative approach will be taken to elucidate the biochemical and physiological functions of XTHs. Mutations within XTH genes will be sought and mutant phenotypes characterized with respect to growth, development and overall fitness, in addition to wall properties and ability to adapt to diverse environments. Expression patterns of XTHs will be determined. Reporter gene analyses will shed light on tissue, organ, and developmental specificity of expression. Enzymes will be produced with heterologous systems and their properties, such as substrate preferences and reaction conditions, will be compared among the different isozymes. Completion of these experiments will improve concepts of how plant cell walls are formed, maintained and modified, and how these properties impact the overall fitness, development and physiology of plants.
Research results will be disseminated through a website (www.bioc.rice.edu/~braam/projects/xth.html), research publications, and public presentations. Mutant seed stocks will be deposited in the ABRC at Ohio State University for distribution to the community. In addition, this research will enhance the infrastructure of research and training through the continued support and laboratory training of postdoctoral, graduate and undergraduate students. The PI is committed to increasing the representation of women and underrepresented minorities in science. Undergraduates will also participate in the scientific discovery process through Rice University laboratory courses. PCR-based screening methods and reporter gene expression analyses have been optimized such that undergraduates can contribute to research through lab courses. The students supported by this grant will be encouraged to participate in conferences and teaching opportunities.
