INVESTIGATORS: Zhaohua Peng, Pamela Ronald, Guo-Liang Wang
INSTITUTION: Mississippi State University
NON-TECHNICAL SUMMARY: It is estimated that the potential global bio-ethanol production from major crop residues is 4.42 x 1011 liters annually. Half of the residues are rice (Oryza sativa) straw, which is burned to waste causing severe environmental and health problems. Although agronomic lignocellulosic biomass holds tremendous promise to biofuel industry, the cellulosic ethanol from crop residues has not been commercialized due to the high cost in bio-refinery. To reduce the cost, the characteristics of the cell wall, the main component of the crop residue biomass, have to be modified to fit the bio-refinery requirement.
When the plant cell wall is removed, cell wall synthesis is highly activated in the plant cell. We will identify genes whose expression levels correlate with cell wall synthesis activities during cell wall removal and regeneration using a large scale gene expression analysis technology called DNA oligo microarray. In addition, we will also use a large scale protein analysis technology called proteomics to identify proteins whose expression and modification correlates with cell wall synthesis activities. Once the regulatory genes and proteins are identified, we will identify mutants of the corresponding genes. The mutants will help us find out the role of each gene in cell wall synthesis. After we understand the function of each individual gene in cell wall synthesis, we can genetically manipulate these genes to change the cell wall composition for cost efficient ethanol fermentation. The results of this project will lead us to make use of crop residues for ethanol production because what we have learned from rice can be applied to other cereal crops.
OBJECTIVES: The objectives of this proposal are: 1) Identify genes, particularly transcription factors, whose expression profiles correlate with cell wall synthesis activities during cell wall removal and regeneration. 2) Identify proteins whose expression correlate with cell wall synthesis activities during cell wall removal and regeneration. 3) Identify proteins whose phosphorylation patterns correlate with cell wall synthesis activities. 4) Identify and characterize rice mutants of the differentially regulated genes, particularly the genes encoding transcription factors and phosphoproteins.
APPROACH: The cell wall synthesis activities will be stimulated by removal of the cell wall in rice cells. Gene expression profile change will be examined using rice whole genome DNA oligao microarray made by Dr. Ronald's group at UC Davis. Protein differential expression will be studied using comparative proteomics approaches. Protein phosphorylation will be revealed by Pro-Q Diamond Phosphoprotein Stain coupled with mass spectrometry analysis. Rice mutants will be generated by making RNAi transgenic lines and searching for T-DNA and transposon insertion and activation lines in worldwide mutant collections.
Name: Zhaohua Peng