Stephanie Battle, Biochemistry and Molecular Biology
"Structure-function Analysis of the Novel Defense Protein SUP3 in Arabidopsis thaliana"
Faculty Mentor: Dr. Hua Lu
Expected Graduation Date: May 2010
Pathogen infection activates expression reprogramming of thousands of genes in plants. It remains challenging to identify which genes regulate plant disease resistance and how they function. Taking advantage of the unique defense-dependent dwarfism conferred by the Arabidopsis mutant acd6-1, we developed a genetic screen to identify acd6-1 suppressor (sup) mutants, which potentially harbors mutations in novel defense genes. Among the genes identified wasSUP3, encoding a phosphate transporter. The sup3-1 mutant harbors a T-DNA insertion in the fifth exon of the SUP3 gene, leading to the accumulation of a partial transcript. When introduced into the double mutant acd6-1sid2-1 (Thesid2-1 mutant confers disease susceptibility and suppresses acd6-1 phenotype), one copy of sup3-1 allele dominantly suppresses acd6-1sid2-1 morphology. Thusacd6-1sid2-1 can be used to dissect the functional region of the SUP3 protein. We made a series of deletions of the SUP3 gene and transferred each fragment into acd6-1sid2-1 plants. We expect that a functional SUP3 fragment would cause visible morphological changes in acd6-1sid2-1 transgenic plants. Functional SUP3 fragments will be further tested in wild type for disease resistance. This study will reveal the functional domain of SUP3 that regulates plant defense and helps us to understand the mechanism of SUP3 action.