Characterization of the Arabidopsis lysine-rich arabinogalactan-protein AtAGP17 mutant (rat1) that results in a decreased efficiency of agrobacterium transformation

© 2004 American Society of Plant BiologistsArabinogalactan-proteins (AGPs) are a family of complex proteoglycans widely distributed in plants. The Arabidopsis rat1 mutant, previously characterized as resistant to Agrobacterium tumefaciens root transformation, is due to a mutation in the gene for the Lys-rich AGP, AtAGP17. We show that the phenotype of rat1 correlates with down-regulation of AGP17 in the root as a result of a T-DNA insertion into the promoter of AGP17. Complementation of rat1 plants by a floral dip method with either the wild-type AGP17 gene or cDNA can restore the plant to a wild-type phenotype in several independent transformants. Based on changes in PR1 gene expression and a decrease in free salicylic acid levels upon Agrobacterium infection, we suggest mechanisms by which AGP17 allows Agrobacterium rapidly to reduce the systemic acquired resistance response during the infection process.Yolanda Maria Gaspar, Jaesung Nam, Carolyn Jane Schultz, Lan-Ying Lee, Paul R. Gilson, Stanton B. Gelvin and Antony Baci