A NEW, PATHOGEN-INDUCIBLE GENE OF ARABIDOPSIS IS EXPRESSED IN AN ECOTYPE-SPECIFIC MANNER

In this study we describe a novel gene, which was isolated in an attempt to search for specific plant resistance genes of Arabidopsis against isolates of the phytopathogenic bacterium Xanthomonas campestris pv. campestris. The gene was cloned by differential screening of a genomic library of the Xcc 750-resistant ecotype Col-0, using cDNA populations derived from ecotype Col-0 and the Xcc 750-susceptible ecotype Oy-0. The isolated gene, CXc750, is differentially expressed in ecotypes of Arabidapsis thaliana. In addition, although highly expressed in uninfected plants, gene expression increases in response to pathogen attack. CXc750 potentially codes for a small, basic protein of about 10 kDa. The predicted protein product contains a potential signal leader peptide at the amino-terminal end but no ER retention sequence and no further transmembrane domain. This indicates that the gene product is transported to other compartments or out of the cell. The possible function of CXc750 as a member of the plant defense response system is discussed.