T-DNA tagging of a pathogen inducible promoter in Arabidopsis thaliana

Many events associated with the plant defence responses are regulated on the transcriptional level. Here we report the results of a promoter tagging approach to identify promoters that are induced upon pathogen attack in Arabidopsis thaliana. A line was identified in a T-DNA UidA tagged Arabidopsis library with induced GUS expression after Botrytis cinerea infection around the site of fungal infection. The upstream sequence was isolated and fused to the UidA gene and tested in transgenic Arabidopsis thaliana and Brassica napus plants. Promoter function was very similar to the expression pattern found in the original promoter tagged line. We found that the promoter sequence was located on Arabidopsis chromosome III and linked to a predicted open reading frame in the reverse orientation. The predicted gene codes for a putative receptor serine threonine protein kinase of 383 amino acids in size. The clone contains a protein kinase ATP binding region, a protein kinase active site, a region with similarity to motifs found in Alpha Isopropylmalate/homocitrate synthase enzymes and a putative leucine zipper motif Analysis of the expression pattern of the gene using RTPCR demonstrated that the putative receptor serine threonine protein kinase is up-regulated after Salicylic acid treatment and Botrytis infection.