A 20-BP CIS-ACTING ELEMENT IS BOTH NECESSARY AND SUFFICIENT TO MEDIATE ELICITOR RESPONSE OF A MAIZE PRMS GENE

Transient gene expression assays in barley aleurone protoplasts were u sed to identify a cis-regulatory element involved in the elicitor-resp onsive expression of the maize PRms gene. Analysis of transcriptional fusions between PRms 5' upstream sequences and a chloramphenicol acety ltransferase reporter gene, as well as chimeric promoters containing P Rms promoter fragments or repeated oligonucleotides fused to a minimal promoter, delineated a 20 bp sequence which functioned as an elicitor -response element (ERE). This sequence contains a motif (-246 AATTGACC ) similar to sequences found in promoters of other pathogen-responsive genes. The analysis also indicated that an enhancing sequence(s) betw een -397 and -296 is required for full PRms activation by elicitors. T he protein kinase inhibitor staurosporine was found to completely bloc k the transcriptional activation induced by elicitors. These data indi cate that protein phosphorylation is involved in the signal transducti on pathway leading to PRms expression.