SALICYLIC ACID-INDUCIBLE BINDING OF A TOBACCO NUCLEAR-PROTEIN TO A 10-BP SEQUENCE WHICH IS HIGHLY CONSERVED AMONGST STRESS-INDUCIBLE GENES

A 10 bp sequence motif (TCATCTTCTT) which is repeated several times in the 5' non-transcribed region of a barley beta-1,3-glucanase gene is also present in the non-translated regions of over 30 different plant genes which are known to be induced by one or more forms of stress. Gel retardation assays and South-western blotting experiments provide evidence that the motif is the binding site for a tobacco nuclear protein with an apparent molecular weight of 40 kDa. Binding activity is increased when nuclear extracts from salicylic acid-treated plants are anlaysed compared with extracts from control plants, indicating that the protein itself is either induced or modified under conditions of stress. These observations suggest roles for the 10 bp motif and its binding protein as cis- and trans-acting regulators of gene expression during response to stress.