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. Ge l retardation assays and South-western blotting experiments provide ev idence that the motif is the binding site for a tobacco nuclear protei n with an apparent molecular weight of 40 kDa. Binding activity is inc reased when nuclear extracts from salicylic acid-treated plants are an laysed compared with extracts from control plants, indicating that the protein itself is either induced or modified under conditions of stre ss. These observations suggest roles for the 10 bp motif and its bindi ng protein as cis- and trans-acting regulators of gene expression duri ng response to stress.