Abstract
Salicylic acid (SA) is an important signal molecule in plant disease resistance. Two pathways for the biosynthesis of SA are proposed: the isochorismate pathway and the benzoic acid (BA) pathway. In the former, ICS1 gene encoding isochorismate synthase has been identified. However, genes involved in the latter pathway are not known. To study the BA pathway for SA biosynthesis, mutant screening was performed. The growth of wild-type is inhibited in the presence of SA. On the other hand, BA has no such inhibitory effect. Based on this property, we isolated benzoic acid hypersensitive (bah) 1 mutant that exhibit an inhibited growth in the presence of BA. bah1 grew normally in the absence of BA. The transcript of SA-inducible PR1 gene accumulated in bah1 in the presence of BA. These results raise a possibility that the accumulation of SA occurs in bah1 by application of BA.
