Abstract
Plant hormones, ABA, is deeply involved in abiotic response. Recent studies showed that ABA also has pivotal functions in defense response where salicylic acid (SA) or jasmonic acid (JA) functions actively. In our previous work, we showed that treatments with ABA and SA simultaneously evoke a physiological state distinct from those induced by single hormone treatments. In this study, we conducted transcriptome assay in order to get more insights into the nature of simultaneous treatments using cultured Arabidopsis cells. The obtained data showed that there are considerable number of genes whose expressions are affected only in the presence of both ABA and SA. We found that the genes involved in the cell cycle progression were down-regulated by the ABA+SA treatment significantly and indeed the proportion of 4C cells was increased upon the double hormone treatment. These results indicate that multiple hormone signal is not the simple sum of each hormone function but behaves as a distinct physiological signal.
