Abstract
Plants have evolved a unique hormonally regulated self-protection system to defend themselves from various stresses, such as pathogen attacks and environmental stress. In plants, salicylic acid (SA), jasmonic acid (JA) and abscisic acid (ABA) play important roles in adaptation to biotic and abiotic stresses. In addition, recent studies have shown that the mutually antagonistic interactions between stress-related hormones in complex networks of various signaling pathways. For instance, treatment with ABA suppresses the induction of systemic acquired resistance (SAR) by inhibiting the pathway both upstream and downstream of SA accumulation. Conversely, the activation of SAR suppresses the expression of ABA biosynthesis-related and ABA-responsive genes. These results show that antagonistic crosstalk occurs at multiple steps between the SA-mediated signaling of SAR induction and the ABA-mediated signaling of environmental stress responses. Here, we will discuss the complex plant hormone-networks by analyzing expression of plant hormone related-genes in hormone mutant of Arabidopsis.
