Genetic interactions between ABA, ethylene and sugar signaling pathways

The identification of genes through mutant screens is beginning to reveal t he structure of a number of signaling pathways in plants. In the past year, genes that determine the plant's response to the hormones ethylene and abs cisic acid have also been shown to be involved in sugar sensing in early se edlings. These results suggest that hormone signaling and carbon homeostasi s are tightly coupled but that the architecture of these interactions is co mplex. Part of this complexity may be because some genetic screens on exoge nous compounds produce signaling linkages that are not necessarily pertinen t under normal growth conditions. Because many of the genes identified in t hese screens are cloned, the relevance of these interactions can now be unr aveled at the molecular level.