48.フシコクシンによる種子発芽促進機構に関する研究(口頭発表)

概要

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Fusicoccins (FCs) are a class of diterpenoid glucosides produced by the plant-pathogenic fungus Phomopsis amygdali. FC-A exhibits auxin-like activity on plant cells via the continuous activation of proton ATPase through the formation of a ternary complex consisting of 14-3-3 protein (GRF), and a phosphopeptide from the C-terminus of proton-ATPase. GRFs are a family of regulatory molecules, and have the ability to bind various signaling proteins in eukaryotic cells. There are common binding motifs for GRFs that contain a phosphorylated serine or threonine residue. FC stimulates germination of lettuce and Arabidopsis seeds in the presence of abscisic acid (ABA). In this study, the molecular mechanism of germination-stimulation by FC has been investigated. We focused on the interaction of GRF and ABI5, a positive transcription factor responsible for ABA signaling in Arabidopsis. It was suggested that ABI5 interacted with an Arabidopsis GRF by in vitro pull-down assay, and was confirmed by yeast-two-hybrid assay. The assay using a mutant ABI5 strongly suggested ABI5 interacted a GRF through a conserved binding motif.
2010-10-01