Strawberry MOTHER OF FT AND TFL1 regulates seed germination and post-germination growth through integrating GA and ABA signaling in Arabidopsis

Abstract

The phytohormones gibberellic acid (GA) and abscisic acid (ABA) are known to play antagonistic roles in the control of seed germination and seedling establishment. Here, the regulatory roles of woodland strawberry MOTHER OF FT AND TFL1 (FvMFT) involved in GA and ABA signaling were investigated. FvMFT, which encodes a phosphatidylethanolamine-binding protein, was predominantly expressed in young strawberry fruits. Transient over-expression of FvMFT repressed the expression of several DELLA genes in strawberry fruits. Ectopic over-expression of FvMFT in Arabidopsis thaliana markedly altered the expression levels of ABA-INSENSITIVE (ABI) and DELLA genes, which is accompanied by partially restoring the impaired post-germination growth when the seeds were germinated on sugar-free medium. The same transgenic Arabidopsis plants also exhibited hypersensitivity to GA3 and ABA treatments during seed germination and post-germination growth. In addition, the fluorescence-tagged FvMFT proteins exhibited intriguing subcellular localizations in integument cells and endosperm cells of transgenic Arabidopsis. Taken together, our results support the notion that FvMFT could act as a dual regulator of seed germination and post-germination growth in response to GA and ABA signaling in plants.