Transcriptomic and proteomic profiling of FsPP2C1-overexpressing Arabidopsis plants

Abstract

FsPP21 is a functional protein phosphatase type-2C (PP2C) isolated from beech (Fagus sylvatica L.) seeds. Previously, this gene was shown to be upregulated by abscisic acid (ABA) treatment and specifically expressed in ABA-treated seeds. It was demonstrated that constitutive FsPP2C1 overexpression in Arabidopsis (Arabidopsis thaliana (L.) Heynh.) confers ABA insensitivity to seeds and a reduced degree of seed dormancy. Transgenic 35S:FsPP2C1 plants resistant to different stresses (.i.e. paclobutrazol, NaCl and mannitol) showed ABA-resistant early root growth and diminished induction of RAB18 and KIN2 suggesting that FsPP2C1 is a negative regulator of ABA signalling. To fully characterize this insensitive phenotype and the contribution of FsPP2C1 to promoting the transition from seed dormancy to germination, transcriptomic and proteomic tools have been used. A complete transcriptomic analysis in Arabidopsis highlights the insensitive phenotype of the FsPP2C1-overexpressing plants, the cross-talk of ABA with other signalling pathways and the conservation of the ABA transduction pathway between beech and Arabidopsis. Similarly, proteomic analysis in ABA-treated seeds exhibits significant changes in the protein pattern of transgenic 35S:FsPP2C1 compared with wild-type (WT) seeds. These results are discussed to confirm and open new insights into the role of FsPP2C1 and the possible interactions between ABA and other plant hormones.