Overexpression of a novel Arabidopsis PP2C isoform, AtPP2CF1, enhances plant biomass production by increasing inflorescence stem growth

Abstract

In contrast to mammals, higher plants have evolved to express diverse protein phosphatase 2Cs (PP2Cs). Of all Arabidopsis thaliana PP2Cs, members of PP2C subfamily A, including ABI1, have been shown to be key negative regulators of abscisic acid (ABA) signalling pathways, which regulate plant growth and development as well as tolerance to adverse environmental conditions. However, little is known about the enzymatic and signalling roles of other PP2C subfamilies. Here, we report a novel Arabidopsis subfamily E PP2C gene, At3g05640, designated AtPP2CF1. AtPP2CF1 was dramatically expressed in response to exogenous ABA and was expressed in vascular tissues and guard cells, similar to most subfamily A PP2C genes. In vitro enzymatic activity assays showed that AtPP2CF1 possessed functional PP2C activity. However, yeast two-hybrid analysis revealed that AtPP2CF1 did not interact with PYR/PYL/RCAR receptors or three SnRK2 kinases, which are ABI1-interacting proteins. This was supported by homology-based structural modelling demonstrating that the putative active- and substrate-binding site of AtPP2CF1 differed from that of ABI1. Furthermore, while overexpression of ABI1 in plants induced an ABA-insensitive phenotype, Arabidopsis plants overexpressing AtPP2CF1 (AtPP2CF1oe) were weakly hypersensitive to ABA during seed germination and drought stress. Unexpectedly, AtPP2CF1oe plants also exhibited increased biomass yield, mainly due to accelerated growth of inflorescence stems through the activation of cell proliferation and expansion. Our results provide new insights into the physiological significance of AtPP2CF1 as a candidate gene for plant growth production and for potential application in the sustainable supply of plant biomass.

Phenotypic diversification by enhanced genome restructuring after induction of multiple DNA double-strand breaks

“…Additionally, compared to wild-type plants, the TAQed mutants showed a 40% increase in biomass (dry weight of aerial parts) (Fig. 4e ) 26 . Importantly, the relative distribution of stem lengths in the 81 TAQed tetraploid (TQ4) plants was significantly broader ( P < 0.01, F -test) than that in the 40 TAQed diploid (TQ2) plants (Supplementary Fig.…”

Transcriptome analysis reveals a complex array of differentially expressed genes accompanying a source‐to‐sink change in phytoplasma‐infected sweet cherry leaves

“…Protein phosphatase 2C (PP2C) is a key player in the ABA signalling. Studies showed that PP2C was inhibited by ABA (Park et al, ) and an overexpression of a PP2C isoform was able to activate cell proliferation and expansion (Sugimoto et al, ). Our transcriptome data revealed that a gene encoding PP2C was up‐regulated in phytoplasma‐infected leaves of sweet cherry.…”

Protein Phosphatase 2Cs and Microtubule-Associated Stress Protein 1 Control Microtubule Stability, Plant Growth, and Drought Response

“…In particular, EGR-mediated regulation of proline accumulation was MASP1 independent and EGR2 also had some effect to enhance MT stability and alleviate root swelling independently of MASP1. An effect of EGR1 on inflorescence growth, as well as characterization of EGR1 phosphatase activity, has been reported (Sugimoto et al, 2014); however, there has been no reported mechanism of EGR action or analysis of EGR stress function. Likewise, our data show that MASP1 is a MT binding protein.…”

“…An important aspect of drought-related signaling is the activity of Type 2C protein phosphatases (PP2Cs), especially the Clade A PP2Cs whose activity is regulated by interaction with Pyrabactin Resistant-Like/Regulatory Component of Abscisic Acid Receptor (PYL/ RCAR) ABA receptors (Cutler et al, 2010;Fuchs et al, 2013). Interaction with PYLs is specific to Clade A PP2Cs, which account for only nine of the 80 PP2Cs present in Arabidopsis (Arabidopsis thaliana; Fuchs et al, 2013;Sugimoto et al, 2014). For most of the other PP2Cs in Clades B to F, there is little information on their physiological function or on the phosphorylation sites they regulate.…”