Root morphogenic pathways in Eucalyptus grandis are modified by the activity of protein arginine methyltransferases

Krista L Plett,Anita E Raposo,Ian C Anderson,Sabine C Piller,Stephen Bullivant,Jonathan M Plett

doi:10.1186/s12870-017-1010-x

Krista L Plett, Anita E Raposo + Show 4 more

Open Access

https://doi.org/10.1186/s12870-017-1010-x

Copy DOI

Journal: BMC Plant Biology	Publication Date: Mar 9, 2017
Citations: 8	License type: open-access

Affiliation: Western Sydney University

Abstract

BackgroundMethylation of proteins at arginine residues, catalysed by members of the protein arginine methyltransferase (PRMT) family, is crucial for the regulation of gene transcription and for protein function in eukaryotic organisms. Inhibition of the activity of PRMTs in annual model plants has demonstrated wide-ranging involvement of PRMTs in key plant developmental processes, however, PRMTs have not been characterised or studied in long-lived tree species.ResultsTaking advantage of the recently available genome for Eucalyptus grandis, we demonstrate that most of the major plant PRMTs are conserved in E. grandis as compared to annual plants and that they are expressed in all major plant tissues. Proteomic and transcriptomic analysis in roots suggest that the PRMTs of E. grandis control a number of regulatory proteins and genes related to signalling during cellular/root growth and morphogenesis. We demonstrate here, using chemical inhibition of methylation and transgenic approaches, that plant type I PRMTs are necessary for normal root growth and branching in E. grandis. We further show that EgPRMT1 has a key role in root hair initiation and elongation and is involved in the methylation of β-tubulin, a key protein in cytoskeleton formation.ConclusionsTogether, our data demonstrate that PRMTs encoded by E. grandis methylate a number of key proteins and alter the transcription of a variety of genes involved in developmental processes. Appropriate levels of expression of type I PRMTs are necessary for the proper growth and development of E. grandis roots.

Highlights

Methylation of proteins at arginine residues, catalysed by members of the protein arginine methyltransferase (PRMT) family, is crucial for the regulation of gene transcription and for protein function in eukaryotic organisms
E. grandis encodes PRMT-like genes that exhibit similar expression patterns in major plant tissues By searching for the conserved functional domains common to arginine methyltransferases, seven PRMT-like genes were found within the E. grandis genome (v. 2.0; [24])
Stem, apical and root tissues were collected from 10 week-old E. grandis seedlings and the relative expression of seven of the PRMT genes in each tissue type was determined by qPCR (Fig. 2a)

Summary

Introduction

Methylation of proteins at arginine residues, catalysed by members of the protein arginine methyltransferase (PRMT) family, is crucial for the regulation of gene transcription and for protein function in eukaryotic organisms. Protein targets of PRMTs are often histones resulting in altered gene transcription [7], many non-histone methylated proteins have been identified [2, 8] These non-histone proteins are often involved in RNA binding or transcription [9, 10], Plett et al BMC Plant Biology (2017) 17:62 and include cytoplasmic proteins involved in various cellular developmental processes [8]. While these proteins have been well characterised in mammalian- and yeastbased systems, our understanding of PRMT activity in regulating plant development and signalling is still developing [3]. AtPRMT5, a Type II PRMT, has been found to affect pre-mRNA splicing [17, 18], flowering time [18, 19], salt stress tolerance [20], primary root length [21], root stem cell maintenance during DNA damage [22] and circadian rhythms [23]

Methods

Results

Discussion

Conclusion