LreEF1A4, a Translation Elongation Factor from Lilium regale, Is Pivotal for Cucumber Mosaic Virus and Tobacco Rattle Virus Infections and Tolerance to Salt and Drought.

Daoyang Sun,Yong Jia,Shiying Si,Dan Huo,Lixin Niu,Yanlong Zhang,Lingling Zeng,Xiaotong Ji

doi:10.3390/ijms21062083

Abstract

Eukaryotic translation elongation factors are implicated in protein synthesis across different living organisms, but their biological functions in the pathogenesis of cucumber mosaic virus (CMV) and tobacco rattle virus (TRV) infections are poorly understood. Here, we isolated and characterized a cDNA clone, LreEF1A4, encoding the alpha subunit of elongation factor 1, from a CMV-elicited suppression subtractive hybridization library of Lilium regale. The infection tests using CMV remarkably increased transcript abundance of LreEF1A4; however, it also led to inconsistent expression profiles of three other LreEF1A homologs (LreEF1A1–3). Protein modelling analysis revealed that the amino acid substitutions among four LreEF1As may not affect their enzymatic functions. LreEF1A4 was ectopically overexpressed in petunia (Petunia hybrida), and transgenic plants exhibited delayed leaf and flower senescence, concomitant with increased transcription of photosynthesis-related genes and reduced expression of senescence-associated genes, respectively. A compromised resistance to CMV and TRV infections was found in transgenic petunia plants overexpressing LreEF1A4, whereas its overexpression resulted in an enhanced tolerance to salt and drought stresses. Taken together, our data demonstrate that LreEF1A4 functions as a positive regulator in viral multiplication and plant adaption to high salinity and dehydration.

Highlights

Eukaryotic translation elongation factor 1 alpha is one of the four subunits composing the elongation factor 1, as well as a member of the G protein superfamily [1,2]
Phylogenetic tree revealed that LreEF1A4 was highly similar to three copies (LreEF1A1–3) from L. regale, and homologs from Arabidopsis thaliana (AteEF1A1–4), Oryza sativa (OseEF1A1–4), Gossypium hirsutum (GheEF1A1–9), Zea mays (ZmeEF1A1–7), and other species (Figure 1B)
The suppression subtractive hybridization (SSH) analysis of cucumber mosaic virus (CMV)-infected L. regale led to the identification of a translation elongation factor LreEF1A4

Summary

Introduction

Eukaryotic translation elongation factor 1 alpha (eEF1A) is one of the four subunits composing the elongation factor 1, as well as a member of the G protein superfamily [1,2]. EEF1A plays a canonical role in the polypeptide chain elongation phase of the protein-synthesis pathway [4]. It catalyzes the delivery of aminoacyl-tRNA to the A-site of the elongating ribosome in a guanosine 5 -triphosphate (GTP)-dependent manner during protein translation. This binding action induces the GTPase activity of eEF1A to cause GTP hydrolysis. The eEF1A-bound guanosine 5 -diphosphate (GDP) is dissociated from the ribosome, and is replaced with the active GTP

Methods

Results

Discussion

Conclusion