Role of cassava CC-type glutaredoxin MeGRXC3 in regulating sensitivity to mannitol-induced osmotic stress dependent on its nuclear activity

Meng-Bin Ruan,Ming Peng,Ping-Juan Zhao,Xin Guo,Xiao-Ling Yu

doi:10.1186/s12870-022-03433-y

Abstract

BackgroundWe previously identified six drought-inducible CC-type glutaredoxins in cassava cultivars, however, less is known about their potential role in the molecular mechanism by which cassava adapted to abiotic stress.ResultsHerein, we investigate one of cassava drought-responsive CC-type glutaredoxins, namely MeGRXC3, that involved in regulation of mannitol-induced inhibition on seed germination and seedling growth in transgenic Arabidopsis. MeGRXC3 overexpression up-regulates several stress-related transcription factor genes, such as PDF1.2, ERF6, ORA59, DREB2A, WRKY40, and WRKY53 in Arabidopsis. Protein interaction assays show that MeGRXC3 interacts with Arabidopsis TGA2 and TGA5 in the nucleus. Eliminated nuclear localization of MeGRXC3 failed to result mannitol-induced inhibition of seed germination and seedling growth in transgenic Arabidopsis. Mutation analysis of MeGRXC3 indicates the importance of conserved motifs for its transactivation activity in yeast. Additionally, these motifs are also indispensable for its functionality in regulating mannitol-induced inhibition of seed germination and enhancement of the stress-related transcription factors in transgenic Arabidopsis.ConclusionsMeGRXC3 overexpression confers mannitol sensitivity in transgenic Arabidopsis possibly through interaction with TGA2/5 in the nucleus, and nuclear activity of MeGRXC3 is required for its function.

Highlights

We previously identified six drought-inducible CC-type glutaredoxins in cassava cultivars, less is known about their potential role in the molecular mechanism by which cassava adapted to abiotic stress
MeGRXC3 has transcriptional activation ability in yeast and involved in mannitol‐induced stress response in transgenic Arabidopsis We have previously identified six CC-type GRX genes, MeGRXC3, MeGRXC4, MeGRXC7, MeGRXC14, MeGRXC15, and MeGRXC18 responded to drought in leaves of two cassava cultivars [8]
To analyze the abiotic stress tolerance of transgenic Arabidopsis, it is commonly to use in vitro setups in which different growth inhibitory compounds are added to the growth medium

Summary

Introduction

We previously identified six drought-inducible CC-type glutaredoxins in cassava cultivars, less is known about their potential role in the molecular mechanism by which cassava adapted to abiotic stress. Reactive oxygen species (ROS) have been considered harmful to plant cells; they are playing signaling roles in plant response to stress [1]. The roxy18/grxs mutant showed a higher basal and photo-oxidative stress induced ROS accumulation and caused sensitivity to methyl viologen (MV) and high light (HL), while overexpression of ROXY18/GRXS13 resulted lower ROS accumulation under MV and HL treatments [14]. These results indicate that CC-type GRXs may play antagonistic roles in ROS homeostasis

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