Gene 833 (2022) 146591 Available online 18 May 2022 0378-1119/© 2022 Elsevier B.V. All rights reserved. Genome-wide identifcation, characterization and expression analysis of glutaredoxin gene family (Grxs) in Phaseolus vulgaris Hatem Boubakri * , Eya Najjar, Nada Jihnaoui, Saif-Allah Chihaoui, Fathi Barhoumi, Moez Jebara Laboratory of Legumes and Sustainable Agrosystems, Centre of Biotechnology of Borj-Cedria, BP 901, 2050 Hammam-Lif, Tunisia A R T I C L E INFO Edited by Tzen-Yuh Chiang Keywords: Abiotic stress Common bean Gene expansion Real-Time q-PCR Redox regulation Symbiosis Glutaredoxin ABSTRACT Glutaredoxins (Grxs) are ubiquitous oxidoreductase proteins implicated in development and abiotic stress response mainly through maintaining redox homoeostasis. Here, we conducted the frst systematic analysis of the Grx gene family (PvGrx) in the most popular legume Phaseolus vulgaris (common bean). A total of 50 PvGrx genes were identifed, and divided into four classes (CC-type, CGFS-type, CPYC-type and Grl-type) based on the phylogenetic analysis. The different classes have different introns-exons structures and conserved motifs, indi- cating functional divergence in the PvGrx family. Both tandem and segmental duplications were found to be involved in the expansion of PvGrx family that underwent a purifying selection by excluding the deleterious loss- of-function mutations. Cis-acting regulatory elements and gene ontology analyses predicted their role of distinctive members in abiotic stress response and hormonal signalling. RNA-seq based expression analysis revealed their differential expression pattern during plant development. On the other hand, RT q-PCR analysis revealed that target PvGrx isoforms were associated with nodule organogenesis and symbiosis based on their expression profles. In addition, a battery of PvGrx candidates were markedly upregulated by different abiotic stressors suggesting their broad spectrum of functions. These fndings serve as a reference for functional analysis and genetic improvement in P. vulgaris and related legume species. 1. Introduction Environmentally adverse conditions seriously threaten plant growth and crop yields. Drought and salinity are the most frequently faced abiotic factors limiting plant growth and development. Recently, a report by Ning et al. (2018) have described that 33% of arable land experiences drought and salinization every year which means a loss of approximately 1,500,000 ha of crop land. Abiotic stressors are capable to induce several metabolic dysfunctions and to disturb the cell redox state via an excessive generation of reactive oxygen species (ROS) (Ning et al., 2018) . Natural developmental processes including seed germi- nation and nodule organogenesis might also lead to ROS generation in plants. Several reports have described that ROS must be kept at non- toxic levels in plant cells to avoid oxidative damage and cell death via a delicate balancing between their production and scavenging (Shai- khali and Wingsle, 2017). In fact, plants are usually well furnished with both enzymatic and non-enzymatic ROS-scavenging antioxidants that are located at different sites and function together in a well-structured network. These antioxidants include superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione (GSH), oxidized glutathione (GSSG), glutathione reductase (GR), glutathione-S-transferase (GST) (Hong et al. 2017). SOD consists the frst line of defense against ROS by converting superoxide radical (O2 • ) into hydrogen peroxide (H 2 O 2 ). Thereafter, CAT, APX, and GPX detoxify H 2 O 2 . APX activity depends on the ascorbic acid (AsA) and/or a glutathione (GSH) regenerating cycle involving MDHAR, DHAR, and GR. However, under abiotic stress conditions, ROS may provoke the oxidation of thiol groups in protein cysteine (Cys) residues leading to inactivation of enzymes and metabolic dysfunction (Begas et al., 2017) ). In that case, peroxiredoxins (Prxs) intervene to reduce H 2 O 2 and organic hydroperoxydes via a thiol-redox reaction involving GSH, thioredoxin (Trx) or glutaredoxin (Grx) as reducing agents (Begas et al., 2017). Besides reducing Prxs, Grxs which are ubiquitous oxidoreductases may act in different manners to reduce the negative effects of ROS like reducing peroxides and dehydroascorbates Abbreviations: Grx, glutaredoxin; ROS, reactive oxygen species; H 2 O 2 , hydrogen peroxide; Cys, cysteine; RT-qPCR, Reverse Transcription-Quantitative Polymerase Chain Reaction. * Corresponding author. E-mail address: hatem.boubakri@cbbc.rnrt.tn (H. Boubakri). Contents lists available at ScienceDirect Gene journal homepage: www.elsevier.com/locate/gene https://doi.org/10.1016/j.gene.2022.146591 Received 4 January 2022; Received in revised form 19 April 2022; Accepted 16 May 2022