Identification of Glutathione Peroxidase Gene Family in Ricinus communis and Functional Characterization of RcGPX4 in Cold Tolerance

Xiaoyu Wang; Xuming Liu; Yong-Qiang Charles An; Hongyu Zhang; Di Meng; Yanan Jin; Hongyan Huo; Lili Yu; Jixing Zhang

doi:10.3389/fpls.2021.707127

Identification of Glutathione Peroxidase Gene Family in Ricinus communis and Functional Characterization of RcGPX4 in Cold Tolerance

Front Plant Sci. 2021 Nov 5:12:707127. doi: 10.3389/fpls.2021.707127. eCollection 2021.

Authors

Xiaoyu Wang^{1

2}, Xuming Liu^{1

2}, Yong-Qiang Charles An³, Hongyu Zhang^{1

2}, Di Meng^{1

2}, Yanan Jin^{1

2}, Hongyan Huo^{1

2}, Lili Yu¹, Jixing Zhang^{1

2}

Affiliations

¹ College of Life Science and Food Engineering, Inner Mongolia Minzu University, Tongliao, China.
² Horqin Plant Stress Biology Research Institute of Inner Mongolia Minzu University, Tongliao, China.
³ U.S. Department of Agriculture-Agricultural Research Service, Plant Genetics Research Unit, Donald Danforth Plant Science Center, Saint Louis, MO, United States.

Abstract

Glutathione peroxidases (GPXs) protect cells against damage caused by reactive oxygen species (ROS) and play key roles in regulating many biological processes. Here, five GPXs were identified in the Ricinus communis genome. Phylogenetic analysis displayed that the GPXs were categorized into five groups. Conserved domain and gene structure analyses showed that the GPXs from different plant species harbored four highly similar motifs and conserved exon-intron arrangement patterns, indicating that their structure and function may have been conserved during evolution. Several abiotic stresses and hormone-responsive cis-acting elements existed in the promoters of the RcGPXs. The expression profiles indicated that the RcGPXs varied substantially, and some RcGPXs were coordinately regulated under abiotic stresses. Overexpression of RcGPX4 in Arabidopsis enhanced cold tolerance at seed germination but reduced freezing tolerance at seedlings. The expression of abscisic acid (ABA) signaling genes (AtABI4 and AtABI5), ABA catabolism genes (AtCYP707A1 and AtCYP707A2), gibberellin acid (GA) catabolism gene (AtGA2ox7), and cytokinin (CTK)-inducible gene (AtARR6) was regulated in the seeds of transgenic lines under cold stress. Overexpression of RcGPX4 can disturb the hydrogen peroxide (H₂O₂) homeostasis through the modulation of some antioxidant enzymes and compounds involved in the GSH-ascorbate cycle in transgenic plants. Additionally, RcGPX4 depended on the MAPK3-ICE1-C-repeat-binding factor (CBF)-COR signal transduction pathway and ABA-dependent pathway to negatively regulate the freezing tolerance of transgenic plants. This study provides valuable information for understanding the potential function of RcGPXs in regulating the abiotic stress responses of castor beans.

Keywords: RcGPX4; Ricinus communis L.; cold tolerance; functional analysis; genome-wide identification.