Genome-wide characterization of ascorbate peroxidase gene family in pepper (Capsicum annuum L.) in response to multiple abiotic stresses

Xin Pang; Jun Chen; Yang Xu; Jia Liu; Yangmin Zhong; Linlin Wang; Jiaqiu Zheng; Hongjian Wan

doi:10.3389/fpls.2023.1189020

Genome-wide characterization of ascorbate peroxidase gene family in pepper (Capsicum annuum L.) in response to multiple abiotic stresses

Front Plant Sci. 2023 May 8:14:1189020. doi: 10.3389/fpls.2023.1189020. eCollection 2023.

Authors

Xin Pang¹, Jun Chen¹, Yang Xu², Jia Liu³, Yangmin Zhong⁴, Linlin Wang⁴, Jiaqiu Zheng⁵, Hongjian Wan²

Affiliations

¹ Suzhou Polytechnic Institute of Agriculture, Suzhou, China.
² State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
³ Wulanchabu Academy of Agricultural and Husbandry Sciences, Wulanchabu, China.
⁴ Institute of Crops, Lishui Academy of Agricultural and Forestry Sciences, Lishui, China.
⁵ Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, China.

Abstract

Pepper is widely grown all over the world, so it faces many abiotic stresses, such as drought, high temperature, low temperature, salt damage, and so on. Stresses causing the accumulation of reactive oxidative species (ROS) in plants are removed by antioxidant defense systems, and ascorbate peroxidase (APX) is an important antioxidant enzyme. Therefore, the present study performed genome-wide identification of the APX gene family in pepper. We identified nine members of the APX gene family in the pepper genome according to the APX proteins' conserved domain in Arabidopsis thaliana. The physicochemical property analysis showed that CaAPX3 had the longest protein sequence and the largest molecular weight of all genes, while CaAPX9 had the shortest protein sequence and the smallest MW. The gene structure analysis showed that CaAPXs were composed of seven to 10 introns. The CaAPX genes were divided into four groups. The APX genes of groups I and IV were localized in the peroxisomes and chloroplasts, respectively; the group II genes were localized in the chloroplasts and mitochondria; and the group III genes were located in the cytoplasm and extracell. The conservative motif analysis showed that all APX genes in the pepper had motif 2, motif 3, and motif 5. The APX gene family members were distributed on five chromosomes (Chr. 2, 4, 6, 8, and 9). The cis-acting element analysis showed that most CaAPX genes contain a variety of cis-elements related to plant hormones and abiotic stress. RNA-seq expression analysis showed that the expression patterns of nine APXs were different in vegetative and reproductive organs at different growth and development stages. In addition, the qRT-PCR analysis of the CaAPX genes revealed significant differential expression in response to high temperature, low temperature, and salinity stresses in leaf tissue. In conclusion, our study identified the APX gene family members in the pepper and predicted the functions of this gene family, which would provide resources for further functional characterization of CaAPX genes.

Keywords: ascorbate peroxidase; bioinformatics analysis; gene expression; pepper; phylogenetic relationship.

Grants and funding

This research was funded by the National Natural Science Foundation of China (32100302, 31960601, 32060446, 32260769), Young and middle-aged academic leaders of the “Qing Lan Project” in universities of Jiangsu Province (2022), Technology Cultivation Project of Suzhou Polytechnic Institute of Agriculture (PY2005), Jiangsu Provincial Natural Science Foundation of China (BK20211113), Natural Science Foundation of Inner Mongolia Autonomous Region of China (2021MS03106, 2021MS03071), Zhejiang Provincial Natural Science Foundation of China (LQ23C020004), and Basic Research Project of Ulanqab, Inner Mongolia Autonomous Region of China (2021JC202).