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Article|19 Feb 2022|OPEN
BrpNAC895 and BrpABI449 coregulate the transcription of the afflux-type cadmium transporter BrpHMA2 in Brassica parachinensis
Shuai Liu1,2,3 , Limei Li4,5 , Yanwu Deng1 , Yongsheng Bai1 , Chao Sun6 , Shili Huang1 , Jiajie Zhou1 , Liyu Shi1 and Xuewei Yang1 , Ling Li4 , Xuemei Chen7 , Yulin Tang,1 ,
1Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Science, Longhua Institute of Innovative Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, Guangdong Province, China
2Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
3Shaanxi Academy of Traditional Chinese Medicine, Xi’an, Shaanxi 710003, China
4Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China
5Life Sciences College, Zhaoqing University, Zhaoqing, 526061, China
6College of Horticulture, Nanjing Agricultural University, No. 1 Weigang, 8210095 Nanjing, China
7Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
*Corresponding author. E-mail: yltang@szu.edu.cn

Horticulture Research 9,
Article number: uhac044 (2022)
doi: https://doi.org/10.1093/hr/uhac044
Views: 203

Received: 29 Aug 2021
Revised: 16 Jun 2022
Accepted: 18 Jan 2022
Published online: 19 Feb 2022

Abstract

Brassica parachinensis is a popular leafy vegetable. It is able to accumulate high concentrations of cadmium (Cd), but the molecular mechanism of Cd accumulation is unknown. This study investigated the function and regulatory mechanism of the Cd-responsive metal ion transporter gene BrpHMA2BrpHMA2 was induced by Cd stress and specifically expressed in vascular tissues, and the protein was localized in the plasma membrane. Heterologous expression of BrpHMA2 enhanced Cd accumulation and Cd sensitivity in transgenic Arabidopsis and yeast. After Cd stress, the transcription factors BrpNAC895 and BrpABI449, which may recognize the abscisic acid-responsive elements in the BrpHMA2 promoter, were also differentially expressed. The transcriptional regulation of BrpHMA2 was further investigated using the chromatin immunoprecipitation–quantitative PCR (ChIP–qPCR) assay, the electrophoretic mobility shift assay (EMSA), and luciferase (LUC) reporter activity analysis employing the transient expression system of B. parachinensis protoplasts and tobacco leaves and the Escherichia coli expression system. By binding to the promoter, BrpNAC895 induced the transcription of BrpHMA2. BrpABI449 might bind to the BrpHMA2 promoter or interact with BrpNAC895 to interfere with the action of BrpNAC895. The findings suggest that BrpHMA2 is a membrane-based afflux-type Cd transporter involved in Cd2+ uptake and long-distance transport in plants. BrpNAC895 and BrpABI449, which function as the transcription activator and repressor, respectively, coregulate BrpHMA2 expression.