Transcriptome Response to Cadmium Exposure in Barley (Hordeum vulgare L.)

Abstract

Cadmium is an environmental pollutant with high toxicity that negatively affects plant growth and development. To understand the molecular mechanisms of plant response to cadmium stress, we have performed a genome-wide transcriptome analysis on barley plants treated with an increased concentration of cadmium. Differential gene expression analysis revealed 10,282 deregulated transcripts present in the roots and 7,104 in the shoots. Among them, we identified genes related to reactive oxygen species metabolism, cell wall formation and maintenance, ion membrane transport and stress response. One of the most upregulated genes was PLANT CADMIUM RESISTACE 2 (HvPCR2) known to be responsible for heavy metal detoxification in plants. Surprisingly, in the transcriptomic data we identified four different copies of the HvPCR2 gene with a specific pattern of upregulation in individual tissues. Heterologous expression of all five barley copies in a Cd-sensitive yeast mutant restored cadmium resistance. In addition, four HvPCR2 were located in tandem arrangement in a single genomic region of the barley 5H chromosome. To our knowledge, this is the first example showing multiplication of the PCR2 gene in plants.

Genome-Wide Identification of the HMA Gene Family and Expression Analysis under Cd Stress in Barley

“…Studies on the SBP-box [ 19 ], WRKY [ 20 ], ABC [ 21 ], F-box [ 22 ], and SOD [ 23 ] gene family in barley have been successfully completed. Although the functions of several HMA proteins in barley have been reported [ 24 , 25 ], genome-wide analysis of the HvHMA family is lacking. In this study, the HvHMA gene family was genome-widely identified in barley, and the phylogenetic relationships, structural characteristics, physicochemical properties, chromosomal location, as well as the tissue expression of identified members were analyzed.…”

De Novo transcriptome combined with physiological analyses revealed key genes for cadmium accumulation in Zhe-Maidong (Ophiopogon japonicus)

“…HMA transporters also play an essential role in the loading of Cd in xylem vessels and phloem loading. Members of the HMA family have been identified in a variety of plant species, including A. thaliana ( Wong and Cobbett, 2009 ), rice ( Treesubsuntorn and Thiravetyan, 2019 ), barley ( Zhang et al., 2021 ), and wheat ( Kintlová et al., 2021 ). As ATPases, they can transport the cation from the cytosol into the xylem sap against its electrochemical gradient.…”

Exploring the Adaptive Responses of Plants to Abiotic Stresses Using Transcriptome Data

“…Heavy metal stress induces the activation of different mitogen-activated protein kinases (MAPKs) [120]. Kintlová et al [121] identified the HvPCR2 gene in barley as one of the most responsive genes to a Cd stimulus. Li et al [122] conducted a Populus × canadensis comparative transcriptomic study and found 35 TFs from 11 TF families in response to Cd stress, of which 16 were up-regulated while 19 were down-regulated.…”