Genome-wide identification of ETHYLENE INSENSITIVE 2 in Triticeae species reveals that TaEIN2-4D.1 regulates cadmium tolerance in Triticum aestivum

Abstract

ETHYLENE INSENSITIVE 2 (EIN2), as the core component of the ethylene signaling pathway, can widely regulate plant growth, development, and stress responses. However, the comprehensive study and function of EIN2 in wheat Cadmium (Cd) stress remain largely unexplored. Here, we identified 33 EIN2 genes and designated as TaEIN2-2B to TaEIN2-Un.3 in Triticum aestivum. The analysis of cis-regulatory elements in promoter regions and RNA-Seq showed that TaEIN2s were functionally related to plant growth and development, as well as the response to biotic and abiotic stress. qRT-PCR analysis of TaEIN2s indicated their sensitivity to Cd stress. Compared with WT plants, TaEIN2-4D.1-RNAi transgenic wheat lines showed enhanced shoot and root elongation, dry weight and chlorophyll accumulation, together with a reduced accumulation of Cd in wheat grain. In addition, TaEIN2-4D.1-RNAi transgenic wheat lines showed enhanced Reactive Oxygen Species (ROS) scavenging capacity compared with WT plants. In conclusion, our research indicates that TaEIN2 plays a key role in response to cadmium stress in wheat, which provides valuable information for crop improvement.