PROSiCAPE14 regulates salt tolerance through ROS and ion homeostasis in foxtail millet

Area of Science:

• Plant Biology
• Genetics
• Agricultural Science

Background:

• Soil salinization threatens global food security, necessitating the use of saline-alkaline lands.
• Foxtail millet (Setaria italica) is a vital crop for arid regions and a model for C4 plant research, but its salt tolerance mechanisms are unclear.
• Understanding foxtail millet's salt tolerance is crucial for improving crop resilience and genetic enhancement.

Purpose of the Study:

• To investigate the CAPE gene family in foxtail millet.
• To identify and characterize key genes involved in the plant's response to salt stress.
• To elucidate the regulatory mechanisms of salt tolerance in foxtail millet.

Main Methods:

• Identified PROSiCAPE14 as a salt-responsive gene downregulated under stress.
• Analyzed the effects of exogenous peptide application and transgenic overexpression of PROSiCAPE14 on plant growth under salt stress.
• Utilized yeast one-hybrid and dual-luciferase reporter assays to identify interacting transcription factors (SibHLH49 and SiMYBS1).

Main Results:

• PROSiCAPE14 overexpression compromised growth, reduced plant height and root length, and increased sodium ion accumulation under salt stress.
• Overexpression lines showed elevated reactive oxygen species (ROS) accumulation.
• Transcription factors SibHLH49 and SiMYBS1 were confirmed to regulate PROSiCAPE14 expression by interacting with its promoter.

Conclusions:

• PROSiCAPE14 plays a significant role in foxtail millet's salt stress response, negatively impacting growth.
• The study identifies a novel regulatory pathway involving PROSiCAPE14, SibHLH49, and SiMYBS1 in salt tolerance.
• Findings provide a basis for future research on CAPE genes in abiotic stress adaptation in foxtail millet.