ZmASR6 positively regulates salt stress tolerance in maizeResearch Paper

Abstract

High salinity stress severely impacts plant growth and yield. ABA, stress, ripening (ASR) proteins play critical roles in plant responses to various abiotic stresses. This study characterizes a salt-induced ASR gene, ZmASR6, in maize and investigates its role in salt stress tolerance. Transcriptional analysis revealed significant induction of ZmASR6 under salt stress over 24 hours. Subcellular localization experiments confirmed ZmASR6 protein presence in the nucleus and cytoplasm of maize protoplasts. Using CRISPR/Cas9, we generated ZmASR6 knockout lines, which displayed reduced salt tolerance compared to wild-type (WT) plants. These mutants exhibited higher reactive oxygen species (ROS) and malondialdehyde accumulation, elevated Na^⁺/K^⁺ ratios, and increased ionic conductivity, indicating impaired oxidative stress tolerance. RNA sequencing further revealed that ZmASR6 deficiency significantly altered the expression of key stress-regulatory genes. Collectively, our findings demonstrate that ZmASR6 is essential for salt stress tolerance in maize, making it a promising candidate for genetic improvement of maize salt tolerance.