The crucial role of vascular tissues and COE2-mediated retrograde signaling in mitigating cadmium stress in Arabidopsis thaliana

Abstract Cadmium is a heavy metal that significantly harms plant growth and development by impairing enzyme activity and photosynthesis, leading to chloroplast damage. In this study, we discovered that genes specifically expressed in vascular tissues regulate the plant’s response to heavy metals by scRNA-seq. The overexpression of vascular-specific genes such as AHP1 , DOF2.4 , NHL1 , CDF4 , and ATARFB1A increased tolerance to cadmium stress by maining the chloroplast functions. In addition, we found that two chloroplast proteins PSBO1 and J3 are involved in regulating the function of chloroplasts, starch metabolism, and leaf vein development in response to cadmium stress. Further analysis revealed that COE2-mediated retrograde signaling protects chloroplast structure and function by regulating the expression of J3 and PsbO1 , and managing the quality control of damaged chloroplasts via FC1 and PUB4 . These findings provide insights into the mechanisms plants use to counteract the detrimental effects of cadmium stress.