Overexpression of OsDUF846.2 enhances the sensitivity of rice to salt and heat stresses

Abstract Soil salinity and heat stress are major abiotic stress factors restricting rice growth, development, and yield potential. DUFs (Domains of Unknown Function) are proteins with structurally conserved but functionally undefined domains, widely present across organisms. The DUF846 family has been demonstrated to participate in plant growth and development as well as trans-Golgi network sorting and secretion. However, their functional roles in abiotic stress tolerance responses in rice remain poorly understood. In this study, we focused on OsDUF846.2, a member of the rice DUF846 family. Our investigation revealed that OsDUF846.2 responds to both salt and heat stress in rice. Following salt and heat stress treatments, OsDUF846.2 overexpression lines exhibited more severe damage, lower survival rates, elevated reactive oxygen species (ROS) and malondialdehyde (MDA) accumulation, reduced antioxidant enzyme activities, and decreased proline and soluble sugar contents compared to wild type (WT). Transcriptome analysis indicated that OsDUF846.2 may enhance the sensitivity of rice to salt stress and heat stress by regulating salt stress-related pathways such as cytoskeletal stability and antioxidant defense system, and heat stress-related pathways such as protein homeostasis maintenance and RNA metabolism. These findings indicate that OsDUF846.2 negatively regulates the response of rice to salt stress and heat stress.