Identification of a Novel Glycosyl Transferase Family 17 Protein Involved in Cd Accumulation in Rice (Oryza sativa).

Abstract

Cadmium (Cd) is a heavy metal widely distributed in the environment that poses a significant threat to living organisms because of its strong mobility and toxicity. In this study, a novel gene named Osß-glu from the glycosyltransferase (GT) family was investigated for its role in the Cd stress response in rice. Various experiments were conducted using the japonica cultivar Nipponbare (Nip) and its mutants (Osß-glu-1 and Osß-glu-2). The results showed that Osß-glu was specifically induced by Cd stress rather than by other mineral deficiencies. The Osß-glu mutants exhibited higher sensitivity to Cd stress, with more significant inhibition of root elongation, reduced biomass, and increased Cd accumulation in the roots, shoots, and xylem sap than Nip. Nitro-Blue Tetrazolium (NBT) staining indicated a larger acumulation of superoxide anion in the mutant roots under Cd stress, 3,3'-Diaminobenzidine (DAB) staining showed more pronounced H₂O₂ accumulation, and Evans Blue staining revealed more dead cells, demonstrating more severe reactive oxygen species (ROS) accumulation and cell damage in mutant roots. Moreover, the mutants had higher hemicellulose content and elevated Cd-binding capacity in the root cell wall, as well as abnormal expression of genes related to Cd absorption and translocation. Overall, multiple lines of evidence suggest that Osß-glu plays a crucial regulatory role in the response of rice to Cd stress, acting as an inhibitor of Cd accumulation. This contributes to a better understanding of the precise control network for Cd tolerance in rice, providing a basis for breeding rice varieties with lower Cd uptake.