水稻木聚糖合酶基因IRX10在镉积累中的作用OA

To address the food safety risks posed by cadmium(Cd)contamination in rice,we identified the role of the cell wall-related gene IRX10(Irregular xylem 10)in regulating Cd uptake and allocation in rice,and validated its potential as a promising candidate gene for breeding rice varieties with low-Cd accumulation.We generated gene-edited rice transgenic lines using the CRISPR/Cas9 system and performed Cd treatments to determine Cd content and its distribution patterns in various rice tissues.Furthermore,by integrating gene expression profiling and cell wall composition analysis,the underlying regulatory mechanism was systematically investigated.The results showed that IRX10 exhibited distinct expression patterns in different tissues.The IRX10 promoter region harbored elements associated with metal and stress responses,indicating its role in metal stress responses.When treated with Cd,the irx10 mutants showed a significantly reduced Cd accumulation in roots and shoots compared with the wild type,but phenotypic differences were not pronounced.Under Cd stress conditions,the irx10 mutants exhibited significantly decreased Cd content in brown rice but increased Cd content in hulls compared with the wild type.No significant differences in zinc(Zn)content were observed in either brown rice or hulls between the mutant and the wild type.Furthermore,the expression of Cd-related genes was changed in multiple tissues in the mutant,leading to reduced Cd loading towards the grain and enhanced Cd accumulation in the hull.Moreover,the altered hemicellulose in the irx10 hull exhibited enhanced Cd-fixing capacity.Natural variation analysis identified advantageous haplotypes associated with low Cd accumulation.Therefore,the loss of IRX10 function can reduce Cd accumulation in brown rice without significant alteration in Zn content by retaining more Cd in the hull,which offers a new candidate gene for breeding low-Cd rice varieties.