Abstract：
Minimizing cadmium (Cd) contamination in rice grains is crucial for ensuring food security and promoting sustainable agriculture. Utilizing genetic modification to generate rice varieties with low Cd accumulation is a promising strategy due to its cost-effectiveness and operational simplicity. Our study demonstrated that the CRISPR-Cas9-mediated quadruple mutation of the multicopper oxidase genes OsLPR1/3/4/5 in the japonica rice cultivar Tongjing 981 had little effect on yields. However, a notable increase was observed in the cell wall functional groups that bind with Cd. As a result, the quadruple mutation of OsLPR1/3/4/5 enhanced Cd sequestration within the cell wall while reducing Cd concentrations in both xylem and phloem sap, thereby inhibiting Cd transport from roots to shoots. Consequently, Cd concentrations in brown rice and husk in oslpr1/3/4/5 quadruple mutants (qm) decreased by 52% and 55%, respectively, compared to the wild-type. These findings illustrate that the quadruple mutation of OsLPR1/3/4/5 is an effective method for minimizing Cd contamination in rice grains without compromising yields. Therefore, the quadruple mutation of OsLPR1/3/4/5 via biotechnological pathways may represent a valuable strategy for the generation of new rice varieties with low Cd accumulation.
摘要：
减少稻谷中的镉（Cd）污染对于确保粮食安全和促进可持续农业至关重要。由于其成本效益和操作简单，利用遗传修饰产生低Cd积累的水稻品种是一种有前途的策略。我们的研究表明，CRISPR-Cas9介导的多铜氧化酶基因OsLPR1/3/4/5在粳稻品种通经981中的四重突变对产量影响不大。然而,与Cd结合的细胞壁官能团显着增加。因此,OsLPR1/3/4/5的四重突变增强了细胞壁内的Cd固存，同时降低了木质部和韧皮部汁液中的Cd浓度，从而抑制Cd从根到芽的运输。因此,oslpr1/3/4/5四重突变体中糙米和稻壳中的Cd浓度（qm）分别下降了52％和55％，分别,与野生型相比。这些发现表明，OsLPR1/3/4/5的四重突变是在不影响产量的情况下最大程度地减少水稻籽粒中Cd污染的有效方法。因此,通过生物技术途径对OsLPR1/3/4/5进行的四重突变可能是产生低Cd积累的水稻新品种的有价值的策略。
