Effects of high manganese-cultivated seedlings on cadmium uptake by various rice (Oryza sativa L.) genotypes

• Published in: Ecotoxicology and environmental safety 2023-10, Vol.264, p.115440-115440, Article 115440
• Main Authors: Huang, Gaoxiang, Huang, Yunpei, Ding, Xinya, Ding, Mingjun, Wang, Peng, Wang, Zhongfu, Jiang, Yinghui, Zou, Long, Zhang, Wendong, Li, Zhenling
• Format: Article
• Language: English
• Subjects: Accumulation; Distribution; Manganese enrichment; Rice genotypes; Transporter
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2023.115440

Cadmium (Cd) contamination in paddy soil threatens rice growth and food safety, enriching manganese (Mn) in rice seedlings is expected to reduce Cd uptake by rice. The effects of 250 μM Mn-treated seedlings on reducing Cd uptake of four rice genotypes (WYJ21, ZJY1578, HHZ, and HLYSM) planted in 0.61 mg kg−1 Cd-contaminated soil, were studied through the hydroponic and pot experiments. The results showed that the ZJY1578 seedling had the highest Mn level (459 μg plant–1), followed by WYJ21 (309 μg plant–1), and less Mn accumulated in the other genotypes. The relative expression of OsNramp5 (natural resistance-associated macrophage protein) was reduced by 42.7 % in ZJY1578 but increased by 23.3 % in HLYSM. The expressions of OsIRT1 (iron-regulated transporter-like protein) were reduced by 24.0–56.0 % in the four genotypes, with the highest reduction in ZJY1578. Consequently, a greater reduction of Cd occurred in ZJY1578 than that in the other genotypes, i.e., the root and shoot Cd at the tillering were reduced by 27.8 % and 48.5 %, respectively. At the mature stage, total Cd amount and distribution in the shoot and brown rice were also greatly reduced in ZJY1578, but the inhibitory effects were weakened compared to the tillering stage. This study found various responses of Cd uptake and transporters to Mn-treated seedlings among rice genotypes, thus resulting in various Cd reductions. In the future, the microscopic transport processes of Cd within rice should be explored to deeply explain the genotypic variation. [Display omitted] •High Mn cultivation resulted in various Mn accumulation in different rice genotypes.•Mn induced various inhibitions on OsNramp5 and OsIRT1 expression among rice genotypes.•Cd uptake and transport within rice were depressed variously by Mn among genotypes.•Mn induced a lower Cd reduction at the mature than that at the tillering stage.