Robust identification of low-Cd rice varieties by boosting the genotypic effect of grain Cd accumulation in combination with marker-assisted selection

• Published in: Journal of hazardous materials 2022-02, Vol.424 (Pt D), p.127703-127703, Article 127703
• Main Authors: Sun, Liang, Wang, Ruigang, Tang, Wenbang, Chen, Yuchao, Zhou, Jieqiang, Ma, Haoran, Li, Sai, Deng, Hubing, Han, Lei, Chen, Yibo, Tan, Yongjun, Zhu, Yuxing, Lin, Dasong, Zhu, Qihong, Wang, Jiurong, Huang, Daoyou, Chen, Caiyan
• Format: Article
• Language: English
• Subjects: Cadmium; Cadmium - analysis; CCd; Edible Grain - chemistry; Genetic variation; Genotype; Low-grain-Cd rice; Oryza - genetics; Soil; Soil heterogeneity; Soil Pollutants - analysis
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.127703

Rice (Oryza sativa L.), a staple for half of the world’s population, usually accumulates high levels of cadmium (Cd) in the grain when planted in the Cd-contaminated paddy fields. Genetic improvements using natural variation of grain-Cd accumulation is the most cost-effective way to mitigate the risk of excess Cd accumulation. However, as a complex trait, grain-Cd accumulation is susceptible to environmental variation, which challenges to characterize the genetic nature and subsequently the stable performance of grain-Cd accumulation. To boost the genetic effect on grain-Cd performance, we established an approach of normalization using the comparative grain-Cd value (CCd) following a contrasting field design. Identification of the genetic locus responsible for CCd variation help us develop a low-grain-Cd variety de novo, named ‘Lushansimiao’, which had lower grain-Cd levels in a large-scale field test and can produce Cd-safe rice following prolonged irrigations in the field with intermediate levels of Cd pollution. Combined CCd evaluating and low-Cd allelic genotyping, another six varieties were also identified as low-grain-Cd rice. Our study paves the way to efficiently quantify the genetic nature of grain-Cd accumulation in rice, and the stable low-Cd rice varieties will help to mitigate the risk of excess Cd accumulation in rice. [Display omitted] •Environmental factors interfere with the stable expression of genotypic differences in grain-Cd accumulation in rice.•We established an approach to normalize the environmental heterogeneity using a comparative grain-Cd value (CCd).•Our CCd evaluation boosted the genetic effect on grain-Cd performance and showed advantages on low-Cd rice identification.•A novel rice cultivar was developed and six widely-planted varieties were identified as low-Cd rice.