College of Resource Science & Technology, Sichuan Agricultural University, 211 Huimin Road, Chengdu, Sichuan, 611130, China.
College of Agronomy, Sichuan Agricultural University, 211 Huimin Road, Chengdu, Sichuan, 611130, China.
Ecotoxicol Environ Saf. 2019 Oct 30;182:109422. doi: 10.1016/j.ecoenv.2019.109422. Epub 2019 Jul 10.
Breeding the rice cultivar with high cadmium (Cd) accumulation in straw but with low Cd in brown rice using marker-assisted selection (MAS) based on quantitative trait loci (QTL) is meaningful for phytoremediation as well as safety in production. A restorer rice line, YaHui2816, steadily showed low Cd translocation from straw to brown rice and carried alleles for reducing Cd concentration in brown rice (BRCdC). In this study, one F population (C268A/YaHui2816) was used to identify the QTLs for BRCdC in 2016, and other two different F populations (Lu98A/YaHui2816 and 5406A/YaHui2816) were used to furtherly validate the QTLs in 2017. Furthermore, a pot experiment was conducted to investigate the relative expression of predicted genes in the regions of these QTLs for BRCdC. Here 4 QTLs for BRCdC were identified, among which, 2 novel QTLs (qBRCdC-9 and qBRCdC-12) were identified on chromosomes 9 and 12 in rice. The YaHui2816 alleles in the QTLs qBRCdC-9 and qBRCdC-12 could effectively reduce BRCdC under different genetic backgrounds. Importantly, the QTL qBRCdC-12 was simultaneously associated with the Cd translocation from shoot to brown rice (T-s-b), genetically explaining that the low T-s-b of the YaHui2816 resulted in its low BRCdC. The interval length of the QTL qBRCdC-12 was only narrowed to 0.28 cM, making it possible to develop molecular markers and excavate genes for reducing BRCdC. It is worth noting that genes existed in these QTL regions have not been reported for regulating the Cd translocation in rice. 6 candidate genes (OS05G0198400, OS05G0178300, OS09G0544400, OS12G0161100, OS12G0162100 and OS12G0165200) up-regulated expressed in nodeⅡof the YaHui2816 in response to Cd treatment, and encoded ZRT/IRT-like protein (ZIP) 4, the protein similar to glutathione transferase (GSTs) 16, heat shock protein Hsp20 domain containing protein, MAP kinase-like protein and Cd tolerant protein 5, respectively.
利用基于数量性状位点（QTL）的标记辅助选择（MAS）培育稻草中镉（Cd）积累量高但糙米中镉含量低的水稻品种，对于植物修复和生产安全都具有重要意义。恢复系水稻品种 YaHui2816 表现出稳定的低 Cd 从稻草向糙米的转移，并携带降低糙米中 Cd 浓度（BRCdC）的等位基因。在这项研究中，2016 年使用一个 F 群体（C268A/YaHui2816）来鉴定 BRCdC 的 QTL，其他两个不同的 F 群体（Lu98A/YaHui2816 和 5406A/YaHui2816）在 2017 年进一步验证了这些 QTL。此外，还进行了盆栽实验来研究这些 BRCdC QTL 区域中预测基因的相对表达。在此，鉴定到 4 个 BRCdC 的 QTL，其中 2 个新的 QTL（qBRCdC-9 和 qBRCdC-12）分别位于水稻的第 9 号和 12 号染色体上。QTL qBRCdC-9 和 qBRCdC-12 中的 YaHui2816 等位基因可以在不同的遗传背景下有效降低 BRCdC。重要的是，QTL qBRCdC-12 同时与 Cd 从茎叶向糙米的转运（T-s-b）相关联，这从遗传上解释了 YaHui2816 低 T-s-b 导致其低 BRCdC。QTL qBRCdC-12 的区间长度仅缩小到 0.28 cM，这使得开发分子标记和挖掘降低 BRCdC 的基因成为可能。值得注意的是，这些 QTL 区域中存在的基因尚未被报道在水稻中调节 Cd 转运。6 个候选基因（OS05G0198400、OS05G0178300、OS09G0544400、OS12G0161100、OS12G0162100 和 OS12G0165200）在 Cd 处理下，在 YaHui2816 的节点Ⅱ中上调表达，分别编码 ZRT/IRT-like protein（ZIP）4、与谷胱甘肽转移酶（GSTs）16 相似的蛋白、热休克蛋白 Hsp20 结构域包含蛋白、MAP 激酶样蛋白和 Cd 耐受蛋白 5。
