NAC300调控水稻镉吸收及其在土壤镉污染修复中的应用

土壤镉（Cd）污染不仅影响作物产量和品质，还可经食物链危及人类的健康，已经成为世界性的环境问题。近年来作物吸收镉的机制取得较大进展，但其调控机制仍不清楚。申请人前期通过不同浓度Cd胁迫下的水稻转录组以及突变体离子组分析，发现NAC转录因子家族基因NAC300的表达受Cd专一性诱导，而NAC300突变体对Cd胁迫超敏感且植株积累高浓度的Cd。为阐明NAC300在水稻中调控Cd积累的分子机制，本项目将通过分析NAC300的表达模式，利用NAC300突变体材料进行转录组分析筛选其下游基因及结合元件，研究NAC300与下游Cd转运体基因的互作关系明确其调控水稻Cd吸收的作用机制。同时通过土培试验，将不同Cd积累型的转基因材料种植于镉污染土壤，分析根系、秸秆、以及籽粒Cd积累和分布规律。通过本研究，可以为筛选和培育低Cd积累水稻品种提供理论依据，同时可为Cd污染土壤的修复提供高富集Cd的植物材料。

Cd-contaminated soil not only affects the productivity and quality of crops, but also endanger human health when enters into food chain. Therefore it has become a world-wide environmental issue. Recent progress has been made in the mechanism of Cd uptake in crops, less is known about its regulation mechanism. The applicant used a high-throughput sequencing approach analyzing different levels of heavy metal treated rice seedlings combined with mutants ionmics analysis, one NAC family gene NAC300 was identified for its specificity induced by Cd treatment. And the NAC300 mutant showed a Cd hyper-sensitive phenotype and more Cd accumulation in the seedlings. In this project, to explore the regulation mechanism of NAC300 on Cd accumulation in rice, we will determine the expression pattern of NAC300, find out the downstream genes of NAC300 by performing RNA-seq analysis on its mutant vs wild type. Moreover, we will look at the role of Cd transporter genes involved to get clearer figure of the regulation mechanism of NAC300 on Cd accumulation in rice. In addition, we will carry out soil culture experiment to test the Cd distribution ratio between root, straw and seeds after cultivated on Cd-contaminated soil. It will give theoretical support to breeding low Cd crops, and also provide new plant material for remediating Cd-contaminated soil.