Silicon(Si)has been shown to alleviate Cd stress in rice.Here,we investigated the beneficial effects of foliar Si in an indica rice Huanghuazhan(HHZ).Our results showed that foliar Si in-creases the dry weight and decreases Cd translocation in Cd-exposed rice at the grain-filling stage only,implying that the filling stage is critical for foliar Si to reduce Cd accumulation.We also investigated the transcriptomics in flag leaves(FLs),spikelets(SPs),and node Is(NIs)of Cd-exposed HHZ after foliar Si application at the filling stage.Importantly,the gene expression profiles associated with the Si-mediated alleviation of Cd stress were tissue spe-cific,while shared pathways were mediated by Si in Cd-exposed rice tissues.Furthermore,after the Si treatment of Cd-exposed rice,the ATP-binding cassette(ABC)-transporters were mostly upregulated in FL and SP,while the bivalent cation transporters were mostly down-regulated in FL and NI,possibly helping to reduce Cd accumulation.The genes associated with essential nutrient transporters,carbohydrate and secondary metabolite biosynthesis,and cytochrome oxidase activity were mostly upregulated in Cd-exposed FL and SP,which may help to alleviate oxidative stress and improve plant growth under Cd exposure.Inter-estingly,genes responsible for signal transduction were negatively regulated in FL,but pos-itively regulated in SP,by foliar Si.Our results provide transcriptomic evidence that foliar Si plays an active role in alleviating the effects of Cd exposure in rice.In particular,foliar Si may alter the expression pattern of genes associated with transport,biosynthesis and metabolism,and oxidation reduction.

Chongjun Sun;Xiaoyu Liang;Xiaomei Gong;Huamei Chen;Xiulian Liu;Shuchang Zhang;Fangbai Li;Junliang Zhao;Jicai Yi

College of Life Sciences,South China Agricultural University,Guangzhou 510642,China;Guangdong Institute of Eco-environmental Science and Technology,Guangzhou 510650,China;Rice Research Institute and Guangdong Key Laboratory of New Technology in Rice Breeding,Guangdong Academy of Agricultural Sciences,Guangzhou 510640,China

环境科学学报（英文版）

[1]Chongjun Sun;Xiaoyu Liang;Xiaomei Gong;Huamei Chen;Xiulian Liu;Shuchang Zhang;Fangbai Li;Junliang Zhao;Jicai Yi-.Comparative transcriptomics provide new insights into the mechanisms by which foliar silicon alleviates the effects of cadmium exposure in rice)[J].环境科学学报（英文版）,2022(05):294-307

Huanghuazhan,NIs,itively

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