Li Xiang, Mao Xiuhong, Xu Yujin, Li Yan, Zhao Nan, Yao Junxiu, Dong Yufeng, Tigabu Mulualem, Zhao Xiyang, Li Shanwen
State Key Laboratory of Tree Genetics and Breeding, School of Forestry, Northeast Forestry University, Harbin 150040, China.
Key Laboratory for Genetics and Breeding in Forest Trees of Shandong Province, Shandong Academy of Forestry, Jinan 250014, Shandong, China.
Ecotoxicol Environ Saf. 2021 Mar 30;216:112179. doi: 10.1016/j.ecoenv.2021.112179.
Cadmium (Cd), a heavy metal element has strong toxicity to living organisms. Excessive Cd accumulation directly affects the absorption of mineral elements, inhibits plant tissue development, and even induces mortality. Populus × canadensis 'Neva', the main afforestation variety planted widely in northern China, was a candidate variety for phytoremediation. However, the genes relieving Cd toxicity and increasing Cd tolerance of this species were still unclear. In this study, we employed transcriptome sequencing on two Cd-treated cuttings to identify the key genes involved in Cd stress responses of P. × canadensis 'Neva' induced by 0 (CK), 10 (C10), and 20 (C20) mg/L Cd(NO) 4HO. We discovered a total of 2,656 (1,488 up-regulated and 1,168 down-regulated) and 2,816 DEGs (1,470 up-regulated and 1,346 down-regulated) differentially expressed genes (DEGs) between the CK vs C10 and CK vs C20, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses in response to the Cd stress indicated that many DEGs identified were involved in the catalytic activity, the oxidoreductase activity, the transferase activity, and the biosynthesis of secondary metabolites. Based on the enrichment results, potential candidate genes were identified related to the calcium ion signal transduction, transcription factors, the antioxidant defense system, and transporters and showed divergent expression patterns under the Cd stress. We also validated the reliability of transcriptome data with the real-time PCR. Our findings deeper the understanding of the molecular responsive mechanisms of P. × canadensis 'Neva' on Cd tolerance and further provide critical resources for phytoremediation applications.
镉（Cd）是一种重金属元素，对生物具有很强的毒性。过量的镉积累直接影响矿质元素的吸收，抑制植物组织发育，甚至导致死亡。欧美杨107（Populus × canadensis 'Neva'）是中国北方广泛种植的主要造林品种，是植物修复的候选品种。然而，该品种缓解镉毒性和提高镉耐受性的基因尚不清楚。在本研究中，我们对两个经镉处理的插条进行了转录组测序，以鉴定欧美杨107在0（CK）、10（C10）和20（C20）mg/L Cd(NO₃)₂·4H₂O诱导的镉胁迫响应中涉及的关键基因。我们分别在CK与C10、CK与C20之间发现了总共2656个（1488个上调和1168个下调）和2816个差异表达基因（DEGs）（1470个上调和1346个下调）。基因本体论（GO）和京都基因与基因组百科全书（KEGG）对镉胁迫的富集分析表明，鉴定出的许多DEGs参与了催化活性、氧化还原酶活性、转移酶活性和次生代谢物的生物合成。基于富集结果，鉴定出了与钙离子信号转导、转录因子、抗氧化防御系统和转运蛋白相关的潜在候选基因，并在镉胁迫下表现出不同的表达模式。我们还通过实时PCR验证了转录组数据的可靠性。我们的研究结果加深了对欧美杨107镉耐受性分子响应机制的理解，并进一步为植物修复应用提供了关键资源。
