摘要： 为了找到玉米缓解重金属镉胁迫的方法，采用稀土镧缓解玉米镉胁迫的生理生化反应，结合转录组分析，研究其缓解机理。试验发现：Cd²⁺处理会抑制玉米幼苗的根长和地上部分的正常生长，并且这种抑制作用会随着Cd²⁺浓度的升高而变的愈发明显。低浓度的La³⁺溶液（10，20 mg/L）会对玉米幼苗的生长产生一定的促进作用，而较高浓度的La³⁺溶液（40 mg/L）则会对玉米幼苗的生长产生抑制作用。喷施镧溶液会使Cd²⁺胁迫下的玉米幼苗生长状况得到改善，SOD、POD、CAT的活性与镉胁迫相比显著降低，但是与对照相比还是略高。采用二代测序技术，对镧处理下镉胁迫玉米根部样品进行转录组分析。以单独镉处理为对照，分析其差异表达基因，发现差异表达基因主要富集在淀粉和蔗糖代谢、氨基糖和核苷酸糖代谢、苯丙氨酸代谢以及植物激素信号转导4条通路。通过试验得出，喷施镧溶液可以缓解玉米幼苗受到的镉胁迫，但不会使其恢复到正常状态。通过转录组测序推测出稀土缓解重金属胁迫的原因可能与以上4条通路的相关基因有关，为后续针对稀土响应重金属胁迫的相关研究提供了候选分子资源。

关键词: 玉米, 镧, 镉, 转录组, 差异表达基因

Abstract: In order to find a way to alleviate the stress of heavy metal cadmium in maize, this experiment used rare earth lanthanum to reduce the physiological and biochemical reactions of cadmium stress in maize, and combined with transcriptome analysis to study its mitigation mechanism. The experiment found that:Cd²⁺ treatment would inhibit the normal growth of the root length and aboveground part of maize seedlings, and this inhibitory effect would become more obvious with the increase of Cd²⁺ concentration. Low concentration of La³⁺ solution (10, 20 mg/L) would promote the growth of corn seedlings to a certain extent, while the higher concentration of La³⁺ solution (40 mg/L) would inhibit the growth of corn seedlings. Spraying lanthanum solution would improve the growth of corn seedlings under Cd²⁺ stress, and the activities of SOD, POD and CAT would significantly reduced compared with cadmium stress, but they were still slightly higher than the control. Transcriptome analysis of cadmium-stressed maize root samples was carried out using a second-generation sequencing technique. The cadmium treatment was used as a control to analyze the differentially expressed genes. It was found that the differential genes were mainly enriched in four pathways:Starch and sucrose metabolism,amino sugar and nucleotide sugar metabolism,plant hormone signal transduction,phenylpropanoid biosynthesis.Through experiments, it concluded that spraying lanthanum solution could alleviate the cadmium stress on corn seedlings, but it cannot restore it to its normal state.Through transcriptome sequencing,we hypothesize that the reason for the mitigation of heavy metal stress by rare earths may be related to the related genes of the above four pathways, and provide candidate molecular resources for the subsequent research on the response of rare earths to heavy metal stress.

Key words: Maize, Lanthanum, Cadmium, Transcriptome, Differentially expressed genes

中图分类号: 

• S513.01