Abstract：
Chelator-assisted phytoremediation is an efficacious method for promoting the removal efficiency of heavy metals (HMs). The effects of N, N-bis(carboxymethyl)-L-glutamic acid (GLDA) and polyaspartic acid (PASP) on Cd uptake and pyrene removal by Solanum nigrum L. (S. nigrum) were compared in this study. Using GLDA or PASP, the removal efficiency of pyrene was over 98%. And PASP observably raised the accumulation and transport of Cd by S. nigrum compared with GLDA. Meanwhile, both GLDA and PASP markedly increased soil dehydrogenase activities (DHA) and microbial activities. DHA and microbial activities in the PASP treatment group were 1.05 and 1.06 folds of those in the GLDA treatment group, respectively. Transcriptome analysis revealed that 1206 and 1684 differentially expressed genes (DEGs) were recognized in the GLDA treatment group and PASP treatment group, respectively. Most of the DEGs found in the PASP treatment group were involved in the metabolism of carbohydrates, the biosynthesis of brassinosteroid and flavonoid, and they were up-regulated. The DEGs related to Cd transport were screened, and ABCG3, ABCC4, ABCG9 and Nramp5 were found to be relevant with the reduction of Cd stress in S. nigrum by PASP. Furthermore, with PASP treated, transcription factors (TFs) related to HMs such as WRKY, bHLH, AP2/ERF, MYB were down-regulated, while more MYB and bZIP TFs were up-regulated. These TFs associated with plant stress resistance would work together to induce oxidative stress. The above results indicated that PASP was more conducive for phytoremediation of Cd-pyrene co-contaminated soil than GLDA.
摘要：
螯合剂辅助植物修复是提高重金属去除效率的有效方法。N的影响，N-双（羧甲基）-L-谷氨酸（GLDA）和聚天冬氨酸（PASP）对龙葵吸收Cd和去除芘的影响（S.nigrum)在这项研究中进行了比较。使用GLDA或PASP，芘的去除效率达到98%以上。与GLDA相比，PASP显著提高了黑草对Cd的积累和运输。同时,GLDA和PASP均显着提高了土壤脱氢酶活性（DHA）和微生物活性。PASP处理组的DHA和微生物活性分别是GLDA处理组的1.05和1.06倍,分别。转录组分析显示，在GLDA治疗组和PASP治疗组中，1206和1684个差异表达基因（DEGs）被识别，分别。在PASP治疗组中发现的大多数DEGs参与碳水化合物的代谢，油菜素类固醇和类黄酮的生物合成，他们被上调了。筛选了与Cd运输相关的DEGs，发现ABCG3，ABCC4，ABCG9和Nramp5与PASP降低黑曲霉的Cd胁迫有关。此外，用PASP处理，与HMs相关的转录因子（TFs），如WRKY，bHLH,AP2/ERF,MYB下调,而更多的MYB和bZIPTFs上调。这些与植物胁迫抗性相关的TF将共同作用以诱导氧化胁迫。以上结果表明，PASP比GLDA更有利于Cd芘共污染土壤的植物修复。
