Steel slag and rice husk bokashi are the ameliorant that expected can decrease P-retention Phytoremediation represents an effective, low-cost, environmentally friendly alternative that improves soil properties, although there have been significant developments in the last decade. From the scientific point of life, the main challenge is to decipher the metabolic pathways involved in response to contaminants and to understand their regulation. This information is essential if we aspire to improve the natural capacities of some plant species to remediate contaminated soils. A comprehensive study of the molecular response to polychlorinated biphenyls (PCBs), a family of persistent organic pollutants of particular relevance on a global scale, was obtained. A transcriptomic approach based on RNA-seq technology has been used to identify the genes involved in the metabolism of in-plant compounds and to quantify their activation levels in different controlled situations. It is surprising that this response is virtually unknown at the molecular level, despite its great potential applied in the context of phytoremediation technology. We apply to hybrid poplar (Populus tremula x alba) crops with Aroclor 1221. And we took samples of RNA, thus generating a matrix of four elements with their corresponding controls. On the other hand, we perform functional analyzes with bioinformatic tools based on sequence comparisons and gene co-expression networks. The response of genes of particular interest was validated using qRT-PCR technology. This is the first comprehensive study of the response of a plant organism to the presence of PCBs. A considerable number of structural and regulatory genes have been found, defining new transcription factors whose expression is proportional to the concentration of pollutant in the medium or the time of exposure to it. Correlation analyzes allow us to state that the metabolic response to PCBs, including possible degrading pathways, is involved in at least fifteen transcription factors and approximately forty proteins or enzymes that are particularly induced.