Gene expression of maize plants (Zea mays L.) in response to petroleum hydrocarbon stress

Abstract

Petroleum contamination in soil fields is a serious problem, particularly in countries that produce, transport, and refine oil. Phytoremediation is a promising approach for the cleanup of soil contaminated with petroleum hydrocarbons (PHCs) and heavy metals (HMs). For this purpose, this study was conducted to identify gene expression profiles for two related genes in response to petroleum stress in maize leaves at two contaminated sites. Two sites were chosen to collect polluted soil with oily residues: AL-Daura power station and AL-Daura oil refinery in Baghdad province. The soil was subjected to chronic pollution for many years. In addition, one unpolluted site was chosen for comparison as control around 4 Km upwind from ALDaura thermal power station. The gene expression of Opr1 and Pao1 genes in addition to ZmAct as reference gene was analysis in the maize leaves using RT-PCR. All data were statistically analyzed using analysis of variance, and treatment means were differentiated using the Least Significant Difference (LSD) test at P ≤ 0.05. The expression of Opr1 and Pao1 genes in maize leaves was overexpressing with 42.86 and 10.25 folds at refinery soil, respectively, while at power station soil increased with 5.16 and 5.04 folds, respectively but not differ significantly from control soil. The study show that the Real-time PCR analysis confirmed the expression patterns of the Opr1 and Pao1 genes, which play critical roles in mediating plant tolerance to petroleum stress.