Abstract
As one of the largest gene families, F-box domain proteins have been found to play important roles in abiotic stress responses via the ubiquitin pathway. TaFBA1 encodes a homologous F-box protein contained in E3 ubiquitin ligases. In our previous study, we found that the overexpression of TaFBA1 enhanced drought tolerance in transgenic plants. To investigate the mechanisms involved, in this study, we investigated the tolerance of the transgenic plants to oxidative stress. Methyl viologen was used to induce oxidative stress conditions. Real-time PCR and western blot analysis revealed that TaFBA1 expression was up-regulated by oxidative stress treatments. Under oxidative stress conditions, the transgenic tobacco plants showed a higher germination rate, higher root length and less growth inhibition than wild type (WT). The enhanced oxidative stress tolerance of the transgenic plants was also indicated by lower reactive oxygen species (ROS) accumulation, malondialdehyde (MDA) content and cell membrane damage under oxidative stress compared with WT. Higher activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD), were observed in the transgenic plants than those in WT, which may be related to the upregulated expression of some antioxidant genes via the overexpression of TaFBA1. In others, some stress responsive elements were found in the promoter region of TaFBA1, and TaFBA1 was located in the nucleus, cytoplasm and plasma membrane. These results suggest that TaFBA1 plays an important role in the oxidative stress tolerance of plants. This is important for understanding the functions of F-box proteins in plants’ tolerance to multiple stress conditions.
Highlights
Reactive oxygen species (ROS), including the superoxide anion radical (O2−), the hydroxyl radical (OH) and hydrogen peroxide (H2O2), are products of normal metabolic reactions in cells and are usually formed at low levels
The results indicated that the levels of reactive oxygen species (ROS) accumulation, MDA content, and cell membrane damage were less in the transgenic plants than in wild type (WT) under oxidative stress, suggesting improved antioxidative capability in the transgenic plants
In our previous reports [14], a 978-bp full-length cDNA of TaFBA1 was amplified by RT-PCR from wheat leaves
Summary
Reactive oxygen species (ROS), including the superoxide anion radical (O2−), the hydroxyl radical (OH) and hydrogen peroxide (H2O2), are products of normal metabolic reactions in cells and are usually formed at low levels. Under conditions of various environmental stresses, such as salinity, drought and extreme temperature, the ROS levels tend to increase in PLOS ONE | DOI:10.1371/journal.pone.0122117. Overexpressing Wheat TaFBA1 Improved Oxidative Stress Tolerance plant cells [1, 2]. The overproduction of ROS in plants causes oxidative damage to DNA, pigments, proteins and lipids, and it subsequently leads to a series of destructive processes [3, 4]. Oxidative stress is the most universal second stress involved in almost all stress conditions [5], and it is the common mechanism by which abiotic stresses affect plant growth and development. To protect themselves against ROS, plants have developed a combination of enzymatic and non-enzymatic antioxidative mechanisms [3, 6,7]
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