<p class="Body">Three superoxide dismutase genes from Tetranychus cinnabarinus (Boisduval) involved in the responses to temperature and acaricide stresses

Abstract

In almost all aerobic organisms, the superoxide dismutase (SOD) is considered as an important antioxidant enzyme regulating oxidative stress. Tetranychus cinnabarinus is an economically important polyphagous pest mite, which harms a variety of economic crops and ornamental plants. In the present study, the full-length cDNA sequences of cytoplasmic Cu/ZnSOD (TcSOD1), extracellular Cu/ZnSOD (TcSOD2) and mitochondrial MnSOD (TcSOD3) from T. cinnabarinus were cloned by combining RT-PCR and rapid amplification of cDNA ends (RACE). The corresponding open reading frames (ORFs) encode three putative polypeptides of 152, 232, 225 amino acid residues, respectively. These sequences share the conserved SOD functional domains, signature motifs and metal binding sites. Multiple alignment analysis revealed that cytosolic Cu/ZnSOD and mitochondrial MnSOD sequences are relatively conserved, while extracellular Cu/ZnSODs are more diverse. Phylogenetic analysis showed that SODs are organized into two major clades, corresponding to Cu/ZnSODs, and MnSODs. Cu/ZnSODs are subdivided into two branches, one being composed of cytoplasmic Cu/ZnSODs, and the other corresponding to extracellular Cu/ZnSODs. Expression profiles of the three genes were determined at different temperatures (4°C, 25°C, and 40°C) for 2 hours. The relative expression of TcSOD1, TcSOD2, and TcSOD3 were significantly down-regulated (0.344-, 0.287-, and 0.358-fold, respectively) at 4°C compared to 25°C (P&lt;0.05). The relative expression levels of TcSOD1 and TcSOD2 genes were significantly down-regulated at 40°C (0.481- and 0.291-fold less than in the control group, respectively) (P&lt;0.05), while there was no significant difference in the relative expression level of TcSOD3(P&gt;0.05). Moreover, expression levels were altered after exposition to different acaricides. TcSOD1, TcSOD2, and TcSOD3 were significantly down-regulated (0.450-, 0.147- and 0.663-fold decreases, respectively) in the abamectin-treated group (P&lt;0.05). TcSOD1 and TcSOD2 were down-regulated, in the fenpropathrin-treated group with 0.794- and 0.201-fold decreases, respectively. On the other hand, the expression of TcSOD3 was significantly increased (P&lt;0.05), being 2.774-fold higher than in the control group. The expression of TcSOD2 was significantly down-regulated both the propargite- and cyflumetofen-treated groups (0.655- and 0.397-fold, respectively) (P&lt;0.05). The data reported here indicate that SODs from T. cinnabarinus may play different and vital roles in anticipating the effects of oxidative damage at extreme temperatures and under different acaricides stress.

Prologue: Scientific and Societal Importance of Mites and Acarology From the Viewpoint of International Publication

“…The permanent darkness and the low oxygen level do not cause problems either. In most of their species resistance had developed to the special acaricides as well [3][4][5]. In case of a record-breaking mass extinction due to the destruction of the environment by mankind, they will have representatives among the survivors, since many of their groups had survived the most devastating Permian-Triassic extinction to date almost without any change.…”