Regulation of three isoforms of SOD gene by environmental stresses in citrus red mite, Panonychus citri

Superoxide dismutase (SOD) is a family of enzymes with multiple isoforms that possess antioxidative abilities in response to environmental stresses. Panonychus citri is one of the most important pest mites and has a global distribution. In this study, three distinct isoforms of SOD were cloned from P. citri and identified as cytoplasmic Cu-ZnSOD ( PcSOD1 ), extracellular Cu-ZnSOD ( PcSOD2 ), and mitochondrial MnSOD ( PcSOD3 ). mRNA expression level analysis showed that all three isoforms were up-regulated significantly after exposure to the acaricide abamectin and to UV-B ultraviolet irradiation. In particular, PcSOD3 was up-regulated under almost all environmental stresses tested. The fold change of PcSOD3 expression was significantly higher than those of the two Cu-ZnSOD isoforms. Taken together, the results indicate that abamectin and UV-B can induce transcripts of all three SOD isoforms in P. citri . Furthermore, PcSOD3 seems to play a more important role in P. citri tolerance to oxidative stress.