Identification of Glutathione Peroxidase (GPX) Gene Family in <i>Rhodiola crenulata</i> and Gene Expression Analysis under Stress Conditions

Glutathione peroxidases (GPXs) are important enzymes in the glutathione-ascorbate cycle for catalyzing the reduction of H2O2 or organic hydroperoxides to water. GPXs play an essential role in plant growth and development by participating in photosynthesis, respiration, and stress tolerance. Rhodiola crenulata is a popular traditional Chinese medicinal plant which displays an extreme energy of tolerance to harsh alpine climate. The GPXs gene family might provide R. crenulata for extensively tolerance to environment stimulus. In this study, five GPX genes were isolated from R. crenulata. The protein amino acid sequences were analyzed by bioinformation softwares with the results that RcGPXs gene sequences contained three conserve cysteine residues, and the subcellular location predication were in the chloroplast, endoplasmic reticulum, or cytoplasm. Five RcGPXs members presented spatial and temporal specific expression with higher levels in young and green organs. And the expression patterns of RcGPXs in response to stresses or plant hormones were investigated by quantitative real-time PCR. In addition, the putative interaction proteins of RcGPXs were obtained by yeast two-hybrid with the results that RcGPXs could physically interact with specific proteins of multiple pathways like transcription factor, calmodulin, thioredoxin, and abscisic acid signal pathway. These results showed the regulation mechanism of RcGPXs were complicated and they were necessary for R. crenulata to adapt to the treacherous weather in highland