Overexpression of the Glutathione Peroxidase 5 (RcGPX5) Gene From Rhodiola crenulata Increases Drought Tolerance in Salvia miltiorrhiza

Abstract

Excessive cellular accumulation of reactive oxygen species (ROS) due to environmental stresses can critically disrupt plant development and negatively affect productivity. Plant glutathione peroxidases (GPXs) play an important role in ROS scavenging by catalyzing the reduction of H2O2 and other organic hydroperoxides to protect plant cells from oxidative stress damage. RcGPX5, a member of the GPX gene family, was isolated from a traditional medicinal plant Rhodiola crenulata and constitutively expressed in Salvia miltiorrhiza under control of the CaMV 35S promoter. Transgenic plants showed increased tolerance to oxidative stress caused by application of H2O2 and drought, and had reduced production of malondialdehyde (MDA) compared with the wild type. Under drought stress, seedlings of the transgenic lines wilted later than the wild type and recovered growth 1 day after re-watering. In addition, the reduced glutathione (GSH) and total glutathione (T-GSH) contents were higher in the transgenic lines, with increased enzyme activities including glutathione reductase (GR), ascorbate peroxidase (APX), and GPX. These changes prevent H2O2 and O2- accumulation in cells of the transgenic lines compared with wild type. Overexpression of RcGPX5 alters the relative expression levels of multiple endogenous genes in S. miltiorrhiza, including transcription factor genes and genes in the ROS and ABA pathways. In particular, RcGPX5 expression increases the mass of S. miltiorrhiza roots while reducing the concentration of the active ingredients. These results show that heterologous expression of RcGPX5 in S. miltiorrhiza can affect the regulation of multiple biochemical pathways to confer tolerance to drought stress, and RcGPX5 might act as a competitor with secondary metabolites in the S. miltiorrhiza response to environmental stimuli.

Drought-hardening improves drought tolerance in Nicotiana tabacum at physiological, biochemical, and molecular levels

“…200 μL sample supernatant was taken and 60 μL reagent 1, 100 μL reagent 2, 240 μL reagent 3, and 1400 μL dd H 2 O was added and mixed equally for the quantification of ASA. The absorbance was recorded at 420 nm [ 94 ].…”

“…Subsequently, 100 μL sample supernatant was taken and evenly mixed with 700 μL reagent 1 and 200 μL reagent 3. The OD was measured at 412 [ 94 ].…”

Biochemical changes in sunflower plant exposed to silver nanoparticles / silver ions

“…Reactive oxygen species are generated during the normal metabolism of eukaryotic cells [38] and may cause oxidative damage to macromolecules such as lipids, proteins, and DNA [39]. We analysed four antioxidant enzymes (SOD, CAT, GST, GPx) and LPO to evaluate the response to ROS in leaves of sunflowers exposed to 150 mg/kg AgNPs or Ag + in soil.…”

“…The GPx activity in plants depends on physiological and genetic status, time interval, type and concentration of exposure to pollutants including heavy metals and is a response to oxidative stress [54]. GPx catalyses the reduction of H 2 O 2 via GSH to protect plant cells from oxidative stress [38] not only caused by heavy metals but also by salinity and drought conditions [55].…”

CRISPR/Cas9-Mediated Knockout of HOS1 Reveals Its Role in the Regulation of Secondary Metabolism in Arabidopsis thaliana

“…Exposure to adverse environmental conditions, including extreme temperatures, water deprivation, excessive soil salinity, high radiation and chemical pollution, can negatively impact plant quality, accumulation of biomass and yield [9,10]. Different strategies in plant biotechnology have been developed to increase resistance and mitigate stress responses in plants, including overexpression of antioxidant genes [11,12], stress-responsive genes and transcription factors [13][14][15] or genes participating in biosynthesis of osmoprotectants [16,17]. Recently, CRISPR/Cas9-mediated mutagenesis of negative regulators of stress-responsive pathways became an alternative way of producing stress-tolerant plants [18,19].…”