Abstract
Increased transcriptional levels of genes encoding antioxidant enzymes play important protective roles in coping with excessive accumulation of reactive oxygen species (ROS) in plants exposed to various abiotic stresses. To fully elucidate different evolutions and functions of ROS-scavenging enzymatic genes, we isolated iron superoxide dismutase (FeSOD), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) from white clover for the first time and subsequently tested dynamic expression profiles of these genes together with previously identified other antioxidant enzyme genes including copper zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase (MnSOD), glutathione reductase (GR), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in response to cold, drought, salinity, cadmium stress and exogenous abscisic acid (ABA) or spermidine (Spd) treatment. The cloned fragments of FeSOD, DHAR and MDHAR genes were 630, 471 and 669 bp nucleotide sequences encoding 210, 157 and 223 amino acids, respectively. Phylogenetic analysis indicated that both amino acid and nucleotide sequences of these three genes are highly conservative. In addition, the analysis of genes expression showed the transcription of GR, POD, MDHAR, DHAR and Cu/ZnSOD were rapidly activated with relatively high abundance during cold stress. Differently, CAT, APX, FeSOD, Cu/ZnSOD and MnSOD exhibited more abundant transcripts compared to others under drought stress. Under salt stress, CAT was induced preferentially (3–12 h) compared to GR which was induced later (12–72 h). Cadmium stress mainly up-regulated Cu/ZnSOD, DHAR and MDHAR. Interestingly, most of genes expression induced by ABA or Spd happened prior to various abiotic stresses. The particular expression patterns and different response time of these genes indicated that white clover differentially activates genes encoding antioxidant enzymes to mitigate the damage of ROS during various environmental stresses.
Highlights
In the aerobic metabolism action of plant organelles like chloroplast, mitochondria, peroxisomes etc., molecular oxygen (O2) can be reduced to low amounts of reactive oxygen species (ROS) at various degrees
The ROS family is mainly comprised of superoxide radicals (O2 ̈ ́), singlet oxygen (1O2), hydrogen peroxide (H2O2), and hydroxyl radicals (OH) [1], which act as signal molecules in the process of plant growth, development and response to environmental stress conditions
Three genes including FeSOD, dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) will be isolated from white clover for the first time and the dynamically transcriptional levels of nine different antioxidant enzymes will be investigated by unsing quantitative real-time ploymerase chain reaction when white clover are exposed to a short-term abiotic stress including cold, drought, salinity, cadmium stresses as well as exogenous abscisic acid (ABA) and spermidine (Spd) treatments
Summary
In the aerobic metabolism action of plant organelles like chloroplast, mitochondria, peroxisomes etc., molecular oxygen (O2) can be reduced to low amounts of reactive oxygen species (ROS) at various degrees. Three genes including FeSOD, DHAR and MDHAR will be isolated from white clover for the first time and the dynamically transcriptional levels of nine different antioxidant enzymes will be investigated by unsing quantitative real-time ploymerase chain reaction (qRT-PCR) when white clover are exposed to a short-term abiotic stress including cold, drought, salinity, cadmium stresses as well as exogenous abscisic acid (ABA) and spermidine (Spd) treatments. The results will contribute to better understanding of specific expression patterns of genes encoding antioxidant enzymes in response to different abiotic stresses and the regulatory role of exogenous PGRs on enzymatic antioxidant defense system based on different transcriptional levels of genes in white clover
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
