Nitrate reductase (NR)-dependent NO production mediates ABA- and H2O2-induced antioxidant enzymes.
Abscisic acid (ABA), H2O2 and nitric oxide (NO) are important signals in gene expression and physiological responses during plant adaptation to environmental stresses. The essential role of NR-derived NO production in ABA and H2O2 induced antioxidant enzymes were studied using transgenic tobacco plants over-expressing Stylosanthes guianensis 9-cis-epoxycartenoid dioxygenase gene (SgNCED1) for elevated ABA level, or over-expressing wheat oxalate oxidase gene (OxO) for elevated H2O2 level in comparison to the wild type. Compared to the wild type, higher levels of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and nitrate reductase (NR) activities and NO production were observed in all transgenic plants. For investigating the relationship of ABA, H2O2, and NR-produced NO in the induction of antioxidant enzyme activities, an inhibitor of ABA biosynthesis, scavengers of H2O2 and NO, and an inhibitor of NR were used in the experiments. The results indicate that H2O2-induced activities of SOD, CAT, and APX depends on NR-derived NO in OxO transgenic plants, while ABA-induced activities depends on H2O2 and NR-derived NO in SgNCED1 transgenic plants. Compared to unaltered nitrate reductase 2 (NIA2), NIA1 transcript was induced in both types of transgenic plants. It is suggested NR-derived NO is essential for ABA- or H2O2-induced antioxidant enzyme activities.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou 510642, China.
Shaoyun
S
Lu
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou 510642, China.
Chunliu
C
Zhuo
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou 510642, China.
Xianghui
X
Wang
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou 510642, China. Electronic address: zhfguo@scau.edu.cn.
Zhenfei
Z
Guo
D000040:Abscisic Acid / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism; D060387:Ascorbate Peroxidases / Q000096:biosynthesis*; D002374:Catalase / Q000096:biosynthesis*; D004790:Enzyme Induction; D006861:Hydrogen Peroxide / Q000378:metabolism*; D050901:Nitrate Reductase / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000378:metabolism; D013482:Superoxide Dismutase / Q000096:biosynthesis*; D014026:Nicotiana / Q000201:enzymology / Q000378:metabolism; D014158:Transcription, Genetic
D000975:Antioxidants; D009569:Nitric Oxide; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D050901:Nitrate Reductase
Abscisic acid (ABA); Antioxidants; Hydrogen peroxide; Nitrate reductase (NR); Nitric oxide (NO)