A cotton ascorbate peroxidase is involved in hydrogen peroxide homeostasis during fibre cell development.
Reactive oxygen species (ROS) play important roles in multiple physiological processes such as cellular signalling and stress responses, whereas, the hydrogen peroxide (H(2)O(2)) scavenging enzyme ascorbate peroxidase (APX) participates in the regulation of intracellular ROS levels. Here, a cotton (Gossypium hirsutum) cytosolic APX1 (GhAPX1) was identified to be highly accumulated during cotton fibre elongation by proteomic analysis. GhAPX1 cDNA contained an open reading frame of 753-bp encoding a protein of 250 amino acid residues. When GhAPX1 was expressed in Escherichia coli, the purified GhAPX1 was a dimer consisting of two identical subunits with a molecular mass of 28 kDa. GhAPX1 showed the highest substrate specificity for ascorbate. Quantitative real-time polymerase chain reaction (PCR) analyses showed that GhAPX1 was highly expressed in wild-type 5-d postanthesis fibres with much lower transcript levels in the fuzzless-lintless mutant ovules. Treating in vitro cultured wild-type cotton ovules with exogenous H(2)O(2) or ethylene induced the expression of GhAPX1 and hence increased total APX activity proportionally, followed by extended fibre cell elongation. These data suggest that GhAPX1 expression is upregulated in response to an increase in cellular H(2)O(2) and ethylene. GhAPX1 encodes a functional enzyme that is involved in hydrogen peroxide homeostasis during cotton fibre development.
Li
Hong-Bin
HB
National Laboratory of Protein Engineering and Plant Genetic Engineering and Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing, 100871, China.
Qin
Yong-Mei
YM
National Laboratory of Protein Engineering and Plant Genetic Engineering and Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing, 100871, China.
Pang
Yu
Y
National Laboratory of Protein Engineering and Plant Genetic Engineering and Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing, 100871, China.
Song
Wen-Qiang
WQ
National Laboratory of Protein Engineering and Plant Genetic Engineering and Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing, 100871, China.
Mei
Wen-Qian
WQ
National Laboratory of Protein Engineering and Plant Genetic Engineering and Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing, 100871, China.
Zhu
Yu-Xian
YX
National Laboratory of Protein Engineering and Plant Genetic Engineering and Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing, 100871, China.
D000595:Amino Acid Sequence; D060387:Ascorbate Peroxidases; D032561:Cotton Fiber; D005030:Ethylenes / Q000494:pharmacology; D003368:Gossypium / Q000196:embryology / Q000201:enzymology* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D008969:Molecular Sequence Data; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D020543:Proteome; D016415:Sequence Alignment; D014158:Transcription, Genetic / Q000187:drug effects
D005030:Ethylenes; D010940:Plant Proteins; D020543:Proteome; C036216:ethylene; D006861:Hydrogen Peroxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases