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Gene knockout study reveals that cytosolic ascorbate peroxidase 2(OsAPX2) plays a critical role in growth and reproduction in rice under drought, salt and cold stresses.

Zhang Z, Zhang Q, Wu J, Zheng X, Zheng S, Sun X, Qiu Q, Lu T - PLoS ONE (2013)

Bottom Line: Loss of function in OsAPX2 affected the growth and development of rice seedlings, resulting in semi-dwarf seedlings, yellow-green leaves, leaf lesion mimic and seed sterility.H2O2 and MDA levels were high in Osapx2 mutants but low in OsAPX2-OX transgenic lines relative to wild-type plants after stress treatments.Taken together, the cytosolic ascorbate peroxidase OsAPX2 plays an important role in rice growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences/National Key facility for Gene Resources And Genetic Improvement, Beijing, China.

ABSTRACT
Plant ascorbate peroxidases (APXs), enzymes catalyzing the dismutation of H2O2 into H2O and O2, play an important role in reactive oxygen species homeostasis in plants. The rice genome has eight OsAPXs, but their physiological functions remain to be determined. In this report, we studied the function of OsAPX2 gene using a T-DNA knockout mutant under the treatment of drought, salt and cold stresses. The Osapx2 knockout mutant was isolated by a genetic screening of a rice T-DNA insertion library under 20% PEG-2000 treatment. Loss of function in OsAPX2 affected the growth and development of rice seedlings, resulting in semi-dwarf seedlings, yellow-green leaves, leaf lesion mimic and seed sterility. OsAPX2 expression was developmental- and spatial-regulated, and was induced by drought, salt, and cold stresses. Osapx2 mutants had lower APX activity and were sensitive to abiotic stresses; overexpression of OsAPX2 increased APX activity and enhanced stress tolerance. H2O2 and MDA levels were high in Osapx2 mutants but low in OsAPX2-OX transgenic lines relative to wild-type plants after stress treatments. Taken together, the cytosolic ascorbate peroxidase OsAPX2 plays an important role in rice growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species.

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Related in: MedlinePlus

The expression of OsAPX2 and seed setting rate in wild-type, Osapx2, complementation and OsAPX2-OX plants.A: RT-qPCR analysis of OsAPX2 expression in wild-type (WT), Osapx2, complementation plants (cp1 and cp2) and OsAPX2-OX plants. B: Seed setting rates of wild-type (WT), Osapx2, complementation plants (cp1 and cp2) and OsAPX2-OX plants. Values represent means ± SD of three replicates.
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pone-0057472-g005: The expression of OsAPX2 and seed setting rate in wild-type, Osapx2, complementation and OsAPX2-OX plants.A: RT-qPCR analysis of OsAPX2 expression in wild-type (WT), Osapx2, complementation plants (cp1 and cp2) and OsAPX2-OX plants. B: Seed setting rates of wild-type (WT), Osapx2, complementation plants (cp1 and cp2) and OsAPX2-OX plants. Values represent means ± SD of three replicates.

Mentions: Since the homozygous mutants were male sterile, the small seeds segregated from the heterozygous lines were used for complementary test. Calli derived from homozygous Osapx2 mutant seeds were confirmed by PCR and transformed with pOsAPX2::OsAPX2, a construction of the full-length cDNA of OsAPX2 driven by its own promoter. Among all the fifty-one transgenic plants obtained, thirty five plants showed the wild-type expression level of OsAPX2 gene as determined by RT-qPCR (Figure 5-A) and recovered the wild-type phenotype in terms of seedling height, leaf appearance, anther shape, pollen viability and seed setting rate (Figure 4-A,E; Figure 5-B).


Gene knockout study reveals that cytosolic ascorbate peroxidase 2(OsAPX2) plays a critical role in growth and reproduction in rice under drought, salt and cold stresses.

Zhang Z, Zhang Q, Wu J, Zheng X, Zheng S, Sun X, Qiu Q, Lu T - PLoS ONE (2013)

The expression of OsAPX2 and seed setting rate in wild-type, Osapx2, complementation and OsAPX2-OX plants.A: RT-qPCR analysis of OsAPX2 expression in wild-type (WT), Osapx2, complementation plants (cp1 and cp2) and OsAPX2-OX plants. B: Seed setting rates of wild-type (WT), Osapx2, complementation plants (cp1 and cp2) and OsAPX2-OX plants. Values represent means ± SD of three replicates.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585366&req=5

pone-0057472-g005: The expression of OsAPX2 and seed setting rate in wild-type, Osapx2, complementation and OsAPX2-OX plants.A: RT-qPCR analysis of OsAPX2 expression in wild-type (WT), Osapx2, complementation plants (cp1 and cp2) and OsAPX2-OX plants. B: Seed setting rates of wild-type (WT), Osapx2, complementation plants (cp1 and cp2) and OsAPX2-OX plants. Values represent means ± SD of three replicates.
Mentions: Since the homozygous mutants were male sterile, the small seeds segregated from the heterozygous lines were used for complementary test. Calli derived from homozygous Osapx2 mutant seeds were confirmed by PCR and transformed with pOsAPX2::OsAPX2, a construction of the full-length cDNA of OsAPX2 driven by its own promoter. Among all the fifty-one transgenic plants obtained, thirty five plants showed the wild-type expression level of OsAPX2 gene as determined by RT-qPCR (Figure 5-A) and recovered the wild-type phenotype in terms of seedling height, leaf appearance, anther shape, pollen viability and seed setting rate (Figure 4-A,E; Figure 5-B).

Bottom Line: Loss of function in OsAPX2 affected the growth and development of rice seedlings, resulting in semi-dwarf seedlings, yellow-green leaves, leaf lesion mimic and seed sterility.H2O2 and MDA levels were high in Osapx2 mutants but low in OsAPX2-OX transgenic lines relative to wild-type plants after stress treatments.Taken together, the cytosolic ascorbate peroxidase OsAPX2 plays an important role in rice growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences/National Key facility for Gene Resources And Genetic Improvement, Beijing, China.

ABSTRACT
Plant ascorbate peroxidases (APXs), enzymes catalyzing the dismutation of H2O2 into H2O and O2, play an important role in reactive oxygen species homeostasis in plants. The rice genome has eight OsAPXs, but their physiological functions remain to be determined. In this report, we studied the function of OsAPX2 gene using a T-DNA knockout mutant under the treatment of drought, salt and cold stresses. The Osapx2 knockout mutant was isolated by a genetic screening of a rice T-DNA insertion library under 20% PEG-2000 treatment. Loss of function in OsAPX2 affected the growth and development of rice seedlings, resulting in semi-dwarf seedlings, yellow-green leaves, leaf lesion mimic and seed sterility. OsAPX2 expression was developmental- and spatial-regulated, and was induced by drought, salt, and cold stresses. Osapx2 mutants had lower APX activity and were sensitive to abiotic stresses; overexpression of OsAPX2 increased APX activity and enhanced stress tolerance. H2O2 and MDA levels were high in Osapx2 mutants but low in OsAPX2-OX transgenic lines relative to wild-type plants after stress treatments. Taken together, the cytosolic ascorbate peroxidase OsAPX2 plays an important role in rice growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species.

Show MeSH
Related in: MedlinePlus