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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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Developmentally regulated OsAPX2 expression in rice tissues.A: RT-qPCR was performed to analysis the expression of OsAPX2 in root, leaf, blade sheath, blade ear, flower (fl), apical meristem and internode (in). B: The expression of OsAPX2 in leaves at different stages. C,D,E,F,G Expression patterns of OsAPX2 revealed by GUS staining. Leaf (D), internode (D), blade ear (F) and the transversely side of internode (G), flower (E). Bar = 200 µm.
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pone-0057472-g006: Developmentally regulated OsAPX2 expression in rice tissues.A: RT-qPCR was performed to analysis the expression of OsAPX2 in root, leaf, blade sheath, blade ear, flower (fl), apical meristem and internode (in). B: The expression of OsAPX2 in leaves at different stages. C,D,E,F,G Expression patterns of OsAPX2 revealed by GUS staining. Leaf (D), internode (D), blade ear (F) and the transversely side of internode (G), flower (E). Bar = 200 µm.

Mentions: RT-qPCR was performed to analyze the expression pattern of OsAPX2 in different tissues and in leaves at different developmental stages. As show in Figure 6-A, the expression of OsAPX2 was low in root, leaf and blade sheath but high in blade ear, flower, apical meristem and internode. To further examine the expression pattern of OsAPX2 comprehensively, the pCAMBIA1391Z vector with the fusion of the OsAPX2 pormoter (from −2111 bp to −1 bp) and the GUS coding sequence was transformed into calli in the wild-type background by Agrobacterium tumefaciens-mediated transformation. Strong GUS activity was detected in organs including young leaf (Figure 6-C), internode (Figure 6-D) and blade ear (Figure 6-F), stem (Figure 6-G) and anther (Figure 6-E), which are consistent with above RT-qPCR results. Then we compared the gene expression at different developmental stages using leaves at seedling and tillering stages, and flag leaves at heading stage. Results showed that the expression of OsAPX2 was higher in mature leaves than young leaves; OsAPX2 was most strongly expressed in flag leaves at heading stage (Figure 6-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)

Developmentally regulated OsAPX2 expression in rice tissues.A: RT-qPCR was performed to analysis the expression of OsAPX2 in root, leaf, blade sheath, blade ear, flower (fl), apical meristem and internode (in). B: The expression of OsAPX2 in leaves at different stages. C,D,E,F,G Expression patterns of OsAPX2 revealed by GUS staining. Leaf (D), internode (D), blade ear (F) and the transversely side of internode (G), flower (E). Bar = 200 µm.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0057472-g006: Developmentally regulated OsAPX2 expression in rice tissues.A: RT-qPCR was performed to analysis the expression of OsAPX2 in root, leaf, blade sheath, blade ear, flower (fl), apical meristem and internode (in). B: The expression of OsAPX2 in leaves at different stages. C,D,E,F,G Expression patterns of OsAPX2 revealed by GUS staining. Leaf (D), internode (D), blade ear (F) and the transversely side of internode (G), flower (E). Bar = 200 µm.
Mentions: RT-qPCR was performed to analyze the expression pattern of OsAPX2 in different tissues and in leaves at different developmental stages. As show in Figure 6-A, the expression of OsAPX2 was low in root, leaf and blade sheath but high in blade ear, flower, apical meristem and internode. To further examine the expression pattern of OsAPX2 comprehensively, the pCAMBIA1391Z vector with the fusion of the OsAPX2 pormoter (from −2111 bp to −1 bp) and the GUS coding sequence was transformed into calli in the wild-type background by Agrobacterium tumefaciens-mediated transformation. Strong GUS activity was detected in organs including young leaf (Figure 6-C), internode (Figure 6-D) and blade ear (Figure 6-F), stem (Figure 6-G) and anther (Figure 6-E), which are consistent with above RT-qPCR results. Then we compared the gene expression at different developmental stages using leaves at seedling and tillering stages, and flag leaves at heading stage. Results showed that the expression of OsAPX2 was higher in mature leaves than young leaves; OsAPX2 was most strongly expressed in flag leaves at heading stage (Figure 6-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