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The rice Os03g0285700 was reported as OsAPXa in 2010 [1] by researchers from Japan.

Annotated Information

Gene Symbol

  • Os03g0285700 <=> OsAPX1, APXa, OsAPx01, OsAPx1, OSAPX1, APx1, cAPX


  • OsAPXa is a member of ascorbate peroxidase (APX) family.
  • It is a haeme-containing enzyme of the ascorbate glutathione cycle that detoxifies reactive oxygen species in plants by catalyzing the conversion of hydrogen peroxide to water using ascorbate as a specific electron donor.
  • OsAPXa can affect the ability of rice plants to withstand chilling at the booting stage. When overexpress OsAPX1 in rice, it can increase APX activity which determine the antioxidant capacity.

Phenotypic analysis

  • To determine whether antioxidant capacity affects the ability of rice plants to withstand chilling at the booting stage, researhcers produced transgenic rice plants that overexpress OsAPXa and have increased APX activity.
  • The effect of increased APX activity on the levels of H2O2 and lipid peroxidation were determined by measuring H2O2 levels and malondialdehyde (MDA) contents in spikelets during cold treatments at the booting stage.
  • The levels of H2O2 and the MDA content increased by 1.5-fold and twofold, respectively in WT plants subjected to a 12°C treatment for 6 days. In contrast, transgenic lines showed small changes in H2O2 levels and MDA content under cold stress, and

H2O2 levels and MDA content were significantly lower than in WT plants.

  • APX activity showed negative correlations with levels of H2O2 and MDA content, which increased during cold treatment. Cold tolerance at the booting stage in transgenic lines and WT plants was evaluated.
  • Spikelet fertility was significantly higher in transgenic lines than in WT plants after a 12°C treatment for 6 days.

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Labs working on this gene

  • National Agricultural Research Center for Hokkaido Region, Hitsujigaoka 1, Toyohira, Sapporo 062-8555, Japan
  • National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan



Structured Information

  1. 1.0 1.1 Sato Y, Masuta Y, Saito K, Murayama S, Ozawa K. Enhanced chilling tolerance at the booting stage in rice by transgenic overexpression of the ascorbate peroxidase gene, OsAPXa. Plant Cell Rep. 2011 Mar;30(3):399-406. doi: 10.1007/s00299-010-0985-7. PubMed PMID: 21203887.