High CO2 concentrations stimulate net photosynthesis by increasing CO2 substrate availability for Rubisco, simultaneously suppressing photorespiration. Previously, we reported that silencing the chloroplast vesiculation (cv) gene in rice increased source fitness, through the maintenance of chloroplast stability and the expression of photorespiration-associated genes. Because high atmospheric CO2 conditions diminished photorespiration, we tested whether CV silencing might be a viable strategy to improve the effects of high CO2 on grain yield and N assimilation in rice. Under elevated CO2 , OsCV expression was induced, and OsCV was targeted to peroxisomes where it facilitated the removal of OsPEX11-1 from the peroxisome and delivered it to the vacuole for degradation. This process correlated well with the reduction in the number of peroxisomes, the decreased catalase activity and the increased H2 O2 content in wild-type plants under elevated CO2 . At elevated CO2 , CV-silenced rice plants maintained peroxisome proliferation and photorespiration and displayed higher N assimilation than wild-type plants. This was supported by higher activity of enzymes involved in NO3 - and NH4 + assimilation and higher total and seed protein contents. Co-immunoprecipitation of OsCV-interacting proteins suggested that, similar to its role in chloroplast protein turnover, OsCV acted as a scaffold, binding peroxisomal proteins.

中文翻译：

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沉默的OsCV（叶绿体囊泡化）保持了CO2浓度升高的水稻植株的光呼吸和氮同化作用。

高CO2浓度可通过增加Rubisco的CO2底物利用率来刺激净光合作用，同时抑制光呼吸。以前，我们报道说，通过维持叶绿体稳定性和光呼吸相关基因的表达，使水稻中的叶绿体囊泡（cv）基因沉默可以提高源适应性。由于大气中的高CO2条件减少了光呼吸，因此我们测试了CV沉默是否可能是提高高CO2对水稻籽粒产量和氮同化影响的可行策略。在升高的CO2下，诱导OsCV表达，并将OsCV靶向过氧化物酶体，从而促进过氧化物酶体中OsPEX11-1的去除并将其传递至液泡进行降解。该过程与过氧化物酶体数量的减少密切相关，CO2浓度升高时，野生型植物中过氧化氢酶活性降低，H2 O2含量升高。在升高的CO2浓度下，CV沉默的水稻植物保持了过氧化物酶体的增殖和光呼吸，并显示出比野生型植物更高的N同化率。参与NO3-和NH4 +同化的酶活性更高，总蛋白和种子蛋白含量更高，也证明了这一点。OsCV相互作用蛋白的共免疫沉淀表明，与它在叶绿体蛋白更新中的作用相似，OsCV充当结合过氧化物酶体蛋白的支架。参与NO3-和NH4 +同化的酶活性更高，总蛋白和种子蛋白含量更高，也证明了这一点。OsCV相互作用蛋白的共免疫沉淀表明，与它在叶绿体蛋白更新中的作用相似，OsCV充当结合过氧化物酶体蛋白的支架。参与NO3-和NH4 +同化的酶活性更高，总蛋白和种子蛋白含量更高，也证明了这一点。OsCV相互作用蛋白的共免疫沉淀表明，与它在叶绿体蛋白更新中的作用相似，OsCV充当结合过氧化物酶体蛋白的支架。