• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The New Phytologist >Low CO2 results in a rearrangement of carbon metabolism to support C-4 photosynthetic carbon assimilation in Thalassiosira pseudonana
【24h】

Low CO2 results in a rearrangement of carbon metabolism to support C-4 photosynthetic carbon assimilation in Thalassiosira pseudonana

机译：低CO2导致碳代谢的重排，以支持拟南芥中C-4光合碳的同化作用

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The mechanisms of carbon concentration in marine diatoms are controversial. At low CO2, decreases in O-2 evolution after inhibition of phosphoenolpyruvate carboxylases (PEPCs), and increases in PEPC transcript abundances, have been interpreted as evidence for a C-4 mechanism in Thalassiosira pseudonana, but the ascertainment of which proteins are responsible for the subsequent decarboxylation and PEP regeneration steps has been elusive. We evaluated the responses of T.pseudonana to steady-state differences in CO2 availability, as well as to transient shifts to low CO2, by integrated measurements of photosynthetic parameters, transcript abundances and quantitative proteomics. On shifts to low CO2, two PEPC transcript abundances increased and then declined on timescales consistent with recoveries of F-v/F-m, non-photochemical quenching (NPQ) and maximum chlorophyll a-specific carbon fixation (P-max), but transcripts for archetypical decarboxylation enzymes phosphoenolpyruvate carboxykinase (PEPCK) and malic enzyme (ME) did not change. Of 3688 protein abundances measured, 39 were up-regulated under low CO2, including both PEPCs and pyruvate carboxylase (PYC), whereas ME abundance did not change and PEPCK abundance declined. We propose a closed-loop biochemical model, whereby T.pseudonana produces and subsequently decarboxylates a C-4 acid via PEPC2 and PYC, respectively, regenerates phosphoenolpyruvate (PEP) from pyruvate in a pyruvate phosphate dikinase-independent (but glycine decarboxylase (GDC)-dependent) manner, and recuperates photorespiratory CO2 as oxaloacetate (OAA).
机译：海洋硅藻中碳浓度的机制存在争议。在低CO2浓度下，抑制磷酸烯醇丙酮酸羧化酶（PEPC）后O-2的生成减少以及PEPC转录物丰度的增加已被解释为拟南芥中C-4机制的证据，但要确定哪些蛋白质负责随后的脱羧和PEP再生步骤难以实现。我们通过对光合作用参数，转录本丰度和定量蛋白质组学的综合测量，评估了假单胞菌对二氧化碳可利用量的稳态差异以及向低二氧化碳的瞬时转变的响应。向低CO2转变时，两个PEPC转录本的丰度增加，然后按与Fv / Fm的回收率，非光化学猝灭（NPQ）和最大叶绿素a特异性碳固定（P-max）一致的时间尺度下降，但原型脱羧化的转录本磷酸烯醇丙酮酸羧激酶（PEPCK）和苹果酸酶（ME）没有变化。在3688种测定的蛋白质丰度中，有39种在低CO2下上调，包括PEPC和丙酮酸羧化酶（PYC），而ME丰度没有变化，PEPCK丰度下降了。我们提出了一个闭环生化模型，由此假单胞菌通过PEPC2和PYC分别产生并随后使C-4酸脱羧，从而在丙酮酸磷酸盐二激酶不依赖的情况下从丙酮酸再生磷酸烯醇丙酮酸（PEP）（但甘氨酸脱羧酶（GDC）依赖）方式，并恢复光呼吸二氧化碳为草酰乙酸（OAA）。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号