Can the Cyanobacterial Carbon-Concentrating Mechanism Increase Photosynthesis in Crop Species? A Theoretical Analysis
Can the Cyanobacterial Carbon-Concentrating Mechanism Increase Photosynthesis in Crop Species? A Theoretical Analysis
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DOI：
10.1104/pp.113.232611
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发表时间：
2014-04-01
期刊：
影响因子：
7.4
通讯作者：
Long, Stephen P.
中科院分区：
文献类型：
--
作者：
McGrath, Justin M.;Long, Stephen P.
实验表明，在C-3作物周围升高[CO2]可以抑制Rubisco加氧酶反应，进而抑制光呼吸作用，从而提高产量。生物工程将蓝细菌的碳浓缩机制（CCM）转化为C-3作物提供了一种提高Rubisco [CO2]的潜在手段，从而降低光呼吸作用，提高光合效率和产量。与其他CCM相比，蓝藻CCM是一个有吸引力的选择，因为它的特征不需要对叶组织进行解剖改变。然而，将整个CCM改造成C-3叶片的潜在好处尚未得到检验。本文建立了CO2和HCO3-扩散反应模型，以研究蓝藻CCM的成分如何影响叶片光饱和CO2吸收（a (sat)），并确定不同的Rubisco异构体是否在具有蓝藻CCM的叶片中表现更好。结果表明，添加不含其他CCM成分的羧基体可显著降低A(sat)，最好的第一步是添加HCO3-转运体，单个HCO3-转运体可使模型A（sat）增加9%。所有主要成分的加入使A（sat）从24 μ mol m（-2）增加到38 μ mol m（-1）。几种Rubisco异构体在模型中进行了比较，通过使用适应高[CO2]的Rubisco异构体，提高二磷酸核酮糖再生率将允许进一步改进。田间研究结果表明，人工提高[CO2]浓度可使A（sat）浓度增加60%，从而使产量增加36%至60%。
Experimental elevation of [CO2] around C-3 crops in the field has been shown to increase yields by suppressing the Rubisco oxygenase reaction and, in turn, photorespiration. Bioengineering a cyanobacterial carbon-concentrating mechanism (CCM) into C-3 crop species provides a potential means of elevating [CO2] at Rubisco, thereby decreasing photorespiration and increasing photosynthetic efficiency and yield. The cyanobacterial CCM is an attractive alternative relative to other CCMs, because its features do not require anatomical changes to leaf tissue. However, the potential benefits of engineering the entire CCM into a C-3 leaf are unexamined. Here, a CO2 and HCO3- diffusion-reaction model is developed to examine how components of the cyanobacterial CCM affect leaf light-saturated CO2 uptake (A(sat)) and to determine whether a different Rubisco isoform would perform better in a leaf with a cyanobacterial CCM. The results show that the addition of carboxysomes without other CCM components substantially decreases A(sat) and that the best first step is the addition of HCO3- transporters, as a single HCO3- transporter increased modeled A(sat) by 9%. Addition of all major CCM components increased A(sat) from 24 to 38 mu mol m(-2) s(-1). Several Rubisco isoforms were compared in the model, and increasing ribulose bisphosphate regeneration rate will allow for further improvements by using a Rubisco isoform adapted to high [CO2]. Results from field studies that artificially raise [CO2] suggest that this 60% increase in A(sat) could result in a 36% to 60% increase in yield.