Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China.
Heilongjiang Provincial Key Laboratory of Modern Agricultural Cultivation and Crop Germplasm Improvement, Heilongjiang Bayi Agricultural University, Daqing 163319, China.
J Agric Food Chem. 2021 Jan 13;69(1):112-125. doi: 10.1021/acs.jafc.0c05809. Epub 2020 Dec 22.
The growth and development of plants are dependent on the interaction between carbon and nitrogen metabolism. Essential information about the metabolic regulation of carbon-nitrogen metabolism is still lacking, such as possible interactions among nitrogen metabolism, photosynthesis, and photorespiration. This study shows that higher photorespiration consumes more CO fixed by photosynthesis, making the high photosynthetic efficiency mutant fail to increase production. In order to clarify the effects of photosynthesis and photorespiration on carbon and nitrogen metabolism in high photosynthetic efficiency mutant, a yellow-green leaf mutant () was isolated from rice ( L.). Its chlorophyll (Chl) content decreased, but chloroplast development was not affected. Genetic analysis demonstrated that encodes the magnesium chelatase D subunit (ChlD). The mutant showed an increased net assimilation rate (An) and electron transport flux efficiency and catalase (CAT) activity, and it also had a higher photorespiration rate (Pr), lower HO, and reduced nitrogen uptake efficiency (NUpE); however, there was no loss in yield. The higher activities of glutamate synthase (GOGAT) and glutamine synthetase (GS) ensure the α-ketoglutaric acid (2-OG) and ammonia (NH) availabilities, which are produced from photorespiration in the mutant. These have an important function for carbon and nitrogen metabolism homeostasis in . Further analysis indicated that the energy and substances derived from carbon metabolism supplemented nitrogen metabolism in the form of photorespiration to ensure its normal development when the An of photosynthesis was increased in the mutant with reduced NUpE.
植物的生长和发育依赖于碳氮代谢之间的相互作用。对于碳氮代谢的代谢调控，仍然缺乏重要信息，例如氮代谢、光合作用和光呼吸之间可能存在的相互作用。本研究表明，较高的光呼吸会消耗更多由光合作用固定的 CO，从而使高光效突变体无法增加产量。为了阐明光合作用和光呼吸对高光效突变体碳氮代谢的影响，本研究从水稻中分离出一个黄绿叶突变体（）。该突变体的叶绿素（Chl）含量降低，但叶绿体发育不受影响。遗传分析表明，编码镁螯合酶 D 亚基（ChlD）。突变体表现出更高的净同化率（An）和电子传递通量效率以及过氧化氢酶（CAT）活性，同时具有更高的光呼吸速率（Pr）、更低的 HO 和降低的氮吸收效率（NUpE）；然而，产量并没有损失。谷氨酸合酶（GOGAT）和谷氨酰胺合成酶（GS）的更高活性确保了来自突变体光呼吸的α-酮戊二酸（2-OG）和氨（NH）的可用性。这些对于突变体中碳氮代谢的平衡具有重要功能。进一步的分析表明，当光合作用的 An 增加时，来自碳代谢的能量和物质以光呼吸的形式补充氮代谢，从而确保突变体在减少 NUpE 的情况下正常发育。
