Is the Entner-Doudoroff pathway an overlooked glycolytic route in cyanobacteria and did cyanobacteria transfer its key enzyme via endosymbiotic gene transfer to plants?

Entner-Doudoroff 途径是蓝藻中被忽视的糖酵解途径吗？蓝藻是否通过内共生基因转移将其关键酶转移到植物中？

• 批准号: 275052541
• 负责人: Professorin Dr. Kirstin Gutekunst
• 金额: --
• 依托单位: Fachgebiet Molekulare Pflanzenphysiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/275052541?language=en
• 关键词: Entner; Doudoroff; pathway; overlooked; glycolytic

The oxidation of glucose is central for energy metabolism throughout all domains of life. It supplies cells with ATP, reduction equivalents (NADH, NADPH) and precursors for biosynthesis. Cyanobacteria and plants are known to break down glucose either via the Embden-Meyerhoff-Parnass (EMP, often referred to as glycolysis) or the oxidative pentose phosphate (OPP) pathway. We interrupted both the EMP and OPP pathway in the cyanobacterium Synechocystis sp. PCC 6803 and found to our surprise that this mutant was still able to enhance its growth on glucose in the light. Whereas the EMP and OPP pathway are the most prevalent glycolytic routes in eukaryotes, prokaryotes display an impressive diversity in glycolytic pathways. The most prevalent are EMP, OPP and the Entner-Doudoroff (ED) pathway. We therefore searched the genome of Synechocystis for the key enzymes of the ED pathway, namely Edd (6P-gluconate dehydratase) and Eda (KDPG-aldolase) and found candidate genes for both. A knockout mutant in which the key enzymes of EMP, OPP and ED pathway and a bypass reaction of the OPP pathway were knocked out, could no longer enhance its growth on glucose. This suggests that the ED pathway might operate in Synechocystis. Labelling experiments with 13C glucose confirmed that glucose is metabolized both via the EMP and ED pathway in the light. A search for the key enzymes of both EMP (namely Pfk) and ED (namely Eda) pathway revealed that 96% of all sequenced cyanobacteria hold Eda, 58% hold both Pfk and Eda, 4% hold Pfk alone and remarkably 38% hold Eda alone. This indicates that the ED pathway might be a glycolytic route of physiological significance in cyanobacteria that has been overlooked. Remarkably Eda was also found to be widespread in plants. Phylogenetic analyses revealed that plants received this key enzyme of the ED pathway via endosymbiotic gene transfer from cyanobacteria. The physiological significance of the Enter-Doudoroff pathway as a glycolytic route in both cyanobacteria and plants is discussed.

葡萄糖的氧化是生命各个领域能量代谢的核心。它为细胞提供 ATP、还原当量（NADH、NADPH）和生物合成前体。已知蓝藻和植物可通过 Embden-Meyerhoff-Parnass (EMP，通常称为糖酵解) 或氧化戊糖磷酸 (OPP) 途径分解葡萄糖。我们中断了蓝藻集胞藻属中的 EMP 和 OPP 途径。 PCC 6803，令我们惊讶的是，该突变体仍然能够在光照下增强其在葡萄糖上的生长。虽然 EMP 和 OPP 途径是真核生物中最普遍的糖酵解途径，但原核生物的糖酵解途径却表现出令人印象深刻的多样性。最常见的是 EMP、OPP 和 Entner-Doudoroff (ED) 途径。因此，我们在集胞藻的基因组中搜索了 ED 途径的关键酶，即 Edd（6P-葡萄糖酸脱水酶）和 Eda（KDPG-醛缩酶），并找到了这两种酶的候选基因。 EMP、OPP和ED途径的关键酶以及OPP途径的旁路反应被敲除的敲除突变体不能再增强其对葡萄糖的生长。这表明 ED 途径可能在集胞藻中发挥作用。 13C 葡萄糖标记实验证实，葡萄糖在光下通过 EMP 和 ED 途径代谢。对 EMP（即 Pfk）和 ED（即 Eda）途径的关键酶的搜索显示，所有已测序的蓝藻中 96% 含有 Eda，58% 含有 Pfk 和 Eda，4% 单独含有 Pfk，38% 含有 Eda独自的。这表明ED途径可能是蓝藻中被忽视的具有生理意义的糖酵解途径。值得注意的是，Eda 也被发现广泛存在于植物中。系统发育分析表明，植物通过蓝细菌的内共生基因转移接收了 ED 途径的关键酶。讨论了 Enter-Doudoroff 途径作为蓝藻和植物中糖酵解途径的生理意义。

项目成果

The Entner–Doudoroff pathway is an overlooked glycolytic route in cyanobacteria and plants

Entner-Doudoroff 途径是蓝细菌和植物中一条被忽视的糖酵解途径

• DOI: 10.1073/pnas.1521916113
• 发表时间: 2016-04-25
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Xi Chen;K. Schreiber;Jens Appel;A. Makowka;Berit Fähnrich;M. Roettger;M. Hajirezaei;F. Sönnichsen
• 通讯作者: F. Sönnichsen

The Non-Coding RNA Ncr0700/PmgR1 is Required for Photomixotrophic Growth and the Regulation of Glycogen Accumulation in the Cyanobacterium Synechocystis sp. PCC 6803.

非编码 RNA Ncr0700/PmgR1 是蓝藻集胞藻属光合营养生长和糖原积累调节所必需的。

• DOI: 10.1093/pcp/pcw128
• 发表时间: 2016-10-01
• 期刊: Plant & cell physiology
• 影响因子: 4.9
• 作者: A. D. de Porcellinis;Stephan Klähn;Lisa Rosgaard;R. Kirsch;Kirstin Gutekunst;J. Georg;W. Hess;Y. Sakuragi
• 通讯作者: Y. Sakuragi