Biochemistry and physiological importance of alternative photorespiratory pathways in higher plants

高等植物替代光呼吸途径的生物化学和生理重要性

• 批准号: 134777993
• 负责人: Professor Dr. Christoph Peterhänsel
• 金额: --
• 依托单位: Institut für Botanik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/134777993?language=en
• 关键词: Biochemistry; physiological; importance; alternative; photorespiratory

Besides oxidation of glycolate in peroxisomes as part of the main photorespiratory pathway, higher plants are also capable of converting glycolate in the chloroplast or the mitochondrium. Data from us and partners in the Promics network indicate that homologues to these additional pathways are found in cyanobacteria and green algae of the chlorophyte subclade, respectively. This suggests evolutionary conservation over a period of at least 400 Million years. However, the molecular regulation and biological importance of these two alternative opportunities for glycolate conversion in higher plants is mostly unknown. In this project, Arabidopsis genes encoding candidate components of the pathways will be overexpressed or suppressed and the effects on metabolite profiles, photorespiratory flow rates, and glycolate conversion in isolated organelles will be measured. Moreover, the activity of the three possible glycolate conversion pathways will be modulated in a combinatorial manner by genetic crossing of the generated lines. The resulting genotypes will be subjected to diverse stress conditions such as reduced CO2 supply, nitrogen depletion, or drought, and relative growth rates will be determined. This will allow new insights into the control of alternative glycolate oxidation reactions and the evolution of photorespiration.

除了过氧化物酶体中乙醇酸的氧化作为主要光呼吸途径的一部分外，高等植物还能够在叶绿体或叶绿体中转化乙醇酸。来自我们和合作伙伴的数据表明，这些额外的途径的同源物分别在蓝藻和绿藻亚支的绿色藻类中发现。这表明进化保护至少有4亿年的时间。然而，在高等植物中乙醇酸转化的这两种替代机会的分子调控和生物学重要性大多是未知的。在这个项目中，拟南芥基因编码的候选成分的途径将被过表达或抑制，代谢产物的配置文件，光呼吸流量，和乙醇酸在孤立的细胞器转换的影响将被测量。此外，三种可能的乙醇酸转化途径的活性将通过产生的品系的遗传杂交以组合方式调节。所得基因型将经受不同的胁迫条件，例如减少的CO2供应、氮耗尽或干旱，并且将确定相对生长速率。这将使新的见解控制替代乙醇酸氧化反应和光呼吸的演变。