Impact of engineering the ATP synthase rotor ring on photosynthesis in tobacco chloroplasts
Impact of engineering the ATP synthase rotor ring on photosynthesis in tobacco chloroplasts
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DOI：
10.1093/plphys/kiad043
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发表时间：
2023-01-26
期刊：
影响因子：
7.4
通讯作者：
Shikanai, Toshiharu
中科院分区：
文献类型：
--
作者：
Yamamoto, Hiroshi;Cheuk, Anthony;Shikanai, Toshiharu
叶绿体ATP合成酶中含有c15环的转质体烟草植株通过增加质子动力的大小维持正常的光合生长，叶绿体ATP合成酶产生光合作用和植物生长所需的ATP。质子通过ATP合酶的跨膜流动使c亚基的寡聚体组装体（c环）旋转。旋转F1 F0-ATP酶中的离子与ATP比率由转子C环中的C亚基的数目定义。因此，工程化的C-环化学计量是一种可能的途径来操纵ATP合成酶的ATP合成，从而在植物中的光合效率。在这里，我们描述了烟草（Nicotiana tabacum）叶绿体atpH（叶绿体ATP合成酶亚基c基因）突变体的C-环化学计量从14个增加到15个C-亚基的建设。虽然ATP合酶的丰度降低到野生型（WT）水平的25%，突变株系生长以及WT植物和光合电子传递保持不受影响。为了合成生长所需的ATP，我们发现膜电位对质子动力的贡献增强，以确保通过c（15）环的更高质子通量，而没有不必要的低pH诱导的电子传递反馈抑制。我们的工作开辟了途径，以操纵植物离子与ATP的比例与光合作用的潜在有益的后果。
Transplastomic tobacco plants with the c15-ring in the chloroplast ATP synthase maintain the normal photosynthetic growth by increasing the magnitude of proton motive force.The chloroplast ATP synthase produces the ATP needed for photosynthesis and plant growth. The trans-membrane flow of protons through the ATP synthase rotates an oligomeric assembly of c subunits, the c-ring. The ion-to-ATP ratio in rotary F1F0-ATP synthases is defined by the number of c-subunits in the rotor c-ring. Engineering the c-ring stoichiometry is, therefore, a possible route to manipulate ATP synthesis by the ATP synthase and hence photosynthetic efficiency in plants. Here, we describe the construction of a tobacco (Nicotiana tabacum) chloroplast atpH (chloroplastic ATP synthase subunit c gene) mutant in which the c-ring stoichiometry was increased from 14 to 15 c-subunits. Although the abundance of the ATP synthase was decreased to 25% of wild-type (WT) levels, the mutant lines grew as well as WT plants and photosynthetic electron transport remained unaffected. To synthesize the necessary ATP for growth, we found that the contribution of the membrane potential to the proton motive force was enhanced to ensure a higher proton flux via the c(15)-ring without unwanted low pH-induced feedback inhibition of electron transport. Our work opens avenues to manipulate plant ion-to-ATP ratios with potentially beneficial consequences for photosynthesis.