Endoplasmic reticulum adenylate transporter activity affects amino acid metabolism under photorespiratory conditions

文献类型： 外文期刊

第一作者： Li, Jieni

作者： Li, Jieni;Song, Yuxin;Xie, Tao;Hong, Yu;Liu, Na;Su, Yao;Fu, Xueli;Zhang, Xiang-Qian;Li, Jieni;Zhang, Yuexiong;Qin, Gang;Luan, Xin;Gou, Yajun;Zhong, Tianxiu;Chen, Shu

作者机构：

关键词： Endoplasmic reticulum; Photorespiration; Amino acid; Glutamate/alanine aminotransferase; ER-ANT1

期刊名称：CROP JOURNAL （ 影响因子：5.6； 五年影响因子：6.0 ）

ISSN： 2095-5421

年卷期： 2024 年 12 卷 6 期

页码：

收录情况： SCI

摘要： The involvement of the endoplasmic reticulum (ER)-localized adenylate transporter1 (ER-ANT1) in photorespiratory metabolism has been established, yet its precise physiological function remains uncertain. Rice er-ant1 mutant plants grown in ambient air exhibited stunted growth and substantial alterations in amino acid metabolites, but recovery in a high CO2 condition (1.5%). We show that the absence of ERANT1 hindered the breakdown of glycine without affecting its synthesis, leading to a substantial accumulation of glycine, diminished levels of serine, and depleted reserves of glutamate and alanine. Intriguingly, the er-ant1 plants grown in high CO2 and later exposed to ambient air displayed reduced serine levels within 12 h, yet they accumulated serine a week after transferring to ambient air due to induced phosphorylated serine synthesis pathways. Furthermore, knockout of ER-ANT1 marginally impacted the transcription of genes governing core enzymes in photorespiration, but notably upregulated BOU expression that encodes a putative mitochondrial glutamate transporter and AGAT1 that encodes an alanine:glyoxylate aminotransferase gene. Surprisingly, AGAT1, an ER-localized protein, exhibited higher activity that correlates with the decreased alanine levels observed in the er-ant1 mutant. Lack of ER-ANT1 activity also led to a significantly elevated NADH/NAD* ratio that potentially hinders the glycine-to-serine conversion process. This supports the hypothesis that the lack of ER-ANT1-induced limitation of ATP usage might inhibit GDC activity by modulating the NADH/NAD* ratio. Moreover, non-proteinogenic amino acids, including b-alanine and c-aminobutyrate (GABA), underwent significant alterations, even under high CO2 conditions in the er-ant mutant, implying additional non-photorespiration roles of ER-ANT1. Taken together, our results indicate that ER-localized ER-ANT1 plays a crucial role in amino acid metabolism during photorespiration. (c) 2024 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC- ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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