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

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

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The involvement of the endoplasmic reticulum(ER)-localized adenylate transporter1(ER-ANT1)in pho-torespiratory 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 ER-ANT1 hindered the breakdown of glycine without affecting its synthesis,leading to a substantial accumu-lation 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 phos-phorylated serine synthesis pathways.Furthermore,knockout of ER-ANT1 marginally impacted the tran-scription 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:glyoxy-late 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 p-alanine and γ-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.

Endoplasmic reticulumPhotorespirationAmino acidGlutamate/alanine aminotransferaseER-ANT1

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

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Department of Horticulture,College of Agricultural and Biological Engineering,Foshan University,Foshan 528000,Guangdong,China

Rice Research Institute,Guangxi Academy of Agricultural Sciences/Guangxi Key Laboratory of Rice Genetics and Breeding,Nanning 530007,Guangxi,China

Rice Research Institute,Guangdong Academy of Agricultural Sciences,Guangzhou 510640,Guangdong,China

College of Forestry and Landscape Architecture,South China Agricultural University,Guangzhou 510642,Guangdong China

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2024

10.1016/j.cj.2024.10.002

作物学报(英文版)

作物学报(英文版)

CSTPCD
ISSN：
年,卷(期)：2024.12(6)