ABSTRACT High temperatures during seed development can affect the seed yield and quality in many crops. Here, we analyzed how high temperature alters the main seed storage compounds (lipid and protein) in soybean. At five days after R5 stage (initial seed filling stage), soybean plants were treated with control (20/20ºC day/night) and high temperature (30/30ºC day/night). After treatment, immature seed was sampled, analyzed for lipid and protein contents and for expression of seed storage compounds related genes. High temperature during seed filling increased lipid content but decreased protein content, associating with yield reduction. It increased the expression of two genes related to seed lipid biosynthesis (GmBCCP2 and GmKAS1) and genes for a lipid biosynthesis regulator (GmWRI1) and its transcription factor (GmDREBL), and decreased the expression of genes related to lipid degradation such as GmACXs. High temperature downregulated genes related to seed storage protein (GmGy1, GmGy2, GmGy4, GmGy5 and Gmβ-conglycinin) and upregulated genes for cysteine and aspartate proteinases. Therefore, high temperature during seed filling preferentially accumulates lipid than protein content in seed, although seed yield reduction was associated with lower seed protein content in soybean. Our study provides insights for further improvements of soybean seed oil under abiotic stress such as heat stress. Abbreviations: DAT: days after treatment; TF: transcription factor; DREBL: Dehydration-responsive Element-binding L; WRI1: Wrinkled 1; PK: Ketoacyl acyl carrier protein synthase 1; PEP: phosphoenolpyruvate; BCCP2: Biotin carboxyl carrier protein; KAS1: ketoacyl acyl carrier protein synthase 1; ACX: Acyl-coenzyme A peroxidase; MS: Malate synthase; PEPCK: Phosphoenolpyruvate carboxykinase; Gy: Glycinin; CysP: Cysteine Proteinase; SoyAP: Aspartic Proteinase; EF1b: Elongation factor 1b. Graphical abstract

中文翻译：

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大豆种子发育过程中的高温不同地改变脂质和蛋白质代谢

摘要 种子发育过程中的高温会影响许多作物的种子产量和质量。在这里，我们分析了高温如何改变大豆中的主要种子储存化合物（脂质和蛋白质）。在 R5 阶段（初始种子灌浆阶段）后 5 天，用对照（20/20ºC 日/夜）和高温（30/30ºC 日/夜）处理大豆植株。处理后，对未成熟种子取样，分析脂质和蛋白质含量以及种子贮藏化合物相关基因的表达。种子灌浆期间的高温增加了脂质含量，但降低了蛋白质含量，与产量降低有关。它增加了与种子脂质生物合成相关的两个基因（GmBCCP2 和 GmKAS1）和脂质生物合成调节基因（GmWRI1）及其转录因子（GmDREBL）的表达，并降低与脂质降解相关的基因（如 GmACXs）的表达。高温下调与种子贮藏蛋白相关的基因（GmGy1、GmGy2、GmGy4、GmGy5 和 Gmβ-伴大豆球蛋白）和上调半胱氨酸和天冬氨酸蛋白酶基因。因此，尽管种子产量降低与大豆中较低的种子蛋白质含量有关，但种子灌浆期间的高温优先积累种子中的脂质而不是蛋白质含量。我们的研究为在非生物胁迫（如热胁迫）下进一步改进大豆籽油提供了见解。缩写： DAT：治疗后的天数；TF：转录因子；DREBL：脱水反应性元素结合 L；WRI1：皱纹1；PK：酮酰基酰基载体蛋白合酶1；PEP：磷酸烯醇式丙酮酸；BCCP2：生物素羧基载体蛋白；KAS1：酮酰基酰基载体蛋白合酶1；ACX：酰基辅酶A过氧化物酶；MS：苹果酸合酶；PEPCK：磷酸烯醇式丙酮酸羧激酶；Gy：甘氨酸；CysP：半胱氨酸蛋白酶；SoyAP：天冬氨酸蛋白酶；EF1b：伸长率因子 1b。图形概要