Soybean is an important oilseed crop grown globally. However, two examples of environmental stresses that drastically regulate soybean growth are low light and high temperature. Emerging evidence suggests a possible interconnection between these two environmental stimuli. Low light and high temperature as individual factors have been reported to regulate plant hypocotyl elongation. However, their interactive signal effect on soybean growth and development remains largely unclear. Here, we report that gibberellins (GAs) and auxin are required for soybean hypocotyl elongation under low light and high temperature interaction. Our analysis indicated that low light and high temperature interaction enhanced the regulation of soybean hypocotyl elongation and that the endogenous GA3 , GA7 , indole-3-acetic acid (IAA) and indole-3-pyruvate (IPA) contents significantly increased. Again, analysis of the effect of exogenous phytohormones and biosynthesis inhibitors treatments showed that exogenous GA, IAA, and paclobutrazol (PAC), 2, 3, 5,-triiodobenzoic acid (TIBA) treatments significantly regulated soybean seedlings growth under low light and high temperature interaction. Further qRT-PCR analysis showed that the expression level of GA biosynthesis pathway genes (GmGA3ox1, GmGA3ox2, and GmGA3) and auxin biosynthesis pathway genes (GmYUCCA3, GmYUCCA5, and GmYUCCA7) significantly increased under (i) low light and high temperature interaction and (ii) exogenous GA and IAA treatments. Altogether, these observations support the hypothesis that gibberellins and auxin regulate soybean hypocotyl elongation under low light and high temperature stress interaction. This article is protected by copyright. All rights reserved.

中文翻译：

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赤霉素和生长素在弱光和高温相互作用下调节大豆下胚轴伸长

大豆是全球种植的重要油料作物。然而，环境压力的两个例子是严重调节大豆生长的两个例子是低光和高温。新出现的证据表明这两种环境刺激之间可能存在联系。据报道，弱光和高温作为单独的因素可以调节植物下胚轴的伸长。然而，它们对大豆生长和发育的交互信号影响在很大程度上仍不清楚。在这里，我们报告了在低光和高温相互作用下大豆下胚轴伸长需要赤霉素（GA）和生长素。我们的分析表明，弱光和高温相互作用增强了大豆下胚轴伸长的调节，而内源性 GA3 、 GA7 、吲哚-3-乙酸（IAA）和吲哚-3-丙酮酸（IPA）含量显着增加。再次，外源植物激素和生物合成抑制剂处理的影响分析表明，外源 GA、IAA 和多效唑 (PAC)、2, 3, 5,-三碘苯甲酸 (TIBA) 处理显着调节了弱光和高温下的大豆幼苗生长相互作用。进一步的qRT-PCR分析表明，在（i）弱光和高温相互作用下，GA生物合成途径基因（GmGA3ox1、GmGA3ox2和GmGA3）和生长素生物合成途径基因（GmYUCCA3、GmYUCCA5和GmYUCCA7）的表达水平显着增加和（ ii) 外源性 GA 和 IAA 处理。共，这些观察结果支持赤霉素和生长素在低光和高温胁迫相互作用下调节大豆下胚轴伸长的假设。本文受版权保护。版权所有。