The APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factors (TFs) are involved in the regulation of specialized terpenoids biosynthesis. However, the AP2/ERF TFs in the Litsea cubeba have not been characterized, and their role in the biosynthesis of terpenoids is unknown. Here, 174 LcAP2/ERF TFs were identified in L. cubeba and categorized into four subfamilies: 27 AP2, 7 RAV, 1 Soloist, and 139 ERF (I to Xb-L). Transcriptomic and qRT-PCR assays both showed that the expression levels of LcERF19 were similar to that of terpene synthase LcTPS42 in pericarp, which is related to the synthesis of geranial and neral in L. cubeba. LcERF19 was further identified to encode a nuclear-localized protein and was strongly induced at the transcriptomic level by jasmonate. Furthermore, a yeast one-hybrid and dual-luciferase experiment showed that LcERF19 bonded to the GCC box elements of the LcTPS42 promoter and promoted its activity. Transient overexpression of LcERF19 in L. cubeba and overexpression of LcERF19 in tomato both resulted in a significant increase in geranial and neral. Our findings show that LcERF19 enhances geranial and neral biosynthesis mightily through activation of LcTPS42 expression, which provides strategies to improve the flavor of tomato fruit and other crops’ fruit.

中文翻译：

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LcERF19，一种来自山苍子的 AP2/ERF 转录因子，正向调节香叶和神经的生物合成

APETALA2/乙烯反应因子 (AP2/ERF) 转录因子 (TFs) 参与调节特定的萜类生物合成。然而，山苍子中的 AP2/ERF TFs 尚未被表征，它们在萜类生物合成中的作用尚不清楚。在这里，在 L. cubeba 中鉴定了 174 个 LcAP2/ERF TF，并分为四个亚科：27 个 AP2、7 个 RAV、1 个 Soloist 和 139 个 ERF（I 到 Xb-L）。转录组学和qRT-PCR检测均显示LcERF19的表达水平与果皮中萜合酶LcTPS42的表达水平相似，这与L. cubeba中香叶醛和香叶醛的合成有关。LcERF19 被进一步鉴定为编码一种核定位蛋白，并在转录组水平上被茉莉酸强烈诱导。此外，酵母单杂交双荧光素酶实验表明，LcERF19 与 LcTPS42 启动子的 GCC 盒元件结合并促进其活性。LcERF19 在 L. cubeba 中的瞬时过表达和 LcERF19 在番茄中的过表达均导致香叶和 neral 的显着增加。我们的研究结果表明，LcERF19 通过激活 LcTPS42 的表达，极大地增强了香叶和香叶​​的生物合成，这为改善番茄果实和其他作物果实的风味提供了策略。