This study aimed to gain insights into the molecular mechanisms underlying the role of ethylene in regulating germination and seedling growth in wheat by combining pharmacological, molecular and metabolomics approaches. Our study showed that ethylene does not affect radicle protrusion but controls post-germination endospermic starch degradation through transcriptional regulation of specific α-amylase and α-glucosidase genes, and this effect is mediated by alteration of endospermic bioactive GA levels, and GA sensitivity via expression of TaGAMYB. Our data implicated ethylene as a positive regulator of embryo axis and coleoptile growth through transcriptional regulation of specific TaEXPA genes, and these effects are associated with modulation of GA levels and sensitivity, through expression of GA metabolism (TaGA20ox1, TaGA3ox2 and TaGA2ox6) and TaGAMYB genes, respectively, and/or ABA level and sensitivity, via expression of specific ABA metabolism (TaNCED2 or TaCYP707A1) and signaling (TaABI3) genes, respectively. Ethylene appeared to regulate the expression of TaEXPA3 and thereby root growth through its control of coleoptilar ABA metabolism, and root ABA signaling via expression of TaABI3 and TaABI5. These results show that spatiotemporal modulation of ABA/GA balance mediates the role of ethylene in regulating post-germination starch degradation and seedling growth in wheat.

中文翻译：

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乙烯通过ABA / GA平衡的时空调节来调节小麦发芽后的幼苗生长。

这项研究旨在通过结合药理，分子和代谢组学方法，深入了解乙烯在调节小麦发芽和幼苗生长中的潜在分子机制。我们的研究表明，乙烯不会影响胚根突出，但会通过特定α-淀粉酶和α-葡萄糖苷酶基因的转录调控来控制发芽后胚乳淀粉的降解，这种作用是通过改变胚乳生物活性GA水平和通过表达的GA敏感性介导的。 TaGAMYB。我们的数据表明，乙烯通过特定TaEXPA基因的转录调控而成为胚胎轴和胚芽鞘生长的正向调节剂，这些作用与GA水平和敏感性的调节（通过GA代谢的表达（TaGA20ox1，TaGA3ox2和TaGA2ox6）和TaGAMYB基因，和/或ABA水平和敏感性，分别通过表达特定ABA代谢（TaNCED2或TaCYP707A1）和信号传导（TaABI3）基因来实现。乙烯似乎通过调节胚芽鞘ABA代谢来调节TaEXPA3的表达，从而调节根系的生长，并通过表达TaABI3和TaABI5来调节根系的ABA信号传导。这些结果表明，ABA / GA平衡的时空调节介导乙烯在调节小麦发芽后淀粉降解和幼苗生长中的作用。乙烯似乎通过调节胚芽鞘ABA代谢来调节TaEXPA3的表达，从而调节根系的生长，并通过表达TaABI3和TaABI5来调节根系的ABA信号传导。这些结果表明，ABA / GA平衡的时空调节介导乙烯在调节小麦发芽后淀粉降解和幼苗生长中的作用。乙烯似乎通过调节胚芽鞘ABA代谢来调节TaEXPA3的表达，从而调节根系的生长，并通过表达TaABI3和TaABI5来调节根系的ABA信号传导。这些结果表明，ABA / GA平衡的时空调节介导乙烯在调节小麦发芽后淀粉降解和幼苗生长中的作用。