Table_3_Melatonin Attenuates the Urea-Induced Yields Improvement Through Remodeling Transcriptome and Rhizosphere Microbial Community Structure in Soybean.XLSX

Foliar application of nitrogen to enhance crop productivity has been widely used. Melatonin is an effective regulator in promoting plant growth. However, the effects of melatonin and the combination of melatonin and nitrogen on soybeans yields production remain largely unknown. In this study, a field experiment was conducted to evaluate the effects and mechanisms of spraying leaves with melatonin and urea on soybeans. Foliar application of urea significantly increased soybean yields and melatonin did not affect the yields, while combination of melatonin and urea significantly reduced the yields compared to the application of urea alone. A leaf transcriptional profile was then carried out to reveal the underlying mechanism and found that foliar spraying of urea specifically induced the expression of genes related to amino acid transport and nitrogen metabolism. However, foliar application of melatonin significantly changed the transcriptional pattern established by urea application and increased the expression of genes related to abiotic stress signaling pathways. The effects of melatonin and urea treatment on soil microbiome were also investigated. Neither melatonin nor urea application altered the soil microbial alpha diversity, but melatonin application changed rhizosphere microbial community structure, whereas the combination of melatonin and urea did not. Melatonin or urea application altered the abundance of certain taxa. The number of taxa changed by melatonin treatment was higher than urea treatment. Collectively, our results provide new and valuable insights into the effects of foliar application of melatonin to urea and further show that melatonin exerts strong antagonistic effects on urea-induced soybean yields, gene expression and certain soil microorganisms.

叶面喷施氮肥以提升作物生产力的栽培措施已得到广泛应用。褪黑素(Melatonin)是一类可有效调控植物生长的生理调节剂。然而，目前关于褪黑素单独施用以及褪黑素与氮肥配施对大豆产量的影响机制仍未被充分阐明。本研究开展田间试验，旨在评估叶面喷施褪黑素与尿素对大豆的作用效果及内在机制。结果表明，单独叶面喷施尿素可显著提升大豆产量，褪黑素单独施用对大豆产量无显著影响；而与单独喷施尿素相比，褪黑素与尿素配施会显著降低大豆产量。随后我们开展了叶片转录组分析以揭示其潜在机制，发现叶面喷施尿素可特异性诱导氨基酸转运与氮代谢相关基因的表达。而叶面喷施褪黑素则显著改变了尿素处理所构建的转录表达模式，并上调了非生物胁迫信号通路相关基因的表达。本研究同时探究了褪黑素与尿素处理对土壤微生物组的影响。单独施用褪黑素或尿素均未改变土壤微生物的α多样性，但褪黑素施用可显著改变根际微生物群落结构，而二者配施则无此效应。褪黑素或尿素单独施用均可改变部分微生物类群的相对丰度，且褪黑素处理所影响的类群数量多于尿素处理。综上，本研究结果为叶面喷施褪黑素配施尿素的应用提供了全新且具有重要价值的理论参考，并进一步证实褪黑素对尿素诱导的大豆产量变化、基因表达谱及部分土壤微生物类群均具有显著的拮抗作用。