State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
College of Food, Xinyang Agriculture and Forestry University, Xinyang, 464000, China.
BMC Plant Biol. 2023 Nov 22;23(1):584. doi: 10.1186/s12870-023-04565-5.
The aleurone layer is a part of many plant seeds, and during seed germination, aleurone cells undergo PCD, which is promoted by GA from the embryo. However, the numerous components of the GA signaling pathway that mediate PCD of the aleurone layers remain to be identified. Few genes and transcriptomes have been studied thus far in aleurone layers to improve our understanding of how PCD occurs and how the regulatory mechanism functions during PCD. Our previous studies have shown that histone deacetylases (HDACs) are required in GA-induced PCD of aleurone layer. To further explore the molecular mechanisms by which epigenetic modifications regulate aleurone PCD, we performed a global comparative transcriptome analysis of embryoless aleurones treated with GA or histone acetylase (HAT) inhibitors.
In this study, a total of 7,919 differentially expressed genes (DEGs) were analyzed, 2,554 DEGs of which were found to be common under two treatments. These identified DEGs were involved in various biological processes, including DNA methylation, lipid metabolism and ROS signaling. Further investigations revealed that inhibition of DNA methyltransferases prevented aleurone PCD, suggesting that active DNA methylation plays a role in regulating aleurone PCD. GA or HAT inhibitor induced lipoxygenase gene expression, leading to lipid degradation, but this process was not affected by DNA methylation. However, DNA methylation inhibitor could regulate ROS-related gene expression and inhibit GA-induced production of hydrogen peroxide (HO).
Overall, linking of lipoxygenase, DNA methylation, and HO may indicate that GA-induced higher HDAC activity in aleurones causes breakdown of lipids via regulating lipoxygenase gene expression, and increased DNA methylation positively mediates HO production; thus, DNA methylation and lipid metabolism pathways may represent an important and complex signaling network in maize aleurone PCD.
糊粉层是许多植物种子的一部分，在种子萌发过程中，糊粉层细胞经历程序性细胞死亡（PCD），这一过程受到来自胚的 GA 的促进。然而，介导糊粉层 PCD 的 GA 信号通路的众多组成部分仍有待确定。迄今为止，在糊粉层中研究了很少的基因和转录组，以增进我们对 PCD 发生的方式以及在 PCD 过程中调控机制如何发挥作用的理解。我们之前的研究表明，组蛋白去乙酰化酶（HDACs）在 GA 诱导的糊粉层 PCD 中是必需的。为了进一步探讨表观遗传修饰如何调节糊粉层 PCD 的分子机制，我们对用 GA 或组蛋白乙酰转移酶（HAT）抑制剂处理的无胚糊粉层进行了全局比较转录组分析。
在这项研究中，共分析了 7919 个差异表达基因（DEGs），其中 2554 个 DEGs 在两种处理下都被发现是共同的。这些鉴定出的 DEGs 参与了各种生物学过程，包括 DNA 甲基化、脂质代谢和 ROS 信号转导。进一步的研究表明，抑制 DNA 甲基转移酶可以阻止糊粉层 PCD，这表明活跃的 DNA 甲基化在调节糊粉层 PCD 中发挥作用。GA 或 HAT 抑制剂诱导脂氧合酶基因的表达，导致脂质降解，但这一过程不受 DNA 甲基化的影响。然而，DNA 甲基化抑制剂可以调节 ROS 相关基因的表达，并抑制 GA 诱导的过氧化氢（HO）的产生。
总的来说，脂氧合酶、DNA 甲基化和 HO 的联系可能表明，GA 诱导的糊粉层中更高的 HDAC 活性通过调节脂氧合酶基因的表达导致脂质的分解，而增加的 DNA 甲基化正向介导 HO 的产生；因此，DNA 甲基化和脂质代谢途径可能代表玉米糊粉层 PCD 中一个重要而复杂的信号网络。
