K.A. Timiryazev Institute of Plant Physiology RAS, 35 Botanicheskaya St., Moscow 127276, Russia.
Int J Mol Sci. 2024 Nov 15;25(22):12266. doi: 10.3390/ijms252212266.
In plants, abscisic acid (ABA) and melatonin (MT) are conventionally treated as molecules mitigating stress responses. To understand the mechanisms of ABA-MT interplay, we examined the effects of ABA and MT treatment in ABA and MT loss-of-function mutants of exposed to high light (HL) stress. ABA constantly suppressed encoding N-acetylserotonin methyltransferase in the context of differential responses of other MT biosynthesis genes in both the wild type (WT) and mutants. However, this response was absent in the mutant with the disrupted ABI4. Given that the promoter region contains several potential ABI4-binding elements, these data suggest that can be a potential target gene for ABI4. A role for ABI4 in the interactions between ABA and MT is supported by the finding that is constitutively derepressed in the MT signaling mutants and , which exhibited elevated steady state levels of transcripts and were not regulated by either stress or melatonin. In addition, the mutant showed increased modulations in the expression of the MT catabolic genes and in response to ABA treatment, inferring that this transcription factor is a negative regulator of ABA-dependent changes in MT content. Furthermore, all tested mutants with impaired ABA synthesis or signaling displayed elevated steady state MT levels compared to WT, while MT treatment contributed to the downregulation of key ABA synthesis and signaling genes. Collectively, our results suggest that ABA and melatonin act antagonistically, modulating the expression of ABA and MT signaling and metabolism genes. To understand the mechanisms of ABA-MT interactions, we studied the effects of ABA and MT treatment in ABA and MT loss-of-function mutants of exposed to severe light stress (SLS).
在植物中，脱落酸（ABA）和褪黑素（MT）通常被视为减轻应激反应的分子。为了了解 ABA-MT 相互作用的机制，我们研究了在高光照（HL）胁迫下 ABA 和 MT 功能丧失突变体中 ABA 和 MT 处理的影响。ABA 在野生型（WT）和突变体中，其他 MT 生物合成基因的差异反应中，持续抑制编码 N-乙酰血清素甲基转移酶的 。然而，在 ABI4 中断的突变体中，这种反应不存在。鉴于 启动子区域包含几个潜在的 ABI4 结合元件，这些数据表明 可能是 ABI4 的一个潜在靶基因。ABI4 在 ABA 和 MT 之间相互作用中的作用得到了支持，因为发现 在 MT 信号突变体 和 中， 被组成性去阻遏，这两个突变体表现出 的转录物稳定水平升高，不受应激或褪黑素调节。此外，在 ABA 处理下， 突变体表现出 MT 分解代谢基因 和 的表达增加，这表明该转录因子是 MT 含量依赖的 ABA 变化的负调节剂。此外，所有测试的 ABA 合成或信号受损的突变体与 WT 相比，都表现出稳定状态 MT 水平升高，而 MT 处理有助于下调关键的 ABA 合成和信号基因。总之，我们的研究结果表明，ABA 和褪黑素相互拮抗，调节 ABA 和 MT 信号和代谢基因的表达。为了了解 ABA-MT 相互作用的机制，我们研究了在高光照（SLS）胁迫下 ABA 和 MT 功能丧失突变体中 ABA 和 MT 处理的影响。
