背景:将植物预先暴露于非生物胁迫可以诱导胁迫记忆,这对于适应随后的压力暴露至关重要。尽管已经确定了许多参与盐应激反应的基因,对盐胁迫的记忆反应的理解仍然有限。
结果:在这项研究中,我们对遭受反复盐胁迫的玉米植物进行了生理和转录测定,以表征盐胁迫记忆。在第二次暴露于盐胁迫期间,这些植物表现出增强的耐盐性,脯氨酸含量增加,POD和SOD活性提高,随着MDA含量的降低,指示生理记忆行为。转录分析显示,与第一次相比,第二次暴露期间差异表达的基因和反应过程的变化较少,指示转录记忆行为。总共鉴定了2,213个盐胁迫记忆基因(SMG),并将其分为四种反应模式。最突出的一组SMG由在第一次暴露于盐胁迫期间表达升高但在反复暴露于盐胁迫后表达降低的基因组成。反之亦然([+/-]或[-/+]),表明修正后的反应是植物应激记忆中的一个关键过程。此外,9种转录因子(TFs)(WRKY40,WRKY46,WRKY53,WRKY18,WRKY33,WRKY70,MYB15,KNAT7和WRKY54)被确定为与盐胁迫记忆有关的关键因子。这些TFs调节超过53%的SMG,强调它们在盐应激记忆中的潜在意义。
结论:我们的研究表明,玉米可以发展盐胁迫记忆,这里确定的基因将有助于玉米和其他作物的遗传改良。
BACKGROUND: Pre-exposing plants to abiotic stresses can induce stress memory, which is crucial for adapting to subsequent stress exposure. Although numerous genes involved in salt stress response have been identified, the understanding of memory responses to salt stress remains limited.
RESULTS: In this study, we conducted physiological and transcriptional assays on maize plants subjected to recurrent salt stress to characterize salt stress memory. During the second exposure to salt stress, the plants exhibited enhanced salt resistance, as evidenced by increased proline content and higher POD and SOD activity, along with decreased MDA content, indicative of physiological memory behavior. Transcriptional analysis revealed fewer differentially expressed genes and variations in response processes during the second exposure compared to the first, indicative of transcriptional memory behavior. A total of 2,213 salt stress memory genes (SMGs) were identified and categorized into four response patterns. The most prominent group of SMGs consisted of genes with elevated expression during the first exposure to salt stress but reduced expression after recurrent exposure to salt stress, or vice versa ([+ / -] or [- / +]), indicating that a revised response is a crucial process in plant stress memory. Furthermore, nine transcription factors (TFs) (WRKY40, WRKY46, WRKY53, WRKY18, WRKY33, WRKY70, MYB15, KNAT7, and WRKY54) were identified as crucial factors related to salt stress memory. These TFs regulate over 53% of SMGs, underscoring their potential significance in salt stress memory.
CONCLUSIONS: Our study demonstrates that maize can develop salt stress memory, and the genes identified here will aid in the genetic improvement of maize and other crops.