Department of Biology, University of Crete, 70013, Heraklion, Greece.
Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece.
Sci Rep. 2024 Jun 10;14(1):13314. doi: 10.1038/s41598-024-63527-5.
Plants respond to biotic and abiotic stress by activating and interacting with multiple defense pathways, allowing for an efficient global defense response. RNA silencing is a conserved mechanism of regulation of gene expression directed by small RNAs important in acquired plant immunity and especially virus and transgene repression. Several RNA silencing pathways in plants are crucial to control developmental processes and provide protection against abiotic and biotic stresses as well as invasive nucleic acids such as viruses and transposable elements. Various notable studies have shed light on the genes, small RNAs, and mechanisms involved in plant RNA silencing. However, published research on the potential interactions between RNA silencing and other plant stress responses is limited. In the present study, we tested the hypothesis that spreading and maintenance of systemic post-transcriptional gene silencing (PTGS) of a GFP transgene are associated with transcriptional changes that pertain to non-RNA silencing-based stress responses. To this end, we analyzed the structure and function of the photosynthetic apparatus and conducted whole transcriptome analysis in a transgenic line of Nicotiana benthamiana that spontaneously initiates transgene silencing, at different stages of systemic GFP-PTGS. In vivo analysis of chlorophyll a fluorescence yield and expression levels of key photosynthetic genes indicates that photosynthetic activity remains unaffected by systemic GFP-PTGS. However, transcriptomic analysis reveals that spreading and maintenance of GFP-PTGS are associated with transcriptional reprogramming of genes that are involved in abiotic stress responses and pattern- or effector-triggered immunity-based stress responses. These findings suggest that systemic PTGS may affect non-RNA-silencing-based defense pathways in N. benthamiana, providing new insights into the complex interplay between different plant stress responses.
植物通过激活和相互作用多种防御途径来应对生物和非生物胁迫，从而实现有效的全局防御反应。RNA 沉默是一种由小 RNA 指导的基因表达调控的保守机制，在获得性植物免疫中尤为重要，尤其是在病毒和转基因沉默中。植物中的几个 RNA 沉默途径对于控制发育过程以及抵御生物和非生物胁迫以及入侵核酸（如病毒和转座元件）至关重要。各种显著的研究已经揭示了参与植物 RNA 沉默的基因、小 RNA 和机制。然而，关于 RNA 沉默与其他植物应激反应之间潜在相互作用的已发表研究有限。在本研究中，我们检验了这样一个假设，即 GFP 转基因的系统性转录后基因沉默 (PTGS) 的扩散和维持与与非 RNA 沉默为基础的应激反应有关的转录变化有关。为此，我们分析了转基因 Nicotiana benthamiana 中光合作用装置的结构和功能，并在 GFP-PTGS 系统性发生的不同阶段进行了全转录组分析。叶绿素 a 荧光产量的体内分析和关键光合作用基因的表达水平表明，光合作用活性不受 GFP-PTGS 的系统性影响。然而，转录组分析表明，GFP-PTGS 的扩散和维持与参与非生物胁迫反应以及模式或效应物触发免疫为基础的应激反应的基因的转录重编程有关。这些发现表明，系统性 PTGS 可能影响 N. benthamiana 中非 RNA 沉默为基础的防御途径，为不同植物应激反应之间的复杂相互作用提供了新的见解。
