Differential Effects of High-Temperature Stress on Nuclear Topology and Transcription of Repetitive Noncoding and Coding Rye Sequences

Abstract

The plant stress response has been extensively characterized at the biochemical and physiological levels. However, knowledge concerning repetitive sequence genome fraction modulation during extreme temperature conditions is scarce. We studied high-temperature effects on subtelomeric repetitive sequences (pSc200) and 45S rDNA in rye seedlings submitted to 40°C during 4 h. Chromatin organization patterns were evaluated through fluorescent in situ hybridization and transcription levels were assessed using quantitative real-time PCR. Additionally, the nucleolar dynamics were evaluated through fibrillarin immunodetection in interphase nuclei. The results obtained clearly demonstrated that the pSc200 sequence organization is not affected by high-temperature stress (HTS) and proved for the first time that this noncoding subtelomeric sequence is stably transcribed. Conversely, it was demonstrated that HTS treatment induces marked rDNA chromatin decondensation along with nucleolar enlargement and a significant increase in ribosomal gene transcription. The role of noncoding and coding repetitive rye sequences in the plant stress response that are suggested by their clearly distinct behaviors is discussed. While the heterochromatic conformation of pSc200 sequences seems to be involved in the stabilization of the interphase chromatin architecture under stress conditions, the dynamic modulation of nucleolar and rDNA topology and transcription suggest their role in plant stress response pathways.

Linkages between changes in the 3D organization of the genome and transcription during myotube differentiation in vitro

“…As such, in this study, we observe a response of the genome structure and transcription to external stimuli, namely, the AraC drug treatment. Numerous studies have shown a link between relatively rapid alterations of the nuclear architecture as a response to external stimuli including (a) thalidomide-dependent alteration of chromatin supra-organization in drug-resistant myeloma cells [80]; (b) marked ribosomal DNA (rDNA) chromatin decondensation and a significant increase in ribosomal gene expression in rye cells subjected to high-temperature stress [81]; and (c) bursts of action potential in cultured hippocampal neurons that cause remodelling of the nucleus to obtain ‘unfoldings’ which are thought to improve the cellular response to calcium signalling [82]. A possible outcome of the overlapping responses in 3D organization and transcription could be increased cell adaptation to the changed environmental cues.…”

Use of Repetitive Sequences for Molecular and Cytogenetic Characterization of Avena Species from Portugal

“…Portuguese Avena species diversity evaluation was also studied through the analysis of other repetitive sequences previously assessed in cereals, such as pSc200 sequence—a major family of sequences isolated from rye and mapped in subtelomeric domains [ 32 , 45 ]. In this work we amplified in Avena a 444 bp fragment with primers previously used in rye and wheat lines with rye chromatin introgression [ 31 ] and sequence analysis revealed a high level of similarity (99%–100%) with rye original pSc200 sequence (Accession Number Z50039) [ 26 ].…”

Genetic Diversity Assessment of Portuguese Cultivated Vicia faba L. through IRAP Markers

“…FISH analysis was performed as previously described [42]. The Athila4-6 IRAP amplified from "Fava Do Algarve" (5357) labeled with biotin-dUTP (Roche, Basel, Switzerland) was used as probe.…”