Senescing Cells Share Common Features with Dedifferentiating Cells

Abstract

Dedifferentiation signifies the capacity of somatic cells to acquire stem cell-like properties. This process can be induced during normal development and as a response to various stimuli, such as pathogen infection and wounding. Dedifferentiation also characterizes the transition of differentiated leaf cells into protoplasts (plant cells devoid of cell walls), a transition accompanied by widespread chromatin decondensation. Transcriptome profiling of dedifferentiating protoplast cells revealed striking similarities with senescing cells; both display a large increase in the expression of genes of specific transcription factor (TF) families, including ANAC, WRKY, bZIP, and C2H2. Further analysis showed that leaves induced to senesce by exposure to dark display characteristic features of dedifferentiating cells, including chromatin decondensation, disruption of the nucleolus, and condensation of rRNA genes. Considering that premature senescence can be induced by various stress conditions both in plant and animal cells, our results suggest that the response of plant and also animal cells to certain stresses converges on cellular dedifferentiation whereby cells first acquire stem cell-like state prior to acquisition of a new cell fate (e.g., reentry into the cell cycle or death).

Verticillium Infection Triggers VASCULAR-RELATED NAC DOMAIN7–Dependent de Novo Xylem Formation and Enhances Drought Tolerance in Arabidopsis

“…It is currently debated whether or not this biological process involves a dedifferentiation step before differentiation into the new cell type. Damri et al (2009) provided a mechanistic model for stressinduced transdifferentiation and hypothesized that the early phase of senescence resembles a dedifferentiated, stem cell-like state. Pathogen-induced senescence may allow cells to dedifferentiate and subsequently transdifferentiate to switch function (Grafi et al, 2011).…”

Transcriptome analysis indicates that GmAGAMOUS-Like 15 may enhance somatic embryogenesis by promoting a dedifferentiated state

“…Seven also have reduced transcript in 35Spro:GmAGL15 compared to Jack WT explants prior to culture. Of the transcription factors and chromatin remodeling factors that were not flagged as associated with dedifferentiation in Grafi et al, 13 but that do respond to protoplasting (Supplemental Tables 1 and 3 in Damri et al, 16 without the ANACs, WRKYs and b-ZIP previously discussed), 9 are regulated in a similar manner in response to 35Spro:GmAGL15 in explants compared to Jack WT (7 expressed and 2 repressed). Only one TF shows an opposite pattern.…”

“…To look more broadly than just at the TFs associated with dedifferentiation, we looked further at data presented in Damri et al, 16 that was part of the analysis by Grafi et al 13 These genes were responsive to protoplasting and include additional genes with putative soybean orthologs that respond to 35Spro: GmAGL15 in explants or in response to 3 dac induction of SE in Jack WT (ref. 16, Supplemental Table 2).…”

“…16, Supplemental Table 2). These include 13 genes encoding products involved in photosynthesis that show reduced transcript abundance in 3 dac Jack compared to explants with only one gene showing an opposite response where it is upregulated during protoplasting but shows reduced transcript in response to incubation of Jack WT for 3 dac.…”

Light signaling controls nuclear architecture reorganization during seedling establishment

“…2, 11, and 15-17). In somatic cells, massive changes in nuclear architecture occur during developmental switches, such as seed maturation and germination, flowering, and senescence (18)(19)(20)(21)(22). Cotyledon cells…”