GSNOR-dependent nitric oxide homeostasis promotes recovery from repeated climate stress across generations in Arabidopsis thaliana

Climate change exposes plants to recurrent and interacting stresses, yet the extent to which these effects persist across generations, and the mechanisms involved, remain unclear. We propagated Arabidopsis thaliana wild type (WT, Col-0) and nitric oxide homeostasis mutant gsnor1-3 (hereafter, gsnor-ko) for five successive generations. Plants were grown under control, drought, elevated CO2, O3, warm temperature, and combined treatment scenarios for the first three generations (G1-G3), followed by two recovery generations under control conditions (G4-G5). We quantified rosette growth, photosynthetic traits, seed production, and transcriptome dynamics by RNA-seq. Across environments, gsnor-ko showed reduced vegetative growth and reproductive output relative to WT. Transcriptomic responses were strongly scenario- and generation-dependent, with the largest differential expression shifts observed under warm-climate and combined-treatment conditions. Compared with WT, gsnor-ko displayed broader gene overlap across generations and stronger retention or reconfiguration of stress-responsive states after stress withdrawal. Functional enrichment and candidate-gene analyses identified pathways/components linked to DNA methylation, heterochromatin maintenance, histone ubiquitination, m6A RNA regulation, and methyl-donor metabolism. Together, these results support a model in which GSNOR activity promotes transcriptomic recovery after repeated climate stress, whereas impaired GSNOR function shifts responses toward multi-generational persistence and epigenetically associated regulatory reconfiguration. HighlightGSNOR-dependent nitric oxide homeostasis promotes transcriptomic resetting after repeated climate stress, whereas impaired NO homeostasis favours multigenerational persistence and chromatin- and RNA-linked regulatory reconfiguration. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/742973v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@15aa6c2org.highwire.dtl.DTLVardef@7a419eorg.highwire.dtl.DTLVardef@69f278org.highwire.dtl.DTLVardef@1adbc16_HPS_FORMAT_FIGEXP M_FIG C_FIG