Involvement of OsS40-14 in ROS and plastid organization related regulatory networks of dark-induced leaf senescence in rice

Abstract

AbstractDark-induced senescence triggers significant metabolic changes that recycle resources and ensure plant survival. In this study, we identified a transcription factor OsS40-14 in rice, which can form homo-oligomers. Theoss40-14knockout mutants exhibited stay-green phenotype of primary leaf and flag leaf during dark-induced condition, with substantial retention of chlorophylls and photosynthetic capacity as well as remarkably reduced reactive oxygen species (ROS), whileOsS40-14overexpressing transgenic lines (oeOsS40-14) showed an accelerated senescence phenotype under dark-induced leaf senescence conditions. Transcriptome analysis revealed that when the detached leaves ofoss40-14and WT were treated in darkness condition for 72 hours, 1585 DEGs (|Log2FC| ≥1, P value<0.05) were reprogrammed inoss40-14relative to WT. CUT&Tag-seq analysis in protoplast transient expression of OsS40-14 system showed that OsS40-14 was 40.95% enriched in the transcription start site (TSS) of the genome. Sequence clustering analysis showed that OsS40-14 protein was mainly enriched and bound to TACCCACAAGACAC conserved elements. The seed region “ACCCA” of OsS40 proteins was identified by single nucleotide mutagenesis EMSA. The integrative analysis of transcriptome and CUT&Tag-seq datasets showed 153 OsS40-14-targeted DEGs, they mainly enriched in plastid organization and photosynthesis process at dark-induced condition inoss40-14relative to WT. Among them, eleven candidate targets of OsS40-14 such as Glucose 6-phosphate/phosphate translocator, Na+/H+ antiporter, Catalase, Chitinase 2, Phosphate transporter 19, OsWAK32, and OsRLCK319 were directly targeted and upregulated confirmed by ChIP-PCR and RT-qPCR. It demonstrates a novel model of OsS40-14 mediating macromolecule metabolism and nutrient recycling controls the plastid organization during dark-induced leaf senescence.Significant statementInvolvement of OsS40-14 in macromolecule catabolism, nutrient recycling, and ROS homeostasis revealed a plastid organization defection of dark-induced senescence in rice