{"database":"GEO","file_versions":[{"headers":{"Content-Type":["application/json"]},"body":{"files":{"Other":["ftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE292nnn/GSE292110/"]},"type":"primary"},"statusCode":"OK","statusCodeValue":200}],"scores":null,"additional":{"omics_type":["Transcriptomics"],"species":["Arabidopsis thaliana"],"gds_type":["Expression profiling by high throughput sequencing"],"full_dataset_link":["https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE292110"],"repository":["GEO"],"entry_type":["GSE"],"additional_accession":[]},"is_claimable":false,"name":"A suppressor screen uncovers flu as a weak mutant and chloroplastic 1O2 triggers EX1-independent stress responses in Arabidopsis","description":"• Singlet oxygen (1O2) is the main ROS produced in chloroplasts, particularly under environmental stress conditions. Studies using the Arabidopsis conditional flu (flu1-1) mutant have shown that chloroplastic 1O2 acts as a signal, activating retrograde signaling that eventually leads to photoinhibition or cell death. • Through a forward genetic screen for suppressors using EMS-mutagenized Arabidopsis flu1-1/ex1 mutants, we isolated two suppressor mutants (mut1 and mut2) that restored 1O2-induced stress responses. Using combined methods of map-based cloning and high-throughput sequencing, we mapped the causal mutations in both mut1 and mut2 to the FLU gene again. • We verified that the widely used flu1-1 is not the long-recognized null mutant, but rather a weak allele, encoding a variant that binds weakly to GluTR1 and leads to partial shutdown of tetrapyrrole biosynthesis in darkness. We further found that the FLU-knockout mutants produce more 1O2, activating transcriptional changes, enzymatic lipid peroxidation, and PCD even in the absence of EX1. Overexpression of SAFE1 suppressed 1O2-induced PCD in mut2 in a dosage-dependent manner. • Collectively, our findings redefine the nature of the widely used flu1-1 mutant and reveal that excessive 1O2 can overwhelm the inhibitory effect of endogenous SAFE1 and induce stress responses independently of EX1.","dates":{"publication":"2026/05/02"},"accession":"GSE292110","cross_references":{"GSM":["GSM8849365","GSM8849366","GSM8849367","GSM8849368","GSM8849361","GSM8849362","GSM8849363","GSM8849364","GSM8849360","GSM8849369","GSM8849358","GSM8849359"],"GPL":["31102"],"GSE":["292110"],"taxon":["Arabidopsis thaliana"]}}