GUN1 — Arabidopsis thaliana

Summary

AT2G31400, known as GUN1 (genomes uncoupled 1) in Arabidopsis thaliana, encodes a hypothetical protein containing pentatricopeptide repeat (PPR) and small MutS-related (Smr) domains, with DNA-binding molecular function. The gene is associated with chloroplast-to-nucleus retrograde signaling, plastid gene expression, transcription, and translation, as well as tetrapyrrole, heme, phytochromobilin, galactolipid, and MEP pathway metabolism, and the downregulation of photosynthesis. GUN1 is linked to regulation of seedling development, auxin metabolism, and phytochrome chromophore anabolism. Observed phenotypes connect it to anthocyanin biosynthesis and accumulation, root architecture, chloroplast development and biogenesis, photomorphogenesis, hypocotyl elongation, cotyledon expansion and opening, leaf morphogenesis, flowering time, and responses to water stress, oxidative stress, high light, and salicylic acid. The gene is also associated with leaf lamina area, cotyledon morphology, chloroplast development, photochemical quenching, and seedling growth traits. Studies of related pentatricopeptide repeat-containing proteins in other species link the family to leaf shape and germination rate.