Autori: Nakamura M, Buzas DM, Kato A, Fujita M, Kurata N, Kinoshita T.
Editorial: New Phytologist, 199 (4), p.925-35, 2013.
Iron-sulfur proteins have iron-sulfur clusters as a prosthetic group and are responsible for various cellular processes, including general transcriptional regulation, photosynthesis and respiration. The cytosolic iron-sulfur assembly (CIA) pathway of yeast has been shown to be responsible for regulation of iron-sulfur cluster assembly in both the cytosol and the nucleus. However, little is known about the roles of this pathway in multicellular organisms. In a forward genetic screen, we identified an Arabidopsis thaliana mutant with impaired expression of the endosperm-specific gene Flowering Wageningen (FWA). To characterize this mutant, we carried out detailed phenotypic and genetic analyses during reproductive and vegetative development. The mutation affects NAR1, which encodes a homolog of a yeast CIA pathway component. Comparison of embryo development in nar1-3 and other A. thaliana mutants affected in the CIA pathway showed that the embryos aborted at a similar stage, suggesting that this pathway potentially functions in early seed development. Transcriptome analysis of homozygous viable nar1-4 seedlings showed transcriptional repression of a subset of genes involved in ‘iron ion transport’ and ‘response to nitrate’. nar1-4 also exhibited resistance to the herbicide paraquat. Our results indicate that A. thaliana NAR1 has various functions including transcriptional regulation in gametophytes and abiotic stress responses in vegetative tissues.
Cuvinte cheie: Arabidopsis thaliana, cytosolic iron-sulfur (Fe-S) cluster assembly, endosperm, imprinted gene, paraquat resistance // Arabidopsis thaliana, cytosolic iron-sulfur (Fe-S) cluster assembly, endosperm, imprinted gene, paraquat resistance