Article
The CarO rhodopsin of the fungus Fusarium fujikuroi is a light-driven proton pump that retards spore germination
Author/s | Ávalos Cordero, Francisco Javier
García Martínez, Jorge Brunk, Michael Terpitz, Ulrich |
Department | Universidad de Sevilla. Departamento de Genética |
Publication Date | 2015 |
Deposit Date | 2016-02-23 |
Published in |
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Abstract | Rhodopsins are membrane-embedded photoreceptors found in all major taxonomic kingdoms using retinal as their chromophore. They play well-known functions in different biological systems, but their roles in fungi remain ... Rhodopsins are membrane-embedded photoreceptors found in all major taxonomic kingdoms using retinal as their chromophore. They play well-known functions in different biological systems, but their roles in fungi remain unknown. The filamentous fungus Fusarium fujikuroi contains two putative rhodopsins, CarO and OpsA. The gene carO is light-regulated, and the predicted polypeptide contains all conserved residues required for proton pumping. We aimed to elucidate the expression and cellular location of the fungal rhodopsin CarO, its presumed proton-pumping activity and the possible effect of such function on F. fujikuroi growth. In electrophysiology experiments we confirmed that CarO is a green-light driven proton pump. Visualization of fluorescent CarO-YFP expressed in F. fujikuroi under control of its native promoter revealed higher accumulation in spores (conidia) produced by light-exposed mycelia. Germination analyses of conidia from carO2 mutant and carO1 control strains showed a faster development of light-exposed carO2 germlings. In conclusion, CarO is an active proton pump, abundant in light-formed conidia, whose activity slows down early hyphal development under light. Interestingly, CarO-related rhodopsins are typically found in plant-associated fungi, where green light dominates the phyllosphere. Our data provide the first reliable clue on a possible biological role of a fungal rhodopsin |
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THE CARO RHODOPSIN.pdf | 1.226Mb | [PDF] | View/ | |