title: Solar Radiation Stress in Natural Acidophilic Biofilms of Euglena mutabilis Revealed by Metatranscriptomics and PAM Fluorometry.
abstract: The daily photosynthetic performance of a natural biofilm of the extreme acidophilic Euglena mutabilis from Río Tinto (SW, Spain) under full solar radiation was analyzed by means of pulse amplitude-modulated (PAM) fluorescence measurements and metatrascriptomic analysis. Natural E. mutabilis biofilms undergo large-scale transcriptomic reprogramming during midday due to a dynamic photoinhibition and solar radiation stress. Photoinhibition is due to UV radiation and not to light intensity, as revealed by PAM fluorometry analysis. In order to minimize the negative effects of solar radiation, our data supports the presence of a circadian rhythm in this euglenophyte that increases their opportunity to survive. Differential gene expression throughout the day (at 12:00, 20:00 and night) was monitored by massive Illumina parallel sequencing of metatranscriptomic libraries. The transcription pattern was altered in genes involved in Photosystem II stability and repair, UV damaged DNA repair, non-photochemical quenching and oxidative stress, supporting the photoinhibition detected by PAM fluorometry at midday.
authors.affiliation: Centro de Astrobiología (INTA-CSIC). Carretera de Ajalvir Km 4, Torrejón de Ardoz. 28850 Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Puente-Sánchez
authors.affiliation: Centro de Astrobiología (INTA-CSIC). Carretera de Ajalvir Km 4, Torrejón de Ardoz. 28850 Madrid, Spain; Department of Agricultural Sciences, P.O. Box 27, FI-00014 University of Helsinki, Helsinki, Finland.
authors.forename: Sanna
authors.initials: S
authors.lastname: Olsson
authors.affiliation: Centro de Astrobiología (INTA-CSIC). Carretera de Ajalvir Km 4, Torrejón de Ardoz. 28850 Madrid, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Gómez-Rodriguez
authors.affiliation: Instituto Ciencias Agrarias (ICA-CSIC), c/ Serrano 115 dpdo, 28006 Madrid, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Souza-Egipsy
authors.affiliation: Departamento de Biología Vegetal (Botánica), Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Altamirano-Jeschke
authors.affiliation: Centro de Astrobiología (INTA-CSIC). Carretera de Ajalvir Km 4, Torrejón de Ardoz. 28850 Madrid, Spain; Centro de Biología Molecular Severo Ochoa (UAM-CSIC). Universidad Autónoma de Madrid, Canto Blanco, 28049 Madrid, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Amils
authors.affiliation: Centro de Astrobiología (INTA-CSIC). Carretera de Ajalvir Km 4, Torrejón de Ardoz. 28850 Madrid, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Parro
authors.affiliation: Centro de Astrobiología (INTA-CSIC). Carretera de Ajalvir Km 4, Torrejón de Ardoz. 28850 Madrid, Spain. Electronic address: aguileraba@cab.inta-csic.es.
authors.forename: Angeles
authors.initials: A
authors.lastname: Aguilera
mesh_terms: D018441:Biofilms / Q000528:radiation effects*; D005055:Euglena / Q000235:genetics / Q000378:metabolism / Q000502:physiology* / Q000528:radiation effects*; D005453:Fluorescence; D013030:Spain; D013312:Stress, Physiological; D013472:Sunlight / Q000009:adverse effects*; D059467:Transcriptome
keywords: Acidic environments; PAM fluorometry; UV stress; ecophysiology; extremophiles; metatranscriptomics