title: Phosphite cannot be used as a phosphorus source but is non-toxic for microalgae.
abstract: Phosphorous (P) plays a critical role for all living organisms as a structural component of RNA, DNA and phospholipids. Microalgae are autotrophs organisms that have been reported to only assimilate the fully oxidized phosphate (Pi) as P source. However, there are microorganisms capable of utilizing P reduced compounds (i.e. phosphite (Phi) and hypophosphite) as a sole P source, such as bacteria and cyanobacteria. In this study, we evaluated whether microalgae, such as Chlamydomonas reinhardtii, Botryococcus braunii and Ettlia oleoabundans, are capable of using Phi as a sole P source. Our studies revealed that these three microalgae are unable to use Phi as a sole P source. We also found that when Phi is present at concentrations equal or higher than that of Pi, Phi has an inhibitory effect on C. reinhardtii growth. However, since C. reinhardtii was able to survive for a long period of cultivation in the presence of high concentrations of Phi and to recover cell division capacity after transfer to media containing Pi, we noticed that Phi is not toxic for this microalga. We propose that the inhibitory effect of Phi on C. reinhardtii growth might be caused, at least in part, by a competition between the transport of Pi and Phi.
authors.affiliation: Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada del Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Km 9.6 carretera Irapuato León, 36500 Irapuato, Guanajuato, Mexico.
authors.forename: Maribel M
authors.initials: MM
authors.lastname: Loera-Quezada
authors.affiliation: StelaGenomics México, S de RL de CV, Av. Camino Real de Guanajuato s/n, 36821 Irapuato, Guanajuato, Mexico.
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Leyva-González
authors.affiliation: StelaGenomics México, S de RL de CV, Av. Camino Real de Guanajuato s/n, 36821 Irapuato, Guanajuato, Mexico. Electronic address: dlopez@stelagenomics.mx.
authors.forename: Damar
authors.initials: D
authors.lastname: López-Arredondo
authors.affiliation: Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada del Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Km 9.6 carretera Irapuato León, 36500 Irapuato, Guanajuato, Mexico. Electronic address: lhererra@langebio.cinvestav.mx.
authors.forename: Luis
authors.initials: L
authors.lastname: Herrera-Estrella
mesh_terms: D016825:Chlamydomonas reinhardtii / Q000187:drug effects / Q000378:metabolism; D058086:Microalgae / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D017905:Phosphites / Q000378:metabolism* / Q000633:toxicity; D010758:Phosphorus / Q000378:metabolism*
chemical_list: D017905:Phosphites; D010758:Phosphorus
keywords: Chlamydomonas reinhardtii; Microalgae; Phosphate; Phosphite; Reduced phosphorous assimilation