title: Lettuce (Lactuca sativa L.) leaf-proteome profiles after exposure to cylindrospermopsin and a microcystin-LR/cylindrospermopsin mixture: a concentration-dependent response.
abstract: The intensification of agricultural productivity is an important challenge worldwide. However, environmental stressors can provide challenges to this intensification. The progressive occurrence of the cyanotoxins cylindrospermopsin (CYN) and microcystin-LR (MC-LR) as a potential consequence of eutrophication and climate change is of increasing concern in the agricultural sector because it has been reported that these cyanotoxins exert harmful effects in crop plants. A proteomic-based approach has been shown to be a suitable tool for the detection and identification of the primary responses of organisms exposed to cyanotoxins. The aim of this study was to compare the leaf-proteome profiles of lettuce plants exposed to environmentally relevant concentrations of CYN and a MC-LR/CYN mixture. Lettuce plants were exposed to 1, 10, and 100 μg/l CYN and a MC-LR/CYN mixture for five days. The proteins of lettuce leaves were separated by two-dimensional electrophoresis (2-DE), and those that were differentially abundant were then identified by matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF/TOF MS). The biological functions of the proteins that were most represented in both experiments were photosynthesis and carbon metabolism and stress/defense response. Proteins involved in protein synthesis and signal transduction were also highly observed in the MC-LR/CYN experiment. Although distinct protein abundance patterns were observed in both experiments, the effects appear to be concentration-dependent, and the effects of the mixture were clearly stronger than those of CYN alone. The obtained results highlight the putative tolerance of lettuce to CYN at concentrations up to 100 μg/l. Furthermore, the combination of CYN with MC-LR at low concentrations (1 μg/l) stimulated a significant increase in the fresh weight (fr. wt) of lettuce leaves and at the proteomic level resulted in the increase in abundance of a high number of proteins. In contrast, many proteins exhibited a decrease in abundance or were absent in the gels of the simultaneous exposure to 10 and 100 μg/l MC-LR/CYN. In the latter, also a significant decrease in the fr. wt of lettuce leaves was obtained. These findings provide important insights into the molecular mechanisms of the lettuce response to CYN and MC-LR/CYN and may contribute to the identification of potential protein markers of exposure and proteins that may confer tolerance to CYN and MC-LR/CYN. Furthermore, because lettuce is an important crop worldwide, this study may improve our understanding of the potential impact of these cyanotoxins on its quality traits (e.g., presence of allergenic proteins).
authors.affiliation: CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, P 4050-123 Porto, Portugal; Faculty of Sciences, Porto University, Rua do Campo Alegre, 4169-007 Porto, Portugal; Polytechnic Institute of Porto, Escola Superior de Tecnologia da Saúde do Porto, CISA/Research Center in Environment and Health, Rua de Valente Perfeito, 322, 4400-330 Gaia, Portugal.
authors.forename: Marisa
authors.initials: M
authors.lastname: Freitas
authors.affiliation: CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, P 4050-123 Porto, Portugal.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Campos
authors.affiliation: CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, P 4050-123 Porto, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Azevedo
authors.affiliation: CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, P 4050-123 Porto, Portugal.
authors.forename: Aldo
authors.initials: A
authors.lastname: Barreiro
authors.affiliation: Department of Environment and Agro-biotechnologies (EVA), Centre de Recherche Public-Gabriel Lippmann, 41, rue du Brill, 4422 Belvaux, Luxembourg.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Planchon
authors.affiliation: Department of Environment and Agro-biotechnologies (EVA), Centre de Recherche Public-Gabriel Lippmann, 41, rue du Brill, 4422 Belvaux, Luxembourg.
authors.forename: Jenny
authors.initials: J
authors.lastname: Renaut
authors.affiliation: CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, P 4050-123 Porto, Portugal; Faculty of Sciences, Porto University, Rua do Campo Alegre, 4169-007 Porto, Portugal. Electronic address: vmvascon@fc.up.pt.
authors.forename: Vitor
authors.initials: V
authors.lastname: Vasconcelos
mesh_terms: D000470:Alkaloids; D001427:Bacterial Toxins; D057231:Climate Change; D000087522:Cyanobacteria Toxins; D004305:Dose-Response Relationship, Drug; D018545:Lactuca / Q000737:chemistry* / Q000378:metabolism; D008387:Marine Toxins; D052998:Microcystins / Q000494:pharmacology*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010788:Photosynthesis; D018515:Plant Leaves / Q000737:chemistry; D020543:Proteome / Q000378:metabolism; D040901:Proteomics; D014498:Uracil / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins; D020543:Proteome; C089595:cylindrospermopsin; D014498:Uracil; C057862:cyanoginosin LR
keywords: Cylindrospermopsin; Lactuca sativa; Microcystin-LR; Mixture; Proteomics