Glyphosate-dependent effects on photosynthesis of Solanum lycopersicum L.-An ecophysiological, ultrastructural and molecular approach

Cristiano Soares; Ruth Pereira; Maria Martins; Paula Tamagnini; João Serôdio; José Moutinho-Pereira; Ana Cunha; Fernanda Fidalgo

doi:10.1016/j.jhazmat.2020.122871

Glyphosate-dependent effects on photosynthesis of Solanum lycopersicum L.-An ecophysiological, ultrastructural and molecular approach

J Hazard Mater. 2020 Nov 5:398:122871. doi: 10.1016/j.jhazmat.2020.122871. Epub 2020 May 14.

Authors

Cristiano Soares¹, Ruth Pereira², Maria Martins², Paula Tamagnini³, João Serôdio⁴, José Moutinho-Pereira⁵, Ana Cunha⁶, Fernanda Fidalgo²

Affiliations

¹ GreenUPorto - Sustainable Agrifood Production Research Centre, Department of Biology, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal. Electronic address: cfsoares@fc.up.pt.
² GreenUPorto - Sustainable Agrifood Production Research Centre, Department of Biology, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
³ Bioengineering and Synthetic Microbiology Group, i3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal; IBMC - Instituto de Biologia Celular e Molecular, University of Porto, Porto, Portugal; Biology Department, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
⁴ Biology Department and CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
⁵ CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, Universidade de Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal.
⁶ Biology Department & CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, School of Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.

PMID: 32450466
DOI: 10.1016/j.jhazmat.2020.122871

Abstract

This study aimed to assess the toxicity of glyphosate (GLY; 0, 10, 20 and 30 mg kg^-1) in Solanum lycopersicum L., particularly focusing on the photosynthetic metabolism. By combining ecophysiological, ultrastructural, biochemical and molecular tools, the results revealed that the exposure of tomato plants to GLY led to alterations in leaf water balance regulation [increasing stomatal conductance (g_s) and decreasing water use efficiency (WUE_i) at higher concentrations] and induced slight alterations in the structural integrity of cells, mainly in chloroplasts, accompanied by a loss of cell viability. Moreover, the transcriptional and biochemical control of several photosynthetic-related parameters was reduced upon GLY exposure. However, in vivo chlorophyll fluorometry and IRGA gas-exchange studies revealed that the photosynthetic yield of S. lycopersicum was not repressed by GLY. Overall, GLY impacts cellular and subcellular homeostasis (by affecting chloroplast structure, reducing photosynthetic pigments and inhibiting photosynthetic-related genes transcription), and leaf structure, but is not reducing the carbon flow on a leaf area basis. Altogether, these results suggest a trade-off effect in which GLY-induced toxicity is compensated by a higher photosynthetic activity related to GLY-induced dysfunction in g_s and an increase in mesophyll thickness/density, allowing the viable leaf cells to maintain their photosynthetic capacity.

Keywords: Abiotic stress; Calvin cycle; Chlorophyll fluorometry; Gas-exchange; Non-target plants; Photochemistry.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Chlorophyll
Glycine / analogs & derivatives
Glyphosate
Photosynthesis
Plant Leaves
Solanum lycopersicum*

Substances

Chlorophyll
Glycine