Bioinformatics-Assisted Proteomics of Metal(Loid) Tolerance in Arabidopsis

In recent years, the restoration of metal(loid) polluted soils through the combined use of plants-amendments-microorganisms is a strategy that is receiving great attention. However, the molecular processes underlying this synergy are not fully understood. Thus, the aim of this work was to provide insight into the biological mechanisms used by Arabidopsis thaliana to grow in soil contaminated by arsenic and lead and amended with biochar and/or Bacillus sp. inoculum. To accomplish this goal, a pot experiment was set up and the effects of the biochar amendment and the bacterial isolate were evaluated, both alone and in combination. The effects of the plant-biochar-bacteria synergy were assessed on soil physicochemical characteristics, plant growth and ability to stabilize or accumulate metal(loid)s. In addition, a bioinformatics-assisted proteomics approach was used to understand the molecular processes underlying A. thaliana growth in the different tested conditions. Results showed that the use of biochar and/or Bacillus inoculum resulted in improvements in soil properties and plant growth. Bioinformatics-assisted proteomic analysis showed that, on the one hand, the use of biochar alone led to an over-representation of proteins involved in nutrient metabolism providing plants with essential nutrients for growth. However, biochar alone induced plant defense mechanism dysfunction and increased susceptibility to pathogen attack. On the other hand, the use of bacterial inoculation helped plants to grow thanks to the activation of molecular pathways involved in the defense against biotic stress. Only the combined use of biochar and bacteria ensured the correct balance between molecular processes associated with growth and metal(loid) stress response in Arabidopsis plants.