Comparative Analysis of Proteins Regulated during Cadmium Sulfide Quantum Dots Response in Arabidopsis thaliana Wild Type and Tolerant Mutants

Abstract

In previous work, two independent Arabidopsis thaliana Ac/Ds transposon insertional mutant lines, atnp01 and atnp02, were identified that showed a higher level of tolerance than the wild type (wt) line to cadmium sulfide quantum dots (CdS QDs). The tolerance response was characterized at physiological, genetic and transcriptomic levels. In this work, a comparative analysis was performed on protein extracts from plantlets of the two mutants and of wt, each treated with 80 mg L-1 CdS QDs. A comparative protein analysis was performed by 2D-PAGE, and proteins were characterized by MALDI-TOF/TOF mass spectrometry. Of 250 proteins identified from all three lines, 98 showed significant changes in relative abundance between control and CdS QD-treated plantlets. The wt, atnp01, and atnp02 control-treated pairs respectively showed 61, 31, and 31 proteins with differential expression. The two mutants had a different response to treatment in terms of type and quantity of up- and downregulated proteins. This difference became more striking when compared to wt. A network analysis of the proteins differentially expressed in atnp01 and atnp02 included several of those encoded by putative genes accommodating the transposons, which were responsible for regulation of some proteins identified in this study. These included nifu-like protein 3 (Nfu3), involved in chloroplast assembly, elongator complex 3 (Elo3), involved in transcriptional elongation, magnesium-chelate subunit-2 (Chli2), involved in chlorophyll biosynthesis, and protein phosphatase 2C (PP2C) which mediates abiotic stress response.

Engineered Nanomaterial Exposure Affects Organelle Genetic Material Replication in Arabidopsis thaliana

“…With regard to CdS QDs and CdSO 4 , the negative effects on biomass and other physiological parameters were also consistent with previous studies , as with a strong decrease in photosynthetic activity, cellular respiration, and ROS scavenging, as a consequence of disrupted organellar functions with increasing exposure time and CdS QD concentration . It has been demonstrated that CdS QDs and CdSO 4 trigger different regulatory responses at the level of mRNA and proteins. ,,,, Concerning the effects observed for ZnS QDs, the literature related to this pristine type of QD is minimal. However, information related to ZnO NPs effects on plant species is abundant, and mostly in agreement with the results reported in Ruotolo et al: decreased chlorophyll production and induction of secondary metabolite biosynthesis.…”

“…Indeed, for CdS QDs, Marmiroli et al recently demonstrated that nanoparticle biotransformation occurs within the plant cell, resulting in a chemical form different from ionic Cd. This distinction between ionic and nanoscale form has also been demonstrated through specific transcriptomic responses to CdS QDs and Cd 2+ exposure, , and by a nanoscale specific proteomic response . The second component ( x axis; Figure a) is related to the ptDNA and mtDNA copy number; these treatments trigger a copy number increase (Fe 3 O 4 NPs, FeCl 3 , ZnS QDs, ZnSO 4 ) from those that had no effect (CeCl 3 , CeO 2 NPs, Fe 2 O 3 NPs) or those that had a nonuniform impact on ptDNA and mtDNA (CdS QDs, CdSO 4 ).…”

“…9 It has been demonstrated that CdS QDs and CdSO 4 trigger different regulatory responses at the level of mRNA and proteins. 26,28,31,39,45 Concerning the effects observed for ZnS QDs, the literature related to this pristine type of QD is minimal. However, information related to ZnO NPs effects on plant species is abundant, 10 and mostly in agreement with the results reported in Ruotolo et al: 39 decreased chlorophyll production and induction of secondary metabolite biosynthesis.…”

“…This distinction between ionic and nanoscale form has also been demonstrated through specific transcriptomic responses to CdS QDs and 2+ exposure, 9,31 and by a nanoscale specific proteomic response. 45 The second component (x axis; Figure 4a) is related to the ptDNA and mtDNA copy number; these treatments trigger a copy number increase (Fe 3 O 4 NPs, FeCl 3 , ZnS QDs, ZnSO 4 ) from those that had no effect (CeCl 3 , CeO 2 NPs, Fe 2 O 3 NPs) or those that had a nonuniform impact on ptDNA and mtDNA (CdS QDs, CdSO 4 ). With the Ce-based treatments, the effects observed were different: CeCl 3 treatment showed a 56% decrease in biomass vs CeO 2 NPs treatment, which showed a 73% increase in biomass, according to Tukey's HSD (Figure 3; Table S3), whereas the effects on ptDNA and mtDNA copy number were uniformly nonsignificant (Figure 1).…”

Special Issue “The Genetic Changes Induced by Engineered Manufactured Nanomaterials (EMNs)”

“…As explained in one of the reviews included in this Special Issue, the number and quantity of nanomaterials is ever increasing and affecting the environment where humans, bacteria, and plants live, and their genome come in contact with nanomaterials [3]. Although the topic of genotoxicity induced by nanomaterials is important, we had only five contributions for this Special Issue: [3][4][5][6][7][8]. Marmiroli et al, 2022 [3], contributed a minireview on the methods used to analyze genotoxicity in plants.…”