Cell Walls Are Remodeled to Alleviate nY₂O₃ Cytotoxicity by Elaborate Regulation of de Novo Synthesis and Vesicular Transport

Abstract

Yttrium oxide nanoparticles (nY 2 O 3 ), one of the broadly used rare earth nanoparticles, can interact with plants and possibly cause plant health and environmental impacts, but the plant defense response particularly at the nanoparticle−cell interface is largely unknown. To elucidate this, Bright Yellow 2 (BY-2) tobacco (Nicotiana tabacum L.) suspension-cultured cells were exposed to 50 mg L −1 nY 2 O 3 (30 nm) for 12 h. Although 42.2% of the nY 2 O 3 remained outside of protoplasts, nY 2 O 3 could still traverse the cell wall and was partially deposited inside the vacuole. In addition to growth inhibition, morphological and compositional changes in cell walls occurred. Together with a locally thickened (7−13-fold) cell wall, increased content (up to 58%) of pectin and reduction in (up to 29%) hemicellulose were observed. Transcriptome analysis revealed that genes involved in cell wall metabolism and remodeling were highly regulated in response to nY 2 O 3 stress. Expression of genes for pectin synthesis and degradation was up-and down-regulated by 31−78% and 13−42%, respectively, and genes for xyloglucan and pectin modifications were up-and down-regulated by 82% and 81− 92%, respectively. Interestingly, vesicle trafficking seemed to be activated, enabling the repair and defense against nY 2 O 3 disturbance. Our findings indicate that, although nY 2 O 3 generated toxicity on BY-2 cells, it is very likely that during the recovery process cell wall remodeling was initiated to gain resistance to nY 2 O 3 stress, demonstrating the plant's cellular regulatory machinery regarding repair and adaptation to nanoparticles like nY 2 O 3 .

Nano-enabled agriculture: How do nanoparticles cross barriers in plants?

“…NPs are known to affect plant cell wall components to remodel the plant cell wall. Exposure of tobacco suspension-cultured cells to nY 2 O 3 NPs resulted in a 7- to 13-fold thickening of cell walls compared with unexposed controls, together with an up to 58% increase in pectin and a 29% reduction in hemicellulose ( Chen et al., 2021 ). Because the cell wall is a barrier to NP uptake, NP-induced changes in the cell wall and its components may affect NP delivery efficiency into plants.…”

“…Cerium oxide NPs have been reported to be transported into chloroplasts in rice ( Zhou et al., 2021 ), cotton ( Liu et al., 2021 ), rapeseed (Li et al., 2022), and Arabidopsis ( Wu et al., 2017b ). nY 2 O 3 NPs can be transported into the vacuoles of tobacco suspension cells ( Chen et al., 2021 ). At the organelle level, organelle membranes are another barrier for the transport of NPs.…”

Nanomaterial-modulated cellular sodium extrusion and vacuolar sequestration for salt tolerance

“…BY-2 cells at the exponential stage as determined in our previous study 31 were transferred into 1/2 MS medium spiked with 100 mM NaCl (control cells were incubated in 1/2 MS medium without NaCl) for 24 h, followed by addition of NMs (0.05, 0.1, and 0.5 mg L −1 nCeO 2 or N-CDs), and samples were collected at time intervals of 2, 4, 6, 12, 24, 48, and 72 h, respectively. The cell viability from different NM treatments at each time points was measured by the TTC method as previously described (ESI † Text S1).…”

Translocation and transformation of engineered nanomaterials in plant cells and their effect on metabolism

“…After being exposed to Y 2 O 3 NPs, the form and composition of cell wall of tobacco (Nicotiana tabacum L.) were also altered. The cell wall thickness of tobacco increased significantly by 7-12 times, the pectin content increased by 58%, and the hemicellulose content decreased by 29% (Chen et al, 2021). In the presence of ROS, Ag + produced by Ag NPs can bind to hydroxy cellulose structures, breaking hydrogen bonds to promote changes in cell wall structure (Pinheiro et al, 2021).…”