Shoot and root omics signature in phytostabilization and hyperaccumulation model plants

The growing concern over soil contamination has led to increased interest in phytoremediation, a sustainable and cost-effective approach. Among other techniques, phytostabilization and hyperaccumulation have gained a lot of attention for their efficiency. Hyperaccumulation refers to plant potential by extracting metal(loid)s from contaminated soils while simultaneously reducing the toxicity of these tailings for future land development. Phytostabilization implies the reduction and immobilization of contaminants through plant roots. These contaminants are either adsorbed onto the root surface or precipitated within the rhizosphere, thereby hindering their migration into the soil. However, the success of these two approaches rely on the vegetation cover, which could be challenging in the highly contaminated soil. Recently, a variety of solutions, such as the use of different soil amendments/fertilizers, such as biochar and compost, have been explored for improving and accelerating the phytoremediation process (assisted-phytoremediation). However, gaps persist in our understanding of species-specific strategies for metal(loid)s exposure and the key proteins that could be targeted to enhance these desirable processes in the future. Arabidopsis thaliana, whose genome has been extensively studied, is a great model of phytostabilization. In contrast, Arabidopsis halleri is a facultative metallophyte and stoloniferous obligate outcrosser, belonging to the class of plants known as hyperaccumulators. Therefore, we employed a comprehensive approach that integrates proteomic and metabolomic analyses with in- silico techniques able to identify a significant number of differentially expressed proteins (DEPs) and metabolites (DEMs) in both root and shoot of Arabidopsis thaliana and Arabidopsis halleri under varying growing substrates (compost and/or biochar addition in metalloids contaminated soil). In detail, their contrasting responses were dissected by examining plant growth and metal(loid) accumulation capacity in both shoot and root, and related proteomic signatures. Specifically, in the shoot samples, we identified 317 DEPs in A. thaliana and 373 DEPs in A. halleri. In root sample, total of 1538 DEPs were identified in A. thaliana, in contrast to 706 DEPs in A. halleri. The GO enriched analysis, complemented by a comprehensive pathway enrichment analysis, highlighted the distinct mechanisms that each species employs to regulate its response to metal(loid)s stress. Finally, 20 hub and bottleneck proteins were designated in each organ across A. thaliana and A. halleri to pinpoint the foundation for future research aimed at targeted genetic manipulation. Such advancements could revolutionize the field of environmental remediation, offering a sustainable solution to the global challenge of soil contamination.

Audience Take Away:

• The insights gained from this research are expected to significantly advance in understanding peculiar mechanisms adopted by metal(loid)s phytoastabilizing and hyperaccumulating plants.
• More in general, this research represents a challenge for abiotic stress biology studies offering a good integrated analytical system able to decipher i) how plants respond to the different stressors ii) which network are differentially activated and iii) which pathways are elicited.
• This study holds the potential to pave the way for developing genetically engineered plants with optimized phytoremediation abilities.
• Such advancements could revolutionize the field of environmental remediation, offering a sustainable solution to the global challenge of soil contamination.
• This is therefore a “hot” topic for future discoveries that will reveal the evolution of diverse response mechanisms that could be valuable for the design of improvement strategies including for current environmental challenges.