Mycorrhizal stress alleviation in Senecio bonariensis Hook & Arn growing in urban polluted soils

Abstract

Loss of biodiversity and accumulation of contaminants in urban soils and water bodies cause serious issues in metropolitan areas. The Matanza-Riachuelo river basin (metropolitan area of Buenos Aires, Argentina) is one of the most environmentally degraded regions in the world. Senecio bonariensis Hook & Arn (Asteraceae) grows in the periodically flooded soils of this wetland. This plant concentrates potentially toxic trace elements (PTEs) in its tissues and establishes symbiosis with arbuscular mycorrhizal (AM) fungi that collaborate with PTE phytostabilization in soils. The objective of this work was to evaluate tolerance and stress alleviation of AMcolonized S. bonariensis when transplanting and exposing to highly polluted environmental conditions of the river basin. Plants were initially inoculated with different AM strains and maintained in greenhouse conditions. After 6 mo, they were transplanted to the field. These plants showed a more equal distribution between shoot and root biomass production in comparison to field spontaneous S. bonaerensis plants. Plants in earlier contact with native soil inoculum showed positive correlation with phosphorus content and a significant increase of vesicle frequency. Plants belatedly contacted with native inoculum in the field (control) showed a higher catalase level that was positively correlated with the total colonization frequency and chlorophyll content. The ability to establish symbiosis with Rhizophagus intraradices (strain GC3), commonly used in the formulation of biofertilizers, was also analyzed. Plants inoculated with GC3 at the beginning of the assay showed lower colonization and were less efficient in the field. The preservation of spontaneous native plants with ornamental value and bioaugmentation of their associated microbiome can contribute to the stabilization of contaminants in soils.

Scale-up of Mycorrhizal-Assisted Phytoremediation System from Technology Readiness Level 6 (Relevant Environment) to 7 (Operational Environment): Cost-benefits within a Circular Economy Context

“…However, phytoextraction is suitable for those sites with low-moderate levels of HMs, because most plant species are not able to survive in heavily polluted habitats [9,16]. However, some authors have mentioned the potential use of native hyperaccumulating plants with remarkable tolerance strategies facing polluted conditions [17]. Essential pre-requisites for successful phytoextraction include the following: a high uptake and translocation of HMs to aerial parts, an enhanced loading of HMs into the xylem, and an efficient detoxification in the plant [18,19].…”

Arbuscular Mycorrhizal Fungi with different life strategies in an ancient and abandoned Pb-Zn-Ag mine in Andes Mountain

“…In this association, the AM fungus provides nutrients and water to its host plant, and plant supplies part of its photoassimilates to the fungal partner (Smith and Read 2008). Additionally, AM fungi provide protection to its host against pathogens and herbivory, as well as different abiotic stresses, including HM soil pollution (Cornejo et al 2008;Bompadre et al 2021). It is well known that AM fungi can uptake and sequester HM in their structures as a mechanism of HM alleviation (Riaz et al 2021).…”