Foraging for selenium: a comparison between hyperaccumulator and non-accumulator plant species

Abstract

Selenium (Se) hyperaccumulators are a unique group of plants that can accumulate this element in their aerial parts at concentrations exceeding 100 mg kgDW−1. These plants actively search for Se in the soil, a phenomenon known as root foraging, reported to date only by few studies. In this study, the effect of localized Se enrichment, in the form of selenite and selenate, was investigated on the root architecture of two Se-hyperaccumulators (Stanleya pinnata and Astragalus bisulcatus) and two non-accumulators (Brassica juncea and Medicago sativa). Rhizoboxes were divided into two halves: one half was filled with control soil while the other with selenate or selenite (30 mg kgDW−1) spiked soil. Seedling were transferred into the interface of the two soils and allowed to grow for three weeks under controlled light and temperature conditions. Staneya pinnata exhibited equal root density in both halves of the rhizobox when grown in control/control and selenite/control soil treatments. However, in the presence of selenate, S. pinnata developed 76% of the roots towards the selenate-enriched half, indicating an active root foraging. In contrast, A. bisulcatus and the non-accumulators B. juncea and M. sativa did not show any preferential distribution of roots. This study revealed that only S. pinnata showed the ability to detect and forage for Se when provided as selenate. Non-accumulators did not show any morphological or Se-accumulation difference associated with the presence of Se in soil in either form.

Nickelophilic root foraging by the nickel hyperaccumulator, Streptanthus polygaloides subsp. undulatus (Brassicaceae)

“…Root growth responses may be an additional important mechanism of hyperaccumulation (e.g., Boyd et al, 2000;Chen et al, 2023;El Mehdawi et al, 2015;Haines, 2002;Montanari et al, 2023;Moradi et al, 2009;Pinto Irish et al, 2021;Rosatto et al, 2021;Tognacchini et al, 2020;Whiting et al, 2000). Of these root foraging studies, all but two have demonstrated positive root responses of hyperaccumulators to an element.…”

“…Of these root foraging studies, all but two have demonstrated positive root responses of hyperaccumulators to an element. These positive responses include root proliferation (Boyd et al, 2000;Haines, 2002;Montanari et al, 2023;Pinto Irish et al, 2021;Tognacchini et al, 2020), lateral branching and lateral length (Whiting et al, 2000), root hair length (Whiting et al, 2000), and directional growth (Mehdawi et al, 2015). Ni tolerance and root elongation of S. polygaloides and a congeneric nonhyperaccumulator, Streptanthus breweri A.…”

Genome-Wide Identification of OsZIPs in Rice and Gene Expression Analysis under Manganese and Selenium Stress

“…In all, 16 ZIP genes have been authenticated in A. thaliana [17], 14 ZIP genes in Vigna unguiculata [18], and 58 ZIP genes in wheat (Triticum aestivum), 44 of which are homologous to rice ZIP proteins [19]. In potato (Solanum tuberosum), 29 ZIP genes have been identified [20] Selenium (Se) is a nonmetallic element classified in Group 16 of the periodic table along with sulfur (S), due to its similar chemical properties [21]. Se exhibits various biological activities, including immune system support, antioxidant effects, antiviral properties, and anticancer potential [22].…”

“…Selenium (Se) is a nonmetallic element classified in Group 16 of the periodic table along with sulfur (S), due to its similar chemical properties [ 21 ]. Se exhibits various biological activities, including immune system support, antioxidant effects, antiviral properties, and anticancer potential [ 22 ].…”