The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea

Merja Lusa (Corresponding Author), Hanna Help, Ari-Pekka Honkanen, Jenna Knuutinen, Joni Parkkonen, Dominika Kalasová, Malin Bomberg

    Research output: Contribution to journalArticleScientificpeer-review

    23 Citations (Scopus)


    Selenium (Se) is an essential micronutrient but toxic when taken in excessive amounts. Therefore, understanding the metabolic processes related to selenium uptake and bacteria-plant interactions coupled with selenium metabolism are of high importance. We cultivated Brassica oleracea with the previously isolated heterotrophic aerobic Se(IV)-reducing Pseudomonas sp. T5-6-I strain to better understand the phenomena of bacteria-mediated Se(IV) reduction on selenium availability to the plants. B. oleracea grown on Murashige and Skoog medium (MS-salt agar) with and without of Pseudomonas sp. were amended with Se(IV)/75Se(IV), and selenium transfer into plants was studied using autoradiography and gamma spectroscopy. XANES was in addition used to study the speciation of selenium in the B. oleracea plants. In addition, the effects of Se(IV) on the protein expression in B. oleracea was studied using HPLC-SEC. TEM and confocal microscopy were used to follow the bacterial/Se-aggregate accumulation in plants and the effects of bacterial inoculation on root-hair growth. In the tests using 75Se(IV) on average 130% more selenium was translocated to the B. oleracea plants grown with Pseudomonas sp. compared to the plants grown with selenium, but without Pseudomonas sp. In addition, these bacteria notably increased root hair density. Changes in the protein expression of B. oleracea were observed on the ∼30–58 kDa regions in the Se(IV) treated samples, probably connected e.g. to the oxidative stress induced by Se(IV) or expression of proteins connected to the Se(IV) metabolism. Based on the XANES measurements, selenium appears to accumulate in B. oleracea mainly in organic C-Se-H and C-Se-C bonds with and without bacteria inoculation. We conclude that the Pseudomonas sp. T5-6-I strain seems to contribute positively to the selenium accumulation in plants, establishing the high potential of Se0-producing bacteria in the use of phytoremediation and biofortification of selenium.

    Original languageEnglish
    Article number108642
    Number of pages12
    JournalEnvironmental Research
    Publication statusPublished - Oct 2019
    MoE publication typeA1 Journal article-refereed


    The authors acknowledge the financial support for the project “Biosorption and bioaccumulation of heavy metals and radionuclides - use of environmental bacteria in the bioremediation of mining wastewaters” from KAUTE foundation. Hanna Help was supported by Academy of Finland (grant 1295696). Ari-Pekka Honkanen was funded by University of Helsinki Doctoral Program in Materials Research and Nanosciences (MATRENA). Dominika Kalasova acknowledges the project CEITEC 2020 (LQ1601) with financial support from the MEYS CR under the National Sustainability Programme II and Ceitec Nano + project, CZ.02.01/0.0./.0.0./16_013/0001728 under the program OP RDE.


    • Bacteria
    • Bacteria-plant interactions
    • Plant uptake
    • Pseudomonas
    • Selenium


    Dive into the research topics of 'The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea'. Together they form a unique fingerprint.

    Cite this