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

Merja Lusa; Hanna Help; Ari-Pekka Honkanen; Jenna Knuutinen; Joni Parkkonen; Dominika Kalasová; Malin Bomberg

doi:10.1016/j.envres.2019.108642

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

Merja Lusa^*
, Hanna Help
, Ari-Pekka Honkanen
, Jenna Knuutinen
, Joni Parkkonen
, Dominika Kalasová
, Malin Bomberg

^*Corresponding author for this work

University of Helsinki
University of Jyväskylä
Brno University of Technology

Research output: Contribution to journal › Article › Scientific › peer-review

34 Citations (Scopus)

Abstract

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 language	English
Article number	108642
Number of pages	12
Journal	Environmental Research
Volume	177
DOIs	https://doi.org/10.1016/j.envres.2019.108642
Publication status	Published - Oct 2019
MoE publication type	A1 Journal article-refereed

Funding

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.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 15 Life on Land

Keywords

Bacteria
Bacteria-plant interactions
Plant uptake
Pseudomonas
Selenium

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

abstract = "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.",

keywords = "Bacteria, Bacteria-plant interactions, Plant uptake, Pseudomonas, Selenium",

author = "Merja Lusa and Hanna Help and Ari-Pekka Honkanen and Jenna Knuutinen and Joni Parkkonen and Dominika Kalasov{\'a} and Malin Bomberg",

note = "Publisher Copyright: {\textcopyright} 2019",

year = "2019",

month = oct,

doi = "10.1016/j.envres.2019.108642",

language = "English",

volume = "177",

journal = "Environmental Research",

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T1 - The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea

AU - Lusa, Merja

AU - Help, Hanna

AU - Honkanen, Ari-Pekka

AU - Knuutinen, Jenna

AU - Parkkonen, Joni

AU - Kalasová, Dominika

AU - Bomberg, Malin

PY - 2019/10

Y1 - 2019/10

N2 - 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.

AB - 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.

KW - Bacteria

KW - Bacteria-plant interactions

KW - Plant uptake

KW - Pseudomonas

KW - Selenium

UR - https://www.scopus.com/pages/publications/85070669481

U2 - 10.1016/j.envres.2019.108642

DO - 10.1016/j.envres.2019.108642

M3 - Article

AN - SCOPUS:85070669481

SN - 0013-9351

VL - 177

JO - Environmental Research

JF - Environmental Research

M1 - 108642

ER -

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

Abstract

Funding

UN SDGs

Keywords

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