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, M. Bomberg

Research output: Contribution to journalArticleScientificpeer-review

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 languageEnglish
Article number108642
Number of pages12
JournalEnvironmental Research
Volume177
DOIs
Publication statusPublished - Oct 2019
MoE publication typeA1 Journal article-refereed

Fingerprint

Brassica
Selenium
Pseudomonas
selenium
Bacteria
effect
bacterium
hair
Metabolism
inoculation
protein
metabolism
Proteins
Environmental Biodegradation
Oxidative stress

Keywords

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

Cite this

Lusa, Merja ; Help, Hanna ; Honkanen, Ari-Pekka ; Knuutinen, Jenna ; Parkkonen, Joni ; Kalasová, Dominika ; Bomberg, M. / The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea. In: Environmental Research. 2019 ; Vol. 177.
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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 M. Bomberg",
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The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea. / Lusa, Merja (Corresponding Author); Help, Hanna; Honkanen, Ari-Pekka; Knuutinen, Jenna; Parkkonen, Joni; Kalasová, Dominika; Bomberg, M.

In: Environmental Research, Vol. 177, 108642, 10.2019.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

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, M.

PY - 2019/10

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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

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