Role of Selenium-Tolerant Fungi on Plant Growth Promotion and Selenium Accumulation of Maize Plants Grown in Seleniferous Soils

Kaur, Tanveer; Vashisht, Akanksha; Prakash, N. Tejo; Reddy, S. M.

doi:10.1007/s11270-021-05490-9

Cited by 11 publications

(4 citation statements)

References 38 publications

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“…Recent studies have shown that numerous Ascomycete fungi can tolerate and grow in high Se concentrations (>10 mM) in aqueous and soil environments. ,− Further, these fungi are capable of Se redox and biotransformation reactions such as Se(IV) and Se(VI) reduction to various reduced Se forms. These biotransformation products are largely red, amorphous Se(0) nanoparticles (SeNPs) and volatile methylated compounds such as dimethylselenide and dimethyldiselenide. ,,− Some fungi may also produce intracellular organoselenium compounds similar to selenoproteins or selenoamino acids produced by bacteria and other higher organisms. − Until recently, it was thought that fungi did not have the genetic machinery (e.g., Sec synthesis and insertion) to form selenocysteine and related selenoproteins , A 2019 study by Mariotti et al, however, showed that early branching fungal phyla do contain selenoprotein synthesis genes, but these genes were lost by Ascomycota (the phylum of which the fungi in this study belong) and Basidiomycota.…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Examination of Fungal Selenium Redox Transformations

Santelli

Sabuda

Rosenfeld

2023

ACS Earth Space Chem.

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Selenium (Se) is both a micronutrient required for most life and an element of environmental concern due to its toxicity at high concentrations, and both bioavailability and toxicity are largely influenced by the Se oxidation state. Environmentally relevant fungi have been shown to aerobically reduce Se(IV) and Se(VI), the generally more toxic and bioavailable Se forms. The goal of this study was to shed light on fungal Se(IV) reduction pathways and biotransformation products over time and fungal growth stages. Two Ascomycete fungi were grown with moderate (0.1 mM) and high (0.5 mM) Se(IV) concentrations in batch culture over 1 month. Fungal growth was measured throughout the experiments, and aqueous and biomass-associated Se was quantified and speciated using analytical geochemistry, transmission electron microscopy (TEM), and synchrotron-based X-ray absorption spectroscopy (XAS) approaches. The results show that Se transformation products were largely Se(0) nanoparticles, with a smaller proportion of volatile, methylated Se compounds and Se-containing amino acids. Interestingly, the relative proportions of these products were consistent throughout all fungal growth stages, and the products appeared stable over time even as growth and Se(IV) concentration declined. This time-series experiment showing different biotransformation products throughout the different growth phases suggests that multiple mechanisms are responsible for Se detoxification, but some of these mechanisms might be independent of Se presence and serve other cellular functions. Knowing and predicting fungal Se transformation products has important implications for environmental and biological health as well as for biotechnology applications such as bioremediation, nanobiosensors, and chemotherapeutic agents.

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Section: Introductionmentioning

confidence: 99%

Time-Resolved Examination of Fungal Selenium Redox Transformations

Santelli

Sabuda

Rosenfeld

2023

ACS Earth Space Chem.

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“…The element is also known to play a defensive role against AF in animals [ 28 , 29 , 30 ]. In the right amounts, Se can enhance plant growth [ 31 ].…”

Section: Introductionmentioning

confidence: 99%

“…In crop protection, the biofortification of plants with such an element would play the role of indirect control of AF accumulation in important cereals such as maize and wheat while improving the crop’s micronutrient status. However, it should also be noted that Se can be toxic in elevated levels to the plant itself [ 31 , 32 ] other than inhibiting fungal sporulation at high levels.…”

Section: Introductionmentioning

confidence: 99%

Aflatoxigenic Aspergillus Modulates Aflatoxin-B1 Levels through an Antioxidative Mechanism

Katati

Kovács

Njapau

et al. 2023

JoF

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Aflatoxins (AFs) are considered to play important functions in species of Aspergillus section Flavi including an antioxidative role, as a deterrent against fungivorous insects, and in antibiosis. Atoxigenic Flavi are known to degrade AF-B1 (B1). To better understand the purpose of AF degradation, we investigated the degradation of B1 and AF-G1 (G1) in an antioxidative role in Flavi. Atoxigenic and toxigenic Flavi were treated with artificial B1 and G1 with or without the antioxidant selenium (Se), which is expected to affect levels of AF. After incubations, AF levels were measured by HPLC. To estimate which population would likely be favoured between toxigenic and atoxigenic Flavi under Se, we investigated the fitness, by spore count, of the Flavi as a result of exposure to 0, 0.40, and 0.86 µg/g Se in 3%-sucrose cornmeal agar (3gCMA). Results showed that levels B1 in medium without Se were reduced in all isolates, while G1 did not significantly change. When the medium was treated with Se, toxigenic Flavi significantly digested less B1, while levels of G1 significantly increased. Se did not affect the digestion of B1 in atoxigenic Flavi, and also did not alter levels of G1. Furthermore, atoxigenic strains were significantly fitter than toxigenic strains at Se 0.86 µg/g 3gCMA. Findings show that while atoxigenic Flavi degraded B1, toxigenic Flavi modulated its levels through an antioxidative mechanism to levels less than they produced. Furthermore, B1 was preferred in the antioxidative role compared to G1 in the toxigenic isolates. The higher fitness of atoxigenic over toxigenic counterparts at a plant non-lethal dose of 0.86 µg/g would be a useful attribute for integration in the broader biocontrol prospects of toxigenic Flavi.

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“…isolated Se‐tolerant fungi, Fusarium equiseti and Pseudopestalotiopsis theae from seleniferous soil, which significantly increased the growth and selenium accumulating ability of Z. mays . [ 23 ] Similarly, Yasin et al. reported that inoculating selenium‐resistant Bacillus sp.…”

Section: Introductionmentioning

confidence: 99%

Plant Growth Promotion and Selenium Accumulation in Zea mays by Rhizobacteria Isolated from Natural Seleniferous Soils

Kaur

Chadha

Prakash

et al. 2022

CLEAN Soil Air Water

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Selenium (Se) is essential for life's basic functions but its sources are limited. Plant growth promoting bacteria is a potential source to increase Se accumulation and plant growth. Bacteria are isolated from native seleniferous soils,. and based on 16S rRNA (ribosomal RNA) sequenceanalysis, two plant growth promoting and selenium tolerant bacteria are selected. They are identified as Leclercia adecarboxylata (B49) and Cedecea neteri (B71). L. adecarboxylata and C. neteri produce indole acetic acid of 93 ± 3.2 and 68 ± 2.9 mg L−1 and a phosphate solubilization index of 1.26 ± 0.3 and 3.29 ± 0.2, respectively. L. adecarboxylata and C. neteri tolerate up to 350 mm of selenite with an inhibitory concentration 50 value of 225.6 ± 14 and 236.6 ± 14 mm, respectively. Inoculation of bacteria significantly increases the growth of Zea mays plants in seleniferous soil. Plant growth promotion is 36.6% more in C. neteri inoculated plants compared to L. adecarboxylata. Se accumulation significantly increases in plant tissues inoculated with C. neteri (20.2 µg g−1) than L. adecarboxylata (12.1 µg g−1). This study has provided evidence that microbial Se biotransformation through bacterial inoculation is an alternative way to improve the Se uptake in crops and maintain human health.

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Role of Selenium-Tolerant Fungi on Plant Growth Promotion and Selenium Accumulation of Maize Plants Grown in Seleniferous Soils

Cited by 11 publications

References 38 publications

Time-Resolved Examination of Fungal Selenium Redox Transformations

Time-Resolved Examination of Fungal Selenium Redox Transformations

Aflatoxigenic Aspergillus Modulates Aflatoxin-B1 Levels through an Antioxidative Mechanism

Plant Growth Promotion and Selenium Accumulation in Zea mays by Rhizobacteria Isolated from Natural Seleniferous Soils

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