Modulation of oxidative stress machinery determines the contrasting ability of cyanobacteria to adapt to Se(VI) or Se(IV).

Autor: Banerjee M; Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai-400085, India; Homi Bhabha National Institute, Mumbai-400094, India. Electronic address: manishab@barc.gov.in., Kalwani P; Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai-400085, India., Chakravarty D; Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai-400085, India., Pathak P; Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai-400085, India; Homi Bhabha National Institute, Mumbai-400094, India., Agarwal R; Applied Genomics Section, Bhabha Atomic Research Centre, Mumbai-400085, India; Homi Bhabha National Institute, Mumbai-400094, India., Ballal A; Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai-400085, India; Homi Bhabha National Institute, Mumbai-400094, India. Electronic address: aballal@barc.gov.in.
Jazyk: angličtina
Zdroj: Plant physiology and biochemistry : PPB [Plant Physiol Biochem] 2024 Jun; Vol. 211, pp. 108673. Date of Electronic Publication: 2024 May 01.
DOI: 10.1016/j.plaphy.2024.108673
Abstrakt: Excess of selenium (Se) in aquatic ecosystems has necessitated thorough investigations into the effects/consequences of this metalloid on the autochthonous organisms exposed to it. The molecular details of Se-mediated adaptive response remain unknown in cyanobacteria. This study aims to uncover the molecular mechanisms driving the divergent physiological responses of cyanobacteria on exposure to selenate [Se(VI)] or selenite [Se(IV)], the two major water-soluble oxyanions of Se. The cyanobacterium, Anabaena PCC 7120, withstood 0.4 mM of Se(VI), whereas even 0.1 mM of Se(IV) was detrimental, affecting photosynthesis and enhancing endogenous ROS. Surprisingly, Anabaena pre-treated with Se(VI), but not Se(IV), showed increased tolerance to oxidative stress mediated by H 2 O 2 /methyl viologen. RNA-Seq analysis showed Se(VI) to elevate transcription of genes encoding anti-oxidant proteins and Fe-S cluster biogenesis, whereas the photosynthesis-associated genes, which were mainly downregulated by Se(IV), remained unaffected. Specifically, the content of typical 2-Cys-Prx (Alr4641), a redox-maintaining protein in Anabaena, was elevated with Se(VI). In comparison to the wild-type, the Anabaena strain over-expressing the Alr4641 protein (An4641+) showed enhanced tolerance to Se(VI) stress, whereas the corresponding knockdown-strain (KD4641) was sensitive to this stressor. Incidentally, among these strains, only An4641+ was better protected from the ROS-mediated damage caused by high dose of Se(VI). These results suggest that altering the content of the antioxidant protein 2-Cys-Prx, could be a potential strategy for modulating resistance to selenate. Thus, involvement of oxidative stress machinery appears to be the major determinant, responsible for the contrasting physiological differences observed in response to selenate/selenite in cyanobacteria.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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Databáze: MEDLINE
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