Detoxification of polycyclic aromatic hydrocarbons (PAHs) in Arabidopsis thaliana involves a putative flavonol synthase

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants with cytotoxic, teratogenic and carcinogenic properties. Bioremediation studies with bacteria have led to the identification of dioxygenases (DOXs) in the first step to degrade these recalcitrant compounds. In this study, we characterized the role of the Arabidopsis thaliana AT5G05600, a putative DOX of the flavonol synthase family, in the transformation of PAHs. Phenotypic analysis of loss-of-function mutant lines showed that these plant lines were less sensitive to the toxic effects of phenanthrene, suggesting possible roles of this gene in PAH degradation in vivo. Interestingly, these mutant lines showed less accumulation of H2O2 after PAH exposure. Transgenic lines over-expressing At5g05600 showed a hypersensitive response and more oxidative stress after phenanthrene treatments. Moreover, fluorescence spectra results of biochemical assays with the recombinant His-tagged protein AT5G05600 detected chemical modifications of phenanthrene. Taken together, these results support the hypothesis that AT5G05600 is involved in the catabolism of PAHs and the accumulation of toxic intermediates during PAH biotransformation in plants. This research represents the first step in the design of transgenic plants with the potential to degrade PAHs, leading to the development of vigorous plant varieties that can reduce the levels of these pollutants in the environment.

MtBZR1 Plays an Important Role in Nodule Development in Medicago truncatula

“…In the KEGG analysis, the MtFLSs were downregulated in mtbzr1-1 . Their homolog in A. thaliana , At5g05600 , functions as a flavonol synthase and a 2-oxoglutarate/Fe (II)-dependent oxygenase that hydroxylates jasmonic acid (JA) [23]. Consist with this, we found that genes involved in linoleic acid metabolism (ko00591) were enriched with DEGs.…”

“…Consist with this, we found that genes involved in linoleic acid metabolism (ko00591) were enriched with DEGs. Linoleic acids are precursors for JA, which inhibits the calcium spiking induced by Nod factors [23,24]. As an important transcription factor in BR signaling, MtBZR1 might function in hormone cross-talk in nodule development.…”

Assessment of oxidative stress response genes in Avicennia marina exposed to oil contamination – Polyphenol oxidase (PPOA) as a biomarker

“…Coordinated changes in expression levels of NAP2 and GSTU25 in response to oil contamination may be related to their sequential role in the PAHs detoxification process. As the first step of detoxification, members of the cytochrome P450 family catalyze the oxidation of potentially toxic compounds, which are subsequently conjugated to a hydrophilic molecule, such as glucose, glutathione or glucuronide [ 50 , 51 ]. This conjugation step makes the potentially toxic compounds more hydrophilic and prevents the newly formed compounds from crossing membranes by diffusion.…”

Plant-bacteria synergism: An innovative approach for the remediation of crude oil-contaminated soils

“…This beneficial association relies on the fact that bacteria increase the bioavailability and degradation of organic pollutants, in turn, plants provide residency and food to the bacteria (Muratova et al, 2003;Weyens et al, 2009).Despite the fact that rhizoremediation happens naturally, but through deliberate manipulation (inoculating the soil with contaminant degrading and/or PGP bacteria) in rhizosphere it can be enhanced (Hernández-Vega et al, 2017;Vergani et al, 2017).…”