Quercetin Rapidly Potentiates the Biogenesis of Nanoselenium by Orchestrating the Electron Transport Rate and Key Signaling Pathways in Chlorella Vulgaris

Selenium accumulation in ecosystems beyond the limit is highly toxic, thereby provoking the necessity to generate green approaches to convert the toxic selenite to non-toxic and beneficial selenium nanoparticles. Photosynthetic microalgae are emerging as smart green cell factories for biochemical production and pollutant removal. However, there are few reports available on potentiating the algal systems to synthesize SeNPs, particularly, molecular mechanisms underpinning this biotransformation are yet to be dissected. We potentiated Chlorella vulgaris by fortifying quercetin in order to improve the biotransformation of SeNPs. Quercetin supplement remarkably enhanced the SeNPs formation within 72 hrs from 50 μg/L Na2SeO3 by facilitating the intracellular electron transfer flow, with 100% conversion of inorganic selenite to SeNPs. The morphological analysis of the SeNPs with diameters ranging from 100 nm to 200 nm confirmed the system's ability to synthesize SeNPs. Generated SeNPs could dramatically improve physiological features of microalgae. Transcriptomic analysis showed the quercetin provision orchestrated the expression of key metabolic candidates involved in the Se-assimilation pathway, membrane transporters and ROS signal transduction. The present data collectively demonstrate the potential green and eco-friendly approach to reducing the toxic Se into SeNPs and elucidated the mechanistic role underpinning the quercetin-mediated green SeNP biogenesis