title: Silicon ameliorates chromium toxicity through phytochelatin-mediated vacuolar sequestration in the roots of Oryza sativa (L.).
abstract: High chromium (Cr) in rice causes reduced yield and health hazards. This work investigates how Si alleviates Cr toxicity in rice. Addition of Si under Cr stress restored the growth parameters, total protein content, and membrane stability along with reduced Cr content in shoots, confirming that Si plays critical roles in Cr detoxification in rice. However, Si supplementation under Cr stress caused no significant changes in root Cr content but decreased shoot Cr concentrations compared with Cr-stressed plants, indicating that alleviation of Cr toxicity might be associated with Cr sequestration in roots. Further, concentration of Fe and expression of Fe transporter (OsIRT1) showed no significant changes due to Si supplementation under Cr stress, implying that Fe regulation is not involved with Si-mediated mitigation of Cr toxicity in rice. Further, phytochelatin accumulation and OsPCS1 (phytochelatin synthase) transcripts strongly induced due to the dual treatment of Si and Cr compared with Cr-stressed plants, suggesting that phytochelatin might bind to Cr, which leads to vacuolar sequestration in roots. Furthermore, increased glutathione reductase activity in roots implies that active involvement of ROS scavenging partially ameliorates Cr toxicity in rice plants. The study illustrates first evidences on the effect of Si alleviating Cr toxicity in rice plants.
authors.affiliation: a Biotechnology and Genetic Engineering, Islamic University , Kustia , Bangladesh.
authors.forename: A K M Nazmul
authors.initials: AK
authors.lastname: Huda
authors.affiliation: a Biotechnology and Genetic Engineering, Islamic University , Kustia , Bangladesh.
authors.forename: Mohammad Anwarul
authors.initials: MA
authors.lastname: Haque
authors.affiliation: b Department of Botany , University of Rajshahi , Rajshahi , Bangladesh.
authors.forename: Reshma
authors.initials: R
authors.lastname: Zaman
authors.affiliation: c Department of Genetic Engineering and Biotechnology , Jessore University of Science and Technology , Jessore , Bangladesh.
authors.forename: A M
authors.initials: AM
authors.lastname: Swaraz
authors.affiliation: b Department of Botany , University of Rajshahi , Rajshahi , Bangladesh.
authors.forename: Ahmad Humayan
authors.initials: AH
authors.lastname: Kabir
mesh_terms: D001673:Biodegradation, Environmental; D002857:Chromium / Q000378:metabolism*; D012275:Oryza / Q000254:growth & development / Q000378:metabolism*; D054811:Phytochelatins / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D012825:Silicon / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D012989:Soil Pollutants; D002857:Chromium; D054811:Phytochelatins; D012825:Silicon
keywords: Cr toxicity; phytochelatin; sequestration; silicon; vacuolar