Expression of Arabidopsis acyl‐CoA‐binding proteins AtACBP1 and AtACBP4 confers Pb(II) accumulation in Brassica juncea roots

• Published in: Plant, cell and environment cell and environment, 2015, Vol.38 (1), p.101-117
• Main Authors: DU, ZHI‐YAN, CHEN, MO‐XIAN, CHEN, QIN‐FANG, GU, JI‐DONG, CHYE, MEE‐LEN
• Format: Article
• Language: English
• Subjects: absorption; Accumulation; Arabidopsis - genetics; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; beta-glucuronidase; Biodegradation, Environmental; Biomass; Brassica juncea; Carrier Proteins - genetics; Carrier Proteins - metabolism; cytosol; gel electrophoresis; Gene Expression; Gene Expression Regulation, Plant; genes; Genes, Reporter; genetically modified organisms; GUS assays; Heavy metals; Hydrogen peroxide; Hydrogen Peroxide - pharmacology; Lead; Lead - metabolism; Lead - pharmacology; Lipid Peroxidation; Lipids; Mustard Plant - cytology; Mustard Plant - genetics; Mustard Plant - metabolism; Oxidative Stress; Pb(II) tracing; Peroxidation; Phytoremediation; Plant Roots - cytology; Plant Roots - genetics; Plant Roots - metabolism; Plant Shoots - cytology; Plant Shoots - genetics; Plant Shoots - metabolism; Plant tissues; Plants, Genetically Modified; proteins; reverse transcriptase polymerase chain reaction; root tips; Roots; Seedlings - cytology; Seedlings - genetics; Seedlings - metabolism; shoots; Spectral analysis; trichomes; vascular tissues
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.12382

In Arabidopsis thaliana, the expression of two genes encoding acyl‐CoA‐binding proteins (ACBPs) AtACBP1 and AtACBP4, were observed to be induced by lead [Pb(II)] in shoots and roots in qRT‐PCR analyses. Quantitative GUS (β‐glucuronidase) activity assays confirmed induction of AtACBP1pro::GUS by Pb(II). Electrophoretic mobility shift assays (EMSAs) revealed that Pas elements in the 5′‐flanking region of AtACBP1 were responsive to Pb(II) treatment. AtACBP1 and AtACBP4 were further compared in Pb(II) uptake using Brassica juncea, a potential candidate for phytoremediation given its rapid growth, large roots, high biomass and good capacity to accumulate heavy metals. Results from atomic absorption analyses on transgenic B. juncea expressing AtACBP1 or AtACBP4 indicated Pb(II) accumulation in roots. Subsequent Pb(II)‐tracing assays demonstrated Pb(II) accumulation in the cytosol of root tips and vascular tissues of transgenic B. juncea AtACBP1‐overexpressors (OXs) and AtACBP4‐OXs and transgenic Arabidopsis AtACBP1‐OXs. Transgenic Arabidopsis AtACBP1‐OXs sequestered Pb(II) in the trichomes and displayed tolerance to hydrogen peroxide (H₂O₂) treatment. In addition, AtACBP1 and AtACBP4 were H₂O₂‐induced in the roots of wild‐type Arabidopsis, while lipid hydroperoxide (LOOH) measurements of B. juncea AtACBP1‐OX and AtACBP4‐OX roots suggested that AtACBP1 and AtACBP4 can protect lipids against Pb(II)‐induced lipid peroxidation.