Jun Zhang1, Yan Xu1, Tingting Cao1, Jian Chen2, Barry P Rosen2, Fang-Jie Zhao3. 1. Jiangsu Provincial Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China. 2. Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA. 3. Fang-Jie Zhao, Jiangsu Provincial Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Abstract
BACKGROUND AND AIMS: Arsenic (As) is one of the most widespread environmental contaminants. The aim of our study was to test a novel bioremediation system based on the symbiosis between leguminous plant and genetically engineered rhizobia. METHODS: The arsenite [As(III)] S-adenosylmethionine methyltransferase gene (CrarsM) from the alga Chlamydomonas reinhardtii was inserted into the chromosome of Rhizobium leguminosarum bv. trifolii strain R3. The As methylation ability of the recombinant Rhizobium was tested under free living conditions and in symbiosis with red clover plants. Arsenic speciation was determined using high-performance liquid chromatography-inductively coupled plasma mass spectrometry. RESULTS: Under free-living conditions, CrarsM-recombinant R. leguminosarum gained the ability to methylate As(III) to methylated arsenicals, including methylarsenate [MAs(V)], dimethylarsenate [DMAs(V)] and trimethylarsine oxide [TMAs(V)O]. Red clover plants were inoculated with either control (non-recombinant) or CrarsM-recombinant R. leguminosarum and exposed to 5 or 10 μM arsenite. No methylated As species were detected in red clover plants inoculated with control R. leguminosarum. In contrast, all three methylated species were detected in both the nodules and the shoots when the recombinant Rhizobium established symbiosis with red clover, accounting for 74.7-75.1% and 29.1-42.4% of the total As in the two plant tissues, respectively. The recombinant symbiont also volatilized small amounts of As. CONCLUSIONS: The present study demonstrates that engineered rhizobia expressing an algal arsM gene can methylate and volatilize As, providing a proof of concept for potential future use of legume-rhizobia symbionts for As bioremediation.
BACKGROUND AND AIMS: Arsenic (As) is one of the most widespread environmental contaminants. The aim of our study was to test a novel bioremediation system based on the symbiosis between leguminous plant and genetically engineered rhizobia. METHODS: The arsenite [As(III)] S-adenosylmethionine methyltransferase gene (CrarsM) from the alga Chlamydomonas reinhardtii was inserted into the chromosome of Rhizobium leguminosarum bv. trifolii strain R3. The As methylation ability of the recombinant Rhizobium was tested under free living conditions and in symbiosis with red clover plants. Arsenic speciation was determined using high-performance liquid chromatography-inductively coupled plasma mass spectrometry. RESULTS: Under free-living conditions, CrarsM-recombinant R. leguminosarum gained the ability to methylate As(III) to methylated arsenicals, including methylarsenate [MAs(V)], dimethylarsenate [DMAs(V)] and trimethylarsine oxide [TMAs(V)O]. Red clover plants were inoculated with either control (non-recombinant) or CrarsM-recombinant R. leguminosarum and exposed to 5 or 10 μM arsenite. No methylated As species were detected in red clover plants inoculated with control R. leguminosarum. In contrast, all three methylated species were detected in both the nodules and the shoots when the recombinant Rhizobium established symbiosis with red clover, accounting for 74.7-75.1% and 29.1-42.4% of the total As in the two plant tissues, respectively. The recombinant symbiont also volatilized small amounts of As. CONCLUSIONS: The present study demonstrates that engineered rhizobia expressing an algal arsM gene can methylate and volatilize As, providing a proof of concept for potential future use of legume-rhizobia symbionts for As bioremediation.
Authors: Adrien Mestrot; Joerg Feldmann; Eva M Krupp; Mahmud S Hossain; Gabriela Roman-Ross; Andrew A Meharg Journal: Environ Sci Technol Date: 2011-02-01 Impact factor: 9.028
Authors: Y G Zhu; G X Sun; M Lei; M Teng; Y X Liu; N C Chen; L H Wang; A M Carey; C Deacon; A Raab; A A Meharg; P N Williams Journal: Environ Sci Technol Date: 2008-07-01 Impact factor: 9.028
Authors: Adrien Mestrot; M Kalle Uroic; Thomas Plantevin; Md Rafiqul Islam; Eva M Krupp; Jörg Feldmann; Andrew A Meharg Journal: Environ Sci Technol Date: 2009-11-01 Impact factor: 9.028
Authors: Ricardo A R Machado; Lisa Thönen; Carla C M Arce; Vanitha Theepan; Fausto Prada; Daniel Wüthrich; Christelle A M Robert; Evangelia Vogiatzaki; Yi-Ming Shi; Olivier P Schaeren; Matheus Notter; Rémy Bruggmann; Siegfried Hapfelmeier; Helge B Bode; Matthias Erb Journal: Nat Biotechnol Date: 2020-02-17 Impact factor: 54.908
Authors: Xuerong Di; Luke Beesley; Zulin Zhang; Suli Zhi; Yan Jia; Yongzhen Ding Journal: Int J Environ Res Public Health Date: 2019-12-10 Impact factor: 3.390