title: Phytochelatins play key roles for the difference in root arsenic accumulation of different Triticum aestivum cultivars in comparison with arsenate uptake kinetics and reduction.
abstract: In the previous studies, we have found that arsenic (As) accumulation in roots of bread wheat (Triticum aestivum L.) seedlings were significantly different among different wheat cultivars, and As(V) tolerant wheat cultivars have much higher capacities of root As accumulation. However, the reason for the difference remains unclear. Four wheat cultivars with high (MM45 and FM8) or low (QF1 and HM29) levels of arsenic (As) accumulation were selected to investigate the relationship between root As(V) uptake kinetics and root As accumulation. MM45 and HM29 were also used to examine As(V) reduction ability and non-protein thiol (cysteine [Cys], glutathione [GSH], and phytochelatins [PCs]) concentrations in wheat seedlings. MM45 had the lowest Michaelis-Menten constant (Km) and maximum influx rate (Vmax). No difference in the Kmvalues was found among the three other cultivars. No difference in As(V) reduction capacity was observed between MM45 and HM29. GSH and PC2were significantly induced by 10 μM As(V) in roots of wheat seedlings, particularly in MM45. Synthesis of GSH and PCs was completely suppressed in the presence of l-buthionine sulfoximine (BSO), a specific inhibitor of γ-glutamylcysteine synthetase. BSO markedly decreased the As tolerance of wheat seedlings and decreased the accumulation of As in roots, but increased As accumulation in shoots. No significant difference in As concentrations was found between MM45 and HM29 under the BSO treatment. GSH and PCs are the reason why As accumulation and As(V) tolerance differ in roots of different wheat cultivars.
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China; Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
authors.forename: Gao Ling
authors.initials: GL
authors.lastname: Shi
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China. Electronic address: loulq@njau.edu.cn.
authors.forename: Lai Qing
authors.initials: LQ
authors.lastname: Lou
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China.
authors.forename: Dao Jun
authors.initials: DJ
authors.lastname: Li
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China.
authors.forename: Zhu Bing
authors.initials: ZB
authors.lastname: Hu
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China. Electronic address: qscai@njau.edu.cn.
authors.forename: Qing Sheng
authors.initials: QS
authors.lastname: Cai
mesh_terms: D001149:Arsenates / Q000493:pharmacokinetics*; D001151:Arsenic / Q000493:pharmacokinetics*; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D003545:Cysteine / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007700:Kinetics; D010084:Oxidation-Reduction; D054811:Phytochelatins / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D018520:Plant Shoots / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism; D014908:Triticum / Q000378:metabolism*
chemical_list: D001149:Arsenates; D010940:Plant Proteins; D019328:Buthionine Sulfoximine; D054811:Phytochelatins; D005978:Glutathione; D003545:Cysteine; D001151:Arsenic
keywords: Arsenate reduction; Arsenic; Non-protein thiols; Triticum aestivum; Uptake kinetics