title: Decreasing methylation of pectin caused by nitric oxide leads to higher aluminium binding in cell walls and greater aluminium sensitivity of wheat roots.
abstract: Nitric oxide (NO) is an important bioactive molecule involved in cell wall metabolism, which has been recognized as a major target of aluminium (Al) toxicity. We have investigated the effects of Al-induced NO production on cell wall composition and the subsequent Al-binding capacity in roots of an Al-sensitive cultivar of wheat (Triticum aestivum L. cv. Yang-5). We found that Al exposure induced NO accumulation in the root tips. Eliminating NO production with an NO scavenger (cPTIO) significantly alleviated the Al-induced inhibition of root growth and thus reduced Al accumulation. Elimination of NO, however, did not significantly affect malate efflux or rhizosphere pH changes under Al exposure. Levels of cell wall polysaccharides (pectin, hemicelluloses 1, and hemicelluloses 2) and pectin methylesterase activity, as well as pectin demethylation in the root apex, signiﬁcantly increased under Al treatment. Exogenous cPTIO application significantly decreased pectin methylesterase activity and increased the degree of methylation of pectin in the root cell wall, thus decreasing the Al-binding capacity of pectin. These results suggest that the Al-induced enhanced production of NO decreases cell wall pectin methylation, thus increasing the Al-binding capacity of pectin and negatively regulating Al tolerance in wheat.
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecological Health, College of Natural Resource & Environmental Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Chengliang
authors.initials: C
authors.lastname: Sun
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecological Health, College of Natural Resource & Environmental Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Lu
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecological Health, College of Natural Resource & Environmental Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yu
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecological Health, College of Natural Resource & Environmental Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Liu
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecological Health, College of Natural Resource & Environmental Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Hu
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecological Health, College of Natural Resource & Environmental Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Yiquan
authors.initials: Y
authors.lastname: Ye
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecological Health, College of Natural Resource & Environmental Sciences, Zhejiang University, Hangzhou 310058, PR China Key Laboratory of Subtropical Soil Science and Plant Nutrition of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Chongwei
authors.initials: C
authors.lastname: Jin
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecological Health, College of Natural Resource & Environmental Sciences, Zhejiang University, Hangzhou 310058, PR China Key Laboratory of Subtropical Soil Science and Plant Nutrition of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, PR China xylin@zju.edu.cn.
authors.forename: Xianyong
authors.initials: X
authors.lastname: Lin
mesh_terms: D000535:Aluminum / Q000378:metabolism*; D001565:Benzoates / Q000494:pharmacology; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism*; D005070:Evans Blue / Q000378:metabolism; D016166:Free Radical Scavengers / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000494:pharmacology; D008293:Malates / Q000378:metabolism; D008745:Methylation / Q000187:drug effects; D008954:Models, Biological; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism*; D010368:Pectins / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D014908:Triticum / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D014574:Uronic Acids / Q000378:metabolism
chemical_list: D001565:Benzoates; D016166:Free Radical Scavengers; D007093:Imidazoles; D008293:Malates; D014574:Uronic Acids; C079393:1,3-dihydroxy-4,4,5,5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole; D009569:Nitric Oxide; D005070:Evans Blue; C030298:malic acid; D010368:Pectins; D000535:Aluminum; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase
keywords: Aluminium; cell wall; nitric oxide; pectin; pectin methylation; pectin methylesterase.