title: Silicon-mediated changes in polyamines participate in silicon-induced salt tolerance in Sorghum bicolor L.
abstract: Silicon (Si) is generally considered a beneficial element for the growth of higher plants, especially under stress conditions, but the mechanisms remain unclear. Here, we tested the hypothesis that Si improves salt tolerance through mediating important metabolism processes rather than acting as a mere mechanical barrier. Seedlings of sorghum (Sorghum bicolor L.) growing in hydroponic culture were treated with NaCl (100 mm) combined with or without Si (0.83 mm). The result showed that supplemental Si enhanced sorghum salt tolerance by decreasing Na(+) accumulation. Simultaneously, polyamine (PA) levels were increased and ethylene precursor (1-aminocyclopropane-1-carboxylic acid: ACC) concentrations were decreased. Several key PA synthesis genes were up-regulated by Si under salt stress. To further confirm the role of PA in Si-mediated salt tolerance, seedlings were exposed to spermidine (Spd) or a PA synthesis inhibitor (dicyclohexylammonium sulphate, DCHA) combined with salt and Si. Exogenous Spd showed similar effects as Si under salt stress whereas exogenous DCHA eliminated Si-enhanced salt tolerance and the beneficial effect of Si in decreasing Na(+) accumulation. These results indicate that PAs and ACC are involved in Si-induced salt tolerance in sorghum and provide evidence that Si plays an active role in mediating salt tolerance.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, 712100, China.|Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi, 712100, China.|Faculty of Agriculture, Tottori University, Koyama Minami 4-101, Tottori, 680-8533, Japan.
authors.forename: Lina
authors.initials: L
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, 712100, China.|Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi, 712100, China.
authors.forename: Shiwen
authors.initials: S
authors.lastname: Wang
authors.affiliation: Faculty of Agriculture, Tottori University, Koyama Minami 4-101, Tottori, 680-8533, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: NARO Agricultural Research Center, Kannondai 3-1-1, Tsukuba, 305-8666, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Fujihara
authors.affiliation: Faculty of Agriculture, Tottori University, Koyama Minami 4-101, Tottori, 680-8533, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Itai
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, 712100, China.|Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi, 712100, China.
authors.forename: Xiping
authors.initials: X
authors.lastname: Den
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, 712100, China.|Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi, 712100, China.
authors.forename: Suiqi
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000598:Amino Acids, Cyclic / Q000378:metabolism; D001120:Arginine / Q000378:metabolism; D001596:Benzylamines / Q000494:pharmacology; D018533:Biomass; D053898:Biosynthetic Pathways / Q000187:drug effects / Q000235:genetics; D002734:Chlorophyll / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D007477:Ions; D008715:Methionine / Q000378:metabolism; D063245:Plant Development / Q000187:drug effects / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D055049:Salt Tolerance / Q000187:drug effects* / Q000235:genetics; D012825:Silicon / Q000494:pharmacology*; D045868:Sorghum / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013095:Spermidine / Q000494:pharmacology
chemical_list: C552935:2-(2-((2-hydroxybenzyl)amino)ethylamino)-2-(2-hydroxyphenyl)acetic acid; D000598:Amino Acids, Cyclic; D001596:Benzylamines; D007477:Ions; D011073:Polyamines; D002734:Chlorophyll; C023863:1-aminocyclopropane-1-carboxylic acid; D001120:Arginine; D008715:Methionine; D005998:Glycine; D013095:Spermidine; D012825:Silicon
keywords: 1-aminocyclopropane-1-carboxylic acid (ACC); arginine; ethylene; ion concentration; salt stress; spermidine