title: The interaction of salicylic acid and Ca(2+) alleviates aluminum toxicity in soybean (Glycine max L.).
abstract: Both calcium ion (Ca(2+)) and salicylic acid (SA) influence various stress responses in plants. In acidic soils, aluminum (Al) toxicity adversely affects crop yield. In this study, we determined the influences of Ca(2+) and SA on root elongation, Al accumulation, and citrate secretion in soybean plant. We also investigated the activity of antioxidative enzymes in Al-exposed soybean roots. Root elongation was severally inhibited when the roots were exposed to 30 μM Al. The Al-induced inhibition of root elongation was ameliorated by Ca(2+) and SA but aggravated by Ca(2+) channel inhibitor (VP), CaM antagonists (TFP), Ca(2+) chelator (EGTA), and SA biosynthesis inhibitor (PAC). Furthermore, 1.0 mM CaCl2 and 10 μM SA reduced the accumulation of Al in roots, but their inhibitors stimulated the accumulation of Al in roots. Citrate secretion from these roots increased with the addition of either 1.0 mM CaCl2 or 10 μM SA but did not increase significantly when treated with higher Ca(2+) concentration. Enzymatic analysis showed that Ca(2+) and SA stimulated the activities of superoxidase (SOD), peroxidase (POD), and ascorbate peroxidase (APX) in Al-treated roots. In addition, SA restored the inhibition of Ca(2+) inhibitors on root elongation and Al content. Thus, both Ca(2+) and SA contribute to Al tolerance in soybean. Furthermore, Ca(2+) supplements rapidly increased Al-induced accumulation of free-SA or conjugated SA (SAG), while Ca(2+) inhibitors delayed the accumulation of SA for more than 8 h. Within 4 h of treatment, SA increased cytosolic Ca(2+) concentration in Al-treated roots, and upregulated the expression of four genes that possibly encode calmodulin-like (CML) proteins. These findings indicate that SA is involved in Ca(2+)-mediated signal transduction pathways in Al tolerance.
authors.affiliation: College of Plant Science, Jilin University, Changchun 130062, PR China; Laboratory of Soil and Plant Molecular Genetics, Jilin University, Changchun 130062, PR China.
authors.forename: Tu
authors.initials: T
authors.lastname: Lan
authors.affiliation: College of Plant Science, Jilin University, Changchun 130062, PR China; Laboratory of Soil and Plant Molecular Genetics, Jilin University, Changchun 130062, PR China.
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: You
authors.affiliation: College of Plant Science, Jilin University, Changchun 130062, PR China; Laboratory of Soil and Plant Molecular Genetics, Jilin University, Changchun 130062, PR China.
authors.forename: Lingnan
authors.initials: L
authors.lastname: Kong
authors.affiliation: College of Plant Science, Jilin University, Changchun 130062, PR China; Laboratory of Soil and Plant Molecular Genetics, Jilin University, Changchun 130062, PR China.
authors.forename: Miao
authors.initials: M
authors.lastname: Yu
authors.affiliation: College of Plant Science, Jilin University, Changchun 130062, PR China; Laboratory of Soil and Plant Molecular Genetics, Jilin University, Changchun 130062, PR China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Liu
authors.affiliation: College of Plant Science, Jilin University, Changchun 130062, PR China; Laboratory of Soil and Plant Molecular Genetics, Jilin University, Changchun 130062, PR China. Electronic address: zmyang@jlu.edu.cn.
authors.forename: Zhenming
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D019343:Citric Acid / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction; D013025:Glycine max / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*
chemical_list: D000975:Antioxidants; D010940:Plant Proteins; D019343:Citric Acid; D000535:Aluminum; D010088:Oxidoreductases; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D009195:Peroxidase; D020156:Salicylic Acid; D002118:Calcium
keywords: Aluminum; Antioxidative enzyme; Calmodulin-like protein; Salicylic acid; Signal transduction