Stimulation of root acid phosphatase by phosphorus deficiency is regulated by ethylene in Medicago falcata

• Published in: Environmental and experimental botany Vol. 71; no. 1; pp. 114 - 120
• Main Authors: Li, Yan-Su, Gao, Yan, Tian, Qiu-Ying, Shi, Feng-Ling, Li, Ling-Hao, Zhang, Wen-Hao
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2011; Oxford; New York, NY: Elsevier Science; Elsevier
• Subjects: 1-aminocyclopropane-1-carboxylic acid; acid phosphatase; Acid phosphatase activity; aminoethoxyvinylglycine; Biological and medical sciences; cobalt; Ethylene; ethylene production; forage legumes; Fundamental and applied biological sciences. Psychology; gene expression; gene expression regulation; Medicago; Medicago falcata; Medicago sativa subsp. falcata; nutrient availability; nutrient deficiencies; nutrient solutions; Organic phosphorus; Phosphate transporters; phosphates; phosphorus; Phosphorus deficiency; plant nutrition; protein secretion; root exudates; roots; shoots; transport proteins; Organic phosphorus; Phosphate transporters; Medicago falcata; Acid phosphatase activity; Phosphorus deficiency; Ethylene; Enzyme; Deficiency; Phosphate transporter; Plant ecology; Phosphoric monoester hydrolases; Phosphorus; Stimulation; Esterases; Leguminosae; Enzymatic activity; Dicotyledones; Angiospermae; Botany; Hydrolases; Spermatophyta; Fodder crop; Acid phosphatase
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2010.11.007

▶ Phosphorus (P) deficiency induced evolution of ethylene from roots. ▶ The evolved ethylene stimulated root acid phosphatase activity and up-regulated gene encoding the acid phosphatase and high-affinity phosphate transporters. ▶ The enhanced acid phosphatase activity facilitated hydrolysis of organic P in rhizosphere, leading to greater acquisition of P under P-deficient conditions. Plants have developed numerous strategies to cope with phosphorus (P) deficiency resulting from low availability in soils. Evolution of ethylene and up-regulation of root secreted acid phosphatase activity are common for plants in response to P deficiency. To determine the role of ethylene in response of plants to P deficiency, we investigated the effects of ethylene precursor (1-amino cyclopropane-1-carboxylic acid, ACC) and ethylene synthesis antagonists (aminoethoxyvinylglycine AVG, cobalt, Co2+) on P concentrations in roots and shoots of Medicago falcata seedlings grown in P-sufficient (500μM H2PO4−) and P-deficient (5μM H2PO4−) solution. After transferring M. falcata seedlings from P-sufficient to P-deficient solution for 2 days, root P concentration was significantly reduced. The reduction in root P concentration was reversed by AVG and Co2+, and a similar reduction in root P concentration of seedlings exposed to P-sufficient solution was observed by ACC. Expression of high-affinity phosphate transporters (MfPT1, MfPT5) was enhanced by P-deficiency and this process was reversed by AVG and Co2+. There was a marked increase in activity of root acid phosphatase (APase) and expression of gene encoding APase (MfPAP1) under P-deficient conditions, and the increase in APAse activity and expression of MfPAP1 was inhibited by AVG and Co2+. APase activity and expression of MfPAP1 expression in seedlings grown in P-sufficient solution were enhanced by ACC. Root and shoot P concentrations were increased when organic phosphorus was added to the P-deficient solution, and the increase in P concentration was significantly inhibited by AVG and Co2+. These results indicate that ethylene plays an important role in modulation of P acquisition by possibly mobilizing organic P via up-regulating root APase activity and high-affinity phosphate transporters.