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Ethylene is involved in root phosphorus remobilization in rice (Oryza sativa) by regulating cell-wall pectin and enhancing phosphate translocation to shoots
- Zhu, Xiao Fang, Zhu, Chun Quan, Zhao, Xu Sheng, Zheng, Shao Jian, Shen, Ren Fang
- Annals of botany 2016 v.118 no.4 pp. 645-653
- 1-aminocyclopropane-1-carboxylic acid, Oryza sativa, cell walls, cultivars, ethylene, ethylene production, genes, nutrient solutions, pectins, phosphates, phosphorus, rice, roots, shoots, solubilization
- Background and aims Plants are able to grow under phosphorus (P)-deficient conditions by coordinating Pi acquisition, translocation from roots to shoots and remobilization within the plant. Previous reports have demonstrated that cell-wall pectin contributes greatly to rice cell-wall Pi re-utilization under P-deficient conditions, but whether other factors such as ethylene also affect the pectin-remobilizing capacity remains unclear. Methods Two rice cultivars, ‘Nipponbare’ (Nip) and ‘Kasalath’ (Kas) were cultured in the +P (complete nutrient solution), −P (withdrawing P from the complete nutrient solution), +P+ACC (1-amino-cyclopropane-1-carboxylic acid, an ethylene precursor, adding 1 μm ACC to the complete nutrient solution) and −P+ACC (adding 1 μm ACC to −P nutrient solution) nutrient solutions for 7 d. Key Results After 7 d −P treatment, there was clearly more soluble P in Nip root and shoot, accompanied by additional production of ethylene in Nip root compared with Kas. Under P-deficient conditions, addition of ACC significantly increased the cell-wall pectin content and decreased cell-wall retained P, and thus more soluble P was released to the root and translocated to the shoot, which was mediated by the expression of the P deficiency-responsive gene OsPT2, which also strongly induced by ACC treatment under both P-sufficient and P-deficient conditions. Conclusions Ethylene positively regulates pectin content and expression of OsPT2, which ultimately makes more P available by facilitating the solubilization of P fixed in the cell wall and its translocation to the shoot.