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Polyphosphate accumulation is driven by transcriptome alterations that lead to near‐synchronous and near‐equivalent uptake of inorganic cations in an arbuscular mycorrhizal fungus
Author(s) -
Kikuchi Yusuke,
Hijikata Nowaki,
Yokoyama Kaede,
Ohtomo Ryo,
Handa Yoshihiro,
Kawaguchi Masayoshi,
Saito Katsuharu,
Ezawa Tatsuhiro
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12937
Subject(s) - polyphosphate , phosphate , transcriptome , phosphorus , biochemistry , biology , fungus , nutrient , intracellular , microbiology and biotechnology , gene expression , chemistry , gene , botany , ecology , organic chemistry
Summary Arbuscular mycorrhizal ( AM ) fungi accumulate a massive amount of phosphate as polyphosphate to deliver to the host, but the underlying physiological and molecular mechanisms have yet to be elucidated. In the present study, the dynamics of cationic components during polyphosphate accumulation were investigated in conjunction with transcriptome analysis. R hizophagus sp. HR 1 was grown with L otus japonicus under phosphorus‐deficient conditions, and extraradical mycelia were harvested after phosphate application at prescribed intervals. Levels of polyphosphate, inorganic cations and amino acids were measured, and RNA ‐Seq was performed on the Illumina platform. Phosphate application triggered not only polyphosphate accumulation but also near‐synchronous and near‐equivalent uptake of N a + , K + , C a 2+ and M g 2+ , whereas no distinct changes in the levels of amino acids were observed. During polyphosphate accumulation, the genes responsible for mineral uptake, phosphate and nitrogen metabolism and the maintenance of cellular homeostasis were up‐regulated. The results suggest that inorganic cations play a major role in neutralizing the negative charge of polyphosphate, and these processes are achieved by the orchestrated regulation of gene expression. Our findings provide, for the first time, a global picture of the cellular response to increased phosphate availability, which is the initial process of nutrient delivery in the associations.