Polyphosphate accumulation is driven by transcriptome alterations that lead to near-synchronous and near-equivalent uptake of inorganic cations in an arbuscular mycorrhizal fungus
Polyphosphate accumulation is driven by transcriptome alterations that lead to near-synchronous and near-equivalent uptake of inorganic cations in an arbuscular mycorrhizal fungus
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DOI：
10.1111/nph.12937
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发表时间：
2014-11-01
期刊：
影响因子：
9.4
通讯作者：
Ezawa, Tatsuhiro
中科院分区：
文献类型：
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作者：
Kikuchi, Yusuke;Hijikata, Nowaki;Ezawa, Tatsuhiro
丛枝菌根（AM）真菌积累大量的磷酸盐作为多磷酸盐输送给宿主，但其生理和分子机制尚未阐明。在本研究中，阳离子组分的动态聚磷酸盐积累过程中结合转录组分析进行了研究。Rhizophagus sp. HR 1生长与莲在缺磷条件下，和根外菌丝收获后，磷酸盐的应用在规定的时间间隔。测量多磷酸盐、无机阳离子和氨基酸的水平，并在Illumina平台上进行RNA-Seq。施磷不仅引发了多磷酸盐的积累，但也近同步和近等效的Na+，K+，Ca 2+和Mg 2+的吸收，而没有观察到明显的氨基酸水平的变化。在多磷酸盐积累过程中，负责矿物质吸收、磷酸盐和氮代谢以及维持细胞内稳态的基因上调。结果表明，无机阳离子在中和多聚磷酸盐的负电荷中起着重要作用，这些过程是通过基因表达的协调调控来实现的。我们的研究结果首次提供了细胞对磷酸盐可用性增加的反应的全球图景，这是协会中营养物质输送的初始过程。
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.Rhizophagus sp. HR1 was grown with Lotus 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 Na+, K+, Ca2+ and Mg2+, 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.