Functional analysis of the novel mycorrhiza-specific phosphate transporter AsPT1 and PHT1 family from Astragalus sinicus during the arbuscular mycorrhizal symbiosis.
Functional analysis of the novel mycorrhiza-specific phosphate transporter AsPT1 and PHT1 family from Astragalus sinicus during the arbuscular mycorrhizal symbiosis.
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DOI：
10.1111/nph.12188
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发表时间：
2013-05
期刊：
影响因子：
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通讯作者：
Xianan Xie;Wu Huang;Fengchuan Liu;Nianwu Tang;Yi Liu;Hui-Rung Lin;Bin Zhao
中科院分区：
文献类型：
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作者：
Xianan Xie;Wu Huang;Fengchuan Liu;Nianwu Tang;Yi Liu;Hui-Rung Lin;Bin Zhao
丛枝菌根对植物吸收无机磷有重要作用。在AM共生过程中参与豆科植物Pht1家族转运蛋白调控和功能的基因网络尚未完全了解。为了表征菌根紫云英中Pht1转运蛋白的六个不同成员，我们结合细胞定位，在酵母中的异源功能表达与表达/亚细胞定位研究和植物中的反向遗传学方法。Pht1; 1和Pht1; 4个沉默株系的产生揭示了新发现的依赖于另一个磷酸盐转运蛋白AsPT 1除了AsPT 4的AM共生的作用。这些Pht1转运蛋白在Pi饥饿的菌根根中被触发。AsPT1和AsPT4定位于皮层含丛枝细胞。启动子序列的分析揭示了保守的基序在AsPT1和AsPT4。AsPT1过表达显示较高的mycorrhization水平比对照分析的参数，包括丰富的丛枝。相反，通过RNA干扰敲低AsPT1导致与AsPT4沉默系相同的退化或死亡丛枝表型。AsPT4而非AsPT1是共生体摄取Pi所必需的。这些结果表明，AsPT1和AsPT4，所需的AM共生，最重要的是，AsPT1可能作为一个新的共生运输AM的发展。
Arbuscular mycorrhizas contribute significantly to inorganic phosphate (Pi) uptake in plants. Gene networks involved in the regulation and function of the Pht1 family transporters in legume species during AM symbiosis are not fully understood. In order to characterize the six distinct members of Pht1 transporters in mycorrhizal Astragalus sinicus, we combined cellular localization, heterologous functional expression in yeast with expression/subcellular localization studies and reverse genetics approaches in planta. Pht1;1 and Pht1;4 silenced lines were generated to uncover the role of the newly discovered dependence of the AM symbiosis on another phosphate transporter AsPT1 besides AsPT4. These Pht1 transporters are triggered in Pi-starved mycorrhizal roots. AsPT1 and AsPT4 were localized in arbuscule-containing cells of the cortex. The analysis of promoter sequences revealed conserved motifs in both AsPT1 and AsPT4. AsPT1 overexpression showed higher mycorrhization levels than controls for parameters analysed, including abundance of arbuscules. By contrast, knockdown of AsPT1 by RNA interference led to degenerating or dead arbuscule phenotypes identical to that of AsPT4 silencing lines. AsPT4 but not AsPT1 is required for symbiotic Pi uptake. These results suggest that both, AsPT1 and AsPT4, are required for the AM symbiosis, most importantly, AsPT1 may serve as a novel symbiotic transporter for AM development.