Simultaneous in situ detection of alkaline phosphatase activity and polyphosphate in arbuscules within arbuscular mycorrhizal roots
Simultaneous in situ detection of alkaline phosphatase activity and polyphosphate in arbuscules within arbuscular mycorrhizal roots
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DOI：
10.1071/fp06326
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发表时间：
2007-01-01
影响因子：
3
通讯作者：
Aono, Toshihiro
中科院分区：
文献类型：
--
作者：
Funamoto, Rintaro;Saito, Katsuharu;Aono, Toshihiro
尽管最近的研究表明宿主植物通过菌根特异性转运蛋白吸收丛枝周围的无机磷（Pi），但对丛枝菌根真菌的无机磷（Pi）代谢尚不清楚。因此，我们分析了多磷酸盐（polyP）和碱性磷酸酶（ALP）活性在丛枝中的定位，这可能是Pi代谢的指标。我们建立了一种检测聚磷酸酶和碱性磷酸酶活性的双标记方法，即先用荧光探针4 '，6-二脒基-2-苯基吲哚二盐酸盐（DAPI）标记，再用酶标荧光（ELF 97）标记。双标记方法使得在菌根根中同时观察polyP和ALP活性信号成为可能。双标记法显示，ALP活性主要在成熟的丛枝中观察到，而polyP很少观察到。AM真菌ALP基因的表达在AM诱导的Pi转运蛋白基因敲低的植株中受到抑制，并且在表现出低ALP活性的丛枝中存在大量的polyP。这些拓扑观察表明，可能有一些聚磷代谢和ALP活性之间的关系，在丛枝，这些是，在一定程度上，由植物通过AM诱导的Pi-转运蛋白的Pi吸收控制。
Inorganic phosphate (Pi) metabolism in arbuscules of arbuscular mycorrhizal (AM) fungi is not well understood, although recent research has revealed that host plants absorb Pi around arbuscules with mycorrhiza-specific transporters. Therefore, we analysed the localisation of polyphosphate (polyP) and alkaline phosphatase (ALP) activity in arbuscules, which could be indicators of Pi metabolism. We developed a dual-labelling method for polyP and ALP activity, i.e. first labelling with fluorescent probes 4',6-diamidino-2-phenyl-indole dihydrochloride (DAPI) and then labelling with enzyme-labelled fluorescence (ELF97). The dual-labelling method made it possible to observe polyP and ALP activity signals simultaneously in mycorrhizal roots. The dual-labelling method revealed that ALP activity was mainly observed in mature arbuscules where polyP was rarely observed. The expression of the AM fungal ALP gene was suppressed in the knockdown plants of an AM-inducible Pi-transporter, and there was much polyP in arbuscules that showed low ALP activity. These topological observations suggest that there may be some relationships between polyP metabolism and ALP activity in arbuscules, and that these are, in part, controlled by Pi uptake by plants via the AM-inducible Pi-transporter.