Release of acid phosphatase from extraradical hyphae of arbuscular mycorrhizal fungus Rhizophagus clarus
Release of acid phosphatase from extraradical hyphae of arbuscular mycorrhizal fungus Rhizophagus clarus
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DOI：
10.1080/00380768.2014.993298
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发表时间：
2015-01
影响因子：
2
通讯作者：
Takumi Sato;T. Ezawa;W. Cheng;K. Tawaraya
中科院分区：
文献类型：
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作者：
Takumi Sato;T. Ezawa;W. Cheng;K. Tawaraya
摘要 丛枝菌根 (AM) 真菌通过其根外菌丝增强植物从土壤中吸收有效磷 (P)。 AM 真菌增强磷吸收的机制是增加有效磷吸收的表面积。对于 AM 真菌对不可用磷的利用知之甚少。我们研究了 AM 真菌的根外菌丝是否释放酸性磷酸酶（ACP）。将灭菌的 Andosol 装入盆中，用孔径为 30 μm 的尼龙网将其分为菌根室和菌丝室。用 AM 真菌 Rhizophagus clarus (Nicolson & Schenck) Walker & Schüßler 接种或未接种 Allium fistulosum L. 的种子。将莫来石陶瓷管埋入各隔室的土壤中，收集土壤溶液。接种R. clarus的A. fistulosum L.和Linum usitatissimum L.分别在沙培养物和体外单细胞培养物中生长。未接种的A. fistulosum L在水培培养中生长以收集根分泌物。对土壤溶液、菌丝提取物、根提取物和根分泌物进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析。接种处理的地上部磷浓度、地上部磷含量和地上部干重均高于未接种处理。凝胶的活性染色显示，在接种处理的土壤溶液以及从沙培养和体外单生培养收集的菌丝提取物中观察到187 kDa的ACP活性，但在水培培养的非菌根植物的根分泌物中以及无论菌根状态如何的根提取物中都没有观察到ACP活性。这些结果提供了强有力的证据，证明土壤培养中土壤溶液中的相应活性源自红鲫鱼CK001。这些发现表明真菌将 ACP 从根外菌丝释放到菌丝圈中。
Abstract Arbuscular mycorrhizal (AM) fungi enhance plant uptake of available phosphorus (P) from soil through their extraradical hyphae. The mechanism underlying this P uptake enhanced by AM fungi is the increase in the surface area for absorption of available P. Little is known about utilization of unavailable P by AM fungi. We investigated whether extraradical hyphae of AM fungi release acid phosphatase (ACP). Sterilized Andosol was packed in pots that were separated into the mycorrhizal and hyphal compartments with a nylon net of 30-μm pore size. Seeds of Allium fistulosum L. were inoculated or uninoculated with the AM fungus Rhizophagus clarus (Nicolson & Schenck) Walker & Schüßler. Mullite ceramic tubes were buried in the soil of each compartment, and soil solution was collected. A. fistulosum L. and Linum usitatissimum L. inoculated with R. clarus were grown in sand culture and in vitro monoxenic culture, respectively. Uninoculated A. fistulosum L was grown in hydroponic culture to collect root exudate. The soil solution, hyphal extracts, root extract and root exudates were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Shoot P concentration, shoot P content and shoot dry weight were higher in the inoculated treatment than in the uninoculated treatment. Activity staining of the gel revealed that ACP activity at 187 kDa was observed in the soil solution in the inoculation treatment, and in the hyphal extract collected from sand culture and in vitro monoxenic culture, but neither in the root exudate of non-mycorrhizal plant grown in the hydroponic culture nor in the root extracts irrespective of mycorrhizal status. Those results provide strong evidence that the corresponding activity in the soil solutions in soil culture is of R. clarus CK001 origin. These findings suggest that the fungus releases ACP from extraradical hyphae into the hyphosphere.