Secretion of acid phosphatase from extraradical hyphae of the arbuscular mycorrhizal fungus Rhizophagus clarus is regulated in response to phosphate availability
Secretion of acid phosphatase from extraradical hyphae of the arbuscular mycorrhizal fungus Rhizophagus clarus is regulated in response to phosphate availability
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DOI：
10.1007/s00572-019-00923-0
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发表时间：
2019-11
期刊：
影响因子：
3.9
通讯作者：
Takumi Sato;Shihomi Hachiya;Nozomi Inamura;T. Ezawa;W. Cheng;K. Tawaraya
中科院分区：
文献类型：
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作者：
Takumi Sato;Shihomi Hachiya;Nozomi Inamura;T. Ezawa;W. Cheng;K. Tawaraya
丛枝菌根（AM）真菌增加植物对磷的吸收。在大多数农业土壤中，有机磷占全磷的30-80%。一些植物可以通过分泌酸性磷酸酶（ACP）来利用有机磷，特别是在低磷条件下。虽然已报道AM真菌根外菌丝分泌ACP，但影响ACP分泌的具体因素尚不清楚。本研究的目的是调查是否分泌ACP从根外菌丝诱导低磷条件。首先，葱的标本要么接种AM真菌Rhizophagus clarus菌株CK 001，要么保持未接种状态，并使用两室盆在含有0.5 g P2 O 5 kg − 1土壤或不施磷肥的土壤中生长。播种后45天，使用莫来石陶瓷管收集土壤溶液。用对硝基苯磷酸盐分析土壤溶液中ACP活性。第二，Ri T-DNA转化的根（即，在离体培养条件下，用两室培养皿，在两种磷水平（3和30 μM P）的固体基本培养基上培养了接种了明串珠菌的亚麻毛状根。收集菌丝分泌物、根外菌丝和毛状根并分析ACP活性。不施磷肥的菌丝室土壤溶液中ACP活性高于施磷肥。AM定殖率也高于不施磷肥。在离体二室培养中，3 μM处理的菌丝分泌物和根外菌丝的ACP活性高于30 μM处理的。这些结果表明，低磷条件下，促进了根外菌丝向菌丝体分泌ACP。
Arbuscular mycorrhizal (AM) fungi increase phosphate (P) uptake by plants. Organic phosphate comprises 30–80% of total P in most agricultural soils. Some plants can utilize organic phosphate by secreting acid phosphatase (ACP) from their roots, especially under low P conditions. Although secretion of ACP from extraradical hyphae of AM fungi has been reported, the specific factors that affect the secretion of ACP are unknown. The objective of the present study was to investigate whether secretion of ACP from extraradical hyphae is induced by low P conditions. First, specimens ofAllium fistulosumwere either inoculated with the AM fungusRhizophagus clarusstrain CK001 or remained uninoculated and were grown in soil with 0.5 g P2O5kg−1soil or without P fertilization using two-compartment pots. Soil solution was collected using mullite ceramic tubes 45 days after sowing. The soil solution was analyzed for ACP activity by usingp-nitrophenylphosphate. Second, Ri T-DNA transformed roots (i.e., hairy roots) ofLinum usitatissimuminoculated withR.claruswere grown on solid minimal media with two P levels applied (3 and 30 μM P) using two-compartment Petri dishes under in vitro conditions. Hyphal exudates, extraradical hyphae, and hairy roots were collected and analyzed for ACP activity. ACP activity in the soil solution of the hyphal compartment in theA.fistulosuminoculation treatment was higher without P fertilization than with P fertilization. AM colonization also was higher without P fertilization than with P fertilization. In the in vitro two-compartment culture, ACP activity of hyphal exudates and extraradical hyphae were higher under the 3-μM treatment than under the 30-μM treatment. These findings suggest that the secretion of ACP from the extraradical hyphae ofR.clarusinto the hyphosphere is promoted under low P conditions.