title: Increasing phosphorus concentration in the extraradical hyphae of Rhizophagus irregularis DAOM 197198 leads to a concomitant increase in metal minerals.
abstract: Plants associated with arbuscular mycorrhizal fungi (AMF) acquire phosphorus via roots and extraradical hyphae. How soil P level affects P accumulation within hyphae and how P in hyphae influences the accumulation of metal minerals remains little explored. A bi-compartmented in vitro cultivation system separating a root compartment (RC), containing a Ri T-DNA transformed carrot root associated to the AMF Rhizophagus irregularis DAOM 197198, from a hyphal compartment (HC), containing only the extraradical hyphae, was used. The HC contained a liquid growth medium (i.e., the modified Strullu-Romand medium containing P in the form of KH2PO4) without (0 μM) or adjusted to 35, 100, and 700 μM of KH2PO4. The accumulation of P and metal minerals (Ca, Mg, K, Na, Fe, Cu, Mn) within extraradical hyphae and AMF-colonized roots, and the expression of the phosphate transporter gene GintPT were assessed. The expression of GintPT in the extraradical hyphae did not differ in absence of KH2PO4or in presence of 35 and 100 μM KH2PO4in the HC but was markedly reduced in presence of 700 μM KH2PO4. Hyphal P concentration was significantly lowest in absence of KH2PO4, intermediate at 35 and 100 μM KH2PO4and significantly highest in presence of 700 μM KH2PO4in the HC. The concentrations of K, Mg, and Na were positively associated with the concentration of P in the extraradical hyphae developing in the HC. Similarly, P concentration in extraradical hyphae in the HC was related to P concentration in the growth medium and influenced the concentration of K, Mg, and Na. The accumulation of the metal mineral K, Mg, and Na in the extraradical hyphae developing in the HC was possibly related to their function in neutralizing the negative charges of PolyP accumulated in the hyphae.
authors.affiliation: College of Resources and Environmental Sciences; Research Center for Resources, the Environment and Food Safety, China Agricultural University, Beijing, 100193, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Resources and Environmental Sciences; Research Center for Resources, the Environment and Food Safety, China Agricultural University, Beijing, 100193, China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Jiang
authors.affiliation: College of Resources and Environmental Sciences; Research Center for Resources, the Environment and Food Safety, China Agricultural University, Beijing, 100193, China.
authors.forename: Jiachao
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Université Catholique de Louvain, Earth and Life Institute, Applied microbiology, Mycology, Croix du sud 2, bte L7.05.06, B-1348, Louvain-la-Neuve, Belgium.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Declerck
authors.affiliation: State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China.
authors.forename: Changyan
authors.initials: C
authors.lastname: Tian
authors.affiliation: College of Resources and Environmental Sciences; Research Center for Resources, the Environment and Food Safety, China Agricultural University, Beijing, 100193, China. fenggu@cau.edu.cn.
authors.forename: Gu
authors.identifier: http://orcid.org/0000-0002-1052-5009
authors.initials: G
authors.lastname: Feng
mesh_terms: D018552:Daucus carota / Q000382:microbiology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D055137:Glomeromycota / Q000737:chemistry* / Q000378:metabolism; D025301:Hyphae / Q000737:chemistry* / Q000378:metabolism; D008670:Metals / Q000737:chemistry / Q000378:metabolism*; D008903:Minerals / Q000737:chemistry / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D018517:Plant Roots / Q000382:microbiology
chemical_list: D005656:Fungal Proteins; D008670:Metals; D008903:Minerals; D010758:Phosphorus
keywords: Charge neutralization; Extraradical hyphae; GintPT gene expression; Metal minerals; PolyP accumulation