title: Promoter-dependent expression of the fungal transporter HcPT1.1 under Pi shortage and its spatial localization in ectomycorrhiza.
abstract: Mycorrhizal exchange of nutrients between fungi and host plants involves a specialization and polarization of the fungal plasma membrane adapted for the uptake from the soil and for secretion of nutrient ions towards root cells. In addition to the current progress in identification of membrane transport systems of both symbiotic partners, data concerning the transcriptional and translational regulation of these proteins are needed to elucidate their role for symbiotic functions. To answer whether the formerly described Pi-dependent expression of the phosphate transporter HcPT1.1 from Hebeloma cylindrosporum is the result of its promoter activity, we introduced promoter-EGFP fusion constructs in the fungus by Agrotransformation. Indeed, HcPT1.1 expression in pure fungal cultures quantified and visualized by EGFP under control of the HcPT1.1 promoter was dependent on external Pi concentrations, low Pi stimulating the expression. Furthermore, to study expression and localization of the phosphate transporter HcPT1.1 in symbiotic conditions, presence of transcripts and proteins was analyzed by the in situ hybridization technique as well as by immunostaining of proteins. In ectomycorrhiza, expression of the phosphate transporter was clearly enhanced by Pi-shortage indicating its role in Pi nutrition in the symbiotic association. Transcripts were detected in external hyphae and in the hyphal mantle, proteins in addition also within the Hartig net. Exploiting the transformable fungus H. cylindrosporum, Pi-dependent expression of the fungal transporter HcPT1.1 as result from its promoter activity as well as transcript and protein localization in ectomycorrhizal symbiosis are shown.
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, UMR 5004 CNRS/INRA/SupAgro/UM2, Campus INRA/SupAgro, 2 Place Viala, 34060 Montpellier Cedex 2, France.
authors.forename: Kevin
authors.initials: K
authors.lastname: Garcia
authors.forename: Muhammad Zulqurnain
authors.initials: MZ
authors.lastname: Haider
authors.forename: Amandine
authors.initials: A
authors.lastname: Delteil
authors.forename: Claire
authors.initials: C
authors.lastname: Corratgé-Faillie
authors.forename: Geneviève
authors.initials: G
authors.lastname: Conéjero
authors.forename: Marie-Violaine
authors.initials: MV
authors.lastname: Tatry
authors.forename: Adeline
authors.initials: A
authors.lastname: Becquer
authors.forename: Laurie
authors.initials: L
authors.lastname: Amenc
authors.forename: Hervé
authors.initials: H
authors.lastname: Sentenac
authors.forename: Claude
authors.initials: C
authors.lastname: Plassard
authors.forename: Sabine
authors.initials: S
authors.lastname: Zimmermann
mesh_terms: D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D055364:Hebeloma / Q000235:genetics / Q000378:metabolism; D025301:Hyphae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D038821:Mycorrhizae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D028061:Phosphate Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D028223:Pinus / Q000382:microbiology / Q000502:physiology; D011401:Promoter Regions, Genetic; D021381:Protein Transport; D013559:Symbiosis
chemical_list: D005656:Fungal Proteins; D028061:Phosphate Transport Proteins; D010710:Phosphates
keywords: Agrotransformation; Ectomycorrhizal (ECM) symbiosis; GFP-promoter expression; Hebeloma cylindrosporum phosphate transporter HcPT1.1; In situ hybridization; Protein immunolocalization