Expression profiles of a phosphate transporter gene (GmosPT) from the endomycorrhizal fungus Glomus mosseae

• Published in: Mycorrhiza 2005-12, Vol.15 (8), p.620-627
• Main Authors: Benedetto, A, Magurno, F, Bonfante, P, Lanfranco, L
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Amino Acid Sequence; amino acid sequences; Biological and medical sciences; Cloning, Molecular; cucumbers; Cucumis sativus; DNA fingerprinting; DNA, Fungal - chemistry; DNA, Fungal - genetics; endomycorrhizae; Fundamental and applied biological sciences. Psychology; Fungal Proteins - biosynthesis; Fungal Proteins - chemistry; Fungal Proteins - genetics; Fungi; Fungi - genetics; Fungi - metabolism; gene expression regulation; Gene Expression Regulation, Fungal; genes; Genes, Fungal; Glomus mosseae; Hyphae - genetics; infection; Microbiology; Molecular Sequence Data; mycorrhizal fungi; nutrient uptake; Parasitism and symbiosis; Phosphate Transport Proteins - biosynthesis; Phosphate Transport Proteins - chemistry; Phosphate Transport Proteins - genetics; phosphates; Phylogeny; Plant physiology and development; Reverse Transcriptase Polymerase Chain Reaction; ribosomal DNA; RNA, Fungal - analysis; RNA, Messenger - analysis; roots; Sequence Alignment; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Symbiosis; translocation (plant physiology)
• ISSN: 0940-6360; 1432-1890
• DOI: 10.1007/s00572-005-0006-9

Arbuscular mycorrhizal (AM) fungi have long been shown to successfully contribute to phosphate uptake by plant roots. The first step of the fungus-mediated uptake is carried out by fungal membrane Pi transporters (PT) that transfer Pi from the soil into the extraradical hyphae. In the present work we report the identification and characterisation of a PT gene from Glomus mosseae, an AM fungus important for natural and agricultural ecosystems. Degenerate primers and rapid amplification of cDNA ends-polymerase chain reaction (PCR) allowed us to obtain a sequence (GmosPT) showing a highly significant similarity with GiPT and GvPT, the only two other PT genes already isolated from AM fungi. Reverse transcriptase-PCR experiments were carried out to study GmosPT expression profiles in structures corresponding to different fungal life stages (quiescent and germinated sporocarps, intraradical and extraradical hyphae) and in extra- and intraradical hyphae exposed to high and low Pi concentrations. GmosPT showed an expression pattern similar to GiPT, the Glomus intraradices PT gene, since its transcript was more abundant in the extraradical mycelium treated with micromolar Pi levels. In addition, the intraradical mycelium also showed a significant GmosPT expression level that was independent from external Pi concentrations. This finding opens new questions about the role and functioning of high-affinity PT in AM fungi.