A gene repertoire for nitrogen transporters in Laccaria bicolor

Abstract

Summary• Ectomycorrhizal interactions established between the root systems of terrestrial plants and hyphae from soil-borne fungi are the most ecologically widespread plant symbioses. The efficient uptake of a broad range of nitrogen (N) compounds by the fungal symbiont and their further transfer to the host plant is a major feature of this symbiosis. Nevertheless, we far from understand which N form is preferentially transferred and what are the key molecular determinants required for this transfer.• Exhaustive in silico analysis of N-compound transporter families were performed within the genome of the ectomycorrhizal model fungus Laccaria bicolor. A broad phylogenetic approach was undertaken for all families and gene regulation was investigated using whole-genome expression arrays.• A repertoire of proteins involved in the transport of N compounds in L. bicolor was established that revealed the presence of at least 128 gene models in the genome of L. bicolor. Phylogenetic comparisons with other basidiomycete genomes highlighted the remarkable expansion of some families. Whole-genome expression arrays indicate that 92% of these gene models showed detectable transcript levels.• This work represents a major advance in the establishment of a transportome blueprint at a symbiotic interface, which will guide future experiments.

Transcriptome and Secretome Analyses ofPhanerochaete chrysosporiumReveal Complex Patterns of Gene Expression

“…Recent phylogenetic analysis (37) shows large families of OPT genes in P. chrysosporium, Coprinopsis cinereus, and Laccaria bicolor. Differential regulation of OPT genes has been observed in response to growth conditions and developmental state for the ectomycorrhiza L. bicolor and Hebeloma cylindrosporum (3,37). In particular, H. cylindrosporum PTR2A is upregulated under nitrogen limitation, and transcripts of the homologous P. chrysosporium gene (protein model Pchr10757) are highly expressed, showing a modest increase in NLB (NLB/RB ratio of 1.89; see Table S3 in the supplemental material).…”

Fungal aquaporins: cellular functions and ecophysiological perspectives

“…However, there is a still ongoing discussion about the chemical nature of the delivered nitrogen source, the physiological details of provision, and potential export mechanisms by Hartig net hyphae. Fungus-based plant nitrogen sources that are discussed in ECM symbiosis are amino acids, ammonium, and nitrate (Chalot et al 2006;Dietz et al 2011;Lucic et al 2008;Selle et al 2005;Willmann et al 2014). As shown by Dietz et al (Dietz et al 2011), aquaglyceroporins from L. bicolor can confer ammonia permeability of the fungal plasma membrane.…”

A novel fungal family of oligopeptide transporters identified by functional metatranscriptomics of soil eukaryotes

“…Indeed, many phylogenetic analyses of specific eukaryotic transporter families (this study, Figure 1 and also De Hertogh et al, 2002Hellborg et al, 2008;Ló pez et al, 2008;Lucic et al, 2008), show that numerous transporter families and sub-families (as exemplified by clades B and clades D to G in Figure 1) have not been studied experimentally with respect to the substrates they transport. We therefore largely ignore how many nutrients present in the natural environment are absorbed by most microorganisms.…”