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Phosphate availability and ectomycorrhizal symbiosis with Pinus sylvestris have independent effects on the Paxillus involutus transcriptome.

ABSTRACT: Many plant species form symbioses with ectomycorrhizal fungi, which help them forage for limiting nutrients in the soil such as inorganic phosphate (Pi). The transcriptional responses to symbiosis and nutrient-limiting conditions in ectomycorrhizal fungal hyphae, however, are largely unknown. An artificial system was developed to study ectomycorrhizal basidiomycete Paxillus involutus growth in symbiosis with its host tree Pinus sylvestris at different Pi concentrations. RNA-seq analysis was performed on P. involutus hyphae growing under Pi-limiting conditions, either in symbiosis or alone. We show that Pi starvation and ectomycorrhizal symbiosis have an independent effect on the P. involutus transcriptome. Notably, low Pi availability induces expression of newly identified putative high-affinity Pi transporter genes, while reducing the expression of putative organic acid transporters. Additionally, low Pi availability induces a close transcriptional interplay between P and N metabolism. GTP-related signalling was found to have a positive effect in the maintenance of ectomycorrhizal symbiosis, whereas multiple putative cytochrome P450 genes were found to be downregulated, unlike arbuscular mycorrhizal fungi. We provide the first evidence of global transcriptional changes induced by low Pi availability and ectomycorrhizal symbiosis in the hyphae of P. involutus, revealing both similarities and differences with better-characterized arbuscular mycorrhizal fungi.

SUBMITTER: Paparokidou C

PROVIDER: S-EPMC7782400 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Identification of genes differentially expressed in extraradical mycelium and ectomycorrhizal roots during Paxillus involutus-Betula pendula ectomycorrhizal symbiosis.

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Gene expression changes in Paxillus involutus- Betula pendula ectomycorrhizal roots compared to Paxillus involutus mycelium patches

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Project description:Ectomycorrhizal fungi play a key role in mobilizing nutrients embedded in recalcitrant organic matter complexes, thereby increasing nutrient accessibility to the host plant. Recent studies have shown that during the assimilation of nutrients, the ectomycorrhizal fungus Paxillus involutus decomposes organic matter using an oxidative mechanism involving Fenton chemistry (Fe(2+) + H2O2 + H(+) → Fe(3+) + ˙OH + H2O), similar to that of brown rot wood-decaying fungi. In such fungi, secreted metabolites are one of the components that drive one-electron reductions of Fe(3+) and O2, generating Fenton chemistry reagents. Here we investigated whether such a mechanism is also implemented by P. involutus during organic matter decomposition. Activity-guided purification was performed to isolate the Fe(3+)-reducing principle secreted by P. involutus during growth on a maize compost extract. The Fe(3+)-reducing activity correlated with the presence of one compound. Mass spectrometry and nuclear magnetic resonance (NMR) identified this compound as the diarylcyclopentenone involutin. A major part of the involutin produced by P. involutus during organic matter decomposition was secreted into the medium, and the metabolite was not detected when the fungus was grown on a mineral nutrient medium. We also demonstrated that in the presence of H2O2, involutin has the capacity to drive an in vitro Fenton reaction via Fe(3+) reduction. Our results show that the mechanism for the reduction of Fe(3+) and the generation of hydroxyl radicals via Fenton chemistry by ectomycorrhizal fungi during organic matter decomposition is similar to that employed by the evolutionarily related brown rot saprotrophs during wood decay.

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Gene expression changes in Paxillus involutus- Betula pendula ectomycorrhizal roots compared to Paxillus involutus mycelium patches

Project description:Illumina HiSeq technology was used to generate mRNA profiles from Paxillus involutus ectomycorrhizal roots compared to mycelium patches . Mycorrhizal roots were harvested after 4 weeks, pooled and used for RNA extraction. Reads of 2X100bp were generated and aligned to Paxillus involutus (http://genome.jgi-psf.org/Paxin1/Paxin1.home.html) using CLC Genomics Workbench 6. mRNA profiles from Paxillus involutus ectomycorrhizal roots and mycelium patches were generated by paired-end (2x100bp) Illumina HiSeq2000 sequencing. Two biological replicates were sequenced for mycorrhizal and mycelium samples.

2015-02-06 | E-GEOD-63924 | biostudies-arrayexpress

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