A Transcriptomic Atlas of the Ectomycorrhizal Fungus Laccaria bicolor

Author: mycolabadmin
2021-12-17
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Summary

This research explores how symbiotic fungi that help trees obtain nutrients coordinate their genes to develop different structures and functions. The study created a comprehensive gene activity map of the fungus Laccaria bicolor under various conditions to understand how it forms beneficial partnerships with tree roots. This knowledge helps us understand how forests maintain their health and productivity. Impacts on everyday life: • Better understanding of how forests naturally maintain their health and growth • Potential applications for improving tree growth in forestry and agriculture • Insights into how organisms adapt to different environmental conditions • Contribution to sustainable forest management practices • Better understanding of beneficial plant-microbe relationships that could be applied to crop production

Background

Trees are able to colonize, establish and survive in a wide range of soils through associations with ectomycorrhizal (EcM) fungi. Proper functioning of EcM fungi requires differentiation of structures within the fungal colony – a symbiotic structure for nutrient exchange, extramatricular mycelium to explore soil for nutrients, and basidiocarps for sexual reproduction.

Objective

To understand how an EcM fungus uses its gene set to support functional differentiation and development of specialized morphological structures. The study examined the transcriptomes of Laccaria bicolor under various experimental conditions, including growth with Populus tremula x alba at different developmental stages, basidiocarps and free-living mycelium, under various conditions of N, P and C supply.

Results

Nitrogen supply induced global transcriptional changes, while responses to phosphorus supply were largely independent. Symbiosis development with poplar was characterized by transcriptional waves in a two-step process. Basidiocarp development shared transcriptional signatures with other basidiomycetes. The study found overlaps in transcriptional responses of L. bicolor hyphae to host plant and N/C supply, as well as co-regulation of genes in basidiocarps and mature mycorrhiza. Few genes were induced in single conditions only – functional and morphological differentiation involved fine tuning of larger gene sets.

Conclusion

The transcriptomic atlas provides a valuable reference for studying ectomycorrhizal symbiosis function and stability using L. bicolor as a model. It reveals both similarities and differences with other ectomycorrhizal fungi, allowing researchers to distinguish conserved processes like basidiocarp development from nutrient homeostasis. The study demonstrates that morphological and functional differentiation involves coordinated regulation of gene modules rather than condition-specific gene expression.

Published in:Microorganisms,
Study Type:Transcriptomic Analysis,
Source: 10.3390/microorganisms9122612