High rate of gene family evolution in proximity to the origin of ectomycorrhizal symbiosis in Inocybaceae

Abstract

The genomes of ectomycorrhizal (ECM) fungi have a reduced number of genes encoding Carbohydrate-Active EnZymes (CAZymes), expansions in transposable elements (TEs) and small secreted proteins (SSPs) compared with saprotrophs. Fewer genes for specific peptidases and lipases in ECM fungi are also reported. It is unclear whether these changes occur at the shift to the ECM habit or are more gradual throughout the evolution of ECM lineages. We generated a genomic dataset of 20 species in the ECM lineage Inocybaceae and compared them with six saprotrophic species. Inocybaceae genomes have fewer CAZymes, peptidases, lipases, secondary metabolite clusters and SSPs and higher TE content than their saprotrophic relatives. There was an increase in the rate of gene family evolution along the branch with the transition to the ECM lifestyle. This branch had very high rate of evolution in CAZymes and had the largest number of contractions. Other significant changes along this branch included expansions in transporters, transposons-related genes and communication genes such as fungal kinases. There is a high concentration of changes in proximity to the transition to the ECM lifestyle, which correspond to the identified key changes for the gain of this lifestyle.

Keywords

CAZymes; comparative genomics; fungi; Inocybaceae; mycorrhiza; phylogenomics; saprotrophs

Published in

New Phytologist
2024, volume: 244, number: 1, pages: 219-234
Publisher: WILEY

SLU Authors

• Sanchez-Garcia, Marisol

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Botany
Genetics and Genomics

Publication identifier

• DOI: https://doi.org/10.1111/nph.20007

Permanent link to this page (URI)

https://res.slu.se/id/publ/131674