Chowdhury, Md Jamil
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
- Umeå University
Research article2022Peer reviewedOpen access
Chowdhury, Jamil; Kemppainen, Minna; Delhomme, Nicolas; Shutava, Iryna; Zhou, Jingjing; Takahashi, Junko; Pardo, Alejandro G.; Lundberg-Felten, Judith
The development of ectomycorrhizal (ECM) symbioses between soil fungi and tree roots requires modification of root cell walls. The pectin-mediated adhesion between adjacent root cells loosens to accommodate fungal hyphae in the Hartig net, facilitating nutrient exchange between partners. We investigated the role of fungal pectin modifying enzymes in Laccaria bicolor for ECM formation with Populus tremula x Populus tremuloides. We combine transcriptomics of cell-wall-related enzymes in both partners during ECM formation, immunolocalisation of pectin (Homogalacturonan, HG) epitopes in different methylesterification states, pectin methylesterase (PME) activity assays and functional analyses of transgenic L. bicolor to uncover pectin modification mechanisms and the requirement of fungal pectin methylesterases (LbPMEs) for ECM formation. Immunolocalisation identified remodelling of pectin towards de-esterified HG during ECM formation, which was accompanied by increased LbPME1 expression and PME activity. Overexpression or RNAi of the ECM-induced LbPME1 in transgenic L. bicolor lines led to reduced ECM formation. Hartig Nets formed with LbPME1 RNAi lines were shallower, whereas those formed with LbPME1 overexpressors were deeper. This suggests that LbPME1 plays a role in ECM formation potentially through HG de-esterification, which initiates loosening of adjacent root cells to facilitate Hartig net formation.
cell wall; cell-wall remodelling; cell-wall-modifying enzymes; ectomycorrhiza; Laccaria bicolor; pectin; pectin methylesterase; Populus
New Phytologist
2022, Volume: 236, number: 2, pages: 639-655 Publisher: WILEY
Forest Science
DOI: https://doi.org/10.1111/nph.18358
https://res.slu.se/id/publ/118531