Biological interactions between Minjiang fir and local ectomycorrhizal fungi are associated with fir range patterns. undefined

Abstract: Ectomycorrhizal fungi (EcM fungi) are involved in the habitat boundary occupation of host plants by which help shape the local distribution and occurrence of plants. However, it is unclear whether boundary-dependent variations in EcM fungi and plant ECM responses modulate the local range patterns of plants. In this study, we investigated the EcM fungal communities of Minjiang fir (Abies fargesii var. faxoniana, a dominant endemic species of subalpine forests in western Sichuan, China) sapling root tips to explore habitat-dependent variations in root-associated EcM fungal communities and EcM fungi-fir links along with suitable habitats (SH) and range boundaries (LRB). Our results showed that enrichment of fir-cooperation EcM fungal taxa occurred in at suitable habitats and high-elevation boundaryRB, while deficiencies in at the low-elevation boundary RB and southwestern aspect RB and even enriched by fir-antagonist EcM fungal taxa. The relationships between fir and some same definite species shifted from positive in at the SH to negative in at the low-elevation boundary RB and southwestern aspect RB. The EcM fungi-fir links were dominated by positive links at SH and high-elevation RB, while negative links at low-elevation RB and southwestern aspect RB. Our results suggest that the existence of fir-cooperation taxa and the dominance of positive EcM fungi-fir links could support the establishment of fir in high-elevation boundaryRB as potential suitable habitat of fir, while the enrichment of fir-antagonist taxa and the dominance of negative EcM fungi-fir links could contribute to the survival limitation of fir in at low-elevation boundary RB and southwestern aspect RB. Our findings highlight a potential implication of plant-EcM fungi links underlying the local range patterns of plants.