Generalized mycorrhizal interactions and fungal enemy release drive range expansion of orchids in southern Florida
2020
Downing, Jason L. | Liu, Hong | McCormick, Melissa K. | Arce, Jay | Alonso, Dailen | Lopez‐Perez, Jorge
A species’ ability to establish and spread is influenced by different types of biotic interactions encountered in a new range. Species with high dependency on biotic interactions, such as orchids, are believed to have low ability to expand ranges. Using a comparative approach, we addressed the role of below‐ground biotic interactions in the naturalization and spread of two introduced orchids. Using fungus‐specific DNA primers and symbiotic germination trials, we identified the types of fungal taxa associated with Cyrtopodium flavum and Eulophia graminea, two invasive orchids in southern Florida, with that of two native congeners, C. punctatum and E. alta. We quantified the degrees of mycorrhizal specificity as well as associations with pathogenic fungi. We identified a total of 57 distinct fungal taxa, collected from a total of 104 root samples (67 adults and 37 seedlings), and 111 protocorms derived from fungal baits in southern Florida and southwest China. We found that invasive orchids were capable of associating with a broader range of mycorrhizal fungi than co‐occurring native congeners (i.e., generalist strategy). Concurrently, invasive orchid species were less likely to harbor pathogenic fungal groups (Ascomycete) than native congeners, suggesting enemy release played a role as well in these orchids’ naturalization and spread. These findings provided insights into the complex roles of mycorrhizal symbioses in range expansions.
显示更多 [+] 显示较少 [-]