Record ID No. |
5641 |
Author(s) |
Swift S.*, Munroe S., Im C., Tipton L. and Hynson N. A. , 2019 |
Affiliation |
*Department of Botany, University of Hawaii Manoa, 3190 Maile Way, Honolulu, HI 96822 USA. |
Title |
Remote tropical island colonization does not preclude symbiotic specialists: new evidence of mycorrhizal specificity across the geographic distribution of the Hawaiian endemic orchid Anoectochilus sandvicensis. |
Source. Vol.(no):Page |
Annals of Botany. 123: 657-666. |
Categories |
|
Subjects |
Ecology |
Sub-subjects |
Biodiversity Molecular taxonomy |
Host |
Anoectophilus sandvicensis |
Organism |
Ceratobasidium spp. |
Country |
USA |
Abstracts |
For symbiotic organisms, their colonization and spread across remote oceanic islands should favour generalists. Plants that form obligate symbiotic associations with microbes dominate island ecosystems, but the relationship between island inhabitance and symbiotic specificity is unclear, especially in the tropics. To fill this gap, the mycorrhizal specificity of the Hawaiian endemic orchid Anoectochilus sandvicensis across multiple populations encompassing its entire geographic distribution was examined. By molecular phylogenetic approaches the mycorrhizal fungi associated with A. sandvicensis across its entire geographic distribution was identified and the relationship of these fungi to others found elsewhere around the globe was determined. With richness estimators, the mycorrhizal specificity of A. sandvicensis within and among islands was assessed. A test was conducted to know whether geographic proximity of orchid populations was a significant predictor for the presence of particular mycorrhizal fungi and their community composition. It was found that each population of A. sandvicensis formed specific associations with one of three fungi in the genus Ceratobasidium and that the closest relatives of these fungi are globally widespread. Based on diversity indices, A. sandvicensis populations were estimated to partner with one to four mycorrhizal taxa with an estimated total of four compatible mycorrhizal fungi across its entire distribution. However, the geographic proximity of orchid populations was found not to be a significant predictor of mycorrhizal fungal community composition. The findings indicate that the colonization and survival of plant species on even the most remote oceanic islands is not restricted to symbiotic generalists, and that partnering with few, but cosmopolitan microbial symbionts is an alternative means for successful island establishment. We suggest that the spatial distribution and abundance of symbionts in addition to island age, size and isolation should also be taken into consideration for predictions of island biodiversity. |