Mycorrhizal fungal diversity and community composition in a lithophytic and epiphytic orchid

Abstract

Some orchid species are present as epiphytes and lithophytes in the same habitat, but little is known about the differences of their mycorrhizal fungal communities. We used Coelogyne viscosa, which occurs both as an epiphyte and a lithophyte, as a study system to investigate orchid mycorrhizal fungal communities in lithophytes and epiphytes in Xishuangbanna National Nature Reserve (Yunnan Province, China). Twenty-three fungal operational taxonomic units (OTUs) from 18 sampling sites were identified. Results indicated that mycorrhizal fungal community composition was different between epi- and lithophytes. When we analyzed the Tulasnellaceae and Sebacinales communities separately, we found that the Sebacinales fungal communities were significantly different in the two growth habitats, but the Tulasnellaceae fungal communities were not. Our results provide evidence for distinct orchid mycorrhiza fungal communities depending on the growth habitat of the orchid. Consistent with some recent investigations of mycorrhizal fungus community composition, this study suggests that for one orchid, growth habitat affects mycorrhizal symbioses.

The impact of life form on the architecture of orchid mycorrhizal networks in tropical forest

“…Ninety-six clones were randomly selected from each library and sequenced using the M13 forward primer. Our previous studies have shown that this was a large enough clonal pool for assessing total species diversity and sequencing completeness (Xing et al 2015(Xing et al , 2017. All clones were sequenced by GENEWIZ Inc., Beijing, China.…”

Similar mycorrhizal fungal communities associated with epiphytic and lithophytic orchids of Coelogyne corymbosa

“…A previous study has reported OMF have highly modular architecture, reflecting an ecological barrier between epiphytic and terrestrial subnetworks on a paleotropic island ( Martos et al., 2012 ). Other studies have also reported OMF specificities (mostly Sebacinales and Tulasnellaceae), differing between terrestrial, epiphytic, and lithophytic habitats ( Oja et al., 2015 ; Těšitelová et al., 2015 ; Xing et al., 2015 , 2019 ). Because studies on the relationships among OMF compositions and orchid life forms were all conducted in tropical areas, it remains unclear if individual epiphytic and lithophytic orchids harbor different OMF at higher elevations.…”

“…Coelogyne orchids can be both epiphytic and lithophytic at the same site and are always colonized by mycorrhizal fungi. Some Coelogyne species have therefore been studied to assess correlations of OMF composition and life form ( Xing et al., 2015 , 2019 ). Many Coelogyne species are also of high ornamental value, and wild populations of this genus have been threatened by over-collection and habitat destruction.…”

“…Studies on the OMF of Coelogyne orchids have been mainly conducted on two tropical species— Coelogyne viscosa Rchb. f. and Coelogyne ovalis Lindl., and have been based on Sanger sequencing of randomly picked clones from amplicon libraries of the ITS-rDNA region ( Xing et al., 2015 , 2019 ). The OMF Operational Taxonomic Units (OTUs) have been mostly identified as fungi of Sebacinales and Tulasnellaceae, with only a few OTUs designated as Ceratobasidiaceae.…”

“…The OMF Operational Taxonomic Units (OTUs) have been mostly identified as fungi of Sebacinales and Tulasnellaceae, with only a few OTUs designated as Ceratobasidiaceae. Mycorrhizal fungal community composition is significantly different between epiphytic and lithophytic individuals of C. viscosa ( Xing et al., 2015 ). The habitat distribution of C. viscosa is restricted between 1000 m and 2000 m above sea level.…”