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

Abstract

Mycorrhizal fungi are essential for the growth and development of both epiphytic (growing on trees) and lithophytic (growing on rocks) orchids. Previous studies indicate that in lowland tropical areas, orchid mycorrhizal fungal compositions are correlated with the life form (i.e., epiphytic, lithophytic, or terrestrial) of their host plants. We therefore tested if a similar correlation exists in an orchid distributed at higher elevations. Coelogyne corymbosa is an endangered ornamental orchid species that can be found as a lithophyte and epiphyte in subtropical to subalpine areas. Based on high-throughput sequencing of the fungal internal transcribed spacer 2 (ITS2)-rDNA region of mycorrhizae of C. corymbosa , we detected 73 putative mycorrhizal fungal Operational Taxonomic Units (OTUs). The OTUs of two dominant lineages (Cantharellales and Sebacinales) detected from C. corymbosa are phylogenetically different from those of other species within the genus Coelogyne , indicating that different orchid species prefer specific mycorrhizal fungi. We also found that the Non-metric multidimensional scaling (NMDS) plots of orchid mycorrhizal fungi were not clustered with life form, the variations among orchid mycorrhizal fungal communities of different life forms were not significant, and most of the OTUs detected from epiphytic individuals were shared by the lithophytic plants, suggesting that orchid mycorrhizal associations of C. corymbosa were not affected by life form. These findings provide novel insights into mycorrhizal associations with endangered ornamental orchids.

How Mycorrhizal Associations Influence Orchid Distribution and Population Dynamics

“…Herrera et al (2018) further confirmed that terrestrial and epiphytic orchids shared abundant Tulasnellaceae mycobionts in different habitats within tropical forests of southern Ecuador, and the network showed a nested structure with generalists forming the core. Due to the large degree of overlap seen in the mycorrhizal communities of epiphytic and lithophytic orchids, the network structure formed by these two types of orchids and sympatrically distributed terrestrial orchids is highly modular but also shows significant nestedness (Xing et al, 2019;Qin et al, 2020). Notably, the OMF network of Dendrobium species inhabiting the same phorophyte escaped strong selection by the host and showed significant asymmetric specialization (Xing et al, 2020b).…”

Gains and losses of the epiphytic lifestyle in epidendroid orchids: review and new analyses with succulence traits

“…Indeed, unlike the primary terrestrial taxa, many secondary terrestrials are also found as lithophytes, or even as occasional epiphytes (Pridgeon et al ., 2005, 2009, 2014). Even though there are differences between the lithophytic and epiphytic habitats, they still share similar rooting conditions (Zotz, 2016), and similar mycorrhizal fungal communities are shared by orchids between the two habitats (Xing et al ., 2019; Qin et al ., 2020). Moreover, lithophytic Malaxideae were not found on the rock itself but in the humus-rich and mossy substrate (Hermans et al ., 2020), resembling some epiphytic conditions.…”

Orchid conservation in China from 2000 to 2020: Achievements and perspectives

“…In addition, mycorrhizal fungal community composition has been investigated in some genera, such as Bletilla Rchb.f. ( Tao et al., 2013 ; Li et al., 2018 ; Deng et al., 2019 ; Jiang et al., 2019 ; Xi et al., 2020 ) , Coelogyne ( Xing et al., 2015 ; Qin et al., 2020 ), Cymbidium ( Li et al., 2016a ; Liu et al., 2016 ; Sheng et al., 2012 ; Wu et al., 2010 ), Cypripedium ( An, 2017 ; Fu et al., 2019 ; Miao et al., 2015 ; Quan et al., 2015 ), Dendrobium ( Chen et al., 2012 ; Dan et al., 2012 ; Zi et al., 2014 ; Meng et al., 2019a ; Shao et al., 2019 , 2020b ; Sarsaiya et al., 2020 ; Wu et al., 2020 ), Gymnadenia R.Br. ( Gao et al., 2020 ; Xing et al., 2020a ), Liparis ( Ding et al., 2014 , 2016 ; Gai et al., 2016 ), Paphiopedilum ( Ding et al., 2014 , 2016 ; Gai et al., 2016 ), and Pleione ( Qin et al., 2019 ).…”