Identity and Specificity of Rhizoctonia-Like Fungi from Different Populations of Liparis japonica (Orchidaceae) in Northeast China

Abstract

Mycorrhizal association is known to be important to orchid species, and a complete understanding of the fungi that form mycorrhizas is required for orchid ecology and conservation. Liparis japonica (Orchidaceae) is a widespread terrestrial photosynthetic orchid in Northeast China. Previously, we found the genetic diversity of this species has been reduced recent years due to habitat destruction and fragmentation, but little was known about the relationship between this orchid species and the mycorrhizal fungi. The Rhizoctonia-like fungi are the commonly accepted mycorrhizal fungi associated with orchids. In this study, the distribution, diversity and specificity of culturable Rhizoctonia-like fungi associated with L. japonica species were investigated from seven populations in Northeast China. Among the 201 endophytic fungal isolates obtained, 86 Rhizoctonia-like fungi were identified based on morphological characters and molecular methods, and the ITS sequences and phylogenetic analysis revealed that all these Rhizoctonia-like fungi fell in the same main clade and were closely related to those of Tulasnella calospora species group. These findings indicated the high mycorrhizal specificity existed in L. japonica species regardless of habitats at least in Northeast China. Our results also supported the wide distribution of this fungal partner, and implied that the decline of L. japonica in Northeast China did not result from high mycorrhizal specificity. Using culture-dependent technology, these mycorrhizal fungal isolates might be important sources for the further utilizing in orchids conservation.

Diversity of mycorrhizal Tulasnella associated with epiphytic and rupicolous orchids from the Brazilian Atlantic Forest, including four new species

“…Among the species of the genus Tulasnella, T. calospora is considered as a nearly universal orchid symbiont 41 . It has been isolated from orchids in Asia 42,43 , Australia 44,45 , Europe 46 and South America 47,48 . However, the definition of T. calospora species is still unclear, since phylogenies have shown taxonomic problems concerning this species 35 .…”

Progress and Prospects of Mycorrhizal Fungal Diversity in Orchids

“…The OM specificity may be affected by environmental factors, climate changes, extreme host selections, evolutionary history, accompanying plant species, biocompatibility, biogeographic range, and density of OMF in the soil or, for epiphytes, Frontiers in Plant Science | www.frontiersin.org phorophytes (Jacquemyn et al, 2011b(Jacquemyn et al, , 2017aMcCormick et al, 2012McCormick et al, , 2018Pandey et al, 2013;Waud et al, 2016a;Shefferson et al, 2019;Xing et al, 2019), thus showing strong and complex variations. For example, Neottia and Caladenia prefer symbiosis with sebacinales fungi (Těšitelová et al, 2015;Phillips et al, 2016;Reiter et al, 2020); the rare terrestrial orchid Caladenia huegelii specifically associates with Serendipita (= Sebacina) vermifera (Swarts et al, 2010); Cypripedium, Ophrys, and Chiloglottis prefer Tulasnellaceae (Shefferson et al, 2005(Shefferson et al, , 2019Roche et al, 2010;Schatz et al, 2010); Dendrobium nobile and Liparis japonica have high specificity for Tulasnellaceae (Ding et al, 2014;Xing et al, 2017); Pterostylis nutans and Sarcochilus weinthalii are only symbiotic with Ceratobasidium fungi (Irwin et al, 2007;Graham and Dearnaley, 2012); Platanthera leucophaea tends to be associated with Ceratobasidium fungi over a 10-year period (Thixton et al, 2020); Corallorhiza trifida shows high specificity for Thelephoraceae in different countries and varied habitats (McKendrick et al, 2000;Zimmer et al, 2008). Jacquemyn et al (2010) asserted the possibility of promoting widespread associations between orchids and available OMF in an environment devoid of water and nutrients.…”

Mycorrhizal Diversity Associated to Liparis japonica (Miq.) Maxim. in China

“…In the symbiotic relationship between these four mycorrhizal fungi and their hosts, the specificity of orchid plants and their mycorrhizal fungi is much higher than that of other mycorrhizal fungi [17]. In this symbiotic relationship, almost all orchids have to rely on the corresponding mycorrhizal fungi to survive, but the orchid mycorrhizal fungi do not need to rely on the orchid plants to survive well [18][19]. Fifteen strains were determined to be Epulorhiza of Orchid Rhizoctonia after identified by morphology and molecular biology, and took the symbiotic fungus separated from L. japonica (Miq.)…”