Monotropastrum humile var. humile is associated with diverse ectomycorrhizal Russulaceae fungi in Japanese forests

Abstract

Monotropastrum humile is nearly lacking in chlorophyll and obtains its nutrients, including carbon sources, from associated mycorrhizal fungi. We analyzed the mycorrhizal fungal affinity and species diversity of M. humile var. humile mycorrhizae to clarify how the plant population survives in Japanese forest ecosystems. We classified 78 samples of adult M. humile var. humile individuals from Hokkaido, Honshu, and Kyusyu Islands into 37 root mycorrhizal morphotypes. Of these, we identified 24 types as Russula or Lactarius fungal taxa in the Russulaceae, Basidiomycetes, but we could not identify the remaining 13 types in their genus in the Basidiomycetes. The number of fungal species on M. humile var. humile was the highest in the plant subfamily. The diversity of fungal species revealed its increased trends in natural forests at the stand level, fagaceous vegetation, and cool-temperate climate. The most frequently observed fungus colonized mainly samples collected from sub-alpine forests; the second most frequently observed fungus colonized samples collected from sub-alpine to warm-temperate forests. These results suggest that Japanese M. humile populations are associated with specific but diverse fungi that are common ectomycorrhizal symbionts of various forest canopy trees, indicating a tripartite mycorrhizal relationship in the forest ecosystem.

Monotropoid Mycorrhizal Characteristics of Monotropa uniflora (Ericaceae) Collected from a Forest in Korea

“…In particular, the structure of the mantle covered with the cystidia is the typical characteristic of mycorrhiza between Russula spp. and M. uniflora, which has been supported by several studies, including the results of this study [19][20][21]. Moreover, fungal pegs were observed inside the epidermal cell of the mycorrhizal root tips (Fig.…”

“…However, there seems to be strong specificity with fungi among mycoheterotrophic plants. Strong specificity of Russula species with M. uniflora has been reported in studies from Japan and China, which are geographically close to the sample sites of this study [20][21][22].…”

Mycorrhizal features and fungal partners of four mycoheterotrophic Monotropoideae (Ericaceae) species from Yunnan, China

“…The structure of mycorrhizae has been previously described in several MH Monotropeae and Pterosporeae (Duddridge and Read 1982;Robertson and Robertson 1982;Snetselaar and Whitney 1990;Leake et al 2004;Massicotte et al 2005Massicotte et al , 2010Yamada et al 2008). As in ectomycorrhizae, a fungal mantle covers the roots, and some hyphae penetrate between cortical cells, forming the Hartig net.…”

“…as symbionts of Monotropa uniflora L. on herbarium samples (Martin 1986). More identification was undertaken in diverse MH Monotropeae and Pterosporeae species after molecular tools were developed for fungal identification (Cullings et al 1996;Bidartondo and Bruns 2001Young et al 2002;Yokoyama et al 2005;Matsuda et al 2011;Yang and Pfister 2006;Yamada et al 2008;Dowie et al 2011). All these studies showed that MH plant species have extremely specific associations with well-delimited fungal clades.…”

“…Although several studies on MH Monotropeae and Pterosporeae already cover Europe and North America, Asia has not been thoroughly studied. Several species from Japan and Taiwan have been analyzed for mycorrhizal morphology and fungal symbionts (M. uniflora and H. monotropa: Bidartondo and Bruns 2001; Monotropastrum humile (D. Don) Hara: Matsuda and Yamada 2003;Matsuda et al 2011;Yokoyama et al 2005;Yamada et al 2008), but no data is available for the large domain of continental China. Three Monotropeae genera are represented in China, represented by four species (Fang et al 2005; taxonomy after Tsukaya et al 2008; Fig.…”