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

Abstract

We provide a preliminary report of the mycobionts found within four Monotropoideae (Ericaceae) species from China: Monotropa uniflora, Hypopitys monotropa, Monotropastrum humile and Monotropastrum sciaphilum (a rare endemic species never previously studied for mycorrhizae). Such achlorophyllous Monotropoideae plants obtain their carbohydrates from mycorrhizal fungi linking them to surrounding trees, on which these fungi form ectomycorrhizae. Since Monotropoideae were rarely studied in continental Asia, the root systems of the four species sampled in Yunnan were examined using morphological and molecular methods. All the roots of these four species exhibit a typical monotropoid mycorrhizal morphology, including a fungal mantle, a Hartig net and hyphal pegs. In M. uniflora and M. humile mycorrhizae, cystidia typical of Russula symbionts covered the fungal mantle. ITS barcoding revealed that Russulales were the most frequent colonizers in all species, but Hypopitys monotropa displayed various additional mycorrhizal taxa. Moreover, a few additional ectomycorrhizal and saprotrophic Basidiomycota taxa were identified in the three other species, challenging that these four Monotropoideae species are as strictly fungal specific as the other Monotropoideae species hitherto studied. Moreover, a comparison with accompanying fungus sporocarps revealed that the fruiting fungal community significantly differed from that associated with the Monotropoideae roots, so that a clear fungal preference was evident. Finally, four fungal species were found on more than one Monotropoideae species: this contrasted with previous reports of sympatrically growing mycoheterotrophic plants, which did not reveal any overlap. This again challenges the idea of strict fungal specificity.

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.…”

Mitochondrial genome of the nonphotosynthetic mycoheterotrophic plant Hypopitys monotropa, its structure, gene expression and RNA editing

“…A linear structure is typical for the mitochondrial genomes of fungi and protists (Janouškovec et al, 2013;Nosek et al, 1995). Similar to other mycoheteroprophic plants, H. monotropa lives in intimate symbiosis with fungi (Min et al, 2012).…”

Mitochondrial genome of non-photosynthetic mycoheterotrophic plant Hypopitys monotropa,its structure, gene expression and RNA editing

“…A linear structure is usual for mitochondrial genomes of fungi and protists (Nosek et al, 1995), (Janouškovec et al, 2013). As well as other mycoheteroprophic plants, H. monotropa lives in intimate symbiosis with fungi (Min et al, 2012). One would hypothesize that that linear fragment could be the result of either a contamination or HGT from fungi.…”