Phylogenetic distribution and evolution of mycorrhizas in land plants

Abstract

A survey of 659 papers mostly published since 1987 was conducted to compile a checklist of mycorrhizal occurrence among 3,617 species (263 families) of land plants. A plant phylogeny was then used to map the mycorrhizal information to examine evolutionary patterns. Several findings from this survey enhance our understanding of the roles of mycorrhizas in the origin and subsequent diversification of land plants. First, 80 and 92% of surveyed land plant species and families are mycorrhizal. Second, arbuscular mycorrhiza (AM) is the predominant and ancestral type of mycorrhiza in land plants. Its occurrence in a vast majority of land plants and early-diverging lineages of liverworts suggests that the origin of AM probably coincided with the origin of land plants. Third, ectomycorrhiza (ECM) and its derived types independently evolved from AM many times through parallel evolution. Coevolution between plant and fungal partners in ECM and its derived types has probably contributed to diversification of both plant hosts and fungal symbionts. Fourth, mycoheterotrophy and loss of the mycorrhizal condition also evolved many times independently in land plants through parallel evolution.

Facilitation between woody and herbaceous plants that associate with arbuscular mycorrhizal fungi in temperate European forests

“…Irrespective of the plant AM mycorrhizal state definitions used, from Wang and Qiu (2006), or those from Hempel et al. (2013), the relative abundance (11.31% vs. 6.34%—understory vs. canopy, t  = 28.1, p  <   .001) and richness (21.9% vs. 18.7%—understory vs. canopy, t  = 5.18, p  <   .001) of AM plants in the understory was higher than in the canopy.…”

On plant defense signaling networks and early land plant evolution

“…While many liverworts (outlined above) and hornworts [30,31] exhibit interactions with mycorrhizal fungi, mosses generally do not form mycorrhizae [32,33]; for a recent and comprehensive overview see [29]. That mosses do not form mycorrhizae is further corroborated by Wang and colleagues [34], who showed that moss arbuscular mycorrhizal symbiosis genes show high sequence divergence as compared to their homologous counterparts in all other land plants.…”

Mycorrhizal Interactions for Reforestation: Constraints to Dryland Agroforest in Brazil

“…For example, Machado and Bacha [81] evaluated the economic viability of the species included in their experiments, such as C. tomentosum (a nitrogen-fixing tree legume, which can be inoculated with rhizobial bacteria and AMF, being the focus of various studies) [33,34,41], and A. angustifolia (dependant on AMF) [42], but did not mention their functional type, showing a lack of biological data integration. Moreover, for several plant species indicated for reforestation, there is no report of their mycothrophy, such as B. riedelianum, popularly known as "pau marfim" [16]. In this sense, the recently compiled lists of Brazilian plant species (including characteristics and potential uses) presented by Lorenzi [82] and Carvalho [83] are noteworthy; however, the integration of all data must be constantly updated.…”

“…It is believed that most tropical trees associate with arbuscular mycorrhizas (AM); however, a low percent of them have been studied for their symbioses [16][17][18][19]. Additionally, a lower number of ecologically important plant species form ectomycorrhizas (EM) [20], and exotic species such as eucalypts also form EM in tropical areas.…”