Symbiosis: Herbivory Alters Mycorrhizal Nutrient Exchange

A new study shows that a plant gives less carbon to its root-associated mycorrhizal fungus when targeted by herbivores, but the fungus doesn’t retaliate

Evolutionary dynamics of mycorrhizal symbiosis in land plant diversification - supplement

This submission supplements the manuscript entitled Evolutionary dynamics of mycorrhizal symbiosis in land plant diversification by Frida A.A. Feijen, Rutger A. Vos, Jorinde Nuytinck & Vincent S.F.T. Merckx. The submission consists of a specific version of a git repository with all the scripts and data files to perform the comparative analyses. The tree dating results, which are very large, compressed files, are in a separate submission that bypasses github: 10.5281/zenodo.1037548 For more information: https://github.com/naturalis/mycorrhiza/tree/v1.0.

Data from: Global distribution patterns of mycoheterotrophy

Aim: Mycoheterotrophy is a mode of life where plants cheat the mycorrhizal symbiosis, receiving carbon via their fungal partners. Despite being widespread, mycoheterotrophic plants are locally rare, hampering the understanding of their global environmental drivers. Here, we explore global environmental preferences of mycoheterotrophy, and investigate environmental drivers of differential habitat preferences of mycoheterotrophic plants associated with arbuscular (AM) and ectomycorrhizal (EM) fungi. Location: Global. Time period: Current. Major taxa studied: Mycoheterotrophic flowering plants. Methods: We compiled the largest global dataset of epiparasitic mycoheterotrophic plant species occurrences and examined which environmental factors, including soil type, climate, vegetation type and distribution patterns of mycorrhizal autotrophic plants, relate to occurrence patterns of mycoheterotrophic plant species associated with AM and EM fungi. Results: Mycoheterotrophic plant species avoid cold and highly seasonal climates and show a strong preference for forests. AM-associated mycoheterotrophs are predominantly found in broadleaved tropical evergreen forests whereas EM-associated mycoheterotrophs occur in temperate regions, mostly in broadleaved deciduous and evergreen needleleaved forests. The abundance of AM and EM autotrophic plants was a weaker predictor for mycoheterotrophs occurrences than forest type. Temperature and precipitation variables - but not edaphic factors - were the best predictors explaining the distribution patterns of mycoheterotrophs after accounting for the effects of forest type. For individual lineages, major differences in environmental preferences (often related to edaphic factors) occurred which were significantly associated with plant evolutionary relationships, indicating that these cheater plants have limited adaptive capabilities. Main conclusions: The strong global geographic segregation of AM and EM mycoheterotrophs does not reflect the abundance of their potential autotrophic hosts, but seems to be driven by differential climate and habitat preferences. Our results highlight the non-trivial nature of mycorrhizal interactions, and indicate that identity of the partners is not enough to understand the underlying mechanisms promoting plant-fungal interactions in mycoheterotrophic plants

Fungal diversity driven by bark features affects phorophyte preference in epiphytic orchids from southern China.

Epiphytic orchids exhibit varying degrees of phorophyte tree specificity. We performed a pilot study to investigate why epiphytic orchids prefer or avoid certain trees. We selected two orchid species, Panisea uniflora and Bulbophyllum odoratissimum co-occurring in a forest habitat in southern China, where they showed a specific association with Quercus yiwuensis and Pistacia weinmannifolia trees, respectively. We analysed a number of environmental factors potentially influencing the relationship between orchids and trees. Difference in bark features, such as water holding capacity and pH were recorded between Q. yiwuensis and P. weinmannifolia, which could influence both orchid seed germination and fungal diversity on the two phorophytes. Morphological and molecular culture-based methods, combined with metabarcoding analyses, were used to assess fungal communities associated with studied orchids and trees. A total of 162 fungal species in 74 genera were isolated from bark samples. Only two genera, Acremonium and Verticillium, were shared by the two phorophyte species. Metabarcoding analysis confirmed the presence of significantly different fungal communities on the investigated tree and orchid species, with considerable similarity between each orchid species and its host tree, suggesting that the orchid-host tree association is influenced by the fungal communities of the host tree bark