Fern-associated arbuscular mycorrhizal fungi are represented by multiple Glomus spp.: do environmental factors influence partner identity?

Abstract

Symbioses involving arbuscular mycorrhizal fungi (AMF) are among the most important ecological associations for many plant species. The diversity of AMF associated with ferns, however, remains poorly studied. Using recently designed Glomus-specific primers, we surveyed the AMF community associated with ferns from deciduous, broad-leaved second-growth forest habitats at the eastern edge of the piedmont region of central Virginia, USA. Results indicate that this molecular approach may be a useful tool for detecting AMF in ferns compared to traditional techniques based on morphology. Over 30 potential fungal ribotypes were identified from eight fern species using denaturing gradient gel electrophoresis. Fungal ribotypes were found to differ widely in terms of (1) the number of fern partners with which they interact and (2) their relative frequency within each fern. Sequence analysis of fungal isolates from three species of fern indicated that the primers were generally highly specific for Glomus species but some non-target DNA was also amplified. Cloned polymerase chain reaction (PCR) products from Polystichum acrostichoides and Osmunda regalis revealed several phylogenetically distinct Glomus species. A single Glomus species was identified in the cloned PCR products from Botrychium virginianum. These findings challenge the hypothesis that the extent or degree of fern-fungal symbiosis is somehow tied to root complexity. Environmental factors appear to influence the suite of AMF that form partnerships with ferns. Some species of fern from similar habitats associated with dissimilar fungal partners (e.g., P. acrostichoides and Athyrium filix-femina var. asplenioides), whereas others harbored uniform fungal communities (e.g., Asplenium platyneuron). The significance of these data in terms of ecological and evolutionary dynamics of the AMF-fern symbiosis is discussed.

Arbuscular mycorrhizal colonization in field-collected terrestrial cordate gametophytes of pre-polypod leptosporangiate ferns (Osmundaceae, Gleicheniaceae, Plagiogyriaceae, Cyatheaceae)

“…Pteridophyte sporophytes are well known to associate with a wide range of AM fungi (Zhang et al 2004;West et al 2009), whereas mycoheterotrophic gametophytes, such as Botrychium (Winther and Friedman 2007) and Psilotum (Winther and Friedman 2009), exhibit very specific associations with particular members of the Glomeraceae. In the present study, the most frequently observed (≥20 total instances) VTs were VT 80,166,191, and 219 of the Glomeraceae.…”

Efecto de Glomus fasciculatum y su relación con tres abonos orgánicos en dos cultivares de haba

“…Las micorrizas y las bacterias fijadoras de N 2 atmosférico, conocidos como biofertilizantes, inciden favorablemente en el desarrollo de las plantas (West et al, 2009). El humus de lombriz, la gallinaza y el residuo del hongo de champiñón aportan materia orgánica (Eghball et al, 2002).…”

“…Los hongos micorrízicos arbusculares (HMA) actúan como aceleradores del crecimiento al aumentar la absorción del fósforo y ayudan en la protección contra patógenos (Alarcón y Ferrera, 1999Mena et al, 2006;West et al, 2009;Smith y Smith, 2011;Singh et al, 2013); también pueden influir en el proceso estructural y de agregación del suelo (Rilling y Mummey, 2006). Dentro de los HMA se encuentra Glomus con 85 especies, pero la más importante en la agricultura es G. fasciculatum, estudiada en frutales, forestales, hortalizas y leguminosas.…”

“…Vermicompost, manure and mushroom residue contribute organic matter (Eghball et al, 2002). Arbuscular mycorrhizal fungi (HMA) act as growth accelerator by increasing phosphorus absorption and help in protecting against pathogens Ferrera, 1999, 2000;Mena et al, 2006;West et al, 2009;Smith and Smith, 2011;Singh et al, 2013); tt can also influence the structural and soil aggregation process (Rilling and Mummey, 2006). Within the HMA is Glomus with 85 species, but the most important in agriculture is G. fasciculatum, studied in fruit, forestry, vegetables and legumes.…”

“…Mycorrhizae and atmospheric N2-fixing bacteria, known as biofertilizers, favor the development of plants (West et al, 2009). Vermicompost, manure and mushroom residue contribute organic matter (Eghball et al, 2002).…”