Host Preferences of Arbuscular Mycorrhizal Fungi Colonizing Annual Herbaceous Plant Species in Semiarid Mediterranean Prairies

Abstract

In this study, we have analyzed and compared the diversities of the arbuscular mycorrhizal fungi (AMF) colonizing the roots of five annual herbaceous species (Hieracium vulgare, Stipa capensis, Anagallis arvensis, Carduus tenuiflorus, and Avena barbata) and a perennial herbaceous species (Brachypodium retusum). Our goal was to determine the differences in the communities of the AMF among these six plant species belonging to different families, using B. retusum as a reference. The AMF small-subunit rRNA genes (SSU) were subjected to nested PCR, cloning, sequencing, and phylogenetic analysis. Thirty-six AMF phylotypes, belonging to Glomus group A, Glomus group B, Diversispora, Paraglomus, and Ambispora, were identified. Five sequence groups identified in this study clustered to known glomalean species or isolates: group Glomus G27 to Glomus intraradices, group Glomus G19 to Glomus iranicum, group Glomus G10 to Glomus mosseae, group Glomus G1 to Glomus lamellosum/etunicatum/luteum, and group Ambispora 1 to Ambispora fennica. The six plant species studied hosted different AMF communities. A certain trend of AMF specificity was observed when grouping plant species by taxonomic families, highlighting the importance of protecting and even promoting the native annual vegetation in order to maintain the biodiversity and productivity of these extreme ecosystems.A rbuscular mycorrhizal fungi (AMF) form associations with the majority of terrestrial plant species. Among their beneficial effects, they improve the growth and nutrition of individual plants (41, 52), thus promoting plant performance and enhancing the sustainability of ecosystems (54).Plant diversity and productivity in ecosystems are influenced significantly by the AM fungal diversity in the soil (50). In the Mediterranean semiarid areas of southeast Spain, the acceleration of soil degradation due to the climatic characteristics of this area has become an important problem. Both the rainy season, with scarce and irregular rainfall, and the dry summer contribute to this process. Under these conditions, besides a loss of vegetation cover and degeneration of the physical, chemical, and biological soil properties, a reduction in the amount, diversity, and activity of AMF is produced (9, 34). It has been shown that an increase in the number of shrub species used to restore degraded lands increases the AMF diversity in the soil and, thus, the below-ground, positive interactions (5). Previous studies have revealed that AMF stimulate the growth of shrubs and improve their drought tolerance (15, 33), while at the same time, the shrubs exert a selective pressure on the AMF species (2). Thus, it is important to obtain a better understanding of the composition of the AMF community in these ecosystems.Recent reports have shown that AMF-plant associations may not always be species specific (31, 37) and that factors such as soil properties can determine the AMF-plant interactions (24,26,38).The application of molecular techniques in recent years to identity AMF in the field, p...

Changes in the composition of native root arbuscular mycorrhizal fungal communities during a short-term cover crop-maize succession

“…A higher species richness than in our study was detected in Mediterranean semi-arid environments (Torrecillas et al 2012). Using a morphological approach, a previous study on the occurrence of AMF spores in an organic field located in the same area detected a very high number of AMF species (58), never reported from a single site (Njeru et al 2015).…”

Influence of Habitat and Climate Variables on Arbuscular Mycorrhizal Fungus Community Distribution, as Revealed by a Case Study of Facultative Plant Epiphytism under Semiarid Conditions

“…This is a high level of AMF community richness considering that only a single plant species was studied. In previous studies focusing on much more diverse plant communities in semiarid Mediterranean ecosystems (17)(18)(19), we have found values for AMF community richness in individual plant species ranging between 8 and 20. All samples from epiphytic plants showed AMF sequences, thus confirming that S. tenerrimus epiphytic plants establish a symbiotic relationship with AMF.…”

A conserved arbuscular mycorrhizal fungal core-species community colonizes potato roots in the Andes

“…Zangaro et al (2008Zangaro et al ( , 2013 showed that root colonization and spore density decreased among successional stages from grasslands to mature forests and different stages in plant age and succession also influence the AMF communities (Husband et al 2002;Aldrich-Wolfe 2007). Other studies indicate host preferences (Scheublin et al 2004;Sýkorová et al 2007;Torrecillas et al 2012;Yang et al 2012). In general, standardized analyses, possibly based on the methods presented here, may allow a more robust interpretation and comparison of such data in the future.…”