The arbuscular mycorrhizal fungus Glomus geosporum in European saline, sodic and gypsum soils

Abstract

Plants of saline and sodic soils of the Hungarian steppe and of gypsum rock in the German Harz mountains, thus soils of high ionic strength and electric conductivity, were examined for their colonization by arbuscular mycorrhizal fungi (AMF). Roots of several plants of the saline and sodic soils such as Artemisia maritima, Aster tripolium or Plantago maritima are strongly colonized and show typical AMF structures (arbuscules, vesicles) whereas others like the members of the Chenopodiaceae, Salicornia europaea, Suaeda maritima or Camphorosma annua, are not. The vegetation of the gypsum rock is totally different, but several plants are also strongly colonized there. The number of spores in samples from the saline and sodic soils examined is rather variable, but high on average, although with an apparent low species diversity. Spore numbers in the soil adjacent to the roots of plants often, but not always, correlate with the degree of AMF colonization of the plants. As in German salt marshes [Hildebrandt et al. (2001)], the dominant AMF in the Hungarian saline and sodic soils is Glomus geosporum. All these isolates provided nearly identical restriction fragment length polymorphism (RFLP) patterns of the internal transcribed spacer (ITS) region of spore DNA amplified by polymerase chain reaction (PCR). Cloning and sequencing of several PCR products of the ITS regions indicated that ecotypes of the G. geosporum/ Glomus caledonium clade might exist at the different habitats. A phylogenetic dendrogram constructed from the ITS or 5.8S rDNA sequences was nearly identical to the one published for 18S rDNA data (Schwarzott et al. 2001). It is tempting to speculate that specific ecotypes may be particularly adapted to the peculiar saline or sodic conditions in such soils. They could have an enormous potential in conferring salt resistance to plants.

Cytotoxic Activities of Endophytic Fungi Isolated from the Endangered, Chinese Endemic Species Dysosma pleiantha

“…characters of fruiting structures and spores. Moreover, the result was reinforced by comparing the entire ITS (ITS1-5.8s-ITS2) rDNA sequences with the available data of GenBank databases through the NCBI BLAST search algorithm (Altschul et al, 1997;Liang and Gao, 2000;Girlanda et al, 2002;Landwehr et al, 2002;Bougoure and John, 2005). Due to the large number of isolates and complications of identifi cation of the endophytic fungi, 5 strains were identifi ed at the genus or species level, whereas 6 unidentifi ed strains belonging to ascomycetes are still unnamed.…”

Arbuscular mycorrhizal symbiosis and alleviation of salinity stress

“…Most halophyte species are non-mycorrhizal. Molecular biological techniques revealed that 80%, on average, of the AM spores isolated from a range of European saline soils belonged to one single species, Glomus geosporum, which occurred much less in the surrounding non-saline habitats (Hildebrand et al, 2001;Landwehr et al, 2002). The authors speculate that specific AM ecotypes may be particularly adapted to saline conditions and that they could have a great potential in conferring salt tolerance to plants.…”

“…Interestingly, the most commonly observed AM fungus was among Glomus spp. (Landwehr et al, 2002). However, when comparing several Glomus spp., Porras-Soriano et al (2009) observed that each AM fungal species has a different efficiency in alleviating plant salt stress.…”

Properties of the halophyte microbiome and their implications for plant salt tolerance

“…Another factor that has to be taken into account in such habitats is drought, which can be more important than salt for the abundance of AM fungi in halophytes (Füzy et al 2008). Attempts to identify the AM fungal species associated with plants in saline habitats revealed that at least in Europe, most isolates belong to the Glomus geosporum/Glomus caledonium cluster (Hildebrandt et al 2001;Landwehr et al 2002;Sonjak et al 2009). In addition to arbuscular mycorrhiza, some papers report the occurrence of so-called dark septate endophytes (DSEs).…”