An updated morphology of spores of Septoglomus deserticola, an arbuscular mycorrhizal fungus of the phylum Glomeromycota, is presented based on the original description of the species, only one other its definition recently published and spores produced in pot cultures inoculated with the rhizosphere soil and root fragments of an unrecognized grass colonizing maritime sand dunes of the Hicacos Peninsula, Cuba. Phylogenetic analyses of sequences of the large subunit (LSU) nrDNA region of the Cuban fungus confirmed its affinity with S. deserticola deposited in the International Bank for the Glomeromycota (BEG) and indicated that its closest relatives are S. fuscum and S. xanthium. Phylogenetic analyses of sequences of the small subunit (SSU) nrDNA confirmed the Cuban fungus x S. fuscum x S. xanthium relationship revealed in analyses of the LSU sequences and thereby suggested the Cuban Septoglomus is S. deserticola. However, it was impossible to prove directly the identity of the Cuban fungus and S. deserticola from BEG based on SSU sequences due to the lack of S. deserticola SSU sequences in public databases. In addition, phylogenetic analyses of LSU and SSU sequences confirmed the uniqueness of the recently erected genus Corymbiglomus with the type species C. corymbiforme (formerly Glomus corymbiforme) in the family Diversisporaceae and proved that its LSU sequences group in a clade with LSU sequences of G. globiferum and G. tortuosum. Consequently, the two latter species were transferred to Corymbiglomus and named C. globiferum comb. nov. and C. tortuosum comb. nov., and the definitions of the family Diversisporaceae and the genus Diversispora were emended.
The objective of this investigation was to study the effects of three Glomus species: G. etunicatum, G. intraradices and G. versiforme on the development of verticillium wilt in cotton plants. Results indicated that the influence of arbuscular mycorrhizal fungi as a biocontrol agents were different among three Glomus species. In diseased cotton plants colonized by G. etunicatum, the disease index was lower than others and also, higher colonization percentage was relevant to these plants. On the other hand, the establishment of mycorrhizal symbiosis and development of structure of AMF were reduced when both symbiotic and pathogenic fungi infected the same root. In addition, the symptoms of veticillium wilt were diminished too. These results revealed that the beneficial effects of mycorrhiza could alleviate the pathogenic effects of V. dahliae and also a competitive interaction existed between these pathogenic and symbiont fungi.
The results of studies of the mycorrhizal status of plant species spontaneously established on the soda heap located in Jaworzno (Upper Silesia, Poland) are presented. Additionally, the species of arbuscular fungi of the phylum Glomeromycota extracted from field-collected rhizosphere substrate samples of the heap are showed. Arbuscular mycorrhizae were described in 17 plant species. Five Glomus spp. were recognized in the spore populations of arbuscular fungi isolated. The investigation presented in this paper for the first time revealed Centaurea stoebe and Trifolium montanum to be hosts of arbuscular fungi.