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Lugo M.A.,CONICET | Crespo E.M.,Diversidad Vegetal I | Cafaro M.,University of Puerto Rico at Mayaguez | Jofre L.,Diversidad Vegetal I
Boletin de la Sociedad Argentina de Botanica | Year: 2013

The ant genera Atta and Acromyrmex (Tribe Attini) include the mowers or trimmers of leaves called leaf-cutting ants, which are the only ants that show an obligate dependence of fungal symbionts as a food source. Fragments of plants collected bythese ants are used to grow the fungal symbionts, which produce gongylidia for the larvae and queen of the colony to feed on. The aim of this study was to isolate and characterize both, genetically and taxonomically the fungi cultured by two populations of Acromyrmex lobicornis from San Luis province. Samples were collected from the most superficial chambersof the nests and fungal isolates were cultured in malt extract (ME) and potato dextrose agar (PDA) media. The fungal symbiont associated to A. lobicornis nests was identified as Leucoagaricus gongylophorus (Möller) Singer (Holobasidiomycetes, Agaricales) through its morpho-anatomic characteristics and sequencing of ITS1, ITS2 and 5.8S ribosomal gene. Fungal growth in ME was higher than in PDA, and symbiont isolates showed differential growth rates depending on ant populationsfrom where they originated. Fungal symbiont nutritional features and distributional aspects are discussed.

Rivero Mega M.S.,Diversidad Vegetal I | Crespo E.M.,Diversidad Vegetal I | Molina M.G.,Morfologia Vegetal | Lugch M.A.,Diversidad Vegetal I | Lugch M.A.,CONICET
Boletin de la Sociedad Argentina de Botanica | Year: 2014

Arbuscular mycorrhizal fungi (AMF) are associated with most of the plants, forming arbuscular mycorrhizas. Bromeliaceae is an American family living from the tropics to temperate and arid zones. Sierra de las Quijadas has species of terrestrial Bromeliaceae colonized by AMF with different degree of association. The aim of this work was to study the AMF spore diversity (richness and density) in the rhizospheric soil of three native species of Bromeliaceae from Sierra de las Quijadas. Richness and density of spores differed significantly between the Bromeliaceae species studied, with the lowest values in Bromelia urbaniana. Meanwhile, Deuterocohnia longipetala and Dyckia floribunda showed the highest values and only differed between them in richness of spores. This AMF differential diversity between the three bromeliads species may be related to the host species and also due to different levels of root colonization that were previously reported. Moreover, the low richness and density of AMF in the rhizosphere of B. urbaniana may be either due to an allelopathic effect of this plant or due to its particular root morphology.

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