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The evolutionary history of the symbiotic association between arbuscular mycorrhizal fungi (AMF) and embryophytes dates back to the Devonian period. Previous ecological and physiological studies have described the presence of arbuscules, inter- and intracellular hyphae, vesicles, coils and spores, in liverworts and hornworts, which are considered absent in mosses. This study aimed to report the presence of AMF in a community of bryophytes (mosses and liverworts) from Punta Lara Natural Reserve, Argentina. Senescent and green sections of gametophytes were stained and, following microscopic observation, revealed AMF structures. We found intracellular hyphae, vesicles, spores and sporocarps associated with thallus and rhizoids of mosses and liverworts and senescent moss caulidia. The morphological characterization of spores resulted in the determination of Rhizophagus intraradices and Dominikia aurea. The species D. aurea is reported for the first time for Argentina. Sequencing of the D1 variable domain of the LSUrDNA from AMF spores mixes plus hyphae resulted in high similitude to the Dominikia sequences available from NCBI. This study reported the presence of AMF associated with declining and senescent gametophytes of bryophytes (mosses and liverworts) in a Natural Reserve in Argentina. These findings open up new lines of study, which should further investigate these associations and their diversity, physiology and significance. [ABSTRACT FROM AUTHOR]

Polylepis forests represent one of the most endangered high mountain ecosystems in South America. Therefore, it is necessary to inform local nurseries of the best soil inoculum to grow healthy and strong P. australis seedlings for forest restoration purposes. Arbuscular mycorrhizal fungi (AMF) affect plant performance and plants respond differently to them. Previous studies show that the best AMF source is from non-degraded P. australis forests. However, inoculum from degraded areas has never been tested. The response of P. australis seedlings to inoculation with soils from four sites differing in livestock-associated forest degradation and the identification of root-colonizing of AMF species were evaluated. Natural soils inoculum was collected within the Sierras Grandes Mountain range in central Argentina and belongs to degraded grassland, degraded P. australis forest, intermediate degraded and non-degraded P. australis forests. The samples were described with regard to AMF diversity, soil characteristics, and mycorrhizal inoculum potential. The AMF species diversity and the soil infectivity were high in the degraded forest. Contrary to our expectations, the most advantageous AMF inoculum for promoting the shoot growth of P. australis seedlings in production facilities was sourced from degraded soils (forest and grassland). Seven AMF species were trapped by P. australis root plants and six of them were found in degraded forest soils. Only two AMF species, Septoglomus constrictum and Gigaspora sp., were found to be restricted to degraded forest. These data suggest that degraded forest soils provide the most effective inoculum for promoting sapling growth in a greenhouse setting. [Display omitted] • Different indigenous arbuscular mycorrhizal (AM) inoculum were studied to promote the growth of Polylepis australis seedlings. • The greatest diversity of AM fungal species and the most beneficial inoculum was identified from a site with degraded forest. • To promote the growth of P. australis seedlings, the most advantageous AMF inoculum be sourced from degraded forest soils. [ABSTRACT FROM AUTHOR]

Information about the interaction between arbuscular mycorrhizal fungi (AMF) and the false root-knot nematode Nacobbus aberrans (Thorne, 1935) Thorne & Allen, 1944 is scarce. The effect of Glomus intraradices Schenk & Smith on tomato ( Lycopersicon esculentum L.) cv. Platense inoculated with nematode juveniles from Lisandro Olmos (Argentina) was studied under greenhouse conditions. Six treatments with five replications were performed. After 80 days, nematode reproduction and percentage of AMF colonization in roots were estimated. Some plant growth parameters were also measured. In general, plants with AMF and AMF plus nematodes grew as well as the control without AMF and without nematodes. Furthermore, G. intraradices was beneficial in reducing nematode-induced damage in roots (lower number of galls) as well as in having a suppressive effect on parasite reproduction. This is the first study on the use of G. intraradices as a possible strategy in the control of N. aberrans in tomato. [ABSTRACT FROM AUTHOR]

Polylepis woodlands are one of the most threatened mountain ecosystems of South America, and their restoration is a high priority. To assess the mycorrhizal status in Polylepis woodlands of “Quebrada del Condorito” National Park (Córdoba Mountains, Central Argentina), we examined the roots of 22 plant species, belonging to 14 families and determined morphological types of arbuscular mycorrhiza (Arum and Paris type) and colonization level. The 22 species were colonized by arbuscular mycorrhizal fungi and dark septate endophytes. Different arbuscular mycorrhizal structures and colonization patterns were observed, although Paris-type colonization was predominant. Fourteen plant species are reported for the first time as hosts of arbuscular mycorrhizal fungi. We conclude that arbuscular mycorrhizal fungi and dark septate endophyte hosts are widespread in the Polylepis woodlands of Central Argentina and should receive special attention in future revegetation programs. [ABSTRACT FROM AUTHOR]