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Environments contaminated with heavy metals negatively impact the living organisms. Ectomycorrhizal fungi have shown important role in these impacted sites. Thus, this study aimed to evaluate the copper-resistance of ectomycorrhizal fungi isolates Pisolithus microcarpus - UFSC-Pt116; Pisolithus sp. - UFSC-PT24, Suillus sp. - UFSM RA 2.8 and Scleroderma sp. - UFSC-Sc124 to different copper doses in solid and liquid media. The copper doses tested were: 0.00, 0.25, 0.5, 0.75, 1.0 and 1.25 mmol L−1 in the solid medium and 0.00, 0.32, 0.64 and 0.96 mmol L−1 in the liquid medium. Copper was amended as copper sulphate in order to supplement the culture medium MNM at pH 4.8, with seven replicates to each fungus-dose combination. The fungal isolates were incubated for 30 days at 28 °C. UFSC-Pt116 showed high copper-resistance such as accessed by CL50 determinations (concentration to reduce 50% of the growth) as while as UFSC-PT24 displayed copper-resistance mechanism at 0.50 mmol L−1 in solid medium. The UFSC-PT24 and UFSC-Sc124 isolates have increased copper-resistance in liquid medium. The higher production of extracellular pigment was detected in UFSC-Pt116 cultures. The UFSC-Pt116 and UFSC-PT24 isolates showed higher resistance for copper and produced higher mycelium biomass than the other isolates. In this way, the isolates UFSG-Pt116 and UFSC-PT24 can be important candidates to survive in copper-contaminated areas, and can show important role in plants symbiosis in these contaminated sites.

RESUMO: Com o processo de degradação dos solos, extensas áreas da fronteira sudoeste do Rio Grande do Sul estão em processo de arenização. O uso de espécies florestais nativas pode ser uma alternativa para revegetação dessas áreas. O objetivo do trabalho foi avaliar o crescimento de mudas de Ipê amarelo e Leucena submetidas a doses de vermicomposto em solo sob processo de arenização da fronteira sudoeste do Rio Grande do Sul. O delineamento experimental foi inteiramente casualizado, utilizando-se duas espécies florestais, o Ipê amarelo (Tabebuia chrysotricha) e a Leucena (Leucaena leucocephala), três níveis de substrato, composto pela mistura de vermicomposto e solo arenoso (v:v) (0% vermicomposto: 100% solo; 25% vermicomposto: 75% solo; e 50% vermicomposto: 50% solo) com 9 repetições. A resposta à adição de vermicomposto foi diferente entre as duas espécies. A adição de 25% de vermicomposto ao solo arenoso proporcionou maior crescimento nas mudas de Ipê amarelo e Leucena. Contudo, plantas de Leucena apresentaram maior altura, comprimento e área superficial específica radicular que o Ipê amarelo em doses mais elevadas de vermicomposto adicionadas a solo arenoso. Palavra-chave: vermicompostagem, substrato orgânico, degradação do solo.

ii) morphologically identify isolates of Fusarium spp. from plants roots with SDS; iii) evaluate the antagonism between Trichoderma spp. and Fusarium spp. isolates from rhizospheric soil and roots from with and without SDS, respectively; and iv) characterize through the ITS1-5.8S-ITS2 region of rDNA the isolates of Trichoderma spp. with better performance in the direct confrontation. The sampling of soil and roots was performed in an experimental area located in Cruz Alta, RS, Brazil. In the laboratory, serial dilutions of soil samples, counting of the number of Colony Forming Units (UFCs/g -1 of rhizospheric soil) were performed as well as isolation for identification of isolates of Fusarium spp. and Trichoderma spp. and testing of direct confrontation. There were significant differences between the population of Trichoderma spp. in the rhizosphere of plants with and without symptoms of SDS. For the population of Fusarium spp., significant difference was observed only in the rhizosphere of plants without symptoms of SDS. In diseased roots the following species were identified: F. solani, F. avenaceum, F. graminearum, F. oxysporum and F. verticillioides. In the test of direct confrontation, eight isolates of Trichoderma spp. achieved the best performance in the antagonism to Fusarium spp. and Trichoderma spp. from areas with symptoms of SDS had a higher control efficiency in vitro. These isolates showed high similarity to the species of T. koningii agregate.