Browsing by Author "Herrera, Hector"

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    Tree Cover Species Modify the Diversity of Rhizosphere-Associated Microorganisms in Nothofagus obliqua (Mirb.) Oerst Temperate Forests in South-Central Chile
    (2022) Almonacid-Munoz, Leonardo; Herrera, Hector; Fuentes-Ramirez, Andres; Vargas-Gaete, Rodrigo; Larama, Giovanni; Jara, Ronald; Fernandez-Urrutia, Camila; da Silva Valadares, Rafael Borges
    Chilean native forests have been subjected to several types of disturbances, with one of them being the replacement by exotic species. Pinus radiata D. Don is a widespread exotic tree that forms extensive plantations in southern Chile. It covers extended areas, affecting the landscape, biodiversity, and ecosystem services associated with native forest ecosystems. Although advances in assessing the impact of exotic plant species have been conducted, few studies have focused on the alteration of soil microorganisms. This study aimed to characterize the rhizosphere bacterial and fungal communities associated with the tree species Nothofagus obliqua inside a native forest stand and within a P. radiata plantation growing nearby. We used a 16S rRNA gene and ITS region metabarcoding approach. Using bioinformatics, diversity indices, relative abundance, preferential taxa, and predicted functions and guilds were estimated. The beta-diversity analysis showed that both factors, the type of soil (rhizosphere or bulk soil) and the type of site (native forest or P. radiata plantation), were significant, with the site explaining most of the variation among bacterial and fungal communities. Proteobacteria and Basidiomycota were the most abundant bacterial and fungal phyla in both types of soil and sites. Similarly, bacteria showed similar abundant taxa at the family level, independent of the soil type or the site. The main fungal taxa associated with native forests were Tricholomataceae and Cantharellales, whereas in P. radiata plantations, Russulaceae and Hyaloscyphaceae were the most abundant families. The main bacteria functional groups were chemoheterotrophy and aerobic chemoheterotrophy, without significant differences between the type of soil or sites. Overall, these results demonstrate that the composition and diversity of bacterial and fungal communities associated with native N. obliqua forest are influenced by the surrounding forest, and mainly depend on the site's characteristics, such as the lignin-rich wood source. These results improve our understanding of the impact of native forest replacement on soil microbial communities, which can alter microbial-related soil ecosystem services.
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    What fire didn't take away: plant growth-promoting microorganisms in burned soils of old-growth Nothofagus forests in Los Andes Cordillera
    (2024) Almonacid-Munoz, Leonardo; Herrera, Hector; Fuentes-Ramirez, Andres; Vargas-Gaete, Rodrigo; Toy-Opazo, Octavio; Costa, Paulo Henrique de Oliveira; Valadares, Rafael Borges da Silva
    Background and aims Wildfires can dramatically alter forests, their biodiversity and goods they provide to society. In the Andes Cordillera, Nothofagus pumilio is a native, fire-sensitive tree species that is completely excluded from severely burned areas. Therefore, it is of interest to evaluate whether there are differences in the microbial soil communities that could contribute to improve the recruitment of N. pumilio after a fire. We aimed at determining the diversity of soil bacteria and fungi associated with Nothofagus pumilio in old-growth forests affected by a moderate severity wildfire in the Andes Cordillera of south-central Chile in 2015. Methods Eight years after fire, soil samples were collected from selected N. pumilio rhizosphere and bulk soil in fire-affected areas, and were compared with those from unburned areas using a metabarcoding approach. Results We found that symbiotic microorganisms such as saprophytic, ectomycorrhizal fungi, ericoid mycorrhizal taxa and N-fixing bacteria were present with high abundances in the burned area. The most abundant bacterial genera were Mycobacterium, Rhodoplanes and Bryobacter. Meanwhile, Cortinarius and Penicillium were the most common fungal genera identified in burned and unburned sites. Conclusions Moderate severity wildfires in Nothofagus pumilio forests do not result in significantly different soil microbiomes eight years post-burn in either the rhizosphere or bulk soil, which could be key for N. pumilio establishment and survival after fire. Identifying the microbial diversity associated with native trees after fire is essential to know symbiotic microorganisms supporting the recovery of plant species.