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In this study, the effect of microbial inoculants and fertilizer application on cowpea (BRS Pujante) growth and on the structure and composition of arbuscular mycorrhizal fungi (AMF) assemblages were evaluated. A completely randomized experiment was set up involving 17 treatments: four with AMF, three with nodulating bacteria, six with AMF + nodulating bacteria, two with phosphorus, one with nitrogen and one control (reference) in five replicates. Plant growth and nutritional content, mycorrhizal colonization, glomerospores number, spore-based AMF assemblages and ecological indices were evaluated. Mycorrhizal inoculants associated with Bradyrhizobium BR3267 strain were more effective than the Microvirga BR3296 strain. Multidimensional scaling analysis showed that Acaulospora longula treatments were more similar among themselves, and distinct from the other treatments. A difference was observed in the structure of AMF community assemblage between treatments with G. albida + Bradyrhizobium BR 3267 and A. longula, with greater Shannon diversity and Pielou equitability indices in the first treatment and greater dominance in the treatment with A. longula only. Long-term studies are required to determine if the successful establishment of A. longula among indigenous species persists over time and if its dominant behavior is not deleterious to the AMF native community.

Arbuscular mycorrhizal fungi (AMF) play an important role in the dynamic of plant community in the south American Atlantic Rainforest biome. Even in protected areas, this biome is under several anthropic impacts, which can cause shifts in the soil microbiota, including AMF. This study aimed to determine the structure and composition of AMF community in areas of native Atlantic Forest and in natural regeneration and to identify which abiotic factors are influencing this community in these areas. Soil samples were collected at Monte Pascoal National and Historical Park, in Southern Bahia, in native and natural regeneration areas of Atlantic Forest in two seasons (rainy and dry). Greater number of glomerospores and richness and diversity of AMF were found in the area under regeneration, with differences between seasons being observed only for the number of glomerospores. Seventy-seven species of AMF were recorded, considering all areas and seasons, with Acaulospora and Glomus being the most representative genera. Greater abundance of species of the genera Acaulospora, Claroideoglomus, and Septoglomus was found in the regeneration area. The AMF community differed between the study areas, but not between seasons, with soil attributes (pH, K, Al, Mg, m, and clay) structuring factors for this difference in the AMF community. Atlantic Forest areas in natural regeneration and the soil edaphic factors provide changes in the structure and composition of the AMF community, increasing the richness and diversity of these fungi in conservation units., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

In this study, we report the effects of arbuscular mycorrhizal fungi (AMF) and increasing doses of phosphorus (P) on the growth and production of secondary metabolites in Mimosa tenuiflora, a medicinal species native to Brazil. We used a completely randomized design with four inoculation treatments: Control not inoculated (1); Claroideoglomus etunicatum (2); Gigaspora albida (3); and C. etunicatum + G. albida (4) and four doses of P; P0 - baseline dose, P8, P16 and P32. After 70 d in a greenhouse, growth, mycorrhizal variables, biochemical and phytochemical parameters were evaluated. Compared to non-mycorrhizal plants, mycorrhized M. tenuiflora seedlings showed greater: growth, greater photosynthetic performance and content of soluble carbohydrates and secondary metabolites, with the most significant benefits occurring in soil with low to moderate P content (up to 16 mg kg -1 ). The plant growth is severely restricted at low P levels, but the addition of AMF appears to remove this limiting factor. Although M. tenuiflora responds to levels of phosphate fertilization, it responds well to mycorrhizal inoculation, especially with G. albida, which promotes benefits for the initial growth and secondary metabolite content in this plant species of medical and potential commercial interest and may be used instead of phosphate fertilizer., (Copyright © 2018 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

An experiment was conducted to evaluate the tolerance of micropropagated and mycorrhized alpinia plants to the parasite Meloidogyne arenaria . The experimental design was completely randomized with a factorial arrangement of four inoculation treatments with arbuscular mycorrhizal fungi (AMF) ( Gigaspora albida , Claroideoglomus etunicatum , Acaulospora longula , and a non-inoculated control) in the presence or absence of M. arenaria with five replicates. The following characteristics were evaluated after 270 days of mycorrhization and 170 days of M. arenaria inoculation: height, number of leaves and tillers, fresh mass of aerial and subterranean parts, dry mass of aerial parts, foliar area, nutritional content, mycorrhizal colonization, AMF sporulation, and the number of galls, egg masses, and eggs. The results indicated a significant interaction between the treatments for AMF spore density, total mycorrhizal colonization, and nutrient content (Zn, Na, and N), while the remaining parameters were influenced by either AMF or nematodes. Plants inoculated with A. longula or C. etunicatum exhibited greater growth than the control. Lower N content was observed in plants inoculated with AMF, while Zn and Na were found in larger quantities in plants inoculated with C. etunicatum . Fewer galls were observed on mycorrhized plants, and egg mass production and the number of eggs were lower in plants inoculated with G. albida . Plants inoculated with A. longula showed a higher percentage of total mycorrhizal colonization in the presence of the nematode. Therefore, the association of micropropagated alpinia plants and A. longula enhanced tolerance to parasitism by M. arenaria .

In the Northeast of Brazil, expansion of guava crops has been impaired by Meloidogyne enterolobii that causes root galls, leaf fall and plant death. Considering the fact that arbuscular mycorrhizal Fungi (AMF) improve plant growth giving protection against damages by plant pathogens, this work was carried out to select AMF efficient to increase production of guava seedlings and their tolerance to M. enterolobii. Seedlings of guava were inoculated with 200 spores of Gigaspora albida, Glomus etunicatum or Acaulospora longula and 55 days later with 4,000 eggs of M. enterolobii. The interactions between the AMF and M. enterolobii were assessed by measuring leaf number, aerial dry biomass, CO2 evolution and arbuscular and total mycorrhizal colonization. In general, plant growth was improved by the treatments with A. longula or with G. albida. The presence of the nematode decreased arbuscular colonization and increased general enzymatic activity. Higher dehydrogenase activity occurred with the A. longula treatment and CO2 evolution was higher in the control with the nematode. More spores and higher production of glomalin-related soil proteins were observed in the treatment with G. albida. The numbers of galls, egg masses and eggs were reduced in the presence of A. longula. Inoculation with this fungus benefitted plant growth and decreased nematode reproduction.