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Abstract: Root colonization, soil population density and diversity of arbuscular mycorrhizal (AM) fungi were assessed in 188 banana fields in contrasting soil types across five eco-regions in Rwanda (Butare–Gitarama, Gashonga, Bugarama, Kibungo, Ruhengeri). Root colonization was observed in all banana plants, whatever the soil type, field site and farm. The population density was higher on the wetter (1 300–1 500mmyr−1) volcanic soils (Gashonga 59.8 and Ruhengeri 48.5 propagules 100g−1 soil, respectively) as compared to the dryer (900–1 200mmyr−1) soils derived from schist and granite (Butare–Gitarama 2.0, Kibungo 8.5, Bugarama 14.7 propagules 100g−1 soil). The diversity was highest in Kibungo and lowest in Butare–Gitarama (10 and 2 spore morphotypes, respectively). These results suggested that AM fungi were widespread in banana cropping systems in Rwanda, but that root colonization, population density and diversity varied considerably depending on edapho-climatic conditions (i.e. rainfall, soil texture and P content) and soil management practices (tillage). [Copyright &y& Elsevier]

Abstract: This review summarizes current knowledge on the contribution of mycorrhizal fungi to radiocesium immobilization and plant accumulation. These root symbionts develop extended hyphae in soils and readily contribute to the soil-to-plant transfer of some nutrients. Available data show that ecto-mycorrhizal (ECM) fungi can accumulate high concentration of radiocesium in their extraradical phase while radiocesium uptake and accumulation by arbuscular mycorrhizal (AM) fungi is limited. Yet, both ECM and AM fungi can transport radiocesium to their host plants, but this transport is low. In addition, mycorrhizal fungi could thus either store radiocesium in their intraradical phase or limit its root-to-shoot translocation. The review discusses the impact of soil characteristics, and fungal and plant transporters on radiocesium uptake and accumulation in plants, as well as the potential role of mycorrhizal fungi in phytoremediation strategies. [Copyright &y& Elsevier]

Abstract: Contamination by uranium (U) occurs principally at U mining and processing sites. Uranium can have tremendous environmental consequences, as it is highly toxic to a broad range of organisms and can be dispersed in both terrestrial and aquatic environments. Remediation strategies of U-contaminated soils have included physical and chemical procedures, which may be beneficial, but are costly and can lead to further environmental damage. Phytoremediation has been proposed as a promising alternative, which relies on the capacity of plants and their associated microorganisms to stabilize or extract contaminants from soils. In this paper, we review the role of a group of plant symbiotic fungi, i.e. arbuscular mycorrhizal fungi, which constitute an essential link between the soil and the roots. These fungi participate in U immobilization in soils and within plant roots and they can reduce root-to-shoot translocation of U. However, there is a need to evaluate these observations in terms of their importance for phytostabilization strategies. [Copyright &y& Elsevier]