Contribution of arbuscular mycorrhizal fungi to the bioavailability of micronutrients (iron and zinc) in millet accessions.

Introduction: Micronutrient deficiencies, particularly iron (Fe) and zinc (Zn) deficiencies, are prevalent public health issues in developing countries, with children under 5 years old and breastfeeding women being the most affected in Senegal. Agronomic approaches, including soil fertilization and microbial biotechnology, are used to alleviate these deficiencies, yet challenges persist due to poor nutrient availability in staple food crops like pearl millet (Pennisetum glaucum L.). Methods: This study aimed to assess the contribution of one arbuscular mycorrhizal fungal (AMF) strain, Glomus mosseae, to the bioavailability of micronutrients (zinc and iron) in pearl millet biomass. Four pearl millet accessions from the National Laboratory for Research on Plant Production (LNRPV) collection were inoculated with G. mosseae obtained from the Common Microbiology Laboratory (LCM), with four replications. Gaussian regression tests were employed to analyze the data and determine correlations between AMF concentration and micronutrient bioavailability. Results: The results indicate that the combination of Glomus mosseae inoculation and organic residual products improved growth parameters and micronutrient absorption in pearl millet accessions. Analysis revealed significantly greater iron, zinc, phosphorus, and potassium contents in the foliar biomass of mycorrhizal pearl millet plants compared to non-mycorrhizal plants (control). Inoculation with AMF facilitated micronutrient absorption, particularly iron and zinc, not only in roots but also in aerial parts of the plants. Discussion: These findings suggest that incorporating AMF and organic residual products in millet cultivation could be a viable strategy for enhancing plant development and increasing iron and zinc contents in varieties. Further research is needed to elucidate the mechanisms underlying AMF-mediated nutrient uptake and optimize their use in agricultural practices.

Roles of Arbuscular Mycorrhizal Fungi on Soil Fertility: Contribution in the Improvement of Physical, Chemical, and Biological Properties of the Soil.

Many of the world's soils are experiencing degradation at an alarming rate. Climate change and some agricultural management practices, such as tillage and excessive use of chemicals, have all contributed to the degradation of soil fertility. Arbuscular Mycorrhizal Fungi (AMFs) contribute to the improvement of soil fertility. Here, a short review focusing on the role of AMF in improving soil fertility is presented. The aim of this review was to explore the role of AMF in improving the chemical, physical, and biological properties of the soil. We highlight some beneficial effects of AMF on soil carbon sequestration, nutrient contents, microbial activities, and soil structure. AMF has a positive impact on the soil by producing organic acids and glomalin, which protect from soil erosion, chelate heavy metals, improve carbon sequestration, and stabilize soil macro-aggregation. AMF also recruits bacteria that produce alkaline phosphatase, a mineralization soil enzyme associated with organic phosphorus availability. Moreover, AMFs influence the composition, diversity, and activity of microbial communities in the soil through mechanisms of antagonism or cooperation. All of these AMF activities contribute to improve soil fertility. Knowledge gaps are identified and discussed in the context of future research in this review. This will help us better understand AMF, stimulate further research, and help in sustaining the soil fertility.