Enhancing Chickpea Growth via Arbuscular Mycorrhizal Fungal Inoculation: Facilitating Nutrient Uptake and Shifting Potential Pathogenic Fungal Communities

Abstract

<title>Abstract</title> The plant mycobiome makes essential contributions to the host life cycle in both healthy and diseased states. Arbuscular mycorrhizal fungi (AMF) are the most widespread plant symbionts associated with plant roots, and they perform numerous functions that contribute to plants’ health and physiology. However, there exist many knowledge gaps in how the interactions between AMF and host plants’ root mycobiomes influence the performance of host plants. To this end, we inoculated a local chickpea cultivar grown in an agricultural soil under semi-controlled conditions with <italic>Rhizophagus irregularis</italic>. The plants were subjected to low or normal levels of phosphorus (P) fertilization. In addition to examining mycorrhizal colonization, plant biomass, and mineral nutrition, we sequenced the ITS region of the rDNA to assess the chickpea mycobiome and identify key fungal taxa potentially responding to AMF inoculation. Our results showed that AMF inoculation had a stronger effect on chickpea aboveground biomass, in addition to mineral nutrition; whereas P fertilization had a more profound effect on belowground traits. Specifically, AMF promoted shoot (<italic>p</italic> = 0.06), root (<italic>p</italic> = 0.001), and total aboveground biomass (<italic>p</italic> = 0.01), while P fertilization enhanced root biomass (<italic>p</italic> = 0.02), in addition to root diameter (<italic>p</italic> = 0.007), root volume (<italic>p</italic> = 0.01), and root length (<italic>p</italic> = 0.08). Furthermore, the total P (<italic>p</italic> = 0.05) and Na contents (<italic>p</italic> = 0.09) were enhanced in the aboveground biomass by AMF inoculation. ITS metabarcoding revealed Ascomycota as the dominant phylum in both roots and soil biotopes, followed by Basidiomycota, Chytridiomycota, Glomeromycota, Monoblepharomycota, Mucoromycota, and Rozellomycota. Ten ASVs were significantly impacted by AMF inoculation in chickpea roots, including important plant pathogens belonging to <italic>Didymella, Fusarium</italic>, <italic>Neocosmospora</italic>, and <italic>Stagonosporopsis</italic>. Surprisingly, a correlation was established between shoot biomass and some fungal taxa that were differentially abundant in roots. This study confirms the significance of AMF inoculation not for only improving chickpeas’ growth and mineral nutrition in semi-arid conditions but also for shaping plants’ fungal community composition, thereby promoting resilience against both biotic and abiotic stressors.