Impact of AMF inoculation on nutrient uptake and growth of sweet corn (Zea mays) and butternut squash (Cucurbita moschata) seedlings

Authors: Carrara, Joseph; Heller, Wade

Submitted to: Frontiers in Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2022
Publication Date: 10/26/2023
Citation: Carrara, J.E., Heller, W. 2023. Impact of AMF inoculation on nutrient uptake and growth of sweet corn (Zea mays) and butternut squash (Cucurbita moschata) seedlings. Frontiers in Agronomy. 4:1040054. https://doi.org/10.3389/fagro.2022.1040054.
DOI: https://doi.org/10.3389/fagro.2022.1040054

Interpretive Summary: Globally, the negative environmental impact of chemical fertilizers and pesticides has created a critical need to develop alternative ways to enhance crop nutrient uptake. Based on their ability to colonize most crops and to scavenge and transfer nutrients to their hosts, arbuscular mycorrhizal fungi (AMF) have proven to be a promising biofertilizer. In fact, studies have shown that mixed AMF communities grown from field soil increase the yield of many hosts. However, the role in which individual species of AMF play in crop nutrition is less clear. In this study, we inoculated sweet corn and butternut squash seedlings with nine individual species of AMF and one mixed indigenous population. Overall, we found that higher rates of colonization were positively correlated with host phosphorus (P) uptake. Specifically, we found that species in the Rhizophagus genus had the highest colonization rates and benefitted P acquisition in both hosts. Colonization efficiencies of the other species varied among squash and corn hosts, as did their influence on nutrient uptake. Based on this evidence, not all AMF species are equally beneficial to crop health and species that may be considered beneficial will vary by host. Field trials and further research will aid in the development of host-targeted AMF biofertilizers.

Technical Abstract: Globally, the negative environmental impact of chemical fertilizers and pesticides have created a critical need to develop alternative ways to enhance crop nutrient uptake. Based on their ability to colonize most crops and to scavenge and transfer nutrients to their hosts, arbuscular mycorrhizal fungi (AMF) have proven to be a promising biofertilizer. In fact, studies have shown that mixed AMF communities grown from field soil increase the yield of many hosts. However, the role in which individual species of AMF play in crop nutrition is less clear. In this study, we inoculated sweet corn (Zea mays) and butternut squash (Cucurbita moschata) seedlings with nine individual species of AMF and one mixed indigenous population. Overall, we found that higher rates of colonization were positively correlated with host phosphorus (P) uptake. Specifically, we found that species in the Rhizophagus genus had the highest colonization rates and benefitted P acquisition in both hosts. We found that Claroideoglumus etunicatum and Gigaspora margarita increased calcium and magnesium concentration in corn and Gigaspora rosea increased calcium in squash. None of the species that enhanced nutrient content increased seedling biomass; however, S. constrictum and G. rosea positively impacted sweet corn seedling biomass. Based on this evidence, not all AMF species are equally beneficial to crop health and species that may be considered beneficial will vary by host. Further research on the effectiveness of inoculating individual AMF species across a range of hosts will prove useful in the development of host-targeted AMF biofertilizers.