Exploring eco-evolutionary and temporal patterns of arbuscular mycorrhizal fungal communities colonizing Sorghum bicolor across sites of contrasting land use history and climate

Arbuscular mycorrhizal fungal (AMF) symbiosis can influence crop production, but can be variable across environmental conditions, host-partner complementarity and temporal dynamics. Understanding how these factors interact to shape AMF community assembly allows for the selection of crop genotypes that may maximally utilize AMF associations in agricultural systems. We assessed the development of AMF communities colonizing the roots of eight genetically diverse genotypes of Sorghum bicolor across a growing season. We used two field sites with contrasting environments and management histories. Sorghum cultivated in Arizona (AZ) contained low diversity AMF communities, while in Georgia (GA) sorghum harbored more diverse and evenly distributed AMF communities. We observed evidence of host-filtering of AMF communities, though with genotypes displaying more distinct associations in GA than AZ. AZ showed rapid shifts from early Funneliformis mosseae dominance to dominance by either Entrophospora etunicata or Diversispora aurantia. In GA, such drastic abundance shifts were not observed. Instead, consistent temporal turnover was associated more with higher level family abundance patterns driven by the combination of minor variations in multiple low-abundance taxa. Our findings demonstrate that there is potential for leveraging intra-species genetic variation in AMF community assembly as an extended plant phenotype.