Fungi in Mortierellaceae are an ancient lineage of fungi that are dominant in agricultural, forest and alpine soil ecosystems. Mortierellaceae fungi themselves can host bacteria endosymbionts within their living cells. However, the ecological function of Mortierellaceae fungi, and the impact of these endosymbionts on their interactions with plants is still not well understood. In this talk I will discuss the phylogeny, diversity, and function of these fungi with plants and algae, and the role of bacterial endosymbionts on these interactions.