In this project we aim to reveal the genetic background that sustains fungal lifestyles. We focuses on a fungal group Stictidaceae which closely related species live as saprotrophs, lichens, and optionally lichens (fungi that can live either as lichens by forming symbiotic association with algae, or as saprotrophs depending substrate). By comparing the genomic structure of two saprotrophic species (Cryptodiscus pallidus; Stictis radiata), two lichenized species (Ingvariella bispora; Stictis urceolatum), and two optionally lichenized species (Ostropa barbara; Schizoxylon albescens), we will identify the genes that are related to each lifestyle. Also in order to confirm the function of identified lifestyle-related genes, we will also perform RNA-seq analysis using the optional lichen Schizoxylon albescens. Schizoxylon albescens either live as a lichen, forming symbiotic association with Coccomyxa algae or live as a saprotroph, depending on substrate. By comparing the gene expression of the fungus when it is co-cultured with its symbiotic alga, and when it is cultured independently, we will identify genes involved in the lichenized lifestyle. We will also sequence the genome of Coccomyxa sp. to investigate algal genes involved in the lichenized lifestyle. This project will enable us to have comprehensive view of the genetic background underpinning the fungal lifestyles in Stictidaceae.