Genetic Analysis of Four Sexual Differentiation Process Proteins (isp4/SDPs) in and Reveals Their Distinct Roles in Development.

Fungal sexual development requires the involvement of a large number of functional genes. Fungal genes encoding sexual differentiation process proteins (), , have been known for decades. / and its homologs function as oligopeptide transporters (OPTs), yet their roles in reproduction are unknown. Here, we genetically analyzed all four homologs in the sexual species and asexual species Using single gene deletion mutants, we found that () participated in asexual sporulation, whereas the other homologs participated in sexual morphogenesis. In complementary tests, - restored sporulation defects in deletion strains (Δ), and their translated proteins, which were localized onto the cytomembrane, possessed OPT activity. Interestingly, accumulated at the top of the hyphae played a distinct role in determining the sexual cycle, glutathione transport, and lifespan shortening. A unique 72nt-insertion fragment (72INS) was discovered in . Biological analysis of the 72INS deletion and DsRED-tagged fusion strains implied the involvement of 72INS in fungal growth and development. In contrast to , which only contributes to conidial production, the three s play important roles in sexual and asexual reproduction, and harbors a unique functional 72INS that initiates sexual morphogenesis.