Effects of exogenous phospholipids on lipid composition and sporulation by three strains of Lagenidium giganteum.

The California (LGCA) and Butte Sink (LGBS) strains of the sterol auxotrophic fungus Lagenidium giganteum (Oomycetes: Lagenidiales) enter the sexual cycle on media supplemented with sterols. A third isolate of this mosquito pathogen, the North Carolina strain (LGNC), requires sterols plus phospholipids to produce oospores in vitro. Enrichment of the polar and neutral lipid fractions of the LGCA and LGBS strains with unsaturated fatty acids promoted oospore induction, and increased oospore viability. With the exception of the LGCA strain, there was no consistent relationship between phospholipid supplementation in growth media and mycelial phospholipid content.