Genetic connection between fatty acid metabolism and sporulation in Aspergillus nidulans

In the Ascomycete fungus Aspergillus nidulans, the ratio of conidia (asexua l spores) to ascospores (sexual spores) is affected by linoleic acid moieti es including endogenous sporogenic factors called psi factors. Deletion of odeA (Delta odeA), encoding a Delta -12 desaturase that converts oleic acid to linoleic acid, resulted in a strain depleted of polyunsaturated fatty a cids (18:2 and 18:3) but increased in oleic acid (18:1) and total percent f atty acid content. Linoleic acid-derived psi factors were absent in this st rain but oleic acid-derived psi factors were increased relative to wild typ e. The Delta odeA strain was reduced in conidial production and mycelial gr owth; these effects were most noticeable when cultures were grown at 26 deg reesC in the dark. Under these environmental conditions, the Delta odeA str ain was delayed in ascospore production but produced more ascospores than w ild type over time. This suggests a role for oleic acid-derived psi factors in affecting the asexual to sexual spore ratio in A. nidulans, Fatty acid composition and spore development were also affected by veA, a gene previou sly shown to control light driven conidial and ascospore development. Taken together our results indicate an interaction between veA and odeA alleles for fatty acid metabolism and spore development in A. nidulans.