Development of conidia and overwintering bodies (cleistothecia and sclerotia) of Aspergillus nidulans, Aspergillus flavus and Aspergillus parasiticus is affected by linoleic acid and light. Specific morphological effects of linoleic acid include inducing precocious and increased asexual spore development in A. flavus and A. parasiticus strains and altered sclerotial production in some A. flavus strains where sclerotial production decreased in the light but increased in the dark. In A. nidulans, the asexual to sexual spore ratio increased with increasing amounts of linoleic acid. Spore development was also induced in all three spp. by hydroperoxylinoleic acids, linoleic acid seed-derivatives over produced during fungal colonization. The sporogenic effects of these linoleic compounds on A. nidulans are similar to the sporogenic effects of A. nidulans psi factor, an endogenous mixture of hydroxylinoleic acid moieties. Light significantly increased asexual production in all three spp. The sporogenic effects of light, psi factor, linoleic acid and linoleic acid derivatives on A. nidulans required an intact veA gene. To better study the function of linoleic acid in Aspergillus development, the gene required for the formation of linoleic acid, odeA, that encodes a delta-12 desaturase, has been cloned and disrupted in A. nidulans veA+ and veAI strains. A better understanding of the molecular mechanisms governing Aspergillus lipid metabolism could contribute to the design of control strategies to reduce the survival and spread of seed-colonizing aspergilli.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)