Arabidopsis thaliana accumulates dehydroepiandrosterone after infection with phytopathogenic fungi - Effects on plants and fungi.

Progestogens and androgens have been found in many plants, but little is known about their physiological function. We used a previously established UPLC-ESI-MS/MS method to analyze progestogen and androgen profiles in fungal infections. Here we show that dehydroepiandrosterone (DHEA), a C steroid, specifically accumulates in shoots of Arabidopsis thaliana (L.) HEYNH. infected with Alternaria brassicicola (SCHWEIN.) WILTSHIRE. Elevated DHEA levels in plants seem not to be product of fungal sterol/steroid precursor activity, but an intrinsic plant response to the infection. DHEA was applied exogenously to analyze the effects of the androgen on development and gene expression in A. thaliana. Our findings reveal that DHEA treatment downregulates membrane-associated, salicylic acid and abscisic acid-regulated, as well as stress-responsive genes. Notably, DHEA does not inhibit the isoprenoid or post-lanosterol pathway of the ergosterol biosynthesis. Moreover, A. brassicicola was also treated with DHEA to analyze the growth, sterol pattern and membrane-integrity. Our data suggest that DHEA enhances the permeability of plant and fungal biomembranes. We propose that DHEA accumulation is a plant defense response which reduces fungal growth in plant tissues.