The fungicidal diamine (E)‐( N , N , N ′, N ′‐tetraethyl)‐1,4‐diaminobut‐2‐ene increases spermine concentration in the late blight fungus Phytophthora infestans

Abstract

Mycelial growth, polyamine concentrations and the activities of enzymes of polyamine biosynthesis and catabolism were examined in the late blight fungus Phytophthora infestans, grown in the presence of the putrescine analogue (E)‐(N,N,N′,N′‐tetraethyl)‐1,4‐diaminobut‐2‐ene (E‐TED). Growth of P. infestans was significantly reduced by 5 mmol l−1 E‐TED but concentrations of 1 mmol l−1 or less had no effect. All concentrations of E‐TED significantly increased the spermine concentrations in fungal tissue but these increases were not accompanied by any significant alterations in enzyme activities. An examination of the uptake of 14C‐spermine into cells grown in the presence of E‐TED indicated that spermine could be subject to replacement by E‐TED at intracellular binding sites. E‐TED‐treated cells were shown to excrete spermine at significantly higher levels than untreated cells. Permeabilization of cells with n‐butanol removed this difference. Possible causes for this difference are discussed.