Analysis of AURI gene sequence and enzymatic activity in Botrytis cinerea and its mutants with aureobasidin A-resistance

Abstract:

[Objective] To explore the relationship between AURI gene sequences in Botrytis cinerea and its mutants with aureobasidium A-resistance and the activity of Inositol phosphorylceramide (IPC) synthase. [Methods] Molecular-biology methods were adopted to determine the AUR1 gene sequences of the wild type and the mutants. The activity of IPC synthase was analysed by HPLC-FLD. The content of ceramide was used the method of benzene formylation. [Results] The results showed that 4 different mutant strains resisted to inhibitor AbA of IPC synthase. Their mutant types were: (1) AUR1 gene lost an intron; (2) AUR1 gene lost an intron and one amino acid mutated (P155S); (3) AUR1 gene lost an intron and one amino acid mutated (V33A); (4) AUR1 gene lost an intron and three amino acids mutated (F237L, S177P, and P155S). Both the mutant with the AUR1 gene lack of an intron and the mutant with the AUR1 gene lack of an intron and the mutant of P155S had stronger resistance to AbA. The determination of ceramide content showed that IPC synthase of wild type was inhibited to cause ceramide accumulation, and the mutants could resist to AbA inhibition on IPC synthase. [Conclusion] The intron of AUR1 gene plays an important role in the regulation of IPC synthase. AbA inhibites IPC synthase from inducing ceramide accumulation, IPC synthase is a key enzyme in sphingolipid metabolism.