Effect of γ-Aminobutyric Acid (GABA) on the Metabolome of Two Strains of Lasiodiplodia theobromae Isolated from Grapevine.

Maria Michela Salvatore,Vanessa Ferreira,Anna Andolfi,Fernanda Lima,Artur Alves,Ana Sofia Duarte,Carina Félix,Francesco Salvatore,Ana Cristina Esteves

doi:10.3390/molecules25173833

Abstract

The effect of γ-aminobutyric acid (GABA) on the metabolome of two strains of Lasiodiplodia theobromae isolated from grapevine that hold a different degree of virulence to the host plant (LA-SOL3 (more virulent), LA-SV1 (less virulent)) was investigated. The culture filtrates and crude extracts from the two strains grown in the presence and absence of 10 mM of GABA were tested for phytotoxicity on tomato plant cuttings and leaves, respectively. Considering the opportunistic nature of this fungus for humans, crude extracts were also tested for cytotoxicity on mammalian cell lines. We found that culture filtrates and crude extracts have a decreased toxicity in the presence of GABA. Metabolomic analysis, conducted on both strains at both growth conditions, revealed the production of several compounds, such as indole-3-carboxylic acid (ICA, which is the main compound produced by L. theobromae), 3-indolecarboxyaldehyde, (3R,4S)-botryodiplodin, (R)-mellein. Finally, data demonstrate that GABA both induces a decrease in the amount of ICA, and a diversification of the metabolites produced by L. theobromae.

Highlights

IntroductionFungi are challenged by diverse biotic and abiotic stressors (e.g., other organisms, nutrient availability, pH and temperature), which determine several fungal responses
In vivo, fungi are challenged by diverse biotic and abiotic stressors, which determine several fungal responses
The aim of this study was to compare the metabolite’s profile obtained when the strains were grown in potato dextrose broth (PDB), with the one obtained in Czapek medium [8], and to evaluate the effect of GABA on the secondary metabolite production, which is related to the toxicity of culture filtrates and organic extracts

Summary

Introduction

Fungi are challenged by diverse biotic and abiotic stressors (e.g., other organisms, nutrient availability, pH and temperature), which determine several fungal responses. During the interaction between fungi and other organisms, secondary metabolites might be involved in very different functions, such as mediating communication within one species or between different species, defence against competitors, nutrient acquisition, and even in symbiotic interactions [2,3]. It is known that the expression of some fungal genes, including genes required for virulence, is influenced by temperature and nutritional state [4,5]. New evidences have emerged from studies on the effect of abiotic factors on the metabolome of fungi isolated from several hosts fromInstudies on the effect of abioticprofiles factors on thebeen metabolome fungi from several hosts [6]

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