# First description of adenosine production by Gnomoniopsis smithogilvyi, causal agent of chestnut brown rot

## TL;DR

This study reports for the first time that the fungus Gnomoniopsis smithogilvyi produces adenosine, a compound with potential health implications, but does not produce harmful mycotoxins.

## Contribution

The first identification of adenosine production by Gnomoniopsis smithogilvyi, a chestnut rot pathogen.

## Key findings

- Adenosine concentrations in G. smithogilvyi cultures ranged from 176 to 834 µg/kg.
- No mycotoxins were detected in G. smithogilvyi cultures.
- Three secondary metabolites—adenosine, oxasetin, and phytosphingosine—were identified.

## Abstract

Gnomoniopsis smithogilvyi (Gnomoniaceae, Diaporthales) is the main causal agent of chestnut brown rot on sweet chestnut worldwide. The rotting of nuts leads to alterations in the organoleptic qualities and decreased fruit production, resulting in significant economic losses. In 2021, there was an important outbreak of chestnut rot in southern Galicia (Spanish northwest). The profile of secondary metabolites from G. smithogilvyi was studied, especially to determine its capability for producing mycotoxins, as happens with other rotting fungi, due to the possible consequences on the safety of chestnut consumption. Secondary metabolites produced by isolates of G. smithogilvyi growing in potato dextrose agar (PDA) medium were identified using liquid chromatography coupled with high-resolution mass spectrometry. Three metabolites with interesting pharmacological and phyto-toxicological properties were identified based on their exact mass and fragmentation patterns, namely adenosine, oxasetin, and phytosphingosine. The capacity of G. smithogilvyi to produce adenosine in PDA cultures was assessed, finding concentrations ranging from 176 to 834 µg/kg. Similarly, the production of mycotoxins was ruled out, indicating that the consumption of chestnuts with necrotic lesions does not pose a health risk to the consumer in terms of mycotoxins.

The online version contains supplementary material available at 10.1007/s11274-024-03958-4.