Differential Retention and Loss of a Mycotoxin in Fungal Evolution

TL;DR

This paper explores how the mycotoxin Ochratoxin A evolved in fungi, revealing its ancient origins and how it has been lost or degraded over time.

Contribution

The study provides the first investigation into the ecological significance and evolutionary history of the OTA gene cluster in fungi.

Findings

The OTA gene cluster was horizontally transferred from Aspergillus to Penicillium.

The OTA cluster is undergoing degeneration in Aspergillus species.

The OTA cyclase OtaY likely originated from bacteria.

Abstract

Ochratoxin A (OTA) is designated as a mycotoxin and is regulated worldwide due to its harmful effects on humans and animals, but the evolutionary history and ecological significance of OTA in fungi remain poorly understood. Phylogenetic analysis suggested that Aspergillus and Metarhizium obtained an ancient OT cluster, which evolved independently, followed by horizontal OT transfer from Aspergillus to Penicillium. The varying presence of functional, absent and pseudogenized OT genes across Aspergillus species revealed that this cluster is undergoing a degeneration process in this genus. Furthermore, the cyclase OtaY in the OTA cluster is likely derived from bacteria, which was revealed by phylogenetic analysis. This is the first attempt to investigate the ecological significance of OTA in fungi, suggesting that it may be nonfunctional in Aspergillus spp. and has undergone multiple forms of loss during evolution.

Figures