Genetic validation of historical plant pathology records – a case study based on the fungal genus Phoma from the ICMP culture collection

Abstract

Fungal taxonomy and classification, and fungal identification tools, are increasingly based on DNA sequencing technologies. In contrast, many historical records of fungi are based on morphologically identified specimens. Scientific collections of specimens or living cultures provide a resource to enable these early records to be genetically validated using modern techniques. This project uses a set of cultures deposited prior to 2008 in the International Collection of Microorganisms from Plants (ICMP) culture collection as Phoma, a genus of high biosecurity importance that is notoriously difficult to identify accurately using morphological characters. Of the 265 cultures sequenced, 23% had been misidentified. These misidentifications mean that six species previously thought to be present in New Zealand probably do not occur there. Fifty specimens had not previously been identified to species level; amongst these were eight species newly reported from New Zealand. Genetic validation projects such as this, using existing scientific collections, are essential for maintaining a robust global biosecurity system.