A postdoctoral study in the Tree Protection Co-operative Programme (TPCP) describes two novel Huntiella species in the African clade, bringing the number of known species in the genus to 31. Though closely related, the two species display different mating systems. Outcomes from this study appear in the journal MycoKeys.

The aim of the study, led by postdoctoral Fellow Dr FeiFei Liu at the University of Pretoria’s Forestry and Agricultural Biotechnology Institute, was to identify six isolates with “typical culture characteristics of Huntiella species” from wounds on native forest trees in South Africa and Greece. The South African isolates were collected from Colophospermum mopane and Senegalia nigrescens in the Kruger National Park, while the isolates from Greece were collected from Platanus orientalis. 

“These fungi displayed typical culture characteristics of Huntiella spp., including rapid growth on agar medium, white fluffy mycelia when young, as well as the production of a fruity aroma,” wrote the authors.

The isolates were identified using morphological characteristics and multigene phylogenies of the rRNA internal transcribed spacer (ITS) region. The mating strategies of these fungi were also determined through PCR amplification of mating type genes.

“The study revealed two new species; one from Platanus orientalis in Greece and one from Colophospermum mopane and Senegalia nigrescens in South Africa. These novel taxa have been provided with the names, Huntiella hellenica sp. nov. and H. krugeri sp. nov., respectively,” wrote the authors. 

These two novel species bring the number of known Huntiella species to 31. Though generally considered weak pathogens, Huntiella species have been known to cause severe disease symptoms and even death. Huntiella species are grouped in three genealogical lineages namely, the African Clade with species only from Africa; the Asian Clade with species from across Asia and lastly the Indo-Pacific Clade with species distributed across Australia and the Pacific Islands. 

“However, the diversity of Huntiella in most regions, including especially Europe, North and South America, is largely unexplored,” wrote the authors. 

According to the researchers, “Huntiella spp. are particularly interesting in terms of their mating biology” with closely related species in some instances reported to have diverse mating systems. The researchers report that “Huntiella krugeri is closely related to H. hellenica described in the present study, H. cryptoformis (Mbenoun et al. 2014) and H. savannae (Kamgan Nkuekam et al. 2008).”

Studying the mating biology of the two novel species therefore contributes to future genetic studies and a better understanding of Huntiella species. 

“Mating studies showed Huntiella hellenica and H. krugeri were homothallic and heterothallic, respectively. All indications were that these two species are saprobes that grow on the freshly-exposed surfaces of trees,” explained the authors. 

“The new species described here will contribute to future studies considering the evolution of mating in Huntiella,” conclude the authors. 

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