In 2017 several soil samples journeyed from the sparsely vegetated Karoo to the vault-like National Collection of Fungi (NCF) at the Agricultural Research Council (ARC) in Pretoria.

Upon arrival at the facility, a meticulous process was initiated under the watchful eye of Dr. Riana Jacobs-Venter, curator and project manager of the NCF.

The soils were subjected to isolation techniques, followed by the purification, DNA barcoding, and preservation of the obtained fungal isolates   – the strains are preserved in the facility as frozen material.

Approximately 600 Fusarium fungal strains were deposited into the NCF – the largest fungal collection in Africa, according to the World Federation of Culture Collections (WFCC).



Why is this fungal deposit important?

Dr. Jacobs-Venter says that the dataset generated via this Karoo project has been compared with the dataset generated for the grassland biome in South Africa, and Fusarium species that are dominant in each biome were identified.

These Fusarium species can possibly be used as “climate change indicators”, according to Dr. Jacobs-Venter.

READ: The “boring” grassland biome 

Studies have shown that fungi are sensitive to environmental change, making them ideal for use as bioindicators.

“Species that naturally occur in semi-arid regions like the Karoo may be detected in grassland soil samples, indicating a change in the environment (or climate),” she said.

Plugging data gaps

Dr. Jacobs-Venter’s work was funded by a 2017 SANBI Foundational Biodiversity Information Programme (FBIP) Small Grant to explore Fusarium associated with soils in the greater Karoo region of South Africa.

The semi-arid region covering more than 40% of the country’s interior was brought into focus with it being earmarked for several large-scale infrastructure development projects, including shale gas exploration and uranium mining.

Dr Jacobs-Venter’s Fusarium work ran alongside and tied in with the Karoo BioGaps project, an FBIP Large Grant project which set out to plug gaps in understanding which species occur in which parts of the Karoo.

For the Fusarium group, a knowledge gap has indeed been plugged in.

Global distribution data for the genus is now more complete and Dr. Jacobs-Venter says “climate change modeling” will benefit from the data when predicting distribution changes of pathogenic species.

Locally and globally important

Fusarium has stamped its mark on the global agricultural sector – eight of the 14 staple crops cultivated in the world are severely affected by pathogens in this genus.

For example, Fusarium wilt of bananas is caused by the fungus Fusarium oxysporum and is reported to seriously hamper banana production.

A 2010 study reported that since the 1970s, Fusarium wilt has destroyed almost 40% of all Cavendish bananas grown in the Kiepersol and southern KwaZulu-Natal areas of South Africa.

Broadly, ten percent of global food production is lost due to infections caused by fungal pathogens.

These organisms, classified within a kingdom alongside the Plantae and Animalia, are comparatively understudied.

The fungus kingdom has been estimated at an astounding 2.2 million to 3.8 million species.

Of these, only 148 000 have been described.

This means that ~95% of the kingdom is unknown to science.

Amid the high level of taxonomic uncertainty surrounding fungi globally, it comes as a relief to know that there is at least one South African researcher working tirelessly on this economically important group of organisms.