Page 90 - University of Pretoria Research Review 2017

88
Fungi and tree health
Bernard Slippers and Mike Wingfield, Forest Molecular Genetics Research Programme
One of the core areas of research undertaken by students and their advisors in the Forestry and Agricultural Biotechnology Institute (FABI) concerns the health of trees, and among the most serious threats to trees are fungi, perhaps best known as those organisms that include mushrooms.
Fungi cause some of the most serious tree diseases by infecting either roots, stems, shoots or leaves directly, or via physical wounds caused by insects, for example. They threaten forests and plantations, as well as global food security and biodiversity.
Professor Bernard Slippers, the new director of FABI, focuses his research on tree diseases caused by insects and fungi. In 2017 he joined forces with colleagues Professor Mike Wingfield (past director of FABI) and Professor Pedro Crous, an Extraordinary Professor
of FABI and the Director of the Westerdijk Fungal Biodiversity Institute in the Netherlands, to publish a special issue of the journal Fungal Biology* that focused on an important group of tree-infecting fungi known
generally as Botryosphaeria. This special issue brought together important concepts relating to tree health, and included many articles by FABI staff and students.
A fascinating aspect of the Botryosphaeria fungi is that they can live inside trees without resulting in disease. Typically, the fungi begin to cause disease when trees are stressed or where they are growing outside their natural environments. The fact that this type of fungus can live in healthy plant tissues, such as fruit, means that the pathogen can be moved between countries and continents without being detected. When these organisms arrive in new areas where trees have not evolved with them, they can cause serious disease problems.
Studies published in the special journal issue presented a number of new discoveries about the Botryosphaeria fungi. The studies showed, for example, that these fungi are hybridising in nature, leading to new disease- causing agents that could pose serious threats to trees in the future. The fact that these fungi are also moving between fruit trees (such as mango) and native trees in South Africa (such as Maroela, a relative of mango), was also discovered in one of the FABI-led studies.
FABI is internationally recognised for its work on fungi and has played an important part in positioning the University of Pretoria as one of the strongest centres in the world where these organisms can be studied. Fungi such as the Botryosphaerias are examples of the many other fungal and related organisms that are included in the Institute’s focus on plant health and, linked, the focus on food and fibre security.
Michael Wingfield, Réunion Island Inset: Bernard Slippers
* Fungal Biology, 121, 4 (2017). ISSN 1878-6146, https://doi.org/10.1016/S1878-6146(17)30027-2.