New research on grapevine trunk diseases has shown how fungi can collaborate to attack a vine via a kind of ‘extracellular bomb’.
Antioxidants may help wineries to fight back, said the international group of researchers led by the University of Massachusetts Amherst.
Grapevine trunk diseases (GTDs) have been of growing concern to vineyard owners in recent decades. Almost 20% of the world’s vineyards were affected, said the International Organisation for Vine & Wine in 2015.
A 2012 estimate found GTDs were collectively responsible for $1.5bn in annual economic damage worldwide, said the authors of the new research, published in the journals Fungal Biology and Frontiers in Plant Science.
They looked at fungi associated with Eutypa dieback and Esca, two complex and prominent forms of GTD, and reported on how fungal consortia are able to break into a grapevine’s cells.
GTD-causing fungi typically enter a vine via pruning wounds. One of the compounds released by fungi into the wood of the vine is responsible for reducing iron content, said the researchers. Another set of small compounds, meanwhile, produce hydrogen peroxide.
‘When hydrogen peroxide meets reduced iron – Boom – the reaction releases a host of oxygen radicals that damage the woody tissue,’ said Barry Goodell, professor of microbiology at University of Massachusetts Amherst and the paper’s senior author.
‘Once the cell walls are breached, the fungi can feast on the sugar-rich fluid that once was the cellular structure supporting the vine’s own growth,’ according to a press release on the research.
This suggests a potential fix could include antioxidants and ‘low toxicity chelators’, to disrupt the process.
‘There are some select bacteria and fungi that produce these antioxidant and chelating compounds,’ said Goodell. ‘Our research shows that we may be able to manage and stop GTDs through “bio-control” treatments by increasing the natural presence of these antagonistic organisms on the vines.’
More research is needed. ‘Vineyard pathologists need to test our research in the field, and other microbiologists will want to verify our work,’ Goodell said.
He added, ‘But we already have colleagues as part of our larger team that are doing this, and we’re confident that this research represents a breakthrough in ways that we understand this devastating disease of vineyards and how to control that devastation.’
Research on GTDs is ongoing, and authorities and wine bodies have issued guidance on ways to mitigate, control and detect different types of vine diseases within this group.