Could microbiome help avoid grapevine trunk disease?

Grapevines that remain healthy despite “high disease pressure” could be “due to their microbiome function,” according to a recent study.

The investigation, undertaken in New Zealand by a team of researchers, explored the microbiome of grapevines with the “disease escape phenotype” and involved visiting nine vineyards in Hawke’s Bay and Canterbury.

Grapevine trunk disease (GTD) refers to a number of fungal wood diseases that can infect the trunk of a vine, including black foot and Petri disease, esca, eutypa dieback and Botryosphaeria dieback, also known as black dead arm.

It is caused by microscopic spores that are carried by wind and rain and ultimately infect vines through pruning wounds, often during its dormant season. Esca, one of the most common GTDs, is caused by the fungi Phaeomoniella chlamydospora and Togninia minima.

Amidst the investigation, the researchers found that vines that escaped trunk diseases were differentiated from diseased vines using external symptoms such as “leaf chlorosis, shoot stunting, poor canopy growth, and trunk cankers, as well as the chlorophyll content of grapevine leaves”.

According to the researchers: “Findings showed that the GDT escape vines had a significantly different microbiome compared with diseased vines. The GTD escape vines consistently harboured a higher relative abundance of the bacterial taxa Pseudomonas and Hymenobacter.”

The research outlined that “among fungi, Aureobasidium and Rhodotorula were differentially associated with GTD escape vines, while the GTD pathogen, Eutypa, was associated with the diseased vines” noting that “this is the first report of the link between the GTD escape phenotype and the grapevine microbiome”.