A breakthrough by scientists at UC Davis may lead to a new way of fighting Pierce's disease, a deadly grapevine illness that could threaten your favourite California wine and costs the industry $100m annually.


Researchers discovered an enzyme, or ‘trigger’, that appears to enable Pierce’s disease to spread throughout a grapevine plant.

It is a potentially crucial finding that changes the way wine and plant scientists understand Pierce’s disease, which comes from a bacteria carried by the glassy-winged sharpshooter insect.

‘New approaches’

‘We anticipate that this discovery could open new ways to think about dealing with Pierce’s disease,’ said Abhaya Dandekar, professor of plant sciences at UC Davis and a lead author on the study.

There is no cure or treatment for the vine disease other than to prevent infection by targeting the insects known to carry the illness from one vineyard to another.

Pierce’s disease costs the California wine industry an estimated $100m annually, according to UC Davis. Winemakers in Europe will also welcome the new research, after insects known to spread the disease were found on French soil last year.

The new Pierce’s disease theory

UC Davis researchers called the new enzyme ‘LesA‘. It moves through the plant cells, enabling the Xyllela fastidiosa bacteria that causes Pierce’s disease to invade the grapevine.

The bacteria then lives in the grapevine’s xylem tissues, where it feeds on fatlike compounds called lipids.

Previously, it was thought Pierce’s disease caused a xylem blockage, blocking water from reaching vine leaves and causing them to turn yellow – a classic symptom of the disease.

Researchers disovered LesA by analysing the so-called ‘secretome’ of the Xyllela fastidiosa. This is a collection of enzymes and proteins that help the bacteria to infect plants.

Armed with their discovery, the UC Davis team even managed to ‘knock out’ a specific gene that effectively stopped a laboratory strain of Xyllela fastidiosa infecting a grapevine.

But, Dandekar said more research is now needed to understand the new process more fully.

Find the journal article on the LesA enzyme here.