Link between FLN and blackleg


24 January 2023
Professor reveals latest research findings.

ROOT damage by free living nematodes (FLN) may be an important factor in blackleg (pectobacterium atrosepticum) infection, it has been revealed.

Prof Ian Toth of the James Hutton Institute is investigating the link between free living nematodes and blackleg in potatoes and held a workshop to discuss his latest research at the recent Cambridge University Potato Growers’ Association (CUPGRA) annual conference.

Blackleg causes significant losses in the potato industry, with GB losses as high as GBP 50m (USD 61m) being reported by the James Hutton Institute.

Researching the relationship between FLN and blackleg has been challenging, as FLN are difficult to observe, but Ian and his team were able to look at the physical root damage caused by the pest, which may open a way for the blackleg bacteria to enter.

He said: "Collaboration with colleagues at the University of Dundee has shown that the blackleg bacteria are able to sense when the root is damaged because one to two days after occurrence, the inside of this root zone is packed with bacteria. Then, as the root grows, the bacteria colonise it. Studies investigating whether PCN had a similar effect had not found a big effect on blackleg."

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Ian said this suggested that although the main source of blackleg is probably through contaminated seed, it may not always be to blame, opening the way to new possible control measures.

Ways of reducing incidence are currently being explored, and there are possibilities of harnessing microbial populations to defend the plant, he added.

"We already know that pectobacterium produce bacteriocins which kill their close relations and, working with the University of Glasgow, we are exploring whether we could use this to protect infection," he said, adding that this could be done by collecting the bacteriocin and either spraying it on the tuber or onto the field.

"There may also be a way of breeding potatoes which can allow them to protect themselves by using biotechnological approaches so the roots already have sufficient bacteriocin," said Ian.

Further work in collaboration with the University of Durham is investigating whether a way forward could be to identify chemical signals to differentiate resistant potato varieties from susceptible ones, and use them as markers in breeding.

This research is being funded by Scottish Government, Defra, BBSRC and NERC through the Bacterial Plant Diseases Programme.

"Assess Blackleg risk to improve management"
Research to unravel Blackleg and nematode interactions in potato crops